Pool scrubbing and hydrodynamic experiments on jet injection regime
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1 Investigaciones Energéticas, Medioambientales y Tecnológicas Miner Pool scrubbing and hydrodynamic experiments on jet injection regime V. Peyrés M.M. Espigares J. Polo MJ. Escudero L.E. Herranz J. López-Jiménez VOl 2 7 Us 15" Informes Técnicos Ciemat 785 Diciembre 1995
Transcript of Pool scrubbing and hydrodynamic experiments on jet injection regime
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Investigaciones Energéticas,Medioambientalesy Tecnológicas
Miner
Pool scrubbing andhydrodynamic experiments onjet injection regime
V. PeyrésM.M. EspigaresJ. PoloMJ. EscuderoL.E. HerranzJ. López-Jiménez
V O l 2 7 Us 1 5 "
Informes Técnicos Ciemat 785Diciembre 1995
Informes Técnicos Ciemat 785Diciembre 1995
Pool scrubbing andhydrodynamic experiments onjet injection regime
V. PeyrésM.M. EspigaresJ. PoloM.J. EscuderoL.E. HerranzJ. López-Jiménez
Instituto de Tecnología Nuclear
Toda correspondencia en relación con este trabajo debe dirigirse al Servicio deInformación y Documentación, Centro de Investigaciones Energéticas, Medioambientales yTecnológicas, Ciudad Universitaria, 28040-MADRID, ESPAÑA.
Las solicitudes de ejemplares deben dirigirse a este mismo Servicio.
Los descriptores se han seleccionado del Thesauro del DOE para describir lasmaterias que contiene este informe con vistas a su recuperación. La catalogación se hahecho utilizando el documento DOE/TIC-4602 (Rev. 1) Descnptive Cataloguing On-Line, y laclasificación de acuerdo con el documento DOE/TIC.4584-R7 Subject Categories and Scopepublicados por el Office of Scientific and Technical Information del Departamento de Energíade los Estados Unidos.
Se autoriza la reproducción de los resúmenes analíticos que aparecen en estapublicación.
Depósito Legal: M-14226-1995ÑIPO: 238-96-001-0ISSN: 1135-9420
Editorial CIEMAT
CLASIFICACIÓN DOE Y DESCRIPTORES
220900, 220504SCRUBBING, HYDRODYNAMICS, SOURCE TERM, FISSION PRODUCTS, AEROSOLS,EXPERIMENTAL DATA, COMPUTER CODES, BUBBLES, POUDS
"Pool scrubbing and hydrodynamic experiments on jet injection regime"
Peyrés, V.; Espigares, M.M; Polo, J.; Escudero, M.J.; Herranz, L.E.; López, J.125 pp. 15 figs. 15 refs.
Abstract
Plant analyses have shown that pool scrubbing can play an important role in source term during PWR risk dominantsequences. An examination of boundary conditions governing fission products and aerosols transport through aqueous bedsrevealed that most ofradiactivity is discharged into the pool under jet injection regime. This fact and the lack of experimentaldata under such conditions pointed the need of setting out an experimental programme which provided reliable experimentaldata to validate code models.
In this report the major results of a pool scrubbing experimental programme carried out in PECA facility are presented.One of the major findings was that a remarkable fraction of particle absorption was not a function of the residence time ofbubbles rising through the pool. Such a contribution was assumed to be associated to aerosol removal mechanism acting atthe pool entrance. As a consequence, a hydrodynamic experimental plan was launched to examine the gas behaviour duringthe initial stages in the pool. Size and shape of gas nuclei in the pool were measured and fitted to a lognormal distribution.Particularly, size was found to be quite sensitive to inlet gas flow and at minor extent to gas composition and pooltemperature.
SPARC90 and BUSCA-AUG92 were used to simulate the retention tests. Whereas SPARC90 showed a pretty goodagreement with experimental data, BUSCA-AUG92 results were far away from measurements in all the cases. SPARC90consistency apparently pointed out the important role of fission products and aerosols retention at the ijection zone;nonetheless, a peer examination of pool scrubbing phenomenology at the pool entrance should be carried out to test bothhydrodynamic and removal models. Hence, one of the major highlights drawn from this work was the need of furtherresearch under represnetative severe accident conditions (i.e., saturated pools, jet injection regimes, etc.), as well as separateeffect tests to validate, improve and/or develop specific models for the pool entrance region.
"Ensayos hidrodinámicos y experimentos de retención en lechos acuososen régimen de inyección de chorro"
Peyrés, V.; Espigares, M.M.; Polo, J.; Escudero, M.J.; Herranz, L.E.; López, J.125 pp. 15 figs. 15 refs.
Resumen
Los análisis probabilistas de seguridad de secuencias dominantes del riesgo han puesto de manifiesto que la retenciónde productos de fisión en lechos acuosos puede jugar un papel decisivo en ciertos escenarios. Un examen de las condicionesde contorno que gobiernan tales procesos señaló que la principal descarga de radiactividad a las piscinas ocurre bajo regímenesde inyección de alta velocidad (i.e., régimen de chorro). Este hecho, unido a la carencia de datos experimentales en talescircunstancias, sugirió la necesidad de emprender un programa experimental que proporcionase datos fiables válidos para lavalidación de modelos.
En este informe se presentan los resultados más importantes de un programa experimental llevado a cabo en lainstalación PECA sobre los fenómenos de absorción de partículas en piscinas. Uno de los principales resultados fue que unafracción sustancial de los aerosoles inyectados era retenida con independencia de la altura de agua que hubiese sobre elinyector. Se postuló que esta descontaminación ocurría debido a mecanismos que actuaban sobre las partículas a la entradade la piscina. Como consecuencia se realizó un programa experimental de carácter meramente hidrodinámica cuyo objetivofundamental era el estudio del comportamiento del gas durante las primeras etapas de su evolución en el lecho sumergido.Se llevó a cabo un seguimiento tanto del tamaño como de la forma de los núcleos gaseosos y se observó que ambas variablesse ajustaban a una distribución lognormal. El tamaño de los glóbulos mostró una notable sensibilidad con el flujo de gasentrante y, en menor medida, con la composición del gas y la temperatura de la piscina.
Los experimentos de retención fueron simulados con los códigos SPARC90 y BUSCA-AUG92. SPARC90 manifestóun buen acuerdo con las medidas, mientras que BUSCA-AUG92 estuvo en todos los casos lejos de aproximarse a los datosexperimentales. La aparente consistencia de SPARC90 señaló la importancia de la zona de inyección en la eliminación departículas de la corriente gaseosa; sin embargo, un estudio más profundo de la fenomenología a la entrada de la piscina seríanecesario para chequear los modelos existentes. Por tanto, el presente trabajo sugiere la necesidad de su extensión, así comola ejecución de ensayos de efectos separados para validar, mejomr y/o desarrollar modelos específicos para la región deinyección.
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EXECUTIVE SUMMARY
As a part of its contribution to the Source Term Project of the Third Framework Programmeof the European Union, CIEMAT carried out an experimental programme on pool scrubbing.The general aims of the programme were: to extend the database on this field and to checkhow pool scrubbing codes work under representative accidental conditions.
The specific aim of the experimental programme was to study pool retention capability underjet injection regime with particular emphasis on the impact of submergence variation on theresults. This topic was supported by two facts: on one side, most of fission product scrubbingis estimated to take place while gas enters the pool at very high velocities; on the other, thereexist few data on pool scrubbing under these conditions. A total of four retention tests werecarried along with a set of ten hydrodynamic experiments. The latter were focused on theinfluence of injection regime, inlet gas composition and pool temperature on the initialbehaviour of gas in the pool. Test matrix definition was supported by theoretical studiesaimed at assisting in the choice of the values of relevant parameters and in the survey ofpool scrubbing tests expectations.
All the experiments were carried out in PECA facility at CIEMAT, which previously hadhoused other experimental programmes on pool scrubbing. Nonetheless, relevant changesconcerning aerosol generation and experimental measurements were implemented. Thesemajor changes obeyed three fundamental criteria: simplicity, redundancy and diversity. Awell size defined nickel powder was taken as aerosol. Inlet and outlet mass rates weremeasured from different stations and analyzed by different methods (i.e., chemical andgravimetric techniques). Hydrodynamic tests were recorded by a video camera and, then, a2-D image processing was performed.
Both pool scrubbing and hydrodynamic tests were satisfactorily performed. Experimentalmeasurements were discussed and decontamination factors estimated and expressed in termsof intervals. The extension of such margins were seen as highly acceptable in any case. Asexpected, these decontamination factors followed an exponential trend with submergence andshowed the existance of an additional term independent of submergence. On the other side,hydrodynamic data processing confirmed the influence of gas flow and thermohydraulicprocesses on primary bubble size. Conversely, no correlation was found among these factorsand shape or between size and submergence.
Substantial discrepancies were found between SPARC and BUSCA predictions. SPARCshowed a remarkable global agreement with experimental data. Conversely, BUSCAestimates were far away from the data in all the cases. The SPARC consistency with resultswas unquestionable; however, it should be cautioned that further research should be doneunder other conditions to validate models. Anyway, experiments and SPARC results seemedto point out that injection can play a significant role in particle retention under jet injectionregime.
Theoretical models and correlations were unable to estimate experimental hydrodynamictrends whenever phase changes are involved. In particular, Ramakrishman model does notaccount for the postulated break-up of the gaseous main body at high inlet flow rates or thethermal processes while globule formation.
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ACKNOWLEDGEMENTS
The authors wish to express their sincere appreciation to the technical personnel of PECAfacility for their invaluable support. Their expertise and dedication became indispensableingredients without which the successful execution of this experimental programme had notbeen possible. Special mention deserve Pedro Bermudez, Luis Ma del Hoyo, Rosa Pérez andJavier Gallego.
The authors want to thank the Environmental Inorganic Chemistry Project of the Chemistrybranch of CIEMAT for their assisstance in the sampling chemical analysis. In particular, theylike to express their gratitude to Isabel Rucandio for her exceptional interest on thisprogramme and for her excellent work.
Finally, their thanks to Francisco Gómez Moreno of the Combustion and GasificationProgramme for his collaboration while tests execution.
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INDEX
EXECUTIVE SUMMARY i
INDEX iii
LIST OF TABLES vi
LIST OF FIGURES vii
LIST OF ACRONYMS viii
NOMENCLATURE ix
1. INTRODUCTION 1
2. EXPERIMENTAL PROGRAMME DEFINITION 2
2.1 OBJECTIVES 2
2.2 POOL SCRUBBING TESTS 2
2.2.1 Experimental matrix 22.2.2 Supporting studies 32.2.3 Facility description . 52.2.4 Test protocol 7
2.3 HYDRODYNAMIC TESTS 9
2.3.1 Experimental matrix 9
2.3.2 Test protocol and experimental techniques 10
3. EXPERIMENTAL RESULTS 18
3.1 POOL SCRUBBING TESTS 18
3.1.1 Thermohydraulic boundary conditions 183.1.2 Aerosol characterization 193.1.3 Inlet and outlet mass flowrates 203.1.4 Pool sampling 223.1.5 Decontamination factor 24
3.2 HYDRODYNAMICS 26
3.2.1 Hydrodynamic tests . 26
IV
3.2.2 Pool scrubbing tests 31
4. RESULTS INTERPRETATION 35
4.1 POOL SCRUBBING TESTS ANALYSES 35
4.1.1 Hydrodynamic behaviour 354.1.2 Aerosol retention mechanisms 36
4.1.3 Theoretical and experimental comparison 38
4.2 HYDRODYNAMIC ANALYSES 40
4.2.1 Influence of the main variables 41
4.2.2 Theoretical and experimental comparison 43
5. CONCLUSIONS 48
REFERENCES 50APPENDIX I: SAMPLING NOTATION AND LOCATION 51APPENDIX II: THERMOHYDRAULIC VARIABLES EVOLUTION DURING THE
POOL SCRUBBING TESTS 52
APPENDIX III: RELATIVE HUMIDITY IN THE VESSEL ATMOSPHERE . . . . 54
APPENDIX IV: NUMBER AND VOLUME DISTRIBUTIONS IN THE POOLSCRUBBING TESTS 56
APPENDIX V: SCANNING ELECTRON MICROSCOPY. PARTICLESDEPOSITED ON COUPONS 57
APPENDIX VI: RESULTS OF THE CHEMICAL ANALYSIS OF THECONDENSATE . 61
APPENDIX VII: IMAGES RECORDED OF THE GAS STRUCTURE CLOSE TOTHE INJECTOR 62
APPENDIX VIII: BUBBLE DIAMETER VERSUS DISTANCE FROMINJECTOR 72
APPENDIX IX: BUBBLE DIAMETER HISTOGRAMS FOR THEHYDRODYNAMIC TESTS 79
APPENDIX X: a/b RATIO HISTOGRAMS FOR THE HYDRODYNAMICTESTS 87
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APPENDIX XI: CIRCULARITY ANALYSIS FOR THE HYDRODYNAMICTESTS 93
APPENDIX XII: SPARC AND BUSCA INPUT FILES FOR THE POST-TESTANALYSES 94
APPENDIX XIII: HYDRODYNAMIC RESULTS OF SPARC AND BUSCA FORTHE POOL SCRUBBING POST-TEST ANALYSIS 102
APPENDIX XIV: INLET AND OUTLET MASS DISTRIBUTION FOR THE POOLSCRUBBING TESTS (SPARC AND BUSCA POST-TEST ANALYSIS) . . 104
APPENDIX XV: RETENTION MECHANISMS CONTRIBUTION IN THE POST-TEST ANALYSIS 109
VI
LIST OF TABLES
TableTableTableTableTable
TableTableTableTableTableTableTableTableTableTableTableTableTableTable
Table
TableTableTableTableTable
TableTableTableTableTableTable
Table
2.12.22.32.42.5
3.13.23.33.43.53.63.73.83.9
3.103.113.123.133.14
3.15
3.163.173.183.193.20
4.14.24.34.44.54.6
4.7
Pool scrubbing tests matrixInitial conditions for the pretest analysisConditioning phase sequenceTiming of the RCA retention testsHydrodynamic test matrix
Tesi time average values of the main thermohydraulic parametersSampling time average values of the sample and injection flowrates (cc/s)CMD and GSD of pool scrubbing tests along the timeTime average properties of the size distributionsInlet mass rates in the pool scrubbing testsTotal mass injected into the poolOutlet mass rates in the pool scrubbing testsNickel concentration in the pool water (g/1)Nickel concentration from the sampling GC/VP 16 and 17 (g/1)Total mass of Nickel suspended in the poolProvisional DF ranges for pool scrubbing testsFinal DF of pool scrubbing testsActual hydrodynamic test boundary conditionsSize distribution parameters of hydrodynamic tests between 0 and 32 cm fromthe injectorSize distribution parameters of hydrodynamic tests between 32 and 64 cmfrom the injectorBubble classification of hydrodynamic tests bbased on the stability criteriaMean a/b ratio and deviation for the hydrodynamic testsSize distribution parameter for pool scrubbing experiments (0-32 cm)Bubble classification of pool scrubbing tests based on the stability criteriaa/b ratio estimated for pool scrubbing experiments
Main hydrodynamic variables predicted by SPARC and BUSCAMMD and GSD for the inlet and outlet distributionsDecontamination factor for the injection and rise zonesPercentages of the different retention mechanisms to the DFResults of the least squared treatment of the experimental DFExperimental DF at the injection compared with SPARC and BUSCApredictionsExperimental DF during the rise compared with SPARC and BUSCApredictions
Vil
LIST OF FIGURES
Figure 2.1 DF vs. submergence for different particle size and flow (SPARC results)Figure 2.2 DF vs. submergence (SPARC results)Figure 2.3 DF vs. injection flowrate (SPARC and BUSCA results)Figure 2.4 DF uncertainty maps calculated with SPARC vs. size distribution parametersFigure 2.5 DF uncertainty maps calculated with BUSCA vs. size distribution parametersFigure 2.6 PECA facilityFigure 2.7 Operating principle of the Solid Particle DisperserFigure 2.8 Sketch of the image acquisition
Figure 3.1 Frontal image recorded of the gas structure close to the injector (HSlal test)Figure 3.2 Bubble diameter vs. distance from injector (HSlal test)Figure 3.3 Bubble diameter vs. distance from injector (RCA 1 test)
Figure 4.1 DF estimated by SPARC and BUSCA codes compared with the experimentalresults of the pool scrubbing tests
Figure 4.2 Bubble diameter at the injection vs. Weber numberFigure 4.3 SPARC and BUSCA prediction of the bubble diameter against the
experimental results (Hydrodynamic tests)Figure 4.4 SPARC and BUSCA prediction of the bubble diameter against experimental
results (Pool Scrubbing tests)
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LIST OF ACRONYMS
AMMD Aerodynamic Mass Median DiameterBUSCA BUbble Scrubbing AlgorithmBWR Boiling Water ReactorCIEMAT Centro de Investigaciones Energéticas MedioAmbientales y TecnológicasDF Decontamination FactorGSD Geometric Standard DeviationMAAP Modular Accident Analysis ProgramMMD Mass Median DiameterRCA Reinforced Concerted ActionRHR Residual Heat RemovalSEM Scanning Electron MicroscopySGTR Steam Generator Tube RuptureSPARC Suppression Pool Aerosol Removal CodeSTCP Source Term Code PackageVMD Volume Mean Diameter
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N O M E N C L A T U R E
dB Bubble diameterdG Globule diamterQ Gas flowrateq Sampling flowrateM Molecular weightm Massmcond Condensate massm Mass ratePatm Vessel atmosphere pressurePlinc Injection line pressurePsal Saturation pressureR Gas constantr Regression CoefficientRs Saturation ratio for the poolR .H . Relative humidityS SubmergenceTline Injection line temperatureTpooi P° ° l temperaturet TimeUB Bubble velocityVs Steam volumev Swarm velocityXs Steam fraction
Greek letters
a Standard deviation
Subindex
in Inletout Outlet
1. INTRODUCTION
The importance of pool scrubbing on source term has been extensively acknowledged1'2. Plantsafety assessments pointed out that decontamination of fission products bearing bubbles inaqueous volumes could be a key phenomenon for scarce term of risk-dominant sequences.Even though a huge amount of work has been done in the past on this field, there still remainsome areas of crucial significance not thoroughly addressed.
Analyses of relevant severe accident sequences showed that most of fission product scrubbingtakes place while gas enters the pool at very high velocities typical of jet regimes2-3'4. On theother side, a thorough review of the available literature on pool scrubbing5 showed that thereexists few data under such conditions6. Hence, significance and database scarcity encouragedCIEMAT to set out an experimental programme mainly aimed at studying pool retentioncapability under jet regime injection. This pool scrubbing programme was completed witha separate effect hydrodynamic programme focused on the influence of injection regime, inletgas composition and pool temperature on initial behaviour of gas in the pool. Theexperimental programme definition was based on representative and critical conditions (i.e.,near saturated pools) and on simplicity (i.e., unsoluble particles). Both tests preparation andinterpretation were supported by SPARC7 and BUSCA8'9 calculations.
This report is structured as follows. Chapter 2 gives a detailed description of bases,preliminary studies and test protocols of both retention and hydrodynamic tests. Chapter 3provides an exhaustive compilation of the experimental results recorded and their subsequenttreatment. Chapter 4 summarizes the discussions held and the major achievements got in thetest rationalization. Finally, Chapter 5 gives a brief view of the main conclusions drawn fromthis work. Besides these chapters a set of Appendixes illustrates in detail different aspectspresented along the preceding chapters.
2. EXPERIMENTAL PROGRAMME DEFINITION
The experimental programme is made up of two parts: retention experiments andhydrodynamic separated effects tests. A description of the specifications of both parts ispresented below.
2.1 OBJECTIVES
The predictions offered by different codes (MAAP, STCP or MELCOR) for risk-domiantingsequences (i.e., SGTR, RHR, TMLB' and certain sequences characteristic of BWR designs)have underlined the interest in jet regimes at the point of injection1-213-4. This fac:, togetherwith the absence or inacurracy of existing models, make this area a crucial point forexperimental study.
The general objective of this experimental program is to contribute to increasing the databasefor pool scrubbing under severe accident conditions. In this respect, three specific objectivesmay be established:
Widening of the database for aerosol retention in pools with a jet regime at the pointof injection.
Acquisition of experimental results on the formation of bubbles at the injector andtheir subsequent evolution under prototypical severe accident conditions.
Correlation of measures of the efficiency of retention pools with hydrodynamicbehaviour.
2.2 POOL SCRUBBING TESTS
The aerosol retention tests were performed at the PECA facility. The experimental matrixis presented below, along with a description of the facility and the experimental protocol ofthese tests. Also presented are previous studies supporting definition of the experimentalmatrix.
2.2.1 Experimental matrix
Table 2.1 shows the experimental matrix of the retention tests. As may be observed, thisconsists of four tests in which all the conditions except submergence are kept constant. Thisstrategy allows an analysis to be made of the effect of submergence on DF under jet regimeconditions, avoiding the superimposition of other effects which might complicate fullunderstanding of the scenario simulated.
Most of the conditions shown in the Table arise as a result of a compromise being establishedbetween representativity and simplicity in the tests. The pool conditions are close tosaturation (Rs~0.86). The conditions at the point of injection and in the pool are kept asclose as possible in order to avoid strong thermohydraulic changes in the carrier gas, bothat the injector and during the rise of the bubbles. The inlet gas is N2; this is injected at arate of 3000 cc/s via a horizontally oriented injector measuring 1 cm in diameter. These
conditions make it possible to obtain Weber numbers of approximately a factor of 2 abovethe threshold corresponding to the jet regime (We>105). The aerosol injected is metallicNickel, characterized by AMMD and GSD values of approximately 3 /¿m and 1.4,respectively.
Tabla 2.1 Pool scrubbing test matrix
RCA1
RCA2
RCA3
RCA4
InjectionConditions
T (°C) P(bar)
120 2.8
120 2.8
:*o 2.8
120 2.8
Inlet Gas
Q (cc/s)
3000
3000
3000
3000
xs
0
0
0
0
Sp
Ni
Ni
Ni
Ni
Aerosol
AMMD(¿tin)
3.0
3.0
3.0
3.0
GSD
1.4
1.4
1.4
1.4
T(°C)
120
120
120
120
Pool Conditions
P(bar)
2.3
2.3
2.3
2.3
Sub(m)
0.25
0.50
1.25
2.50
2.2.2 Supporting studies
The pretest analyses of the experimental pool scrubbing programme are presented below.The main objectives of these preliminary studies are to establish an optimum choice ofcertain experimental parameters such as inlet gas flow or submergence, and to bound thepossible variation in the decontamination factor on the basis of uncertainty regarding thedistribution of particle sizes. With regard to the choice of flow, it should be pointed out thatit is limited at the top end by the technical restrictions of the PECA facility, and at the lowerby the flow threshold value established by the jet regime. The calculation tools used for thisanalysis were the SPARC7 and BUSCA89codes.
Choice of submergence
Previous studies performed using the SPARC code showed that there is minimum retentionwhen submergence is reduced, this being a result of the model included for additionaldecontamination at the point of injection through small orifices (quencher)5. An exhaustiveanalysis was performed with a view to gaining insight into the possible existence of such aminimum retention and its location; for this purpose the most extreme, favourable andunfavourable, conditions that might arise during retention tests were selected, in relation toinjection flow and particle size.
Table 2.2 shows the initial conditions of the scenario. The two extreme situations selectedwere as follows: first, and favouring retention, injection of a flow of 3500 cc/s with aparticle distribution characterized by an MMD and a GSD of 3.0 /xm and 1.0, respectively;and second, considered unfavourable, an injection flow of 2000 cc/s and an MMD and GSDof 0.75 ¡im and 1.0, respectively.
The results are shown in Figure 2.1, which represents the variation in the decontamination
factor with submergence. A minimum of retention may be observed in the case of high flowand large particle size and with submergence close to 0.4 m, while in the other case nominimum of retention is predicted.
Table 2.2 Initial conditions for the pretest analysis
Pool Temperature:Pool Pressure:Injection Temperature:Injection Pressure:Gas Composition:Injector Diameter:Injector Type:Submergence:Aerosol Compound:Aerosol Inlet Rate:
115 °C2 atm150 °C2.8 atmN2
1 cmQuencher0.1 - 3 . 0 mNi10"7 kg/s
A conclusion which may be drawn from this study, applying a highly conservative criterion,is that at submergence values in excess of 0.4 m the repercussion of the possible influenceof decontamination at the point of injection via small orifices, postulated in the SPARC code,would not yield the retention minimum.
With a view to defining the submergence for each experiment, the SPARC code was usedto analyze the influence of this parameter on retention, using the two flows initially foreseenfor the two tests (2000 and 3000 cc/s), the above being accomplished using the scenarioconditions shown in Table 2.1 and a particle distribution characterized by MMD = 1.0 /xmand GSD = 1.0. The range of submergence studied is 0.25 - 3.0 m.
The results obtained, shown in Figure 2.2, reflect greater decontamination with low valuesof submergence and high flow, while with higher submergence values the decontaminationis higher with lower flow values, the retention corresponding to the two flows approximatingat submergences close to 2.3 m. This is due to the fact that deposition at the point ofinjection is favoured with increasing flow, while with increasing submergence there is anincrease in in retention in the rise zone with decreasing flow, since the bubble residence timein the pool increases.
The range of flow variation (2000 - 3000 cc/s) does not lead to large differences in thedecontamination factor for one same value of submergence. For this reason, theexperimental matrix centres on analysis of submergence as the only variable experimentalparameter. Consequently, the final experimental matrix was established at a flow of 3000cc/s (in order to increase to the extent possible the effects of the jet regime on injection) andat four values of submergence: 0.25, 0.50, 1.25 and 2.50 m. Although this flow valuewould lead to achievement of a minimum retention, the size of the particles is smaller thanthe corresponding value from the previous study5, as a result of which this minimum wouldnot be reached under the conditions of the preliminary studies.
Uncertainty regarding injection flow
The parameter of injection flow is subject to possible variations as regards the valueestablished in the experimental matrix. In order to estimate the repercussion of flowfluctuations on DF, sensitivity studies were carried out using SPARC and BUSCA for thefour values of submergence established (Figure 2.3). The flow range analyzed was 1500 -3500 cc/s.
The DF values predicted by BUSCA are very low, as a result of which its variation isnegligible. The SPARC results, on the other hand, predict a higher influence of flow atlower values of submergence, albeit within the same order of magnitude. It may beconcluded, however, that the possible flow deviations expected (~ 2700-3300 cc/s) do notlead to substantial changes in the decontamination factor.
Uncertainty regarding particle size
Particle size is a determining factor as regards retention in aqueous beds and is subject topossible deviations from the value predicted (AMMD-3 /on); consequently, gaining insightinto its influence on retention is of great interest. Maps have been obtained using theSPARC and BUSCA codes which make it possible to estimate DF value for a distributionof particles characterized by an MMD in the range 0.75 - 1.25 /¿m and a GSD of 1.2 - 2.0,for each value of submergence (Figures 2.4 and 2.5).
The maps obtained with BUSCA show hardly any influence by particle distribution on DF.With SPARC, however, and with the difference of flow, the differences in particledistribution have an important repercussion on DF, the influence of GSD increasing withlarger sizes and higher values of submergence. This underlines the importance of having aconstant distribution throughout each test in order to prevent possible time jumps in the DF,as well as of reproducing particle size in all the tests in order to ensure that the experimentalresults reflect a trend caused only by variation in submergence.
2.2.3 Facility description
The PECA experimental facility is made up of several fundamental sections forming acircuit: the aerosol generation system, mixing section, injection line and vessel-pool. Inaddition, there are several auxiliary systems: gas supply system, steam generating boiler,auxiliary gas scrubbing system, water purification system and chemical analysis system.
The facility's process instrumentation includes a wide range of sensors for the measurementof temperatures, pressures and flows. This instrumentation is backed by a process controlsystem which allows for centralized supervision of the plant, the operation of certain controlloops and data acquisition. In addition, the PECA facility has specific instrumentation foron-line characterization of the aerosols, backed by discontinuous sampling taps. For adetailed description of all the sections and systems of the facility, turn to reference [6].
Finally, the PECA facility vessel is fitted with a series of sight glasses located at differentrdial and axial points for visual tracking of the events occurring inside during performanceof the experiment.
Development of the RCA pool scrubbing experimental programme has required certainmodifications to the design of the facility. The new sections and systems are descibed ingreater detail below. Figure 2.6 shows a general diagram of the adaptations made to PECAfor this experimental programme.
Aerosol generation system
Aerosol generation is accomplished by means of a solid particle disperser10. This device iscapable of generating particles in the size range <0.5 - 100 /xm, at a rate of approximately40 mg/h - 25 g/h for a powder density in the powder reservoir of 1 g/cc.
Figure 2.7 shows schematically the system which uses this device for particle generation.The product, located initially in the reservoir, is pushed by a piston at a constant rate towardsa rotating brush. This progressively transports the product towards a duct where a carriergas disperses the powder in aerosol form. The piston thrust speed, the density of the powderin the reservoir, the speed of brush rotation and the carrier gas flow determine the final rateand concentration of tne aerosol generated.
Connection with the mixing chamber
The outlet of the aerosol generator is connected to the mixing chamber by means of a pipemeasuring 60 cm in length. 6.35 mm in external diameter and ~ 4 mm in internal diameter,in the shape of a circumferential arc. This curvilinear design is due to the fact that thedesign of the facility itself prevents the aforementioned outlet from being aligned with themixing chamber pipe; in addition, the curvature is small, with a view to avoiding particleimpingement at the elbows.
Sampling system
The sampling system is distributed in three sections of the facility: injection line, pool andvessel atmosphere. Appendix I includes a list of all the sampling taps, their identificationand location.
Two types of samples are taken at the injection line: deposition coupons and filters. The aimof the first, consisting of thin foils on a glass support, is tosupport chemical determinationof the aerosol injected and to analyze its morphology by means of scanning electronmicroscopy (SEM). This sampling point is located at the beginning of the mixing section andis made up of three foils. The filters isokinetically collect a part of the aerosol injected inorder to determine mass injection rate. Two sampling points are available for filters in theinjection zone. The first is located in the mixing chamber and the second at a distance ofsome 45 cm from the first on the injection line.
Seven sampling taps are located at different heights in the pool. The five first are distributedfrom the injector towards the surface of the pool, each separated by a distance of some 20cm. The other two are located at the bottom of ihe pool and at the vessel drain. All thesesamples are chemically analyzed in order to determine the mass of nickel collected by each.
Finally, there are two sampling points located in the atmosphere of the pool, leading to two
filters. One is located in the upper part of the vessel, the other being at a distance of 1.5metres above the injector (although its position may vary depending on the submergence ofthe pool). Both taps are used to extract a volume of the atmosphere. The steam extractedis condensed, the condensate being collected in a recipient. Subsequently, the mixture ofnon-consensables and aerosol is channelled to the filter. In addition, there are three foilsamples in the vessel atmosphere for morphological analysis.
2.2.4 Test protocol
The overall set of actions performed in each of the retention tests may be grouped into threeclearly differentiated phases: facility conditioning, operation and post-experimental sampling.Each of these stages is described in more detail below.
Conditioning phase
The objective of the conditioning phase is fundamentally to stabilize the PECA facility underthe intial thermohydraulic conditions established for each test in the experimental matrix.The actions included in this phase are shown in chronological order in Table 2.3.
Table 2.3 Conditioning phase sequence
Action
Filling of pool with ultrapure
Preheating of poolPressurization of atmosphereFinal heating of poolHeating of injection line andStabilization of injection flow
water
auxiliary oven
Value
See Table 2.1
90 °C2.3 bar120 °C
120 °C and 711 °C, respectivelySee Table 2.1
Operating phase
The operating stage includes the set of actions performed during performance of the test.Table 2.4 shows the test operating sequence in chronological order, the initial time dependingon the moment at which aerosol injection begins.
Injection of the inlet gas is performed via two different lines which pass through two heaters.One of these, line 2, corresponds to the aerosol carrier gas leaving the solid particledisperser. Line 1 comes straight from the gas supply system and passes through the auxiliaryoven. Both lines join in the mixing section, in order to achieve the desired injection mix.The injection pressure is close to 2.8 bar, and the flow through lines 1 and 2 is 2838.5 cc/sand 161.5 cc/s, respectivamente.
Table 2.4 Timing of the RCA retention tests
Time (min)
-205
9101515
2030
Action
Cameras in position 1Initiation of Nickel injectionSample of deposition couponsInitiation of atmospheric samplingEnd of deposition coupon samplingInjection filters: Initiation of TM2/63 samplingCameras in position 2Injection filters: End of TM2/63 sampling and initiation ofTM2/64End of injection line samplingEnd of atmospheric sampling1
End of test
1 During the RCA3 test, atmospheric sampling was active between 5-25 min.
Finally, throughout the entire test direct measurements were taken of the size of the aerosolinjected by means of an optical instrument.
Post-experimental sampling phase
On completion of the test, samples are taken from the water volume of the pool, these beingknown as GC samples. Subsequently, following agitation of the pool for at least two hours,the same samples are taken, these now being known as VP samples. The objective of allthese samples is to study the degree of homogeniety of the Ni in the pool and to quantify itsconcentration.
Finally, the injection line and mixing chamber are cleaned. The procedure used to clean thelines is based on injecting air at high pressure. The Nickel initially deposited in the pipesis entrained by the air and collected on a filter for quantification.
The filters collected from the sampling points in the injection line (TM2/63 y TM2/64) andthe atmosphere (TM3/65 y TM4/68) are gravimetrically and chemically analyzed todetermine the mass of retained Nickel. The filters from the line cleaning operation aretreated the same way. The rest of the samples taken from the different sections of thefacility are chemically analyzed.
Determination of Nickel in the chemical analysis is performed using the inductively coupledplasma atomic emission spectrometry technique (ICP-AES)11. This technique is based onmeasuring the radiation from the excited atoms in the sample. The wavelengths of theseradiations are characteristic of each element, and the net intensity corresponding to eachgiven wavelength is a function of the concentration of the element.
The samples in which the Nickel is deposited on a glass fibre filter are subjected to acid
attack in order to dissolve the element without the support being affected. This latter iscarefully washed and separated from the solution to be analyzed. If the filter has beenpartially decomposed, the matter in suspension must be eliminated by filtration. In the caseof samples formed by aqueous suspensions of Nickel, a filtration process is applied (usinga filter of mixed esters of cellulose) to physically separate and concentrate the problemelement. This filter, with the Nickel, is transferred to a beaker and both are dissolved in aconcentrated nitric medium. In both cases a totally transparent solution is generated which,following gaging to a convenient volume, is subjected to ICP-AES analysis.
2.3 HYDRODYNAMIC TESTS
The hydrodynamic tests were performed using the PECA facility. This section describes theexperimental matrix and the test protocol of the hydrodynamic separate effects experimentalprogramme.
2.3.1 Experimental matrix
The hydrodynamic experimental programme includes 10 tests grouped in two series. Thefirst of these series (SI) is performed with the pool at ambient temperature, while in thesecond (S2) the pool is close to saturation conditions. Each of these series is further dividedinto two sub-series depending on the presence or absence of steam in the inlet gas. In thecase of steam injection, the quantity in the inlet gas is sufficient for condensing conditionsto be reached in the pool. Within each sub-series the injection flow varies from bubbly tojet regime. The aim of the above is to have the experimental matrix address the study ofvarious hydrodynamic influences: temperature, composition of the inlet gas and injectionregime. Table 2.5 shows the specifications of the experimental matrix.
Table 2.5 Hydrodynamic test matrix
Series
SI
S2
a
b
a
b
Test
HSlal
HSla2
HSla3
HSlbl
HSlb2
HS2al
HS2a2
HS2a3
HS2bl
HS2b2
Injection
T(°C)
room
room
room
120
120
120
120
120
120
120
Conditions
P(bar)
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
Inlet Gas
Q (cc/s)
1000
2000
3000
1000
3000
1000
2000
3000
1000
3000
xs
0
0
0
0.5
0.5
0
0
0
1
1
T(°C)
room
room
room
room
room
95
95
95
95
95
Pool Conditions
P (bar)
1
1
1
1
1
1
1
1
1
1
Sub (m)
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
10
2.3.2 Test protocol and experimental techniques
The experimental procedure for each of the hydrodynamic separate effects tests consistsmainly of recording the gaseous flow leaving the injector using video cameras. Each test,lasting 10 minutes, is divided into two 5-minute periods, during which the experiment isfilmed from positions 1 and 2, respectively (Fig. 2.8). The visual field of each imagecovers an approximate distance of 0-32 cm, via the window located at the elevation of theinjector (elevation 1), and between 32-64 cm via the upper window (elevation 2).Performance of the hydrodynamic tests requires a phase of conditioning of the PECA facility,the phases of which are practically the same as those used for the retention tests.
Subsequently, the video films are analyzed using digitalized image analysis techniques, inorder to determine the geometric parameters of the distributions of bubbles at each positionand elevation12.
UMD»3OO<JmQ.3SOt)cc/s
0,1 0.5 0,9 1,3 1,7 2,1 2.5 2,9
1.0E+02
t.OE + Oi!
1.0E + 000.1 0.5 0,9 1,3 1,7 2,1 2,5 2.9
Figure 2.1 DF ves. submergence for different particle size and flow (SPARCresults)
1.0E+05
1.0E+04
1.0E+03 y1.0E+02
1.0E+01
1.0E+000 2 0,7 1,2 1,7 2,2 2,7
~MMD=1.0 Q=2000cc/s
~MMD = 1.0 Q=3000cc/S
Submergence (m)
Figure 2.2 DF vs. submergence (SPARC results)
12
1.0E+04
1,0E+03:
I
1.0E+001F
"-Sub=1.25m,SPARC +Sub=1.2Sm,BUSCA ->:Sub=2.Sm,SPARC
-iSub=2.5m,BUSCA — Sub=0.5m,SPARC • Sub=0.5m,BUSCA
¿rSub=0.25m,SPARC -SSub=0.25m BUSCA
1.5E+00 2.5E+00Flowrale (cc/s)
3.5E+00
Figure 2.3 DF vs. injection flowrate (SPARC and BUSCA results)
13
Sub=0-25m
1.0E+M
1.0E+03
a
1.0E+02
1.0E+01i
4 t ;I
t
0,7 0,8 0,9 1,0 1,1 1,2 1,3
Sub=1^5m
\rfiK
1.0E+04
1.0E+03
u.0
1.0E+02
1.0E+01
tOE+00
f
4 i
0,7 0,8 0,9 1,0 1,1 1,2 1,3
Sub=0.5m
1.OE+O41
1.0E+03
Ü
1.0E+02i • -t
1.OE+O1t t
0,7 0,8 0,9 1,0 1,1 1,2 1,3
• GSD=1.2
' GSD=1.5
' GSD=2.0
MUD Vim)
Sub=2.5m
1.0E+05
1.0E+04
1.0E+03
0
1.0E+02
1.0E+01
•
0,7 0,B 0,9 1,0 1,1 1,2 1,3
Figure 2.4 DF uncertainty maps calculated with SPARC vs. size distributionparameters
14
SuMífc
2.5E+00 -
2.0E+00
2,5E+00-
2.0E+00!
Sub=0.5m
I.SE+OO)
1.0E+00!
5.0E-011
O.OE+000,7 0,9 1,0 1,1 1,2 1,3
1,5E+00:
l.QE+OO
5.0E-01 ¡
iO,QE+OOL
0,7 0,8 0,9 1,0 1,1 1,2 1,3
• GS0=1.2
* GSD=1.5 |
' GSD=2.0
Sub=l.!Sn> Sub=2.5m
2,5E+W r
2,06+00
1.5E+00
D
1,OE+00
5.0E-01
O.OE+000,7 0,8 0,9 1,0 I
mtwm
2.5E+00 —
2.0E+0OÍ
1.SE+00
1.0E+00
5.0E-01
O.OE+000,7 0,8 0,9 1,0 1,1 1,2 1,3
Figure 2.5 DF uncertainty maps calculated with BUSCA vs. size distributionparameters
15
mi
V
1n | c
i
r. g
e ¡
o r L i r
r
¡j i fl 7 ~ i * r
: •»
• c r . j 1 e (i 51 n ¡ i t
C '
:i:
CONE i ! O N Ml • NO
t I He SEC: ; Oil
0 1 | ( I ! )•
v • : v : c 4 ' w :
• 1,1.:
r—-1
J
A E R O S O L G E H E B A i O R
i T « J
P O O L S A M P L I N GI G C - V P )
I N J E C l ION L INE
Figure 2.6 PECA Facility
16
aerosol I• I '
Jl dhp«rjlng air
•bruih
powd«
' powder
• funsporUtfon piston
-lend
Figure 2.7 Operating principle of the Solid Particle Disperser
17
SS '©
POSITION 2 POSITION 1
HEIGHT 1
HEIGHT 2
INJECTION UNE
Figure 2.8 Sketch of the image adquisition in the separate tests onhydrodynamics
18
3. EXPERIMENTAL RESULTS
This chapter presents the results of the RCA experimental programme. These are dividedinto two major blocks: the first concerns all the results of the retention tests aimed at finaldetermination of the decontamination factor; the second includes the hydrodynamic resultsof the separate effects test and of the retention tests themselves.
3.1 POOL SCRUBBING TESTS
The results of the thermohydraulic parameters, the characterization of aerosols and theretention test sampling points are presented below. Likewise, the treatment of theseparameters for determination of the decontamination factor is shown.
3.1.1 Thermohydraulic bounding conditions
The process control system measured the main thermohydraulic variables during performanceof each retention test (T,ilK., Tpool, Q y q¡) . Table 3.1 shows the average values of thesemeasures averaged over test time. Table 3.2 shows the average values of the flows at theatmospheric and injection line sampling points averaged over sampling time, along with theaverages of total injection flow over sampling time. Appendix II includes a graphicrepresentation of the evolution of pressure and temperature in the injection line and vesselfor each test. Appendix III shows an estimate of the relative humidity in each of the tests.
In general, the thermohydraulic bounding conditions were satisfactorily controlled duringeach test. Nevertheless, small deviations with respect to the average have been taken intoaccount, each value being assigned an error corresponding to the standard deviation of themeasures for subsequent treatment by error propagation.
Table 3.1 Test time average values of the main thermohydraulic parameters
Injection Line Pressure, Plinc (bar)Vessel Atmosphere Pressure, Palm
(bar)
Injection Line Temperature, TUnc (°C)Pool Temperature, T^, (°C)
Injection Gas Flowrate,Q(cc/s)
RCA1
2.85 ± 0.042.30 ± 0.01
121.9 ± 1.7113.9 ± 2.6
3121.3 ± 55.1
RCA2
2.91 ± 0.042.51 ± 0.02
122.4 + 3.3117.5 ± 1.7
2923.9 ± 65.0
RCA3
2.84 + 0.022.37 ± 0.02
126.3 ± 3.7116.8 + 1.3
2951.3 ± 48.5
RCA4
2.85 ± 0.022.44 + 0.04
141.1 ± 5.1118.5 ± 0.7
3086.2 ± 81.4
The pressure values in the injection line and pool were around the values forecast in theexperimental matrix. The minor variations maintain a relative pressure at the point ofinjection in the range 0.4-0.55 bar, which prevents reversal of the gas flow entering thepool. In all the tests the temperature in the injection line was higher than that in the pool,this being the result of high temperature gas flow. Test RCA 4 showed a greater deviationwith respect to the preestablished value. Nevertheless, the influence of these deviations andof those corresponding to injection flow do not affect the objectives of the retention test.
Table 3.2 Sampling time average values of sample and injection flowrates (cc/s)
19
Sampling RCA1 RCA2 RCA3 RCA4
INJECTION LINE
TM2/63(10-15 min)
TM2/64(15-20 min)
qTM2/63
QTM2/63
QTM2/64
QTM2/W
TM3(5-30 min)
TM4(5-30 min)
qTM3
QTM3
q™4
QTM4
61.2 ±0.073160.1 + 19.3
120.1 ± 0.13170.1 ± 26.8
VESSEL t
193.7 + 17.33151.7 + 29.2
266.3 + 10.43151.7 + 29.2
60,0 ± 0.12831.7 + 24.3
117.8 ± 0.12880.1 ± 9.8
ATMOSPHERE
183.3 + 9.72918.5 ± 67.9
257.1 ± 4.62918.5 + 67.9
62.2 ± 1.12918.9 + 22.1
122.0 ± 2.12966.6 ± 15.2
174.7 ± 6.32936.3 ± 51.2
235.3 + 5.22936.3 ± 51.2
64.2 + 0.033018.5 ± 12.3
126.0 ± 0.063066..7 ± 24.3
172.9 + 7.33062.0 + 63.4
229.6 ± 13.03062.0 ± 63.4
3.1.2 Aerosol characterization
The material used in the retention tests was 99.8% pure Nickel. An optical instrument(POLYTEC) located on the injection line took direct measurements of the size of the aerosolinjected during each test; failure of the lamp of this instrument caused an absence ofmeasures during test RCA 4. Table 3.3 shows the characteristic parameters of the inletdistribution of the particles versus time. Table 3.4 shows the average values of the mostrelevant parameters as regards distribution of the particles injected.
The characteristic values of particle distribution remained fairly constant throughout theperformance of each test. As may be appreciated in Table 3.4, the particle distributions atthe inlet are very similar in the three tests for which measurements were taken.Consequently, it is to be expected that the particle distribution in test RCA4 would be similarto the others.
The volume distributions measured by the optical instrument occasionally show evidence ofthe existence of large particles entrained in the carrier gas along with the aerosol injected.These may arise as a result of resuspension of impurities in the injection line or ofagglomerates of Ni. The presence of these large particles leads to displacement of thevolume distribution towards larger sizes; nevertheless, their contribution to numericaldistribution is negligible, as a result of which momentum is not altered. Appendix IV showsgraphically the characteristic numerical and volume distributions of tests RCA1, RCA2 andRCA3. As shown in the appendix, the presence of impurities is of greater relevance in testRCA1, where the small population of particles measured leads to a considerable increase inthe relative weight of such impurities in the volume distribution. This effect is lesssignificant in test RCA2, where the numerical and volume distributions are centred more onthe characteristic sizes of the aerosol injected.
20
Table 3.3 CMD and GSD of pool scrubbing tests versus time
RCAl
Time(min)
10.
12.
15.
21.
24.
27.
CMD0*m)
0.85
0.85
0.85
0.85
0.82
0.82
GSD
1.42
1.42
1.38
1.39
1.39
1.40
RCA2
Time(min)
1.
9.
12.
16.
19.
22.
25.
27.
CMD(urn)
0.90
0.89
0.86
0.85
0.85
0.86
0.86
0.87
GSD
1.42
1.46
1.43
1.40
1.43
1.46
1.46
1.46
RCA3
Time(min)
8.
10.
13.
18.
21.
25.
29.
CMD(/im)
0.82
0.81
0.80
0.82
0.81
0.82
0.82
GSD
1.37
1.36
1.37
1.39
1.38
1.40
1.38
Table 3.4 Time average properties of size distributions
CMD (jim)
GSD
MMD (/¿m)1
RCAl
0.84
1.40
1.18
RCA2
0.87
1.44
1.30
RCA3
0.81
1.38
1.11
1 MMD = CMD exp(3 lirGSD)
Finally, appendix V shows the results obtained from the deposition foils using the SEMtechnique. In general, the atmospheric foils show particles close to spherical in shape andof sizes smaller than 0.5 ¡xm.
3.1.3 Inlet and outlet mass flowrates
Determination of mass particle inlet and outlet rates is performed on the basis of the massof Nickel collected on the filters corresponding to the different sampling taps. Ascommented on in chapter 2, there are two sampling taps for inlet rate (TM2/63 andTM2/64), and a further two for outlet rate (TM3/65 and TM4/68). For each filter, two typesof analysis are carried out for quantification of the Nickel collected: gravimetric andchemical.
21
On each of these filters the mass rate is provided by the following expression:
m¡ = (1)
where m¡j represents the mass of Nickel collected on the filter of sampling tap i using methodj (gravimetric or chemical analysis), Q¡ is the injection flow averaged throughout the durationof sampling at i, q¡ is the flow across sampling tap i averaged over sampling time, and t¡ isthe duration of sampling at point i.
Table 3.5 shows the inlet rates resulting from the data collected at each of filters TM2/63and TM2/64, while Table 3.6 shows the total mass of Nickel (obtained as the product of rateand test duration time) injected in the pool, in accordance with the data shown in Table 3.5.
Table 3.5 Inlet mass rates in the pool scrubbing tests
SamplingLine
TM2/63
TM2/64
Method
Gravimetric
Chemical
Gravimetric
Chemical
RCA 1(mg/s)
0.159 + 0.001
0.196 ± 0.001
0.871 ± 0.008
0.818 + 0.007
RCA 2(mg/s)
0.250 + 0.002
0.181 ± 0.002
1.620 + 0.007
0.640 ± 0.003
RCA 3(mg/s)
0.782 + 0.020
0.457 + 0.011
0.784 ± 0.017
0.654 ± 0.015
RCA 4(mg/s)
0.545 ± 0.002
0.430 + 0.002
0.534 + 0.011
0.730 + 0.006
Table 3.6 Total mass injected into the pool
SamplingLine
TM2/63
TM2/64
Method
Gravimetric
Chemical
Gravimetric
Chemical
RCA(g)
0.286 ±
0.353 ±
1.568 ±
1.472 +
1
0.002
0.002
0.014
0.013
RCA(g)
0.450
0
2
1
326
920
152
±±±
±
2
0.003
0.003
0.007
0.005
RCA(g)
1.407 +
0.822 ±
1.411 ±
1.177 +
3
0.036
0.020
0.030
0.030
RCA(g)
0.981
0.774
0.961
1.314
±±±±
4
0.004
0.020
0.020
0.011
The data included in Tables 3.5 and 3.6 show that there are discrepancies as regards boththe results of the two methods used for the quantification of Nickel on the filters and theresults for each filter. The origin of these discrepancies varies. On the one hand, the twoquantification methods are associated with different uncertainties: while the gravimetricmethod may have accounted for impurities from various materials (fundamentally componentsof steel), the chemical analysis may have lost part of the Nickel from the filters between thedifferent processes required by this technique. In addition, consideration should be given tothe hypothesis of rate constancy, related to the characteristics of the aerosol generation
22
method used. In view of the above, it is not possible to establish a generalized constant ratefor all the tests, as a result of which all the inlet rate values will be used in determining thedecontamination factor.
Table 3.7 presents the results for outlet rate resulting from analysis of the atmospheric filters(TM3/65 and TM4/68). In estimating this rate, no credit has been given to the contributionmade by the Nickel collected in the condensate upstream of the filter, since this wasnegligible in relation to both mass and rate. Appendix VI shows the mass of Nickel collectedfrom the condensate for each test.
Table 3.7 Outlet mass rates in the pool scrubbing tests
SamplingLine
TM3/65
TM4/68
Method
Gravimetric
Chemical
Gravimetric
Chemical
RCA 1(mg/s)
0.015 + 0.001
0.027 + 0.002
0.088 ± 0.004
0.066 ± 0.003
RCA 2(mg/s)
(9.0 ± 0.7) 10"
(85.0 ±40.4) 10-
0.0475 ± 0.002
0.0400 +0.0001
RCA 3(mg/s)
0.063 ± 0.003
0.0020 ± 0.0001
0.034 ± 0.001
0.0098 ± 0.0004
RCA 4(mg/s)
(9.4 ± 0.6) 10-5
(1.7 ±0 .1 ) 104
—
(5.9 ± 0.4) 10^
Various observations may be established from the data included in Table 3.7. The resultsof the chemical analysis show that a larger amount of Nickel was collected from filterTM4/68 than from TM3/65, this result being expected in view of the closer proximity of theformer to the surface of the pool. In addition, the ratio between the rates obtained with eachfilter by chemical analysis is proportional to some extent, mainly in the case of tests RCA1,RCA2 and RCA3. The results of the gravimetric analysis, on the other hand, reflect majorinconsistencies. Although not at all proportional, in test RCA3 gravimetric analysis of filterTM3/65 showed a larger mass of Nickel than filter TM4/68. It may also be stated that intest RCA4 the gravimetric analysis did not detect any mass in filter TM4/68, and in filterTM3/65 a value of the order of the reliable accuracy of measurement. Consequently, greatercredibility is attached to the results provided by chemical analysis for the atmosphericsampling tap filters.
3.1.4 Pool sampling
The pool is equipped with five sampling taps located at different elevations above the injectorand two more at the bottom and at the vessel drain. Two volume samples were extractedfrom all these taps: one on completion of the test (GC) and the other after agitating the poolfor approximately two hours (VP). Table 3.8 shows the concentration of Nickel suspendedin the water of the pool according to the data provided by the five first sampling taps, whileTable 3.9 presents the concentration resulting from the samples taken from the others.Mention may be made of the fact that in view of the low value of submergence in testsRCA1 and RCA2, there was no sampling with GC/13, GC/14, GC/15 or with GC/15,respectively. Likewise, no VP samples were taken in test RCA1.
23
Table 3.8 Nickel concentration in the pool water (g/1)
Sample
GC/11GC/12GC/13GC/14GC/15
VP/1VP/2VP/3VP/4VP/5
RCA 1
5.33 lo 4
4.90 lo 4
i i
i i
i•
i i
i i
i i
i i
i
RCA 2
3.73 10-4
4.06 lo"4
3.94 l o 4
4.37 lo"4
3.06 lo"4
2.79 lo-4
1.94 10-4
2.44 lo-4
RCA 3
7.20 lO'5
1.20 10-4
2.44 lO-4
2.46 lO-4
2.12 lO-4
9.60 10-5
2.80 10-5
2.40 lO-4
3.00 lo"4
1.50 10-4
RCA 4
1.84 lO-4
2.04 lO-4
4.66 lO-4
2.00 10-4
1.65 lO-4
1.43 10-4
1.82 lO-4
1.59 lO-4
1.48 lO-4
1.50 10-4
Table 3.9 Nickel concentration from sampling GC/VP 16 and 17 (g/1)
Sample
GC/16GC/17
VP/6VP/7
RCA 1
5.50 104
7.95 lO-4
---
RCA 2
7 7
O
OT-H
T—
1
en
esen
es
T—I
T-H
1.24 10-41.61 10°
RCA 3
3.57 10"3
9.11 104
3.46 10"3
1.15 10-3
RCA 4
1.10 10"3
6.70 lO-4
3.02 10-4
2.37 10'3
As may be appreciated in Table 3.8, the results corresponding to samples VP/1-5 showedvalues of Nickel concentration similar to those measured previously (GC). In other words,the pool agitation process maintained the concentration of Nickel suspended in the waterpractically constant and was not capable of efficiently resuspending the mass of Nickelprecipitated at the bottom of the vessel.
It should be pointed out that the concentrations resulting from the sampling taps located atthe bottom and the drain were generally inconsistent with the results provided by the tapslocated above. While in tests RCA1 and RCA2 they were approximately similar (with theexception of RCA2 VP/7), in the other tests they were higher by approximately one orderof magnitude. This underlines two fundamental facts: the low degree of representativity ofthese sampling taps for concentrations suspended in the water, and the presence of animportant quantity of Nickel precipitated at the bottom of the pool. Given the location ofthese taps, a part of the aerosol deposited on the bottom must have been entrained along withthe volume extracted, as a result of which they cannot be treated as concentration samples.
Thus, the Nickel suspended in the pool may be estimated on the basis of the averageconcentration of samples GC/ll-GC/15 and of the volume in the pool during each test. Themass of Nickel estimated using this method has been corrected by subtracting the mass ofNickel present in the pool prior to injection, this being determined by the results providedby sampling tap B/00.
24
Table 3.10 Total mass of Nickel suspended in the pool
Average Concentrationin the pool (g/1)
Pool Volume (1)
Total Mass suspendedin the pool (g)
RCA 1
(5.11 ± 0.21) 104
1258
0.633 + 0.026
RCA 2
(4.03 ± 0.23) 104
1700
0.559 + 0.04
RCA 3
(1.78 + 0.70) 104
3020
0.537 + 0.211
RCA 4
(2.44 + 1.12) 104
4420
1.041 ± 0.495
The data included in Table 3.10 show an increase in the uncertainty attached to the masssuspended with the volume of water in the pool. This reflects some non-homogeneity in thedistribution of Nickel in the pool, due to its being an insoluble aerosol. This observationcontributes to the uncertainty attached to the total mass of Nickel retained by the pool;however, the most important contribution made to this uncertainty arises from the Nickelsedimented at the bottom of the pool. The insoluble nature of this element, along with itshigh density, lead to an important fraction of the mass retained by the pool beingprecipitated at the bottom. Consequently, the data shown in Table 3.10 represent the lowerlimit of the total mass retained by the pool. In view of the above, and of the largeuncertainties attached to the data provided by pool sampling, it may be concluded that theexperimental data from the pool are of no use for determination of the decontaminationfactor.
3.1.5 Decontamination factor
The decontamination factor is determined on the basis of the mass inlet and outlet rates ofthe pool:
(2)m
out
As has been pointed out above, four estimates were made of the inlet rate in each test. Inspite of the different values obtained, most are consistent. Nevertheless, those values of inletrate which are inconsistent with the lower limit of the mass of Nickel retained by the pool(Table 3.10) should be rejected. Thus, and as regards comparison of the mass injected(Table 3.6) to the mass suspended in the pool (Table 3.7), the results for injected mass intests RCA1 and RCA2, based on filter TM2/63, show a lower value for the mass detectedin the pool (including the range of error in both cases). Consequently, these data are nottaken into account in determination of the decontamination factor in tests RCA1 and RCA2.Thus, estimates of the experimental decontamination factor ranges are based on considerationof different inlet rates.
As regards outlet rate, the data provided by chemical analysis of the atmospheric filters areconsidered to be more reliable. The existence of two different filters in the atmosphere ofthe pool (TM3/65 and TM4/68) leads to the estimation of two groups of decontaminationfactors.
25
As a result, up to 8 DF's were estimated for each test, distributed in two groups of up to 4,their extreme values determining the ranges of variation of the experimental DF. Theseranges represent the discrepancies between the different techniques and filters used tocharacterize the inlet rate. Table 3.11 summarizes the ranges of the experimentaldecontamination factor in two groups: the first corresponds to atmospheric filter TM3/65 andthe second to TM4/68.
Table 3.11 Provisional DF ranges for pool scrubbing tests
TM3/65
TM4/68
RCA
54.5-
12.4-
1
58
13.2
RCA 2
75.3-
16-
- 190.6
40.5
RCA
228.5 -
46.6-
3
392
80
RCA 4
2559.5 - 4345.2
719 - 1220.7
The data shown in Table 3.11 are consistent in various ways: the DF ranges are within anacceptable margin of error (less than a factor of 3 in all cases); the i.vo DF groups (TM3/65and TM4/68) show the same tendency; and finally, and as was expected, the results showincreasing DF with submergence.
Finally, the values of DF estimated from TM4/68 are considered to be more representative,due to this sampling tap's greater proximity to the surface of the pool. The particlesescaping from the aqueous volume are affected by various forces in their flow path, whichmight contribute to an important reduction in the inventory of particles reaching sampling tapTM3/65 (located at the top of the vessel). In view of the high density of the Nickel particles(8.9 g/cc), the forces of inertia and sedimentation might be responsible for this effect.Consequently, the final ranges of experimental decontamination factor are those shown inTable 3.12.
Table 3.12 Final DF of Pool scrubbing tests
RCA 1
RCA 2
RCA 3
RCA 4
DF
12.4- 13.2
16 - 40.5
46.6 - 80
719 - 1220.7
Subm. (m)
0.25
0.50
1.25
2.50
The results shown in Table 3.12 reflect a strong dependence on the exponential nature of thedecontamination factor with pool submergence. In addition, the ranges of variation of theDF do not overlap with different values of submergence, as a result of which the tendencyshown by the results is quite clear. Likewise, these DF ranges are within the acceptableexperimental margin of error. Finally, attention should be brought to the fact that the marginof uncertainty as regards mass rates, at both the pool inlet and outlet, do not significantlyalter the ranges shown above, as a result of which these ranges cover both deviations in thethermohydraulic conditions of the pool and the uncertainties related to the absence of a
26
characteristic mass inlet rate for all the tests.
3.2 HYDRODYNAMICS
Analysis of the hydrodynamic behaviour of the gas provides essential information for correctunderstanding of the phenomenon of pool retention. Given the nature and the objectives ofthe retention experiments, attention centred fundamentally on analysis of the initial phasesof the gas in the pool: the formation and release of the primary bubble, and initiation of thegas rise movement in the aqueous volume.
A general observation, applicable both to the retention tests and to the hydrodynamic teststhemselves, was the oscillation of the plume formed by the gas during its rise. This loss ofverticality was associated fundamentally with the transfer of momentum between the gas andthe liquid, both at the point of injection and at the surface of the aqueous volume onrupturing of the bubbles. These interchanges, along with the proximity of the walls of thevessel (1.5 m in diameter) promoted agitation of the aqueous mass at both the surface andwithin the volume, thus altering the azimuthal position of the plume axis.
3.2.1 Hydrodynamic tests
Table 3.13 shows the deviations of the initial test conditions with respect to the valuesforecast in the experimental matrix (Table 2.5).
Table 3.13 Actual hydrodynamic test boundary conditions
Series
SI
S2
b
b
Test
HSlal
HSla2
HSla3
HSlbl
HSlb2
HS2al
HS2a2
HS2a3
HS2bl
HS2b2
Injection
T(°C)
room
room
room
115
117
121
134
149
118
119
Conditions
P(bar)
1.57
1.70
1.60
1.75
1.77
1.65
1.58
1.63
1.74
1.72
Inlet Gas
Q (cc/s)
xs943
2111
3056
945
2848
1049
1981
2847
1023
3043
0
0
0
0.5
0.5
0
0
0
1
1
T(°C)
room
room
room
room
room
93
93
93
93
93
Pool Conditions
P(bar)
1
1
1
1
1
1
1
1
1
1
Sub (m)
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
In sub-series SI a, Sib and S2a the inlet gas behaved analogously. The front imagesmanifested the existence of a certain sequence with regard to the shape of the gaseousvolume: large masses of gas interconnected by much narrower gaseous channels. This
27
pattern was not regular, however; in other words, the position of the large gaseous massesvaried with time in each test and between one test and the next. Figure 3.1 shows an imageof the situation described above. Appendix VII includes a wider collection of figures of thistype.
The observations corresponding to sub-series S2b differed ostensibly from those describedabove. In this case, the gas injected (100% water vapour) formed an initial globule whichcollapsed suddenly, becoming a swarm of very small bubbles that rose through the liquid.Thus, in experiment HS2bl all the bubbles are smaller than 1 cm as from 15 cm above theinjector, and in experiment HS2b2 all the bubbles above 40 cm from the injector are smallerthan 1.5 cm.
Figure 3.2 shows the equivalent diameter of the bubble at a distance of betweenapproximately 0 and 32 cm from the injector, for test HSlal. Appendix VIII includes a fullset of figures of this type for each of the two elevations analyzed in each test. These graphsshow the distribution of the bubbles over a range of sizes as distance from the injectorincreases. They each show bubbles observed in the two positions (frontal and lateral).
As in the case of the visual observations, sub-series Sla, Sib and S2a show certain analogiesin the distribution of bubble sizes with height. The following are particularly outstanding:the existence of large gaseous volumes (10-20 cm in diameter) at distances in excess of 32cm; the growth of a population of small bubbles, with respect to the previous zone ( — 0-32cm); and the fact that fully developed bubbly flow is not achieved at 60 cm from the injector.Contrary to these observations, sub-series S2b did not show large individual gaseous volumesabove 32 cm.
A large number of bubbles was processed in each test (typically between 1000 and 2000).Examination of bubble size distribution showed that this was lognormal in nature (AppendixIX). The parameters chosen for representation were VMD and GSD13. Tables 3.14 and 3.15show both magnitudes broken down into lateral and frontal observations. This quantitativeanalysis is affected by two fundamental errors: the limitations associated with two-dimensional processing of the bubbles and the fact that bubbles measuring less than 1 mmin diameter were not considered. Given the peculiarity of sub-series S2b, only series SI andsub-series S2a were included.
The main observations arising from the two tables are as follows:
Between approximately 0 and 32 cm VMD decreases with inlet gas flow. This is dueto an increase in the number of small bubbles and not to the formation of largergaseous volumes. The Figures included in Appendix VIII corroborate this statement.
The frontal and lateral images show a notable asymmetry between approximately 0 and32 cm. The differences between them are significant in most cases, particularly in testHSla2 and in sub-series Sib and S2a. The observations made in test HSla2 areconsidered anomalous. Between the lateral and frontal images of series Sib there isa factor of more than 2.0 as regards VMD. In sub-series S2a the frontal images donot show any tendency with flow, while the opposite is true of the lateral images.
28
Between approximately 0 and 32 cm, both VMD and GSD undergo displacementtowards lower values, with respect to the previous stage. In other words, the numberof small bubbles increases ostensibly, causing dispersion of the distributions todecrease.
The correlation between inlet gas flow and VMD disappears between approximately 32and 64 cm. With the exception of sub-series Sib, where the lateral images showed asignificantly higher VMD in the preceding zone, the rest of the sub-series do not showany defined tendency.
Table 3.14 Size distribution parameters of hydrodynamic tests between 0 and 32 cmfrom the injector
Series
SI
S2
Sub-series
a
b
a
Test
HSlal
HSla2
HSla3
HSlbl
HSlb2
HS2al
HS2a2
HS2a3
Lateral Images
VMD
3.84
2.34
1.66
7.56
4.19
2.51
2.03
1.84
GSD
3.18
2.86
2.65
2.96
2.73
2.51
2.86
2.67
Frontal
VMD
3.84
16.08
1.84
3.32
1.89
2.60
2.74
2.61
Images
GSD
3.16
3.97
2.65
2.72
2.40
2.79
2.68
2.79
Total
VMD
3.84
9.21
1.75
5.44
3.04
2.78
2.38
2.22
Images
GSD
3.17
3.40
2.65
2.84
2.56
2.65
2.77
2.73
Using the representation of bubble diameter versus height above the injector it was possibleto observe the large dispersion of different sized bubbles for one same test. Forinterpretation of the results, study of bubble diameter was restricted to the first 10 cm abovethe injector. The bubbles were classified in three size groups in this zone. The firstcorresponded to bubbles smaller than the diameter defined by the Weber stability criterion13
i.e. to the diameters characteristic of a plume of stable bubbles; the value of this criticaldiameter under the test conditions was 1.8 cm. The second group corresponded to bubblesof an intermediate size, i.e. a size greater than the Weber critical diameter and smaller thana diameter defined by the Levich stability criterion14 (4.7-4.4 depending on the conditions inthe pool). The last group included bubbles of larger size than the Levich value (i.e.,unstable bubbles according to mechanistic criteria). Table 3.16 shows the results of thisclassification.
29
Table 3.15 Size distribution parameters of hydrodynamic tests between 32 and 64 cmfrom the injector
Series
SI
S2
Sub-series
a
b
a
Test
HSlal
HSla2
HSla3
HSlbl
HSlb2
HS2al
HS2a2
HS2a3
Lateral
VMD
1.08
1.19
0.94
2.15
1.61
1.08
1.02
0.91
Images
GSD
2.33
2.42
2.19
2.33
2.11
2.33
2.25
2.17
Frontal
VMD
1.09
1.47
1.44
2.62
1.68
1.27
1.05
0.93
Images
GSD
2.28
2.30
2.40
2.73
2.44
2.26
2.12
2.08
Total
VMD
1.08
1.33
1.19
2.38
1.64
1.17
1.03
0.92
Images
GSD
2.30
2.36
2.30
2.47
2.77
2.29
2.18
2.12
Table 3.16 Bubble classification of hydrodynamic test based on the stability criteria
Region 0-10 cm
HSlal
HSla2
HSla3
HSlbl
HSlb2
HS2al
HS2a2
HS2a3
HS2bl
HS2b2
dv(cm)
5.27
6.42
7.76
5.1
5.3
4.61
3.38
4.33
5.13
5.37
d<1.8
N%
79.5
82
88
70
68
79
83
85
84
92
V%
1.2
1.4
0.6
2
14
2.3
5
5
1.4
1
1.8<d<4.5
N%
8.9
14
7.5
21
23
11
16
13
10.6
4
V%
15.4
17
8.5
36
26
24
59
38
27
17
d>4.5
N%
10
4.5
4
8.5
8.5
9.5
0.8
2
5.3
4
V%
83
82
91
61
72
67
36
56
71
82
This table shows that most of the gaseous volume is associated with bubbles having adiameter of more than 4.5 cm, in spite of the fact that the numerical population of bubblesbelow this value was in all cases more than 80%. Not all the series exhibited the samebehaviour, thus, in sub-series lb and 2a the weight of the larger sized bubbles is considerablygreater. Test S2a2 is considered to be anomalous, since only one bubble of more than 4.5cm in diameter was analyzed, as a result of which the percentage of all the sizes is affectedby these deficient statistics. On the other hand, the diameter in all the cases is bounded inthe range of 4-7 cm. These narrow range implies that only a trend analysis may beperformed.
30
With a view to establishing a characteristic diameter in the injection zone the mean volumediameter was averaged with respect to the volume percentage for each size interval. Bubbleshaving diameters of less than 1.8 cm were not taken into account. On the one hand, thesebubbles represent less than 5% of the total volume; on the other, the uncertainties associatedwith the measurement technique used prevent us from knowing whether this percentage isin fact real. Thus, neither the average diameter of the bubbles in this range nor the realpercentage of the volume they represent is accurately known, although the latter is expectedto be small. The characteristic diameters are also shown in Table 3.16.
As in the case of size, the a/b ratio shows a lognormal distribution. Appendix X includesnumerous examples of the characteristic distribution of the ratio of axes. Table 3.17 showsthe mean value of a/b and its typical deviation. It may be appreciated that there is no clearrelationship between quotient a/b and inlet gas flow, its composition, the temperature of thepool and the axial position of the bubbles. Most of the bubbles analyzed had values of a/blower than 4.0, and in any case the mean value was around 1.5.
There is a parameter which measures how much different from tL; spherical one is thebubble shape: circularity. Circularities measured in all the tests were higher than 4ir,indicating the high degree of irregularity in the bubble shapes (Appendix XI).
Table 3.17 Mean a/b ratio and deviation of the hydrodynamic tests
Series
SI
S2
Sub-series
a
b
a
Test
HSlal
HSla2
HSla3
HSlbl
HSlb2
HS2al
HS2a2
HS2a3
0-32 cm
LateralImages
a/b a
1.61 1.82
1.52 0.61
1.47 0.53
1.63 0.43
1.53 0.36
1.44 0.33
1.44 0.33
1.40 0.48
FrontalImages
a/b a
1.41 0.42
1.38 0.3
1.48 0.56
1.59 0.39
1.52 0.43
1.47 0.57
1.54 0.54
1.48 0.50
32-64 cm
LateralImages
a/b a
1.52 0.55
1.49 0.54
1.51 0.60
1.58 0.59
1.62 0.57
1.61 0.71
1.46 0.52
1.52 0.57
FrontalImages
a/b a
1.60 0.76
1.52 0.60
1.54 0.64
2.15 0.43
2.08 0.97
1.57 0.59
1.51 0.61
1.54 0.70
31
3.2.2 Pool Scrubbing Tests
All the observations presented below refer exclusively to the region between the injector anda point located some 32 cm above it. Although in test RCA4 it was not possible to analyzethe influence of submergence on hydrodynamic phenomena, due to the unavailability of theimaging system, the pool scrubbing tests did allow this to be studied. The most generalobservation was the absence of any correlation between any of the hydrodynamic parametersanalyzed (i.e., size, shape, rise pattern) and the depth of the injector. Nevertheless, it wasappreciated that as submergence decreased, the oscillation of the plume due to agitation ofthe water increased considerably.
Table 3.18 shows the values of VMD and GSD for each experiment, depending on the pointof recording. As in the previous section, the larger numbers included in the table areassociated with the absence of small bubbles and not with the formation of enormousindividual masses of gas. The acquisition of high VMDs and GSDs in the frontal imagesunderlines the difficulty involved in obtaining a representative population of bubbles fromthis orientation. This is due to the masking effect that the shine of some bubbles produceson others.
Table 3.18 Size distribution parameters for pool scrubbing experiments (0-32 cm)
Test
RCA
RCA
RCA
1
2
3
Lateral
VMD
2.23
4.66
2.55
Images
GSD
2.74
3.04
2.92
Frontal
VMD
2.75
14.33
8.42
Images
GSD
2.77
3.75
3.46
Total
VMD
2.5
8.7
5.5
Images
GSD
2.7
3.4
3.3
Figure 3.3 shows a distribution of equivalent bubble diameter depending on the distance fromthe injector for experiment RCAl. The distributions corresponding to tests RCA2 and RCA3are included in Appendix VIII. Attempts were made to correlate the numerical populationand volume with elevation on the basis of these figures. No relation could be establishedother than the observation that 100% of the gaseous volume is associated with bubbles largerthan 1.3 cm, in spite of the fact that the numerical population of bubbles below this valuewas in all cases larger than 70%. The characteristic diameter was calculated using the sameprocedure as explained in the previous section (Table 3.19).
32
Table 3.19 Bubble classification of the pool scrubbing tests based on the stabilitycriteria
RCA1
RCA2
RCA3
0-10 cm
dv(cm)
5.94
5.90
6.32
d<1.8
%N
88
72
84
%V
2
1
1
1.8<d<4.5
%N
6
16
8
%V
11
13
13
4.5>d
%N
5
12
7.5
%V
86
86
86
The observations made with respect to shape coincide with those made in the previoussection. In general, the mean values of the a/b ratio are situated between 1.5 and 1.7, agreater dispersion being observed in the lateral images than in the frontal (Table 3.20).
Tabla 3.20 a/b ratio estimated for pool scrubbing experiments
RCA1
RCA2
RCA3
Lateral Images
a/b
1.69
1.64
1.57
a
1.97
0.60
1.08
Frontal Images
a/b
1.62
1.66
1.53
o
0.55
0.55
0.51
33
iI: ÜM—n
.; • 'jJftSwjHiWiftnU
Figure 3.1 Frontal image recorded of the gas structure close to the injector(HSlal test)
16
\ .
a
5
l
|HS1a1|
i- +tí*' t * +<-
10 20 30 40y (cm)
Figure 3.2 Bubble diameter vs. distance from injector (HSlal test)
34
Figure 3.3 Bubble diameter vs. distance from injector (RCA 1 test)
35
4. RESULTS INTERPRETATION
The main objective of this chapter is to interpret the results of the experimental poolscrubbing and hydrodynamic programme. The SPARC-907 and BUSCA-AUG928-9 codeshave been used for determination of the DF and comparison with the experimental results,as well as with the hydrodynamic correlations included in the codes, for interpretation of thehydrodynamic results.
4.1 POOL SCRUBBING TEST ANALYSES
This section includes the post-test calculations performed using the SPARC and BUSCAcodes and a comparison with the experimental results. In addition, an analysis is made ofthe contribution of each mechanism to the DF and of the influence of hydrodynamicphenomena. The input files are included by code and experiment in Appendix XII.
4.1.1 Hydrodynamic behaviour
Hydrodynamic phenomena are a determining factor as regards the gas-liquid transfer surfaceand the residence time of the gas in the pool. Appendix XIII shows graphically thehydrodynamic evolution estimated by SPARC and BUSCA for each test. SPARC predictsan increase in the population of bubbles with submergence. In addition, total rupturing ofthe globule occurs only in test RCA4. Analogously to SPARC, BUSCA also predictsincreasing bubble population with submergence; nevertheless, in all the tests it estimates totalrupturing of the globule by approximately 7 cm above the injector.
Table 4.1 shows the most important hydrodynamic variables and residence time estimatedby both codes. In BUSCA the size of the bubble is modified during its rise through the pool,as a result of which eccentricity and speed may vary; consequently, the arithmetic mean ofeach of these variables is included in the following Table.
Table 4.1 Main hydrodynamic variables predicted by SPARC and BUSCA
dc (cm)
dB (cm)
a/b
Ruptureheight (cm)
v (cm/s)
time (s)
U,, (cm/s)
SPARC
RCA 1
11.00
0.681
1.438
132.0
74.80
0.33
25.48
RCA 2
10.74
0.681
1.438
128.9
72.78
0.69
25.42
RCA 3
10.79
0.681
1.438
129.5
72.92
1.72
25.43
RCA 4
10.60
0.681
1.438
127.2
70.86
4.07
25.40
BUSCA
RCA 1
7.36
0.828
2.907
7.23
103.3
0.24
15.92
RCA 2
7.21
0.873
3.093
7.0
99.06
0.50
16.32
RCA 3
7.23
0.926
3.186
7.0
85.52
1.46
16.65
RCA 4
7.33
0.969
3.464
7.6
69.44
3.60
17.48
36
With the exception of rise velocity, which decreases slightly with increasing submergence,the rest of the variables estimated by SPARC show a high degree of constancy from one testto the next. The slight dependency shown by rise velocity on submergence is the result ofestimation including equilibrium flow at half height. In addition, attention should be broughtto the fact that both the diameter estimated by SPARC and eccentricity acquire theirmaximum possible value (Ref. 5).
The results provided by BUSCA also show constancy from one test to the next, with theexception of bubble size and eccentricity, which increase with submergence due to the factthat the time during which evaporation occurs increases.
Finally, in view of the fact that the variables having the greatest influence on DF are thediameter of the bubble and the rise velocity, and as regards the estimates performed by eachcode, the results provided by SPARC point to greater retention in all the tests. In addition,mention might be made of the large difference in the point of total rupture predicted by eachcode; while SPARC estimates that total rupture occurs at some 12 times the diameter of theglobule, BUSCA estimates this phenomenon at once the aforementioned diameter. However,the major difference between these two rupture models is the different approach in each code,a progressive break-up of the globule in SPARC against the stability criteria in BUSCA,which causes the rupture in a specific point.
4.1.2 Aerosol retention mechanisms
The influence of each retention mechanism on the decontamination factor, according to theestimates of SPARC and BUSCA, is presented below. With regard to the input data, thetreatment given by SPARC and BUSCA to input particle distribution may be differentiated.While in the first the actual mass distribution (measured experimentally) is introduced, inBUSCA the input distribution is characterized by the median mass radius, the correspondingGSD and the number of intervals to be considered.
Appendix XIV presents the mass distributions at the injector and in the atmosphere for eachtest, according to the results of each of the codes, and Table 4.2 shows the MMD and GSDvalues of these distributions. As may be appreciated in the appendix, the presence of largesized particles in test RCA1 disperses mass distribution towards larger sizes. Given the smallnumerical population of such impurities, the numerical distribution is not affected.Consequently, the decision was taken to use numerical distribution as a basis for the SPARCcalculation corresponding to this test. A study was made of the repercussion that use of thereal lognormal distribution would have on DF in the SPARC calculations, the DF valuesestimated being slightly lower (factor of 1.3), with the exception of test RCA1 where thedifference was of a factor of 2.4.
The estimates of both codes lead to lower MMD and GSD values in the distribution ofparticles escaping from the pool, this indicating that retention is more efficient with largersized populations. The low values provided by the SPARC estimates reflect greaterdecontamination in the predictions. Finally, the evolution of both parameters withsubmergence indicates an increase in the efficiency of the retention.
37
Table 4.2 MMD and GSD for inlet and outlet distributions
Test
RCA 1
RCA 2
RCA 3
RCA 4
Inlet
Experimental
MMD
1.18
1.30
1.11
1.30
GSD
1.40
1.44
1.38
1.44
SPARC
MMD
0.84
0.80
0.72
0.63
GSD
1.30
1.23
1.21
1.15
Outlet
BUSCA
MMD
1.16
1.08
1.07
1.05
GSD
1.32
1.34
1.31
1.31
Table 4.3 shows the decontamination factor in the injection and rise zones, along with thetotal DF calculated by the two codes.
Table 4.3 Decontamination factor for the injection and rise zones
RCA 1
RCA 2
RCA 3
RCA 4
SPARC
Injection
Imp.
1.41
1.56
1.53
1.55
Qch.
6.68
7.67
5.76
7.13
Rise
1.17
1.79
7.10
61.30
Total
11.02
21.41
62.52
677.42
BUSCA
Injection
1.28
1.33
1.19
1.37
Rise
1.00
1.07
1.17
1.91
Total
1.28
1.42
1.39
2.61
The results of both codes show the same tendency: an increase in retention with submergencein the pool. The differences in the hydrodynamic variables, and mainly the differentresidence time estimated by the two codes, lead to greater decontamination in the rise zoneaccording to the SPARC predictions. As regards total DF, to the above should be added theeffect of the SPARC Quencher model. The contribution made by each mechanism to thetotal decontamination factor is presented in Table 4.4.
38
Table 4.4 Percentages of the different retention mechanisms to the DF
RCA 1
RCA 2
RCA 3
RCA 4
SPARC
Injection
Imp.
14.32
14.69
10.12
6.70
Qch.
79.14
66.39
42.34
30.13
Rise
Grav.
0.0
0.32
0.48
0.88
Cent.
6.54
18.80
47.06
62.30
BUSCA
Injection
100.
81.33
52.56
32.72
Rise
Grav.
0.0
5.32
13.79
18.78
Cent.
0.0
12.79
31.94
46.27
Diff.
0.0
0.56
1.71
2.23
The results show that retention in the injection zone is more important as submergencedecreases. In the SPARC estimates, the retention via small orifices (Quencher) is mainlyresponsible for decontamination in the injection zone. In addition, the mechanismresponsible for most retention in the rise zone is centrifugal deposition. Appendix XVgraphically illustrates the contribution made by each mechanism in the SPARC and BUSCAresults.
4.1.3 Theoretical and experimental comparison
Figure 4.1 shows the decontamination factors predicted by SPARC and BUSCA, along withthe experimental ranges. BUSCA clearly underestimates the decontamination factor, althoughslightly reproducing the tendency. The SPARC results, on the other hand, present a highdegree of experimental agreement, maintaining the same tendency and estimating DF valuespractically within the experimental range of variation.
The experimental results for the decontamination factor may be adjusted to a curveexponential with submergence, of the following type:
DF = e*eaS (1)
Least squares adjustment of the experimental data leads to two experimental values of a and/?, corresponding to the minimum and maximum value of the DF range, as shown in Table3.12. The values found for parameters a and /3 are included in Table 4.5.
39
Table 4.5 Results of least squares treatment of the experimental DF
Minimum experimental range
Maximum experimental range
a
1.82
1.87
0
1.90
2.33
r
0.99
0.98
Expression (1) shows that the experimental decontamination factor may be expressed as theproduct of two contributions: one dependent on submergence and the other not.Submergence and residence time are linked through rise velocity, such that eaS in equation(1) represents the characteristic law of the processes of particle elimination in gaseousvolumes. Consequently, this contribution calculates particle retention during rise. The othercontribution, e3, underlines the existence of additional decontamination regardless of the timetaken by the gas to cross the pool. This retention is postulated as being associated withelimination mechanisms in the injection zone.
Table 4.6 shows the decontamination factor in the injection zone, determined on the basisof the experimental data along with the predictions made by SPARC and BUSCA. It maybe appreciated that there is greater agreement in the SPARC predictions, with importantunderestimating in BUSCA.
Table 4.6 Experimental DF at the injection compared with SPARC and BUSCApredictions
Test
RCA 1
RCA 2
RCA 3
RCA 4
Experimental
6.68 - 10.27
SPARC
9.42
11.96
8.81
11.05
BUSCA
1.28
1.33
1.19
1.37
Table 4.7 shows the experimental DF in relation to the rise zone, compared to the predictionsmade by SPARC and BUSCA; greater agreement may be appreciated with SPARC, althoughthis code underestimates the value of DF during rise in all the tests.
40
Table 4.7 Experimental DF during rise compared with SPARC and BUSCApredictions
Test
RCA 1
RCA 2
RCA 3
RCA 4
Experimental
1.57-1.59
2.48 - 2.54
9.7 - 10.3
94.6 - 107.2
SPARC
1.17
1.79
7.10
61.3
BUSCA
1.00
1.07
1.17
1.91
The results presented above show that the agreement between SPARC and the experimentaldata is excellent, and its sensitivity with the submergence is much greater than BUSCAresults. Nevertheless, it should be taken into account that two important aspects of the poolscrubbing phenomenology have not been treated in this experimental programme: particlegrowth as a result of condensation of the water vapour present inside the bubbles and theelimination of particles due to steam entrainment under conditions of condensation. The firstwas avoided by injecting an insoluble aerosol (i.e., metallic Ni). The latter was preventedthrough the absence of water vapour in the inlet gas.
In addition, the high degree of agreement presented by the SPARC code as regardsestimating the overall decontamination factor is slightly reduced by the breaking down of theDF in the injection and rise zones, where greater deviations may be appreciated. Thedeviations in the injection and rise zones in the SPARC predictions would appear to becounteracted in estimation of total DF; consequently, in the light of the results it may bestated that the overall approach of the SPARC code is capable of reproducing theexperimental trend observed.
On the other hand, attention should be brought to the proximity of the quantitative predictionsmade by SPARC in the injection zone and during rise, to the favour of the injection modelsused by this code (Impactation and Quencher) and of the centrifugal deposition model (mainlyresponsible for retention during rise, according to SPARC). Regarding the latter, the DFevolution with the submergence as predicted by SPARC is quite similar to the experimentaltrend, both have approximately the same relative proportion among the DFs at differentsubmergences. This fact is an evidence of the goodness of the centrifugal deposition modelin SPA?vC.
4.2 HYDRODYNAMIC ANALYSIS
The objective of this section is to analyze the parameters presented in section 3.2 withrespect to the variables of the experimental matrix in the hydrodynamic and retention tests.The hydrodynamic correlations included in the SPARC and BUSCA codes were used for thispurpose. The variable parameters included in the hydrodynamic test matrix were: injectionflow, the composition of the inlet gas and the temperature of the pool. The only variableparameter used in relation to the retention tests was submergence.
41
4.2.1 Influence of the main variables
Effect of flow
The results of the hydrodynamic tests lead to a decrease in VMD with injection flow (Table3.14). The cut-off tension between the liquid and gaseous phases, produced by the inlet gas,causes partial rupturing of the main gaseous body. The efficiency of this rupturing processincreases with flow. Thus, the decrease in VMD is the result of an increase in thepopulation of small bubbles, to the detriment of the number and diameter of larger bubbles.This interpretation agrees with the reduction in GSD with increasing volumetric flow.
Certain exceptions may be seen, however, in Table 3.14. The frontal images correspondingto the hot pool do not show the aforementioned tendency. Evaporation would appear todampen the effect of flow, similar bubble size distributions being obtained in the three cases.The lateral images, however, confirm the effect of flow on bubble size distribution.
In spite of its being consistent with the previous discussion, sub-series Sib is very similarto Sla as regards the frontal images, but is higher by a factor of 2 in relation to the lateralimages. On the one hand, the frontal images are mainly dominated by the presence of largebubbles, whose areas of projection on the focal plane partially mask the presence of smallerbubbles due to the limitations of 2D image treatment. The lateral view, however, is notaffected by this limitation along the direction of flow, and consequently allows the smallerbubbles to be analyzed. The effect of condensation on smaller sized bubbles leads to collapseor to a reduction in size below 1 mm (lower detection limit). The final result of this is adisplacement of bubble distribution towards larger diameters. In the case of the largerbubbles, the effect of condensation also leads to an increase in the percentage of intermediatebubbles.
The data included in Table 3.15 show that size distribution is displaced towards lower valuesof VMD and GSD as the gas rises through the pool. In other words, as the gas rises a largernumber of small bubbles appears, to the detriment of rupture of larger bubbles, as a resultof which the distribution tends towards smaller sizes, becoming narrower. Table 3.15 doesnot show any correlation between diameter and volumetric flow; in other words, theinfluence of gas regime at the inlet is restricted to the area around the injector. Nevertheless,sub-series Sib shows a slight effect with flow. This observation lends support to theinterpretation of the difference between the lateral and frontal images in the 0-32 cm regionfor this sub-series. On disappearance of the smaller bubbles due to the effect ofcondensation, the larger bubbles dominate the population and the distribution of sizes is,therefore, still centred on the larger bubbles.
Effect of inlet gas composition
Figure 4.2 illustrates the behaviour of bubble diameter in the injection zone for the fourscenarios considered, depending on the Weber number. This figure shows that with the poolcold and without steam at the injection, the diameter of the bubble in the injector increaseswith flow. Nevertheless, the result obtained for the rest of the series, constancy of diameterwith respect to Weber, underlines the fact that under conditions of strong condensation or
42
evaporation the effect of flow might be dampened.
The effect of the composition of the gas may be studied by comparing sub-series Sla and Siband S2a and S2b, respectively. The results pointed to above are: the difference between thelateral images for the two sub-series, as a result of condensation, and the different behaviourof bubble diameter in the injector for the two sub-series, versus injection flow.
The effect of the composition is seen even more clearly in series S2, where the differentcomposition of each sub-series leads to a totally different phenomenology in the pool. Thestrong condensation in sub-series 2b leads to the progressively disappearance of bubbleshaving a diameter in excess of 1.8 cm throughout the rise path. In the area surrounding theinjector, however, the bubble behaves similarly, not showing any dependence on flow.
Effect of pool temperature
Comparison of sub-series Sla and S2a allows the effect of evaporation on bubble diameterto be studied. The main observation in this respect is the dampening of the flow effect. Itshould be pointed out that in addition to the increase in size of the smaller bubbles due toevaporation, a smaller percentage of large sized bubbles was obtained. The bubble diametersare close to the critical Levich diameter, i.e. as the volume of the large bubbles increases dueto the effect of evaporation, there might be a stronger tendency to rupture, this contributingto the formation of bubbles of a diameter close to critical.
Effect of submergence
Table 3.17 shows the results of size distribution in the retention tests. It may be observedthat there is no correlation between the diameter of the bubble and submergence.
Apparently, test RCA3, performed with a submergence of 1.25, shows similarthermohydraulic and injection conditions to HS2a3. Nevertheless, they do not show the samebubble diameter at the injection. This discrepancy may be due in part to the uncertaintiesinherent to the measuring system. In addition, it may be pointed out that the differencesbetween the conditions for the two tests iead to a mass inlet flow of approximately 45% lessin H2Sa3.
Shape
In the region studied, injection and the first stages of rupture, there is a great deal ofturbulence, with bubbles continuously rupturing and mutually coalescing; this means thathighly irregular shapes are to be found, far from the dependencies between shape anddiameter known for the bubble regimes.
It should be pointed out that the SPARC correlation relating to the a/b ratio predicts a valueof 1.47 for bubbles of up to 1.5 cm. Furthermore, approximately 80% of the population ofparticles has diameters of less than 1.8 cm, the characteristics a/b being around 1.5.Consequently, the SPARC correlation reproduces the experimental results for bubble shapeto an acceptable degree.
43
Despite the fact that the variation of the a/b ratio in BUSCA coincides with the experimentalrange of variation, the high degree of dependence of the BUSCA correlation on bubblediameter was not observed experimentally.
4.2.2 Theoretical and experimental comparison
The characteristic diameter of the bubble deduced from the experimental data was comparedwith the predictions of the SPARC and BUSCA codes. The correlations analyzed were asfollows: SPARC Quencher correlation, BUSCA Quencher correlation and Ramakrishmancorrelation. The results are illustrated graphically in Figures 4.3 and 4.4.
The Ramakrishman correlation successfully predicts bubble diameter for a flow of 1000 cc/s.On the other hand, it overestimates bubble diameter with increasing flow. In this respect itshould be pointed out that the Ramakrishman correlation does not take into account possiblereleases or rupturing, or the effects of condensation or evaporation.
The Quencher correlation adjusts well to the experimental data for the cold pool withoutsteam injection, with the treatments corresponding to both SPARC and BUSCA. The EPRIexperiments15 on which the Quencher model is based provided Weber number values of 106
under conditions similar to those used for this series of tests, this corroborating the similaritybetween the correlation and experimental results. Furthermore, in the hot pool tests withsteam present, the results of the correlation do not show the damping of the flow effect whichis observed experimentally. Nevertheless, the results at 1000 cc/s agree well with theexperimental data.
The SPARC hypothesis regarding thermal equilibrium at the inlet for calculation of bubblediameter is especially critical in series S2, where strong condensation and evaporation areencountered in S2b and S2a, respectively. There are clear discrepancies between thepredictions made by SPARC and the experimental results for this series.
The treatment given by BUSCA is hardly influenced by variations in the thermohydraulicconditions; nevertheless, the code is not capable of predicting damping of the influence offlow under conditions of condensation/evaporation.
As regards hydrodynamic analysis, it was not possible to establish any relation betweenbubble diameter and submergence in the retention tests. Furthermore, a discrepancy may beappreciated in the SPARC predictions concerning the hypothesis of thermal equilibrium atthe inlet.
Finally, mention may be made of the need for further experimental points, with a view toestablishing conclusive tendencies regarding the flow regimes analyzed in this experimentalprogramme.
44
1.0E+03
1.0E+02
1.0E+01
•i ncxnn
-
D
_ Y
X ,
Q
I I I !
0 0,5 1 1,5 2 2,5
Submergence (m)
a EXP
-+" SPARC
•*- BUSCA
Figure 4.1 DF estimated by SPARC and BUSCA codes compared with theexperimental results of the pool scrubbing tests
45
10
8
6
(cm
)
Q4
2
Q
-
ists
1.0E+04 1.0E+05
We
1.0E+06
Figure 4.2 Bubble diameter at the injection vs. We number
46
HS1a HS1b
2. 6a
2-
1.0E+04 1.0E+05
We
'Exp.
-SPARC Quencher
- BUSCA Quencher
••"Ramakiishman
l.OE+06
S 6
1,06+04 I.OE+05
We
' Exp.
- S P A R C Quencher
- BUSCA Quencher
•"Ramakrishman
l.OE+06
14
12
10
? 8i
! 6
4-
1.0E+04
HS2a
I.0E+05
We
• EXD.
- SPARC Quencher
- BUSCA Quencher
"Ramakrishinan
l.OE+06
HS2b
-..0E+C4 1.0E+05
We
• E x p .
-SPARC Quencher
- BUSCA Quencher
•••Ramakiishman
l.OE+06
Figure 4.3 SPARC and BUSCA prediction of the bubble diameter against theexperimental results (Hydrodynamic tests)
47
Figure 4.4 SPARC and BUSCA prediction of the bubble diameter againstexperimental results (Pool Scrubbing tests)
48
5. CONCLUSIONS
In the preceding sections the major features and results of the pool scrubbing experimentalprogramme carried out by CIEMAT within the Source Term Project of the Third FrameworkProgramme were given. Two types of experiments were performed: retention tests andhydrodynamic tests. The former were aimed at studying pool scrubbing under the jetinjection regime, looking especially at the influence on the results of submergence variations.The latter were devised to analyze how injection flow rate, gas inlet composition and pooltemperature affect hydrodynamics, particularly those phenomena related to primary bubbleformation and the initial decay stages. The conclusions drawn from this work are summarizednext:
The retention test matrix set out was succesfully performed. On one side, most ofboundary conditions met the anticipated targets and no remarkable deviations wererecorded in any of the tests. On the other, experimental plan simplicity (i.e., unsolubleparticles, no steam injection, quite a narrow aerosol distribution) allowed to rationalizeexperimental observations without relevant uncertainties from effects overlapping.
The experimental techniques used and the test protocol followed were proved to besuitable for pool scrubbing experiments. Particularly, the aerosol generation device andthe performance of complementary measurements by different methods worked quitesatisfactorily.
Hydrodynamic tests were succesfully carried out as well. Boundary conditions werecontrolled as anticipated. Despite 2-D image processing constraints, a huge amount ofinformation was obtained and data recorded treated and discussed. Consistently withretention tests goals, most of emphasis was placed on early hydrodynamics in the pool.
Decontamination factors estimated from experimental measurements showed a narrowuncertainty margin in all the experiments. The maximun range supposed no more thana factor of 2.5 between the minimum and maximum bounds.
Experimental decontamination factors followed the expected trends with submergence:the larger submergence the higher the decontamination. A least squared fit ofexperimental data to an exponential curve with submergence revealed the existance oftwo contributions: one exponentially dependent upon submergence and the other fullyindependant of submergence.
From the hydrodynamic point of view, retention tests did not allow to find out acorrelation between submergence and hydrodynamic behaviour during the first stagesof the gas rising through the pool.
SPARC predictions of the overall decontamination factors showed a remarkableagreement with the experimental ones. According to SPARC modelling the DFcontribution independent of submergence would be associated to removal mechanismsat the injection: impaction and acting mechanisms (i.e., settling, centrifugal depositionand diffusion) while globule formation and detachment. Among all these, centrifugaldeposition during primary bubble formation appeared to be the most important.
49
BUSCA largely underestimated experimental decontamination factors. On one side, thelack of removal models specific of small orifices supposed a very low retention at theinjection. On the other, the spherical bubble approach of centrifugal deposition whilerising decreased the efficiency of this process to eliminate particles from the bubble.
SPARC global approach to simulate these scenarios appears to be much more suitablethan BUSCA's. Further, SPARC was capable to predict an additional contribution to thedecontamination factor independent of submergence and centrifugal deposition whilerising showed similar sensitivity to submergence increase to the experimental one.
Hydrodynamic results seemed to suggest that at high injection velocities the interfacialshear stress between the gas and the liquid causes a significant breaking-up of the maingaseous body entering the pool. Therefore, small bubbles population rises as inlet gasflow rate increased. Hence, besides enhancement of inertial mechanisms under jetinjection regime, an additional DF increase should be expected from the transfer surfaceincrease caused by primary bubble break up.
Pool temperature and gas composition did not abruptly affect first stageshydrodynamics, although it was seen that condensation and evaporation processes tendedto deaden the effect of interfacial shear stress. In general, similar qualitatively behaviourof gas in the pool was observed in all the tests between 0 and 10 cm. However, about10 cm those corresponding to pure steam injection showed a remarkable differentbehaviour. Such extreme conditions cause a primary bubble formation that suddenlyturns into a swarm of small bubbles. It is argued that small noncondensible fraction ininlet gas would make these cases much more similar to the rest.
Very irregular shapes were observed during the first hydrodynamic stages. It isnoteworthy, however, that the characteristic a/b ratio for bubbles smaller than 1.8 cm(80%) was around 1.5 (value similar to the maximum estimated by SPARC, 1.47). Onthe other side, the experimental range observed almost coincided with that of BUSCA.Despite these consistencies the dependance of a/b correlations with bubble diametercould not be established in the tests.
Correlations and models for the globule diameter were unable to reproduce theexperimental trends observed. Even though, generally, a good agreement with data wasfound in all the cases for an injection flow of 1000 cc/s, higher flows or differentconditions from which correlations were deduced caused noticeable discrepances. Futherexperimental work is required to conclusively state experimental trends.
Finally, it should be remarked that this experimental programme should be regarded as a stepforward for pool scrubbing: it has extended the preceding database on pool scrubbing andhydrodynamics and it has allowed a partial validation of pool scrubbing codes underrepresentative conditions. However, further experimental work is needed to assess the codeperformance under high jet injection regimes and to check hydrodynamic correlations in poolscrubbing codes. Separate effect tests would be necessary as well to fully validate removalmechanisms, particularly those interval mechanisms which become important at the injectionunder jet injection regime.
50
REFERENCES
1. US NRC, "Severe Accident Risks: An Assessment for Five U.S. Nuclear PowerPlants", NUREG-1150, Vol. 1, (1990).
2. DuttonL.M.C, Jones S.H.,EyinkJ., "PlantAssessments", (907)/PWR/93/REP/001,ST(93)-P35, Issue C, Rev. 1, (1993).
3. Alonso A. et al., "Analysis of Sequence TMLB'-<5 for the ASCO II Nuclear PowerPlant", CT-62/87, (1987).
4. Denning R.S. et al., "Radionuclide Release Calculations for Selected Severe AccidentScenarios", NUREG/CR-4624 (Vol. 1), (1986).
5. Herranz L.E., Escudero M., Peyrés V., Polo J., López-Jiménez J., "Review andAssessment of Pool Scrubbing Models", ITN/TS-13/SP-95, (1995).
6. Marcos M.J., Gómez F.J., Melches I., Martín M., López-Jiménez J., "LACE-ESPAÑA Experimental Programme on the Retention of Aerosols in Water Pools",IT/TS-08/DP-93, (1993).
7. Owczarski P.C., Burk K.W., "SPARC-90: A Code for Calculating Fission ProductCapture in Suppression Pools", NUREG/CR-5765, (1991).
8. Ramsdale S.A., "BUSCA-JUN90 Reference Manual", SRD-R542, (1991).
9. Ramsdale S.A., Bamford J., Fishwick S., Starkie H.C., "Status of the Research andModelling of Water-Pool Scrubbing. Final Report", EUR 14566 EN, (1992).
10. PALAS, "Solid Particle Disperser RGB-1000. Pressure Tight Version. OperatingManual".
11. Rucandio M.I., Escribano A., "Determinación de Níquel Mediante Espectrometríade Plasma en Relación con el Proyecto Término-Fuente, U.E., sobre Retención deAerosoles Insolubles en Lechos Acuosos", DT-PQ-QA-QIAI-9501, (1995).
12. Peyrés V., Marcos M.J., "LACE-ESPAÑA Experimental Programme HydrodynamicStudy", ITN/TS-27/DP-93, (1993).
13. Paul D.D. et al., "Radionuclide Scrubbing in Water Pools -- Gas LiquidHydrodynamics", EPRI NP-4113-SR, (1984).
14. Levich V.G., "Physicochemical Hydrodynamics", Prentice Hall, (1962).
15. Fischer K., Hafner W., "Review of Pool Scrubbing Experiments ad TheoreticalModels", 10th European Pool Scrubbing Meeting, (1993).
51
APPENDIX ISAMPLING NOTATION AND LOCATION
Sample | Type Location Notes
SAMPLES TAKEN DURING TEST TIME
TM1/61TM1/62
TM2/63TM2/64
TM3/65TM4/68
TM3/66TM4/69
Coupons
Filter
Filter
Condensate
Mixing Section
Injection LineMixing Section
Vessel Atmosphere
Vessel Atmosphere Measurement of the Ni collected in theCondensate
SAMPLES TAKEN AFTER TEST PERFORMANCE
GC/11GC/12GC/13GC/14GC/15
GC/16
GC/17
VP/1VP/2VP/3VP/4VP/5
VP/6
VP/7
Volume
Volume
Pool Water
Vessel Drain
Vessel Bottom
Pool Water
Vessel Drain
Vessel Bottom
The samples are taken in the same locations asGC, after shaking the water pool during atleast two hours
SAMPLES FOR THE FINAL MASS BALANCE
B/00
RC
CM/31
LI/41LI/42
GA/51GA/52GA/54
Volume
Volume
Filter
Filter
Filter
Pool
Outside the vessel
Mixing Section
Injection Line
Aerosol Generator
Ni concentration in the pool before the test
Amount of Ni leaked outside the vessel
Lines Cleaning
Lines Cleaning
Sampling from the dispersor pieces washing
52
APPENDIX IITHERMOHYDRAULIC VARIABLES EVOLUTION DURING THE POOL
SCRUBBING TESTS
*CA1-Thermohydraulics Datal
I I I I I I I I M l I I I I I I I I I I I ) I I I I I I I I I I I I I I I
140
- 130
- 120 L
- 110
100
•+ Palm
— P tne
-ir Tune
-HTpool
Figure II. 1 Pressures and Temperatures evolution in the RCA 1 test
3CA2-Thermohydraulics Dataj
3 r-
2. 2
I I I 1 I I I I I I I I I I I 1 I I I .'. I I I I 1 I I I I I I I I I I I I I I I I
>X»0000OOCK.*X>000000(X.
193
140
130
120
110
1C0
•+
—
-é,
-K
Patm
P line
Tune
Tpool
12:07:48 12:16:48 12:25:48 12:34:48Time
Figure II.2 Pressures and Temperatures evolution in tne RCA 2 test
53
I 2
RCA3-Thermohydraulics Data]
n i ni i ni 11 ii i ni m> 1 1 1 1 1 1 : i 1 1 1 1 1 1 1 1 1 1 1 1
O O O O O O O C O C K X >oooooooooyX>O000000O<KXX.
180
1 «
130
120
110
103
-I-Patm
— Pine
-AT une
-H T pool
13:27:36 13:36:30 13:45:33 13:54:33Time
Figure II.3 Pressures and Temperatures evolution in the RCA 3 test
&a.
3CA4-Thermohydraulics Data]
^dWfywd^^
100
150
130
120
110
100
-+ Patm
_ P line
-A T line
. * T pool
15:27:18 15:31:48 15:33:18 15:40:48 15:45:18 15:«:48 15:54:18Time
Figure II.4 Pressures and Temperatures evolution in the RCA 4 test
54
APPENDIX IIIRELATIVE HUMIDITY IN THE VESSEL ATMOSPHERE
During the pool scrubbing tests two sampling lines were available in the vessel atmosphere(TM3 and TM4). A volume sample composed of a mixture of non-condensible gas, steamand particles was taken from the vessel atmosphere. The steam was condensated in the lineand the condensate was removed from the gas stream. The mixture of non-condensible gasand aerosols was conducted to a filter in order to quantify the outlet mass rate of particles.The relative humidity can be estimated by the condensate volume in each sampling line.
Under the pressure conditions in the atmosphere during the tests, it can be assumed that eventhe steam near saturation behaves approximately like an ideal gas. Therefore, the steamvolume can be extracted by the state equation of the ideal gases,
V = m<:°n<lRTP°°l (III.l)
where, mcond is the condensate mass collected in the sampling; M, is the molecular weightof water; R, is the gas constant; Tpool, is the pool temperature; and Patm, is the vesselpressure.
The steam fraction is estimated by,
X = 2 i = TM3,TM4 (III.2)S V hS
where q¡ and t¡ denote the mean flowrate and the sampling time for the sampling line i,respectively.
Finally, the relative humidity is calculated by,
p Y(ffl.3)
sat
where Psat is the saturation pressure at the vessel temperature.
Table III. 1 summarizes the results of the relative humidity estimations for the pool scrubbingtests. These results show that the vessel atmosphere was steam rich and under conditionsclose to saturation.
55
Table III.l Results of the estimation of the Relative Humidity
mcond (g)
Vf(l)
x5R.H. (%)
RCA 1
TM3/66
875
670.9
0.69
97
TM4/69
1560
908.6
0.69
97
RCA 2
TM3/66
1100
779.9
0.74
101.2
TM4/69
. 1430
1013.9
0.72
98.5
RCA 3
TM3/66
1160
867.3
0.805
106.8
TM4/69
900
672.9
0.704
93.4
RCA 4
TM3/66
1170
855.5
0.76
98
TM4/69
1560
1140.7
0.77
99
56
APPENDIX IVNUMBER AND VOLUME DISTRIBUTIONS IN THE POOL SCRUBBING TESTS
RCA 1 (a) RCA 1 (b)
RCA 2 (a) RCA 2 (b)
RCA 3 (a) RCA 3 (b)
(a) Number distribution, (b) Volume distribution
57
APPENDIX VSCANING ELECTRON MICROSCOPY. PARTICLES DEPOSITED ON COUPONS
RCA 1 AtmosphereGeneral View
58
RCA 1 AtmosphereDetailed View
59
RCA 3 Injection LineGeneral View
60
RCA 3 Injection LineDetailed View
61
APENDK VIRESULTS OF THE CHEMICAL ANALYSIS OF THE CONDENSATE
In the atmosphere sampling the mixture of non-condensible gas, steam and particles isconducted to a filter. The steam condensates before the mixture reach the filter and thecondensate is removed from the gas stream. During the condensing process part of Nickelcan be carried with the condensate. The amount of this should be added in the outlet massrate determination. However, as it can be seen in Table V.I its contribution is negligible.
Table VI. 1 Mass of Nickel collected with the condensate in the atmosphere sampling
RCA 1 0*g)
TM3/66
19.3
TM4/69
9.75
RCA 2 fog)
TM3/66
16.3
TM4/69
4.17
RCA 3 (/xg)
TM3/66
9.26
TM4/69
6.24
RCA 4 0¿g)
TM3/66
2
TM4/69
13.8
62
APPENDIX VIIIMAGES RECORDED OF THE GAS STRUCTURE CLOSE TO THE INJECTOR
HSlal Frontal View
HSla2 Lateral View
63
HSla2 Frontal View
HSla3 Lateral View
64
HSla3 Frontal View
HSlbl Lateral View
65
HSlbl Frontal View
HSlb2 Lateral View
66
HSlb2 Frontal View
HS2al Lateral View
67
HS2al Frontal View
HS2a2 Lateral View
68
HS2a2 Frontal View
HS2a3 Lateral View
69
HS2a3 Frontal View
HS2bl Lateral View
70
HS2bl Frontal View
HS2b2 Lateral View
71
HS2b2 Frontal View
72
APPENDIX VIIIBUBBLE DIAMETER VERSUS DISTANCE FROM INJECTOR
73
20
15
10
5
C
r $ > -"i1" 4- * +
10
|HS2ai|
+
• t "
20
y (cm)
4-
4-
+-
4- +• t -
+ •• 4.+-
X 40
74
75
25
20
15
10
5
0
C
-
-
-
10
|HS1b2
+
+ r
20y (cm)
1
+*•
y- lift
-t-
"0 50
76
6
4
2
|HS2b2 [
- +• + + +• +
+ + + ++•
10 20 30 40 SOy (cm)
77
15
Ü 10O
5
•f
0 10
RCA2
20
y (cm)
-t-
+
30 «0
78
20
_. ' 5
O ,o
5•4
)
/ +
10
t-
•í-
|RCA3
+
+ + ++
f tA tf£0 30 40
y (an)
79
APPENDIX IXBUBBLE DIAMETER HISTOGRAMS FOR THE HYDRODYNAMIC TESTS
HSlai
eo«0
«
20Tlrtvi-t i t _i_ i i • •
D(on|
1 HSflftt 1
HS1a1Eqiivtlonl QamoHr
eo
eo
«0
20T U . i i i t i i i t < i i P i i •
D{cnt)
I H*gh(2 IMfcrWVtowl
eoeo40
20
I Holgn
fronMJ
HS1a1Eqiiyitortf Dvnotor
D(cm)
to* |
HS1a1
SO
00
40
20
mj_ i i i i (
D(on)
eo
eo
40
20
r~H5gfil1
HS102 1EqiivalontOlameW |
7V«rf. t i i i • • i i i i i i i
D(on)
aa
eo
40
20
7U
1 Height 2 1
HS1O2
80
00
40
20
|rram Vlgw|
HS1a2B)iivilertn«i»w
D(on)
HS1Q3
W
40
20T^ 1 1 1 1 i j , , , ,
D(on)
I Height í IpronMVtaw¡
HS1a3
00
00
40
20
n
81
00
40
20
-
-
HS2a1
(]_,,,„. _Dton)
]
HS2a1Equivalent Oiamrtor
eo
00
40
20
-
-
-Ilr», 1 .1.,*. 1 t
D(cm)
HSZai
eo
00
40 -
[ ^
D<an)
I tMtfit2 1
DO
60
40
20
1 Higrat I
H S 2 Q 2
, , t r , ,
D(on}
HS2a2EqiMfent Dlametor
60
00
20
^ t t i i i i i i i i
D(cni)
1 HeOjriZ 1
82
eo
20
HS2a2Eqiivalwt Din/new
rin
1 twgnii I
HS183
eo
eo
«0
20• T U » . • • • > • i i i i
O(at!)
\HeKft2 1
60
00
20
HS2a2EqUvBfwHCXameWr
D[an)
rH55ti—i
00
eo
« i
20
1
HS2a2
TLi. t t i 1 i 1 1 1 I 1 1 t 1 1 t
• D(OT)
eo
40
20
H52a2
D(cm)
HS2a2
eo
60
40
20
TLt i i i i i i i i t i i i i i i
Í2-1
Had
83
eoeo
40
20
ru1 Hslgnii 1literal V&m 1
HS2a3EquhllgnlDlinoU
D(an)
HS2a3EqtivriflntaimrtBr
eoeo«o20
0 "n i t i i t i i i t t i i i t i i
D(cm)
1 H«V<2 1
00
eo
20
HS2a3Eqdvtlirt aajueter
D(cm)1 Holghli 1frontil View |
HS2a3EqiinlanDin»»
Iftd
eo
eo
20
TU i i t i i i t i i i
D(em)
HS1b1Eqiivaioit DlBmow
Oían)
84
u
40
to
1 twofiatá
L
«I 1Vtow|
HS1blEqiMfflrtDiimffler
O(on)
RO -
00
40
20
o .- i
L.PronMVWw|
HS1b1E<jJv»«Dli™w
j . i i t i i i i i t i i i i
D(an)
00
40
20
HSlb2EqiMtert Odmrter
hD(on)
1 H«(gnt1 I>jiBc«iyi««|
40
20
HS1b2EoJvilvitDlsiniU
• n
•H• n
D(cm)
[ Height 1 I
85
to
00
40
20
I H*g«1|FH»MV1««
HS1b2
D(OT)
100
M
00
40
0 1
1 H*tft2| F W M V W «
1HS1b2
P(on)
HS2O1BfJyiktlDlin»»
eo00
40
D(OT)
¡T"l
10000eo40200
I Haitfi12ftt»
HS2D1EqKnleitnaniekr
0(011)
100
00
4020
-
HS2H1
D(on)
I H«g«1 I
120100SI004020
_1
HS2b1EqUnknlDlarnfer
0(on)«TI
86
HS2Ü2
100
eo
40
t. i t t t i t • i i i i i i i i i
D(an>
1 H¿0ÍM 1
40
20
[~H5Q
. r
HS2Ü2
D(ait)
M
60
40
20
Fmntd
HS2Ü2
D(an)
HS2D2
100
6000
4020
ni t > i i t i t i i i i i i t >
D(an)
87
APPENDIX Xa/b RATIO HISTOGRAMS FOR THE HYDRODYNAMIC TESTS
29
20
IS
10iiHSU1
*
•ft
HS1«1
TO
16
10
6
" n
•ffinL.Ulh*.
•ft1 H*g«2 I
20
IS
10
8
0
n<5¡
HS1a2
• n•fi ru. 1 ri'IIÍ1 In
•ft
**1 1
HS1a2
252015105
ns;
n• ,-J II |nn
- PI 11 n•
| | l l | | | | | l l l l | | | | | > r ^ • 1 • • • • • •
i»1 IV)8W |
25
20
15
10
5
0
•f!•
ÍHi¡Vn
n| H*tf«2 IfronnlM««|
HS1B2•/t
nrnmnifTn»,,*-!.^-1
«111
20
15
10
5
'fl-I
fl
RT-]w«|
HS1S3
Infin
25
20
15
10
5
0
rs i
HS1S3«b
r i U L
rVv,J.lllllilnmm™^,.^,
•ft
Vl>»|
HS103
20
15
10
5 " flnnn11H i i t i pUiiitiiiUu.^.j. i i iKb
I ÍWKK1 Ifn«MVU«|
89
HS2a1
•ft
30
20
10
• n• UnJ.l.l.I.ln—
•Ib
I Helglti I
HS2S1
20
15
10
6
•
ÍTi. nj HI I• III i ílrin-iIJJI.IIII.I.rimnm^,^^,
•ft
Vlwr |
90
HS2H2
20
15
10
9
• n i l• n•m• Illlll.
PII njirL-,
iiillilrii(rnm^.mj- t i i•A
¡Frond y i « |
HS2a2•ft
20
16
10
s
-
LrL
1.
n
I,
In
]FrermVtow|
20
15
10
5
Oh[LHn
I Malght2 ~1
HS2s3
HS2O3•/o
20
16
10
6
•
-Jl L'"ID Inn. 11 11 I
a/t>
I twtiti IfrcnMVW» |
20
15
10
5
HS2O3Wb
finHnI I,In
llllltllllllilllnimni-^rtim I t t
•A
91
HS1b1•ft
20
15
10
6
y*
• n' n• n n
flUnrv,«fe
20
IS
10
s
I H«chÍ2~~|
HS261
HHnn.(t.11. H.ll.l, m . mml/b
92
15
10
5 "íln ¡TILDIIIIOIIII
I Hot0*1 I
HS2D2i *
PrílmH^rn i
30
20
10
1 >M012 I
HS2U2Vb
* *
93
APPENDIX XICIRCULARITY ANALYSIS FOR THE HYDRODINAMIC TESTS
The circularity is a parameter for expressing the bubble shape irregularity. It can be definedas the ratio of the squared perimeter to the object area. Due to the two-dimensional treatmentof the digital image processing technique, this parameter is estimated from the bubbleprojection in the focal plane of the camera. Therefore, the circularity of a perfectly sphericalbubble is determined by the perimeter and the area of the circunference which is projectedin the focal plane,
Cr - (XI.1)
Table XI. 1 shows the mean values of the circularity for the hydrodynamic tests. In most ofcases the circularity is practically two times the theoretical value corresponding to a sphere,which points to a bubble shape far from the spherical one.
Table XI. 1 Bubble circularity for the hydrodynamic tests
Height
1
2
Window
Lateral
Frontal
Lateral
Frontal
HSlal
25.14
21.96
24.89
24.59
HSla2
24.62
22.1C
24.50
22.87
HSla3
24.54
22.13
23.67
23.51
HS2al
25.31
23.23
24.49
23.13
HS2a2
25.55
23.59
23.83
21.95
HS2a3
24.99
24.84
23.90
21.88
HSlbl
31.73
25.96
23.77
41.20
HSlb2
29.99
22.33
24.62
38.48
APPENDIXSPARC AND BUSCA INPUT FILES FOR THE POST-TEST ANALYSES
SPARC90 RCAl/Ni - - 941990,2,200.,l.8.90,8.904.51,4.51« # f ** • f
58.71,58.710.0,0.0,0.159E-3,0.159E-30.0,0.0,0. ,0. ,0.378E-4,0.447E-4,0.529E-4,0.625E-4,0.739E~4,0.874E-4,1.03E-4,1.22E-4,1.44E-4,1.7lE-4,2.02E-4,2.39E-4,2.82E-4,3.34E-4,3.94E-4,4.66E-4,5.5lE-4,6.52E-4,7.7lE-4,9.1lE-4,6.54E-2,6.54E-20.311,0.3111.15,1.15,3.34,3.34,7.55,7.55,13.3,13.3,18.4,18.4,19.7,19.716.6,16.610.9,10.9 .5.56,5.56,
0.693,0.6930.169,0.1693.20E-2,3.20E-24.75E-3,4.75E-35.50E-4,5.50E-40.497E-4,0.497E-40.35lE-5,0.35lE-50.193E-6,0.193E-60.,0.l.e-6,l.e-6,0. ,0.,0.,0.,7.791,7.7910. ,0.,0.,0. ,0.,0.,121.9,121.92.89,2.89113.9,113.92.33,2.331.0,1.02,1.26,1,1,1.,1,0.8862,1,1,25.,0.,0.,0,00.,l.20
95
SPARC9O RCA2/NÍ1990,2,20O.,.8.90,8.904.51,4.512 . , 2 . ,58.71,58.0.0,0.0,0.250E-3,0.0,0.0,0. ,0. ,0.478E-4,0.935E-4,1•99E—4,24.14E-2,40.2986,0.0.53,0.530.91,0.911.59,1.593.07,3.074.06,4.063.3,3.3,2.4,2.4,8.9,8.9,8.5,8.59.2,9.2,3.4,3.4,9.6,9.615.4,15.41.7,1.76.3,6.312.3,12.33.6,3.64.9,4.90. ,0.
71
0.250E-3
0.519E-4,0.565E-4,0.614E-4,0.668E-4,0.727E-4,0.790E-4,0.860E-4,1.02E-4,1.11E-4,1.20E-4,1.31E-4,1.42E-4,1.55E-4,1.68E-4,1.83E-4,•17E—4,2.35E—4,.14E-22986,
O.,O.f7.440,7.4400. ,0.,
,O.,O122.2.95117.2.541.0,2,1.0. ,120
4,122.4,2.955,117.5,2.541.070,1,1,1.,1,0.8862,1,1,50., O.,O., 0,0
96SPARC90 RCA3/NÍ1990,2,20O. , l .8.90,8.904.51,4.512 . , 2 . ,58.71,58.710.0 ,0 .0 ,0.79lE~3,0.79lE-30.0 ,0 .0 ,0. , 0 . ,
0.34lE-4,0.392E-4,0.452E-4,0.52lE-4,0.600E-4,0.69lE-4,0.797E-4,0.918E-4,
3 ./BE-4,4 .3DE-4,5.02E—4,1.79E-3,1.79E-34.29E-3,4.29E-35.99E-2,5.99E-20.514,0.5141.74,1.745.49,5.499.69,9.6917.2,17.27.3,7.312.5,12.58.5,8.510.6,10.66.5,6.55.6,5.62.1,2.12.7,2.71.1,1.13.3,3.30.0,0.05.1,5.10. ,0 .1 . e -6 ,1 .é -6 ,0. , 0 . ,0. ,0 . ,7.260,7.2600. , 0 . ,0. ,0 . ,0. ,0 . ,126.3,126.32.88,2.88116.8,116.82.41,2.411.0,1.02 , 3 . 0 2 , l , l , l . , l , 0 . 8 8 6 2 , l / l , 1 2 5 . , 0 . , 0 . / 0 , 00 . , l .20
97
SPARC90 RCA4/NÍ1990,2,200. ,1.8.90,8.904.51,4.51z. i z • ,58.71,58.710.0,0.0,0.545E-3,0.545E-30.0,0.0,0. ,0. ,0.478E-4,0.519E-4,0.565E-4,0.614E-4,0.668E-4,0.727E-4,0.790E-4,0.860E-4,0.935E-4,1.02E-4,l.llE-4,1.20E-4,1.3lE-4,1.42E-4,1.55E-4,1.68E-4,1.83E-4,1.99E-4,2.17E-4,2.35E-4,4.14E-2,4.14E-20.2986,0.2986,0.53,0.53,0.91,0.91,1.59,1.59,3.07,3.07,4.06,4.06,3.3,3.3,2.4,2.4,8.9,8.9,8.5,8.59.2,9.2,3.4,3.4,9.6,9.615.4,15.4,1.7,1.76.3,6.312.3,12.33.6,3.64.9,4.90. ,0.l.e-6,l.e-6,0.,0. ,0. ,0. ,7.346,7.3460.,0. ,0. ,0. ,0. ,0. ,141.1,141.12.89,2.89118.5,118.52.47,2.471.0,1.02, 4. 42,1,1,1.,1,0.8862,1,1,250.,0.,0.,0,00.,l.20
98
C DESCRIPTION : BUSCA-AUG92C TEST : RCAl/post-test
CC TP (K) DEPTH (M) PO (PA)
387.1 0.25 2.30E5CC INITIAL BUBBLE SIZE, BUBBLE VELOCITY, BUBBLE SHAPE, BUBBLE BREAK UP, IN. DEP.
261 202 20 20 01C DIA, H NHOLE RATE, CC/S TBUB, K BVOL, M3
0.01 1 3121.3E-6 395.1 0.0C 1 < 1GASES < 11
1C GAS NAMES
N2C Xl(I) I - 1,...NGASES THE DIFFERENCE 1.- SUM OF Xl(I) IS THE STEAM FRACTIONC OR H2O MAY BE INCLUDED AS ONE OF THE GAS NAMES1.0
CC NUMBER OF AEROSOL COMPONENTS, NCOMC
1C READ IN AEROSOL COMPONENT NAMES AND DISTRIBUTION PARAMETERS, K - 1,...NCOMCC AERNAM(K) AMASS(K) R50(K) SIGG(K) MMIN(K) MMAX(K) NCOL(K)C (KG) (M) (KG) (KG)CNI 1.0627E-8 5.90E-7 1.4 2.5229E-16 3.5226e-12 20
CC READ IN PHYSICAL PROPERTIES OF AEROSOL COMPONENTS, K « 1,...NCOHCC RHOCOM(K) KAPPAP(K) BSF(K) ISOL(K) VANT(K) MWSOL(K)C KG/M3 J/M/S/K IONS/ KG/MOLC MOLECULE
8900. 82.7 1. 0 0.001 0.0587CC TIME DT PAIRS <10C.001 l.e-4 .01 l.e-3 .1 l.e-2 1.0 l.e-1 10. 2.e-l
99
cC DESCRIPTION : BUSCA-AUG92C TEST : RCA2/post-testCC TP (K) DEPTH (M) PO (PA)
390.7 0.50 2.51E5CC INITIAL BUBBLE SIZE, BUBBLE VELOCITY, BUBBLE SHAPE, BUBBLE BREAK UP, IN. DEP.
261 202 20 20 01C DIA, M NHOLE RATE, CC/S TBUB, K BVOL, M3
0.01 1 2923.88E-6 395.6 0.0C 1 < 1GASES < 11
1C GAS NAMES
N2C Xl(D I = 1,...NGASES THE DIFFERENCE 1.- SUM OF Xl(l) IS THE STEAM FRACTIONC OR H2O MAY BE INCLUDED AS ONE OF THE GAS NAMES1.0
CC NUMBER OF AEROSOL COMPONENTS, NCOMC
1C READ IN AEROSOL COMPONENT NAMES AND DISTRIBUTION PARAMETERS, K • 1,...NCOMCC AERNAM(K) AMASS(K) R50(K) SIGG(K) MMIN(K) MMAX(K) NCOL(K)C (KG) (M) (KG) (KG)CNI 1.6792E-8 6.50E-7 1.44 5.0767E-16 6.0856e-14 20
CC READ IN PHYSICAL PROPERTIES OF AEROSOL COMPONENTS, K ~ 1,...NCOMCC RHOCOM(K) KAPPAP(K) BSF(K) ISOL(K) VANT(K) MWSOL(K)C KG/M3 J/M/S/K IONS/ KG/MOLC MOLECULE
8900. 82.7 1. 0 0.001 0.0587CC TIME DT PAIRS <10C.001 l.e-4 .01 l.e-3 .1 l.e-2 1.0 l.e-1 10. 2.e-l
100
cC DESCRIPTION : BUSCA-AUG92C TEST : RCA3/post-testCC TP (K) DEPTH (M) PO (PA)
390.0 1.25 2.38E5CC INITIAL BUBBLE SIZE, BUBBLE VELOCITY/ BUBBLE SHAPE, BUBBLE BREAK UP, IN. DEP
261 202 20 20 01C DIA, M NHOLE RATE, CC/S TBUB, K BVOL, M3
0.01 1 2951.33E-6 399.5 0.0C 1 < 1GASES < 11
1C GAS NAMES
N2C Xl(I) I = 1,...NGASES THE DIFFERENCE 1.- SUM OF X1(I) IS THE STEAM FRACTIO1C OR H2O MAY BE INCLUDED AS ONE OF THE GAS NAMES1.0
CC NUMBER OF AEROSOL COMPONENTS, NCOMC
1C READ IN AEROSOL COMPONENT NAMES AND DISTRIBUTION PARAMETERS, K - 1,...NCOMCC AERNAM(K) AMASS(K) R50(K) SIGG(K) MMIN(K) MMAX(K) NCOL(K)C (KG) (M) (KG) (KG)CNI 5.0310E-8 5.55E-7 1.38 1.8397E-16 5.9016e-13 20
CC READ IN PHYSICAL PROPERTIES OF AEROSOL COMPONENTS, K - 1,.»»NCOMCC RHOCOM(K) KAPPAP(K) BSF(K) ISOL(K) VANT(K) MWSOL(K)C KG/M3 J/H/S/K IONS/ KG/MOLC MOLECULE
8900. 82.7 1. 0 0.001 0.0587CC TIME DT PAIRS <10C.001 l.e-4 .01 l.e-3 .1 l.e-2 1.0 l.e-1 10. 2.e-l
101
n
C DESCRIPTION : BUSCA-AUG92C TEST : RCA4/post-test con distribucisn de RCA2
CC TP (K) DEPTH (M) P0 (PA)
391.7 2.50 2.44E5CC INITIAL BUBBLE SIZE, BUBBLE VELOCITY, BUBBLE SHAPE, BUBBLE BREAK UP, IN. DEP.
261 202 20 20 01C DIA, M NHOLE RATE, CC/S TBUB, K BVOL, M3
0.01 1 3086.20E-6 414.3 0.0C 1 < 1GASES < 11
1C GAS NAMES
N2C Xl(I) I - 1,...NGASES THE DIFFERENCE 1.- SUM OF Xl(I) IS THE STEAM FRACTIONC OR H2O MAY BE INCLUDED AS ONE OF THE GAS NAMES1.0
CC NUMBER OF AEROSOL COMPONENTS, NCOMC
1C READ IN AEROSOL COMPONENT NAMES AND DISTRIBUTION PARAMETERS, K - 1,...NCOMCC AERNAM(K) AMASS(K) R50(K) SIGG(K) MMIN(K) MMAX(K) NCOL(K)C (KG) (H) (KG) (KG)CNI 1.6792E-8 6.50E-7 1.44 5.0767E-16 6.0856e-14 20
CC READ IN PHYSICAL PROPERTIES OF AEROSOL COMPONENTS, K - 1,...NCOHCC RHOCOM(K) KAPPAP(K) BSF(K) ISOL(K) VANT(K) MWSOL(K)C KG/M3 J/M/S/K IONS/ KG/MOLC MOLECULE
8900. 82.7 1. 0 0.001 0.0587CC TIME DT PAIRS <10C.001 l.e-4 .01 l.e-3 .1 l.e-2 1.0 l.e-1 10. 2.e-l
102
APPENDIX XIIIHYDRODYNAMIC RESULTS OF SPARC AND BUSCA FOR THE POOL
SCRUBBING POST-TEST ANALYSIS
S = 0.25 m
O 10 20
Distance from injector (cm)
S = 1.25 m
Otb.nu
100
*DOlaWi
o™"™"1 "» —Jo0 10 20 30 40 50 60 70 60 90 100110120
Distance from injector (cm)
S = 0.5 m
10 20 30 40
Distance (rom injector (cm)
S = 2.5 m
50
Is
5 Jg£k
28wml
\
100
80
5Ü
40
20
"0 25 50 75 100 125 150 175 200 225 250
Distance Irom injector (cm)
DifcM»
• iGkbJt
«D BoUtt
•xcttui
« D. BwUli
* D GlDtoU
103
61Mif0 1
2 |
0 "0
6
(cm
)
*J
Ola
m
2
00
S = 0.25 m
I1BSBBj $
M-—~~10 20
Distance from injector (cm)
S = 1.25 m
/
_ ~ •
10 20 30 40 50 60 70 80 90 100110121
Distance liom injecto (era)
B0
60
*
40
20
OlSub»
0
10Í
80
60
*
40
20
0
(cm
)
I0 " "0
10
8
I«IS
§4
2
00
S = 0.5 m
11
i-10 20 30 40 51
IUU
80
60
*
40
20
O%eibU<
0D
Distance from injector (cm)
S = 2.5 m
100
80
60
40
D»a«*• >CUMk
20
1 1025 50 75 100 125 150 175 200 225 250
Distance from injector (cm)
104
APPENDIX XIVINLET AND OUTLET MASS DISTRIBUTION FOR THE POOL SCRUBBING
TESTS (SPARC AND BUSCA POST-TEST ANALYSIS)
SPARCS = 0.25 m
2.0E+01
1.5E+01
0.0E+00*030,378
— % Inlet
•*- % Outlet
3,78
2.5E+01
O.OE+00
SPARCS = 0.25 m
0,378
d (pm)
I
T "
— % Inlet
-'- % Outlet
3,78
105
BUSCAS s 0.25 m
2.5E+01
2.0E+01
1.5E+01¡n01a
1,OE+01
5.0E+00
0,0E+00:
I
0,378
— % Inlet
-*- % Outlet
3,78
1.6E+01
1.4E+01
1.2E+01
1.0E+01
% 8.0E+00to
6.0E+00
4.0E+00
•2,0E+00
SPARCS = 0.5 m
0.0E+00
— % Inlet
-*- % Outlet
0,478 4,78
d (pm)
106
BUSCAS = 0.5 m
— % Inlet
•*- % Outlet
O.OE+000,478 4,78
d (pm)
SPARCS = 1.25 m
2.0E+01
0.0E+00;
1.5E+01 -
83 1,OE+01 -CtJ
5.0E+00 í f —
0,341
— % Inlet
-*- % Outlet
d (f/m)
107
2.0E+01
1.5E+01
1,OE+01
5.0E+00
0.0E+000,341
BUSCAS = 1.25 m
/
7"
í- • & — -
1
\ ¡\VA\\\
V
- —- •
\A
V
-- - •
\i !
- — % Inlet
-*- % Outlet
3,41
SPARCS = 2.5 m
1.6E+01
1.4E+01
1.2E+01
1.0E+01a?S 8.0E+00CO
6.0E+00
4.0E+00
2.0E+00
0.0E+00:0,478
11
111¡11rit t ii \\
*. L it/ ^
•y r
I 1
7̂ iI 1[MI-
iii
i 11L.LJ1
f l 1i L. Jj—1
•Lt ! ^I ¡
ii
iI L
— % Inlet
-*- % Outlet
4,78
d (pm)
BUSCAS = 2.5 m
108
1.0E+01
8.0E+00
6.0E+00
4.0E+00
2.0E+00
0.0E+000,478 4,78
~ % Inlet
-*-% Outlet
109
APPENDIX XVRETENTION MECHANISMS CONTRIBUTION IN THE POST-TEST ANALYSTS
SPARC, Sub-0.25mDF-tl02
SPARC, Sub=O.S0mDF-21.41
SPARC, Sub- 1.25mDF-62.52
SPARC, Sub»2.SmDF-677.4
BUSCA, 5ub=0.25mOF-1.28
BUSCA, Sub=O.5rrDF-1.42
%DlF 0,56%GRAV 5,33
BUSCA, Sub=1.2SmDF-1.39
BUSCA, Sub=2.5mDF=2.61
%DIF2,23
