Design Activity of High Flux Test Module of IFMIF in Kyushu Univ.
A. Shimizu@Kyushu Univ.
Deuteron beams
Li flow
Test piece
Heat exchanger
Injector RFQ DTL
PIE facilities
Accelerator facilities
Magnet pump
Design & Integration Engineering design over the whole system of IFMIF
Provide 40MeV, 250mA deuteron beam by 2 accelerator modules.
Irradiate D+ beams on Li target with beam footprint of 20cm(W) x 5cm(H)
Remove up to 10MW beam power by Lithium flow of 20m/s
Supply 500cm3 irradiation volume with 1014n/s ・ cm2 (20dpa per year) neutron flux
Irradiation temperature: 250~ 1000℃
Target facilities Test facilities
Neutron irradiation
Test Cell
Qualification of candidate materials up to about full lifetime of anticipated use in a fusion DEMO reactor.
Advanced material development for commercial reactors. Calibration and validation of data generated from fission reactors and particle accelerators.
MissionMission
Outline of IFMIF
Test Cell Configuration
Lithium targetD +
shielding plug
for medium flux region
for high flux regionfor low & very low flux regions
2.5m
Li quench tank
Required performance for temperature control in He-cooled high flux test module
Irradiation characteristics has strong dependency on temperature.
Specimens must be kept at a constant temperature (250-1000℃) with acceptable error of less than 1%.
Space for cooling channels, heaters, insulations etc. should be minimized.
Small irradiation volume of about 0.5 l must be assigned to specimens as large as possible.
The temperature control for specimens in HFTM is one of the most challenging issue in IFMIF project!!
Test PiecesCapsuleGap
Rig
T.C.
Original design of test module
Large uncertainty of temperature measurement
• Large uncertainty of temperature measurement is inevitable due to gap conditions and location of thermo-couple, if the T.C. is buried in capsule.
0 0.2 0.4 0.6 0.8 1
40
60
80
100
120
Re=124000, P=0.9MPa
parameter f
tem
pera
ture
dif
fere
nce
T
[K]
0.25mm 0.75mm 1.25mm 1.75mm
location of T.C. in Capcule
Estimation of uncertainty oftemperature measurement
Effective gap conductance gap varies as function of parameter f.
f means the volume fraction of occupation of gas (He) in the gap.
f =1 when the gap width is retained, but f can be change, for example, due to swelling.
HePTgap
ff
..
11
Buried location of T.C. from the capsule inner wall
T.C. can not measure (estimate) the temperature of T.P. due to non-uniformity of temperature in T.P. and inherent uncertainty of measurement procedure.
Change in design & derivation of HFTM
• Ultimate purpose of HFTMTemperature control for irradiated specimens for lo
ng time periods in temperature window of 250-1000 deg. C with adequate volume for specimens.
• Uncertainty of gap condition between specimens and capsules makes identification of specimen temperature very difficult.– Temperature difference of 100 K or so between actual an
d guessed temperature in specimens arises easily.
NaK-bonding (EU) & He-bonding (JP) concept
Features of both design
• NaK-bonding concept (EU)– Problem originated from gap condition is overcome due to h
igh thermal conductivity of NaK filling the gap. Other problems arise
– Nak is available only under 650 deg. C.– How to fill NaK into the gap of 0.1 mm or so?– How to treat activated NaK after irradiation test?
• He-bonding concept (JP)– Whole temperature window up to 1000 deg. C. is feasible.– Cast-type capsule reduces the problem of gap.– Specimen temperature is guessed correctly by measuring d
ummy specimen temperature installed in the capsule.
EU design
Container with three compartments each with three rigs;Helium channels with a width of 1mm between the rigs
He-cooled HFTM with Chocolate-Plate-Shape Rig and Triple-Heater-Capsule
JP design -HFTM with horizontally-elongated capsules-
• Capsules are elongated in the spanwise direction to fit the beam footprint.
• Elongated capsule promote uniform temperature profile in themselves.
• Specimens are housed in cast-type capsules.
• Capsules are made of the same material as specimens to make nuclear heating in the capsules the same as specimens
• Temperature of a capsule is measured to identify that of specimens housed in it.
neutron flux
coolant flow (He)
200
50
50
[mm]
specimensT.C. <capsule inside>
Schematic of HFTM
JP design EU design
HeHe
rig
capsules
upper reflector
lateral reflector
bottom reflector
straightener
upper reflector
lateral reflector
bottom reflector
Comparison of both designitem JP EU Judge
temp. window 250 ~ 1100℃ 250 ~ 650℃ JP> EU
accuracy of temp. measurement of
specimens
He-bonding, measurement of temp. of dummy pieces
NaK-bonding, T.Cs inserted directly in capsule JP=EU
temp. profiledivided into 3 in vertical direction
one in vertical direction (heater capacity is challenge.)
JP> EU
one in horizontal direction
divided into 4 in horizontal direction
JP=EU
divided into 3 in beam direction
divided into 3 in beam direction
JP= EU
in case of 1-beam offheater, coolant flow rate control
heater (capacity is challenge)
JP? EU
number of specimens
to be determined plenty JP? EU
pressure boundary only container container and rig wall JP≧EU
remote assembly mainly threadably mounted, partly welded
welded and tightly-sealed for NaK JP≫EU
remote inspection dimensions and welded part
dimensions, welded part, NaK filling status (the biggest challenge )
JP≫EU
Past activities @ Kyushu Univ.• Experimental tests
– Temperature control experiment for one capsule using N2 gas loop– Pressure test for a module vessel as pressure boundary– Development of porous-type manifold for flow distribution into cooling
channels• Numerical simulations
– Thermal-hydraulic calculation using k- turbulent model– Structural analysis for module vessel– Thermal-hydraulic calculation for expanded vessel using LES– Neutronics analysis in HFTM using PHITS
• Other– Fabrication of full scale dummy in order to show the fabricability for the
design of Kyushu univ. – Design of heater for temperature control
Main achievement (1)
• Temperature control in case of non-uniform nuclear heat generation was examined both experimentally and numerically.
max. 30W/cm3
center
end
neutron flux
assumed spatial distribution of nuclear heating
Test section
295.0
16.5
50.0
183.0
203.0
25.0
25.0
34.6
12.6
1.0
131.5
[mm]
[Front View] [Side View]coolant (N2)
cooling channelcapsule
insulation
Al
Photographs of test section
Test section Capsule and its supporters
1000mm
Mica heater for non-uniform heating
Ceramic heater fortemperature control
specimen for temperature measurement (Copper plate)
Mica heater for non-uniform heating
Non-heating plate
Inside view of heater for simulation of non-uniform nuclear heating
159.8
79.825.015.0
14(W/cm2) 17(W/cm2)19(W/cm2)
14.8t:1.4
0 50 100 150160
170
180
190
200
210
Thermocouple position[mm]
tem
para
ture
[℃]
Ceramic heater for temperature control
Ceramic heater for temperature control(thermal conductivity: 18[W/mK])
Non-uniform Heating heater
Non-heating plate
Photographic view of ceramic heater
Heater Heater
70 15
2.516.5
1.5
t:1.3
Custom-made heaters could not be prepared and ready-made ones were used in the present run.
location of ceramic heaters
heating region = 50mm ( 23 W/cm2)
Numerical simulation
adiabatic boundarysymmetric boundary
<Numerical conditions>Re = 939.3 (Um= 43.7 m/s) 1691 (78.9 m/s) 1880 (87.6 m/s ) 5636 ( 263 m/s)Tin = 50 deg.C, Pout = 0.3MPa
Conjugate solid/fluid heat transfer with turbulent flow
low Reynolds number k- model for flow field (Abe et al., 1993) model for temperature field (Abe et al., 1995)
2TT t
Additional heater is introduced on the end of capsule.
(SUS316)
(He)
Temperature profile in capsule -simulation-
• Temperature distributions are quite improved by heaters for temperature control.
• The use of the end heater is effective.
heater heating
Main achievement (2)
• Development of numerical codes for thermal-hydraulic, structural and neutronics analysis.– Thermal-hydraulic code using both k- model & LES– Structural analysis with thermal effect considering fini
te deformation– Neutronics analysis using PHITS
ex.) Structural analysis for HFTM vessel
• The center region of a wide wall is deflected largely due to pressure difference.
• The largest displacement appears at the corner of the vessel on the symmetry boundary side in case with thermal effect.
wall thickness=1.0 mm
deformation by pressure difference (p= 0. 3 MPa)
Mises stress
deformation by thermal effect (Re=19400)
material; F82H
Structural analysis (previous study)
200 mm
50 mm
computational domain
Max. displacement of vessel v.s. p
ex.) LES for expanded vessel
Instantaneous velocity profile at x =0 A decrease in velocity is not only the vicinity of the expanded region but all round the cross-section.
Instantaneous Temperature on capsule wall Temperature rise in case of expanded duct is remarkable in the center region.
capsule wall vessel wall
ceramic porous plate
coolant flow
bifurcation part
Porous-type manifold
testing volume
~50cm
Main achievement (3)• Development of a porous-
type manifold for flow distribution– Because of its large flow
resistance , porous media can make velocity profile uniform even in a short flow interval.
– Uniform coolant flow achieved by porous media is equally distributed at bifurcation part.
200
piesometer
anemometer200
525
53.2
40
50
straightener part
measurement partbifurcation part
capsule-array port
200 〔 mm〕
cross section of channel1mm×200mm
Test section in detail
Experimental mock-up -capsule-array port
1/1-scale of the HFTM !!
cooling channel(1mm-width)
side reflector-installation port(In this time, coolant flow through this port was not considered)
0 100 2000
2
4
6
8
10
Probe Location (mm)
Gas
Vel
ocity
(m
/s)
without Porous plate #6 ① #6 ①②③ #6 ①②③④⑤
Re=3500
0 100 200
10
20
without Porous plate #6 ① #6 ①②③ #6 ①②③④⑤
Probe Location (mm)
Gas
Vel
ocity
(m
/s)
Re=8000
0 100 20010
20
30 without Porous plate #6 ① #6 ①②③ #6 ①②③④⑤
Probe Location (mm)
Gas
Vel
ocity
(m
/s)
Re=13000
Effect of porous plates on velocity profile
For all Re, velocity profiles are remarkably improved by porous plates.
Increase in pressure drop due to increase in porous plates inserted is small. (Reduction of channel width at the bifurcation part is dominant.)
Fabrication of full scale dummy -overall view-
coolant flow
testing volume
manifold
Fabrication of full scale dummy -each part-
capsule
capsule array with top & bottom reflector
capsule array
capsule arrays in module with side
reflectors
plate heater(for temperature control)
cast-type capsule(the same material with specimens is preferred)
thermocouple
specimens
Capsule design
Can be unified?
Development of Capsule Heaters for HFTM with horizontally-elongated capsules
• Demonstration of heater-printed capsule– Thermal conductivity of conventional heater is poor,
which leads to excessive pumping power for coolant.– Unexpected occurrence of gap between heater and
capsule under operation makes temperature of capsule uncontrollable.
– The higher the heater power is, the bigger a required size of electric terminal.
Heater-printed Capsule -general view-
Side Heater(600Wx2, 40W/cm2)
End Heater(100Wx2, 40W/cm2)
20016.4
15
1.0
1.0
200 16.4
16.5
1.0
1.0
[mm]
Printed Heaters Multi-layered Ceramic Coating[mm]
• Outer mounted heaters may become thermal barrier for cooling control. (Excess pumping power)
• Small gap between heater and capsule wall should cause large non-uniformity of inner temperature distribution of capsule. (Uncontrollable situation)
• Multi-layer coating technique has been already developed in the industrial world.• Possible combination of ceramic and heater materials is Magnesia-Alumina Spine
l (MgAl2O4) and Mo.
1.0
Heat
Fl
ux Neut
ron
Flu
x
Heater-printed Capsule -cross-sectional view-
Possible partner to develop capsule heaters
• Sakaguchi E.H. VOC CORP.
model name MS-1000dimension (mm) 25×25×1.75tworking voltage 100Vcapacity(room temp.) 555±20Wpower density 89W/cm2
working temp. 1000 Max℃
withstand voltage 1500V(terminal-substrate)
substrate of heating part (Almina)2xf0.5 Ni lead-wire (polyimide tube)
model name MS-M5dimension (mm) 5×5×1.75tworking voltage 15Vcapacity(room temp.) 15Wpower density 60W/cm2
working temp. 600 Max℃
withstand voltage 1500V(terminal-substrate)
substrate of heating part (Almina)2xf0.5 Ni lead-wire (polyimide tube)
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