U N C L A S S I F I E D Modeling the Engineered Barrier ...
Transcript of U N C L A S S I F I E D Modeling the Engineered Barrier ...
U N C L A S S I F I E D
Modeling the Engineered Barrier System for the Proposed Yucca
Mountain Repositoryp yPresented to:DOE-EM Performance Assessment Community of yPractice Technical Exchange Meeting
P t d bPresented by:Dr. Neil R. BrownSenior Staff, EES Division OfficeLos Alamos National LaboratoryLos Alamos National Laboratory
July 13-14, 2009
1
Salt Lake City, UT
U N C L A S S I F I E D
Yucca Mountain Lead Laboratory Partners
• Apogen / QinetiQApogen / QinetiQ• Areva• Beckman & Associates• Bechtel SAIC, LLC• Galson Sciences• Geotrans• Intera• ISSI• Itasca• John Hart and Associates• John Hart and Associates• JKRA• Kleinfelder• Longenecker & Associates• NRSS• RESPEC• RHYM• SAIC• Sala & Associates• SSA
2
• SSA• Stoller• URS
U N C L A S S I F I E D
OUTLINEOUTLINE
• YMP Engineered Barrier System Overview
• Total System Performance Assessment Overview
• Waste Package and Drip Shield Corrosion• General Corrosion• Localized Corrosion• Stress Corrosion Cracking
• Waste Form Degradation• Cladding • Spent Nuclear FuelSpent Nuclear Fuel• Defense High Level Waste Glass
• Questions and Answers
3
U N C L A S S I F I E D
The Natural and Engineered Barrier System
4
U N C L A S S I F I E D
LOCATIONS OF EXPLORATORY AND EMPLACEMENT DRIFTSEMPLACEMENT DRIFTS
5
U N C L A S S I F I E D
Yucca Mountain Exploratory Studies Facility
6
U N C L A S S I F I E D
Barriers, Features and Components • Features and
ComponentsSurface soils and– Surface soils and topography
– Unsaturated zone above the repositoryabove the repository
– Drip shield – Waste package– Cladding – Waste form– InvertInvert– Unsaturated zone
below the repositorySaturated zone
7
– Saturated zone
U N C L A S S I F I E D
The Engineered Barrier System
Alloy 22 Waste Package (WP)
Titanium Drip Shield
Alloy 22 Waste Package (WP)Outer Barrier
Type 316NG SSInner Vessel
Transportation, Aging and Disposal Canister (TAD)
EmplacementPallet
TEVRail
8
Pallet
U N C L A S S I F I E D
Drip Shield
Ti-7 Shell(~Ti Gr 2 + 0.12(~Ti Gr 2 + 0.12--0.15% Pd)0.15% Pd)
Ti-29 Struts and Bulkheads
9
Alloy 22 Feet (Ti Gr 5 + 0.08(Ti Gr 5 + 0.08--0.14% Ru)0.14% Ru)
U N C L A S S I F I E D
The Primary Purpose of the Engineered Barrier System is to Dela or Red ce the Rate of Water Contacting theis to Delay or Reduce the Rate of Water Contacting the
Waste, Limiting Radionuclide Release
10
U N C L A S S I F I E D
Waste Sources for Yucca Mountain
Commercial Spent Nuclear Fuel: 63,000 MTHM (~7500 waste packages)
DOE & Naval Spent Nuclear Fuel:DOE & Naval Spent Nuclear Fuel: 2,333 MTHM(65 MTHM naval spent fuel in ~400 waste packages)(DSNF packaged with HLW)
DOE & Commercial High-Level Waste:
Yucca MountainTotal 70,000 MTHM
DOE & Commercial High-Level Waste: 4,667 MTHM (~3000 waste packages of co-disposed DSNF and HLW)
11
DSNF: Defense Spent Nuclear FuelHLW: High Level Radioactive WasteMTHM: Metric Tons Heavy Metal
U N C L A S S I F I E D
Waste Form/Waste Packages in the LA
Notes: All wasteNotes: All waste forms are canisterized
TAD = Transportation, Aging and Disposal
SNF = SpentSNF Spent Nuclear Fuel
12
U N C L A S S I F I E D
Evaluating FEPs andDefining Scenarios• Probability and
significance criteria for FEPs provided in 10 CFR 63.114
• 374 FEPs evaluated222 l d d f TSPA– 222 excluded from TSPA
– 152 included
• Four scenario classes defined for analysisdefined for analysis
13
U N C L A S S I F I E D
TSPA-LA ScenariosTSPA-LA Scenarios
Four scenario classes divided into seven modeling casesNominal Scenario Class
• Nominal Modeling Case (included with Seismic Ground Motion for 1,000,000-yr analyses)
Igneous Scenario Class• Intrusion Modeling Case• Eruption Modeling Case
Early Failure Scenario Class• Waste Package Modeling Case• Drip Shield Modeling Case
Seismic Scenario Class• Ground Motion Modeling Case
Fault Displacement Modeling Case• Fault Displacement Modeling Case
14
U N C L A S S I F I E D
TSPA SYSTEM MODEL
MDL-WIS-PA-000005 REV
15
MDL WIS PA 000005 REV 00 AD 01, Figure 6-1
U N C L A S S I F I E D
Total System Performance Assessment Results
Total Mean Annual DoseTotal Mean Annual Dose
MDL-WIS-PA-000005 REV 00 AD 01 Figure 8 1-1[a] and Figure 8 1-2[a]
10,000 years 1,000,000 years
16
MDL-WIS-PA-000005 REV 00 AD 01, Figure 8.1-1[a] and Figure 8.1-2[a]
U N C L A S S I F I E D
Modeling Cases Contributing to Total Mean Annual Dose
MDL-WIS-PA-000005 REV 00 AD 01, Figure 8.1-3[a]
10,000 years 1,000,000 years
17
, g [ ]
U N C L A S S I F I E D
Objectives of Waste Package and Drip Shield Degradation AbstractionDegradation Abstraction
• Provide EBS flow and transport model and waste form degradation and mobilization modelg
– Number of patch and crack breaches per failed waste package (WP)– Number of drip shield failures (DS)
Number of early failed WPs and DSs– Number of early failed WPs and DSs
18
ANL-EBS-PA-000001
U N C L A S S I F I E D
Engineered System Materials• Drip Shield
– Grade 7 Titanium plates– Grade 29 Titanium supports
Grade 7 / Grade 28 / Grade 29 welds– Grade 7 / Grade 28 / Grade 29 welds
Al Pd Ru Ti V
Grade 7 - 0.12-0.25 - Bal. -
W t P k
Grade 28 2.5-3.5 - 0.08-0.14 Bal. 2-3
Grade 29 5.5-6.5 - 0.08-0.14 Bal. 3.5-4.5
• Waste Package– Annealed Alloy 22– Annealed Alloy 22 welds (longitudinal weld)– Stress relieved Alloy 22 welds (circumferential closure weld)
Alloy 22 Composition (N06022)
Co Cr Fe Mn Mo Ni V W
2 5 max 20 22 5 2 0 6 0 0 5 max 12 5 14 5 Bal 0 35 max 2 5 3 5
19
2.5 max 20-22.5 2.0-6.0 0.5 max 12.5-14.5 Bal. 0.35 max 2.5-3.5
U N C L A S S I F I E D
Alloy 22 has an impressive analog -Hastelloy CHastelloy C
Exposed at Kure Beach, North Carolina since 1941 - 250 meters from oceanOriginal mirror finish still intact after salt and debris washed from surface
20
Original mirror finish still intact after salt and debris washed from surface
U N C L A S S I F I E D
Outstanding Pitting Resistance of Alloy 22:
Superior to Other Candidate Materials
21
U N C L A S S I F I E D
Localized Corrosion of Engineering Alloys
Boiling Green Death Solution 11.5% H2SO4 + 1.2% HCl + 1% FeCl3 + 1% CuCl2
100
708090
100
(mm
/y)
30405060
sion
Rat
e (
0102030
Corr
os
C-22 C-276 C-4 625 825 600 316LSSAlloy
Green Death Solution: Solution Removed From Scrubbers Used to Wash
22
Green Death Solution: Solution Removed From Scrubbers Used to Wash Acidic Gases with Sea Water.
U N C L A S S I F I E D
Environments That May Potentially Contactthe Barrier Materialsthe Barrier Materials
• Seepage environments– Electrolyte chemistry defined by
ambient water composition
• Deliquescent environments– Electrolyte chemistry defined by
salt-bearing dusts deposited – Unlimited contaminant supply– Electrolyte may be continuous
during repository ventilation– Limited contaminants– Electrolyte bound in the dust
layer as dropletsy p
e . C)
(%R
H)
te P
acka
gera
ture
(deg
.
ckag
e R
H (
Was
Tem
per
Was
te P
ac
23
Time (years) Time (years)
U N C L A S S I F I E D
Two Types of Chemical EnvironmentsDeliquescence SeepageDeliquescence
• Dust containing soluble salts deposited on the WP during preclosure
Seepage• Seepage may occur after cooldown
(TWP < 105°C)• WP outer barrier is protected by the
• Multi-salt assemblages control deliquescence at higher temperatures
• NO3- is needed at high T
p ydrip shields
• Residence time (equilibrium with T, RH at WP surface) controls the corrosion environmentNO3 is needed at high T
• Brine compositions become dilute as T decreases and RH increases
• Amount of brine is limited:
corrosion environment• Chemical conditions (pH, Cl-, NO3
-, NO3
-/Cl-) are potentially corrosive during the early stages of cooldown
– 1.8 µL/cm2 (18 µm thick layer) at 120°C – decreasing with increasing temperature
• Chemistry is moderated by contact
• Chemical fractionation may occur during transport
Chemistry is moderated by contact with rock-forming minerals in dust
• Brines can change with time due to degassing, deliquescence
24
U N C L A S S I F I E D
Long Term Corrosion Test Facility(Lawrence Livermore National Laboratory)
Evaluation of General Localized Galvanic and Stress Corrosion
Test specimen rackTest facility tanks
25
Evaluation of General, Localized, Galvanic and Stress Corrosion Over 20,000 specimens tested
U N C L A S S I F I E D
4 Types of Specimens In Test
Galvanic Coupon
U-Bend Specimen
C i C
26
Crevice CouponWeight Loss Coupon
U N C L A S S I F I E D
Long-Term Exposure Testing Conditions– Electrolytes: Simulated dilute water (SDW), Simulated acidified water (SAW)
and Simulated concentrated water (SCW)– Temperatures: 60ºC and 90ºC– Specimen configurations: welded and non-welded, creviced and non-creviced– Specimen locations: inundated, atmospheric and waterline
27
(concentrations are in parts per million)
U N C L A S S I F I E D
WP General Corrosion
• 5-yr crevice geometry specimen weight-loss
• Activation energy from polarization resistance
1 00 1 00
25°C Span 200°C Span
0.75
1.00
babi
lity
Low UncertaintyMedium UncertaintyHigh Uncertainty
0.70
0.80
0.90
1.00
babi
lity
0.25
0.50
Cum
ulat
ive
Prob
g yMeasured Data
0.30
0.40
0.50
0.60
umul
ativ
e Pr
obLow-High 25°CMedium-Medium 25°C
60°C and 90°C DataWith Uncertainty Span
0.000 5 10 15 20 25 30
General Corrosion Rate (nm/yr)
C
0.00
0.10
0.20
0.01 0.1 1 10 100 1000 10000 100000 1000000Corrosion Rate (nm/yr)
C High-Low 25°CLow-Low 200°CMedium-Medium 200°CHigh-High 200°C
28
U N C L A S S I F I E D
Localized Corrosion is Modeled to Initiate When A Critical Potential Criterion is Met
If ΔE ≤ 0, initiate localized corrosionΔE = ERCREV - ECORR
ERCREV = crevice repassivation potential: the potential below which a propagating crevice willRCREV CORR which a propagating crevice will repassivate
ECORR = corrosion potential: the t ti l d d f All 22potential recorded for Alloy 22
following a long-term exposure to an electrolyte
tent
ial
ECORR
Pot
29
Time
U N C L A S S I F I E D
Crevice Repassivation Potential is Modeled to Depend on [Cl-], [NO3
-], and TemperatureS
C)
Mea
sure
dC
RE
V(m
V-S
SE
RC
30
Predicted ERCREV (mV-SSC)
U N C L A S S I F I E D
Data used for SCC Model
2.5
Alloy 22 as received
Alloy 22 creviced
Alloy 22 HT1 (TCP)
Alloy 22 HT1 +creviced
Keno Testing (Full Run 2) Feb '05
Concentrated Salt Solution 105 oC Constant Stress; 185 specimens total
316NG
2.0
σ YS
)
Alloy 22 HT2 (LRO)
Alloy 22 20% CW
Alloy 22 20%CW +LRO
Alloy 22 weld + HAZ
Constant Stress; 185 specimens total
Notched Alloy 22
1.5
(σm
ax a
pplie
d/ oy e d
316NG as received
316NG creviced
Ti Gr 7 as received
Ti Gr 7 creviced
Alloy 22
Ti Gr 7
Creviced and uncrevicedTi Gr.7 and sensitized SS
0 5
1.0Ti Gr 7 creviced
304SS sensitized
304SS sens + creviced
Notched A22 as-rec* σYS as rec used in stress ratio for welded specimens
Pressure increased from 8.67 MPato 10.3 MPa at 168.5 hrs
0.50 5000 10000 15000 20000 25000
Time-to-failure (hrs)
Notched A22 HT1(TCP)Notched A22 weld+HAZ
None of 120 Alloy 22 specimens have failed after 25 000 hours on test*
31
None of 120 Alloy 22 specimens have failed after 25,000 hours on test
Andresen et al., 12th Int’l Conference on Environmental Degradation, Salt Lake City, August 14-18, 2005
U N C L A S S I F I E D
Waste Form Modeling• Civilian Spent Nuclear Fuel Cladding• Civilian Spent Nuclear Fuel Cladding
– No credit taken for postclosure performance– Effort involved in onsite cladding inspection outweighs the benefits– Recognized as unrealized performance marginRecognized as unrealized performance margin
• Civilian Spent Nuclear Fuel– Inventory Uncertainty
– Arrival Scenarios, Burnup– Inventory
Gap/Grain Boundary available for immediate release– Gap/Grain Boundary available for immediate release– Matrix Inventory releases as result of degradation
– Matrix Degradation– Matrix Degradation – Based upon experimental results– Surface area, temperature, pH, carbonate level, oxygen partial
pressure
32
p
U N C L A S S I F I E D
Waste Form Modeling (cont.)• Defense Spent Nuclear Fuel
– Inventory Uncertainty – Waste Package Heterogeneityg g y
– Assumed to Degrade Instantaneously
f G• Defense High Level Waste Glass– Inventory Uncertainty
– Arrival Scenario, – Glass Loading, – Waste Package Heterogeneity
– Degradationg– Based Upon Experimental Results– Surface area, pH, relative humidity, temperature
33
U N C L A S S I F I E D
Questions?Questions?
34