ML041250486
| ML041250486 | |
| Person / Time | |
|---|---|
| Site: | Boiling Water Reactor Owners Group |
| Issue date: | 05/07/2004 |
| From: | Bo Pham NRC/NRR/DLPM/LPD4 |
| To: | |
| Pham B | |
| Shared Package | |
| ML041310023 | List: |
| References | |
| TAC MC2327 | |
| Download: ML041250486 (48) | |
Text
BWR OWNERS' GROUP ALTERNATIVE SOURCE TERMS PRESENTATION FOR NRC MEETING April 28, 2004 GREG BROADBENT (ENTERGY-Grand Gulf)
Committee Chairman April 28, 2004 BWROG AST-NRC Meeting I
I BWROG ALTERNATIVE SOURCE TERMS MEETING PURPOSE
- Preliminary review of LTR submittal.
- Collect NRC observations.
April 28, 2004 BWROG AST-NRC Meeting 22
BWROG ALTERNATIVE SOURCE TERMS BWROG AST COMMITTEE
- Committee Formed: 1995
- Committee Membership: 14 (of 20) BWR Utilities
- Committee Obiective:
Support generic aspects of BWR plant AST NRC application submittals and develop specific generic products necessary for future BWR AST applications.
April 28, 2004 BWROG AST-NRC Meeting 3
BWROG ALTERNATIVE SOURCE TERMS BWROG AST COMMITTEE Past Committee Products:
"Prediction of the Onset of Fission Gas Release from Fuel in Generic BWR", NEDC-32963, July 1996
- Submitted as part of Entergy Grand Gulf-Unit 1 AST Submittal (May 1997)
- NRC issued acceptance SER, September 9, 1999.
"BWROG Generic Source Terms", NEDC-33043P. June 2001
- Defined isotopic inventories for bounding BWR fuel design for radio-nuclide groups in NUREG-1465.
April 28, 2004 BWROG AST-NRC Meeting 4
BWROG ALTERNATIVE SOURCE TERMS BWROG AST COMMITTEE Current Committee Focus:
- Current NRC-approved fuel gap fractions for non-LOCA events [RG 1.183] are contingent on a maximum linear heat generation rate (LHGR) of 6.3kW/ft peak rod average power for rod burnups exceeding 54 GWd/MTU.
- Many BWRs are projecting rod power levels exceeding this currently-approved requirement.
- The BWROG has recently performed fuel gap fraction analyses based on BWR peak rod power histories that bound anticipated rod powers throughout BWR plant life.
April 28, 2004 BWROG AST-NRC Meeting 5s
BWROG ALTERNATIVE SOURCE TERMS BWROG AST COMMITTEE Current Committee Focus (Continued):
- NRC approval will allow B e n.
reference the approved LTR/SER and methodology for future AST applications.
- A Review Fee Waiver request is planned on the basis that NRC LTR approval should assist the Staff with a RG 1.183 revision to address high burnup fuel..
April 28, 2004 BWROG AST-NRC Meeting 6
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL
- BWROG Contractors: NISYS Corporation and KW Consulting were contracted to perform high burnup fuel gap fraction analysis for the BWROG.
- Analysis Approach: Identical to the gap fraction approach used to develop the current RG 1.183 values except:
April 28, 2004 BWROG AST-NRC Meeting 77
More Fuel Types
- GE 11/13 (9x9)
GE 12/14 (1Ox10)
- Framatome ATRIUM-9 (9x9)
- Framatome ATRIUM-10 (1 0xi 0)
ABB SVEA-96/96+
ABB SVEA-96 Optima2 April 28, 2004 BWROG AST-NRC Meeting 8
Higher Exposure
- Higher Exposure:
Current RG 1.183 Gap Fractions Applicable up to 62 GWd/MTU
. New Analysis Applicable to:
- 65 GWd/MTU for full-length rods
- 68 GWd/MTU for partial-length rods April 28, 2004 BWROG AST-NRC Meeting 9
More Aggressive Power History 16 14 12 X 10 8
I 6
4 2
0 0
10000 20000 30000 40000 Rod Bumup (MWd/MTU) 50000 60000 70000 8x8 Rod Power, This Analysis
- 8x8 Peak Local Power, This Analysis
-NUREG/CR-6703 8x8 Rod Power
- NUREG/CR-6703 8x8 Peak Local Power April 28, 2004 BWROG AST-NRC Meeting 10
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Technical Presentation
- Objective
- Gap Release Fraction Analysis Methodology
- Gap Release Fraction Analysis Inputs
- Typical Results
- Conservatisms April 28, 2004 BWROG AST-NRC Meeting 11
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Objective To extend the gap release fraction analyses described in the NRC High Burnup Environmental Impact Statement (EIS)
(NUREG/CR-6703), using the methodology described in the High Burnup EIS, to:
- Higher rod burnups
- Higher rod powers at high burnups
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL High Burnup EIS Methodology
- FRAPCON-3 fuel rod performance code
- Best estimate fuel rod performance models and nominal fuel rod fabrication parameters
- Normalization of the FRAPCON-3 gap release fraction results
- Gap release fractions for long-lived isotopes (Kr-85, Cs-134 and Cs-1 37) given by stable fission gas release fractions
'IFril 28, 2004 BWROG AST-NRC Meeting 13
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Normalization of Gap Release Fraction Results
- FRAPCON-3 has two gas release models:
- "Massih" model
- Predicts only stable fission gas release
- Validated against high burnup stable fission gas release data
- ANS-5.4 model
- ANS standard for radioactive isotope gap release fractions
- Predicts stable fission gas release and radioactive isotope gap release fractions
'April 28, 2004 BWROG AST-NRC Meeting 14
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Normalization of Gap Release Fraction Results (cont'd)
- ANS-5.4 model developed in late 70's, early 80's
- Not validated against high burnup stable fission gas release data
- Over-predicts high burnup stable fission gas release
- Compensate for over-prediction by multiplying the gap release fractions by the ratio of the Massih to the ANS-5.4 stable gas release predictions April 28, 2004 BWROG AST-NRC Meeting 15
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Additional Code Modifications
- At start of project, PNNL personnel responsible for FRAPCON-3 expressed concerns about the FRAPCON-3 implementation of the ANS-5.4 model
- KW Consulting review found coding errors dating back to the initial ANS-5.4 model implementation for FRAPCON-2
- Used only the beginning-of-life axial power distribution
- Did not use fuel pellet radial burnup distribution when calculating the gas diffusion coefficients April 28, 2004 BWROG AST-NRC Meeting 16
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Additional Code Modifications (cont'd)
- Gap release fractions calculated using a FRAPCON-3 code version that corrects these errors
- Code modifications discussed with and evaluated by PNNL personnel
- Also modified gap release fraction output to give results in a more easily used format April 28, 2004 BWROG AST-NRC Meeting 17
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Gap Release Fraction Analysis Inputs
- Fuel rod geometry
- Provided by the fuel vendors
- Nominal plant operating conditions (coolant temperature, flow rate, reactor coolant system pressure)
- Fuel rod power histories
- Bounding power histories for both rod average and local powers needed to obtain bounding results for the gap release fractions
- Bounding rod average power histories provided by the BWROG
- Bounding local power histories based on the Technical Specification LHGR limits for each fuel design April 28, 2004 BWROG AST-NRC Meeting 18
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Bounding Rod Average Power Histories Full Length Rods 12-C 10-I-
4 -8 CDea 2
0 0
10 20 30 40 50 60 70 Rod Average Exposure (GWd/MTU)
I-
-8x8 and9x9Fuel -
x10x0Fuell A'&pril 28, 2004 BWROG AST-NRC Meeting 19
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Bounding Rod Average Power Histories Part Length Rods 14 -
C 12-o 10 XY 8
I..
cs,4 as 2
0 10 20 30 40 50 60 70 Rod Average Exposure (GWd/MTU) l -- 9x9 Fuel 10x1O Fuel BWROG AST-NRC Meeting April 28, 2004 20
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Bounding Local Power Histories 16 i
14 m 12
= 0 co8 6
i co 6
I 10 2
OR Rod Local Exposure (GWd/MTU) l-
-GE8x8, 9x9 - - -
-ATRIU-9 9x9-All 10xl0 A'pril 28, 2004 BWROG AST-NRC Meeting 21
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL FRAPCON Axial Power Shape Inputs
- Generated from bounding rod average and local power histories
- Cycle from bottom-peaked to mid-peaked to top-peaked through each operating cycle
- Eighteen month cycles assumed
- Assure that rod powers used in the gap release fraction analysis are bounded by-both the bounding rod average and local power limits April 28, 2004 BWROG AST-NRC Meeting 22
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Gamma Heating
- Bounding power history limits are based on the total heat generation rates Include both energy deposited in the fuel and heat generated by gamma heating of the coolant and core structural components
- FRAPCON power history inputs are the energy deposited in the fuel
- FRAPCON gap release fraction analysis power-history inputs adjusted to compensate for gamma heating of the coolant and core structural components April 28, 2004 BWROG AST-NRC Meeting 23
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Gadolinia Fuel Rods
- Operate at lower power and attain lower burnups than non-gadolinia fuel rods
- Recent field observations show that gap release fractions of gadolinia rods are less than half those of near-by non-gadolinia rods
- Very little qualification of FRAPCON-3 for gadolinia fuel
- Conservatively assumed that the gadolinia fuel rod gap release fractions are the same as the non-gadolinia fuel rod gap release fractions Apkril 28, 2004 ABWROG AST-NRC Meeting 24
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Gap Release Fraction Results Bundle average gap release fractions calculated from Beginning-of-Life to End-of-Life
- Bundle average conservatively assumes all rods in the bundle are at the lead rod burnup
- Contribution of part-length rods are weighted by their relative fuel mass April 28, 2004 BWROG AST-NRC Meeting 25
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Gap Release-Fraction Results for 10x10 Fuel 1-131 Gap Release Fractions 0.10 0.0 0.0 Ca 0.04
- 0.
+
Ca 0.02 0.00 9
0 10 20 30 40 50 60 70 Bundle Burnup (GwdlMtu)
-Bounding Gap Release Fraction, All 10xlO 0 GE12 GE14 A ATRIUM-10 SVEA-96/96+
+ SVEA-96 Optima2 April 28, 2004 BWROG AST-NRC Meeting 26
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Gap Release Fraction Results for 1 Ox1 0 Fuel April 28, 2004 A 8BWROG AST-NRC Meeting 27
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Gap Release Fraction Results for 1Oxl0 Fuel Other Noble Gas Gap Release Fractions 0
10 20 30 40 Bundle Burnup (GwdlMtu) 50 60 70 Bounding Gap Release Fraction, All 10x10 o GE12 GE14 A ATRIUM-10
- SVEA-96/96+
+ SVEA-96 Optlma2 April 28, 2004 BWROG AST-NRC Meeting 28
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Gap Release Fraction Results for 1 Ox1 0 Fuel Other Halogen Gap Release Fractions 0.04.
0.03.
.2 to;o
/A.$
00.02 (U
s*.
o.01 0.001 0
10 20 30 40 50 60 70 Bundle Burnup (GwdlMtu)
Bounding Gap Release Fraction, All 10x10 o GE12 GE14 A
ATRIUM-10 SVEA-96196+
+ SVEA-96 Optlma2 April 28, 2004 BWROG AST-NRC Meeting 29
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Gap Release Fraction Results for 10x10 Fuel Alkali Metal Gap Release Fractions C
.0 a
m (U
0 0
C, (U
0 10 20 30 40 Bundle Burnup (GwdlMtu) 50.
60 70 Bounding Gap Release Fraction, All 10x10 o GE12 GE14 A
ATRIUM-10 a SVEA-96196+
+.SVEA-96 Optima2 April 28, 2004 BWROG AST-NRC Meeting 30
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Gap Release Fraction Results Typical behavior as a function of burnup consistent with the gas diffusion constant used in the gas release models D oc 00BocaiIBl4cozlst e-Q/RT D: diffusion constant Bulocai: local burnup Buconst: model constant Q: activation energy R: gas constant T: absolute temperature April 28, 2004 BWROG AST-NRC Meeting 31
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Gap Release Fraction Results (cont'd)
- Low burnup: rod powers and fuel temperatures approximately constant, gap release fractions increase with increasing burnup
- Moderate burnups: rod powers and fuel temperatures decrease, compensating for increasing burnup, and gap release fractions plateau and then decrease
- High burnups: peak local burnups exceed the maximum value for the LHGR limits, local powers and fuel temperatures are approximately constant, and gap release fractions plateau or increase April 28, 2004 BWROG AST-NRC Meeting 32
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Peak Gap Release Fractions, All Rod Designs Fuel Design Gap Release Fractions Other Nobles Other Halogens Alkali Metals 1-131 Kr-85 GE 8x8 GE11 9x9 GE13 9x9 ATRILUM-9 GE12 10x10 GE14 10x10 ATRIUM-10 SVEA-96/96+
SVEA-96 Optima 2 RG 1.183, Table 3 0.100 0.092 0.093 0.106 0.062 0.062 0.083 0.080 0.086 0.08 0.173
.0.167 0.167 0.146 0.090 0.090 0.121 0.103 0.117 0.10 0.097 0.081 0.081 0.076 0.042 0.042 0.055 0.054 0.058 0.05 0.051 0.043 0.043 0.040 0.022 0.022 0.029 0.029 0.031 0.05 0.217 0.217 0.218 0.220 0.152 0.151 0.201 0.183 0.187 0.12 April 28, 2004 BWROG AST-NRC Meeting 33
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Changes fro-m Reg. Guide 1.183
- Inclusion of precursor effects effectively doubles the Other Noble Gases gap release fractions After accounting for precursor effects, gap release fractions for the short-lived isotopes (1-131, Other Noble Gases and Other Halogens) are comparable
- Increased gap release fractions for the long-lived isotopes (Kr-85 and Alkali Metals) reflect the use of more aggressive power histories
- Comparable gap release fractions for the short-lived isotopes reflect the corrections to the FRAPCON-3 implementation of the ANS-5.4 model April 28, 2004 BWROG AST-NRC Meeting 34
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Shutdown Pressures
- Calculated at a coolant temperature of 200 OF, reactor coolant pressure of 35 psia and decay heat after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of cooldown =
0.6% of rod power at operating conditions
- End-of-Life rod pressures at shutdown conditions are less than 905 psig
- Bounding value for all earlier times in life April 28, 2004 BWROG AST-NRC Meeting 35
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Conservatisms in This Analysis Primary conservatism is the assumption that the lead fuel operates at the bounding rod average and local powers throughout life
- Gap release fraction results are very sensitive to fuel temperatures
- Typically, cores are designed with -10% margin to the LHGR limits to preclude Licensee Event Reports due to small power transients or small differences between predicted and actual core performance
- 10% reduction in local power limits gives a 40-50% reduction in the peak gap release fractions April 28, 2004 BWROG AST-NRC Meeting 36
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Conservatisms in This Analysis Effect of 0 10,c, < Tech. Spec.
GE12114 IWx10 Full Length Rods 1-131 Gap Fractions 0.07 -
0.06 0.05 4
0.04 c0.04 0.02 0.03
- .U.
0.001 0
10000 20000 30000 40000 60000 60000 70000 Rod Burnup (MWdMT.1 l *Tech Spec Local Powers
- Tech. Spec. Local Powers-10%
April 28, 2004 BWROG AST-NRC Meeting 37
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Conservatisms in This Analysis Effect of 0ioca < Tech. Spec.
GE12114 10x10 Full Length Rods Kr-85 Gap Fractions 0.10 0.0o 0.07*~
v e*+*
0.08 0.03
+
^
4 0.02 0.01
- 9 0
10000 20000 3000 40000 EOOO 60000 70D00 Rod Burnup (MWd1MTt4 l.Tech. Spec Local Pow ers
- Tech Spec. Local Pow ers
- 1EUh Apllril 28, 2004 BWROG AST-NRC Meeting 38
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Additional Conservatisms
- All rods in the bundle are assumed to operate at the bounding rod average and local power limits Typically, peak rod-to-bundle peaking factors are more than 10% at the peak gap fraction burnup
- No credit is taken for the reduced gap release-fractions of the gadolinia rods
- Recent evaluations indicate that the ANS-5.4 model over-predicts 1-131 gap release fractions by as much as a factor of 10
- Scaling by the ratio of the Massih to ANS-5.4 stable gas release values only partially compensates for this conservatism of the ANS-5.4 model April 28, 2004 BWROG AST-NRC Meeting 39
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL Additional Conservatisms 1 0x1 0 analyses use a conservative application of the bounding rod average and local power limit curves
- Due to the axial burnup distribution in the rod, at high burnups the bounding rod average power is greater than that allowed by the local power limit
- At these burnups, the gap release fraction analysis used the rod average power and an unrealistic, but conservative, flat axial power shape April 28, 2004 BWROG AST-NRC Meeting 40
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL BWROG intends to request:
Extension of current RG 1.183 gap fractions to higher BWR burnups and more aggressive power histories
- Approval of this methodology for use with new fuel designs and/or revised design inputs
- Benefits:
Validation of existing RG 1.183 gap fractions No requirements for re-analysis
- No increased consequences under 50.59
- No new submittals April 28, 2004 BWROG AST-NRC Meeting 41
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL
- Current bounding analyses predict slightly higher gap fractions than RG 1.183 Table 3
- However, conservatisms in the calculations (previously described) more than bound these small increases based:
Aplril 28, 2004 BWROG AST-NRC Meeting 42
I BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL
- 8% per Table 3 of RG l.183
- 6.2-10% per BWROG analysis
- Disposition 8x8 and ATRIUM-9 fuel are no longer being reloaded and are well past the exposure of peak gap fraction Remaining 9x9 and lOxlO designs are no more than 1%
greater than the 8% RG value
- More than bounded by the conservatisms in the analysis
~40 - 50% margin with 10% lower peak LHGR
- Another -40% margin considering rod-to-bundle peaking of 10% or more April 28, 2004 BWROG AST-NRC Meeting 43
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL
- Other Halogens
- 5% per Table 3 of RG 1l.183
- 2.2-5.1 % per BWROG analysis
- Disposition BWROG analysis calculates the same 5% fraction or less April 28, 2004 BWROG AST-NRC Meeting 44
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL
- 10% per RG 1.183
- 9-17% per BWROG analysis
- Disposition FHA analysis is insensitive to this isotope
Larger BWROG results are offset by the conservatisms in the analysis
- O40 - 50% margin with 10% lower peak LHGR
- Another 40%O margin considering rod-to-bundle peaking of 10% or more April 28, 2004 BWROG AST-NRC Meeting 45
BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL
- Other Noble Gases 5% per RG 1.183
- 4.2-9.7% per BWROG analysis
- Disposition
- FHA analysis is insensitive to these isotopes
- Larger BWROG results are offset by the conservatisms in the analysis
- ~40 - 50% margin with 1 0% lower peak LHGR
- Another 40%O margin considering rod-to-bundle peaking of 10% or more April 28, 2004 BWROG AST-NRC Meeting 46
I BWROG ALTERNATIVE SOURCE TERMS BWROG AST PLANNED LTR SUBMITTAL
- Disposition FHA analysis is completely insensitive to particulate isotopes since they are completely scrubbed by the fuel pool water
- infinite decontamination factor per RG 1.183, App. B, Section 3 April 28, 2004 BWROG AST-NRC Meeting 47
11 BWROG ALTERNATIVE SOURCE TERMS
SUMMARY
- RG 1.183 is currently limiting for high burnup fuel.
- Currently-planned LTR will request NRC review and approval (SER) for extension of current values in Table 3 of RG 1.183 to more aggressive power histories and burnups
- To address future fuel types, LTR will request NRC approval of defined methodology for developing non-LOCA fuel isotopic inventories.
A pril 28, 2004 BWROG AST-NRC Meeting 48