ML17332A698
| ML17332A698 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 03/24/1995 |
| From: | Fitzpatrick E INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| AEP:NRC:1118I, NUDOCS 9503280253 | |
| Download: ML17332A698 (23) | |
Text
P RI(3RIWY 1 CCELERATED RIDS PROCESSING)
..;REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
III ACCESSION NBR:9503280253 DOC.DATE: 95/03/24 NOTARIZED: NO DOCKET FACIL:50-315 Donald C.
Cook Nuclear Power Plant, Unit 1, Indiana M
05000315 50-316 Donald C.
Cook Nuclear Power Plant, Unit 2, Indiana M
05000316 AUTH.NAME AUTHOR AFFILIATION P
FITZPATRICK,E.
(formerly Indiana
& Michigan Ele RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
R
SUBJECT:
Provides annual rept of LOCA evaluation model changes,per
. 10CFR50.46(a) (3) (ix).
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Indiana Michigan Power Company P.O. Box 16631 Coiumbus, OH 43216 Harch 24, 1995 AEP'NRC:1118I Docket Nos.:
50-315 50-316 U. S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.
C.
20555 Gentlemen:
Donald C.
Cook Nuclear Plant Units 1 and 2
ANNUAL REPORT OF LOCA EVALUATIONMODEL CHANGES Pursuant to the requirements of 10 CFR 50.46(a)(3)(ii), this letter provides our annual submittal of LOCA model changes.
Attachment 1,
which was provided to us by Westinghouse Electric Corporation (Westinghouse),
describes LOCA model changes which have been permanently implemented and provides a discussion in general terms
'of the impact of these changes on calculated peak clad temperatures (PCT's).
Attachment:
2 contains the peak clad temperatures calculated specifically for Donald C.
Cook Nuclear Plant Units 1 and 2.
The calculated SBLOCA PCT's are identical to those contained in our previous submittal (AEP:NRC:1118H, dated December 16, 1994).
The Unit 1 calculated LBLOCA PCT's have not changed since our previous 10CFR50.46 annual report (AEP:NRC:1118E, dated March 25, 1994).
A 50~F penalty that was being carried for the Unit: 2 LBLOCA PCT's has been
- removed, since the entire core is now Westinghouse Vantage 5 fuel.
Previously, Unit 2 contained fuel manufactured by both Siemen's Power Corporation and Westinghouse.
The 50 F penalty had been assessed to account for this mixture of fuel types.
In all cases, the calculated peak clad temperatures remain within the 10 CFR 50.46 limit: of 2200'F.
The plan for revising the Unit 1
cross-ties open SBLOCA run, discussed in our letter designated AEP:NRC:1118G, has been delayed several months to ensure that t:he calculation was made with the most recent code revision.
This calculation has been completed and is being reviewed.
Current plans also include both LBLOCA and SBLOCA reanalyses in conjunction with evaluations and analyses to support an increase in allowable steam generator tube.plugging (SGTP) for Unit 1.
The accumulator temperature for these analyses was revised as
.q~nnn 9503280253 950324 PDR ADOCK 050003l5 R
l
.U.
S. Nuclear Regulatory Commission Page 2
AEP:NRC:1118I discussed in Attachment 1.
This work is tentatively planned to be complete and submitted to the staff by June 1995.
New LBLOCA and SBLOCA analyses of record for Unit 2 will be included as part of a
planned uprating effort.
A revised accumulator temperature is also planned for Unit 2 in the uprating analyses.
The submission of the results of these new Unit 2 analyses is planned for 1996.
Sincerely, E.
E. Fitzpatrick Vice President sic Attachments CC:
A. A. Blind G. Charnoff J.
B. Martin NFEM Section Chief NRC Resident Inspector
- Bridgman J
~ R. Padgett
ATTACHMENT 1 TO AEP:NRC:1118I WESTINGHOUSE ELECTRIC CORPORATION DESCRIPTION OF LOCA MODEL CHANGES
~
PRESSURE SEARCH CONVERGENCE CRXTIHUAINNOTRUMP Bgekg~und The convergence criteria used, during the pressure search in NOTRUMP have been found to not be adequately restrictive to ensure a sufficiently accurate value for Fluid Node pressure when conditions approach the boundary between subcooled and saturated in some cases.
The resulting effects on predicted pressure were more pronounced at pressures below those normally seen during standard Evaluation Model calculations.
The previously hardwired convergence criteria values have been made user input, appropriate values have been determined, and these willbe implemented in all future analyses.
This was determined to be a Non-Discretionary Change as described in Section 4.1.2 of WCAP-13451 and was corrected in accordance. with Section 4.1.3 of WCAP-13451.
Affected Evaluation M del 1985 SBLOCA Evaluation Model (NOTRUMP)
Ih" The nature of this error led to an estimated generic PCT effect of O'F for existing analyses.
~', J I
1
0
~
PELLET POWER RADIALFLUXDEPRESSION ERROR Imhaaumk A coding error (an incorrect sign).was discovered and corrected in a subroutine that calculates radial distribution power factors in the fuel pellet for the LOCBART code.
ected Evaluati n Mod 1981 ECCS LBLOCAEvaluation Model with BASH Sensitivity studies found the error correction to result in less than a +0. 1'F effect on predicted peak clad temperature. The net effect on existing analyses is therefore zero degrees for margin tracking
- purposes, and willbe implicitlyincluded in future recalculations.
ACCUMULATORWATER TEMPERATURI<
Background
The choice of accumulator water temperature can affect the calculated Peak Cladding Temperature (PCT) associated with large break LOCA analyses.
Early Westinghouse Evaluation Models had assumed a generic value of90'F for the accumulator water temperature based on a conservatively low value of containment air temperature at 100% power in fulfillmentof the Appendix K requirements associated with the calculation of a low containment back-pressure.
These containment initial temperature and pressure assumptions in a plant's LBLOCAanalysis have been consistently reported to the NRC in the Final Safety Analysis Report.
The NRC had previously reviewed and approved this aspect of the LBLOCAEvaluation Model via plant specific Safety Evaluation Reports.
Using these assumptions, and with the early Westinghouse models, 90 F was conservative with respect to the overall effect on large break LOCA PCT.
Newer evaluation models have demonstrated that a higher containment air temperature, coupled with higher accumulator water temperatures, may result in an even more conservative calculation for PCT, even ifcontainment pressure is slightly higher than calculated with the 90'F assumption.
Sensitivity studies performed with these newer evaluation models (identified below) have shown a small sensitivity to accumulator water temperature.
The effect on PCT was a 1.3'F change in PCT for a 1'F change in accumulator water temperature when the accumulator water temperature varies over a range from 90'F to 120'F.
Application of this sensitivity over its applicable range results in a PCT effect which is below the 10 CFR 50.46 threshold for determination of a significant change (i.e,
<50'F). It is therefore Westinghouse's position that immediate implementation of this new methodology is not required.
As such, application of the new plant specific methodology and associated change in analysis assumptions can be forward-fit to new large break LOCA analyses.
This position was previously communicated to utilities in July, 1994 (NSAL Reference 3).
In support of future analyses, Westinghouse has developed a set of criteria for selection of the accumulator water temperature for use in large break LOCA analyses which use either the 1981 Evaluation Model with BART or the 1981 Evaluation Model with BASH. These criteria willbe provided to the plant licensees at the time a new large break LOCA analysis is performed.
Affected Evaluation Mod Westinghouse 1981 Large Break Evaluation Model using BART Westinghouse 1981 Large Break Evaluation Model using BASH timated EFFect As stated above, the estimated effect of a change in the accumulator water temperature methodology over a range from 90'F to 120'F is a 1.3'F change in PCI'or a 1'F change in accumulator water temperature.
As accumulator water temperatures are expected to vary greatly during plant operation and are difficultto measure directly, the plant specific effect of this new methodology may only be assessed once detailed accumulator water temperature data are available.
As such, it is expected that these data willbe provided when implementation of the new methodology occurs at the initiation of future plant specific LBLOCAanalyses.
ATTACHMENT 2 TO AEP:NRC'1118I WESTINGHOUSE ELECTRIC CORPORATION DETERMINATION OF EFFECT OF LOCA MODEL CHANGES ON COOK NUCLEAR PLANT LOCA ANALYSES
Attachment 2 to AEP:NRC:1118E Page 1
LARGE BREAK LOCA PLANT NAME:
Donald C.
Cook Unit 1 Comments:
Evaluation Model:BASH, FQT=2.15, FdH=1.55, SGTP=
15%,
Other:
RHR Cross Tie Valve Closed, 3250MWt Reactor Power A.
ANALYSIS OF RECORD B.
PRIOR LOCA MODEL ASSESSMENTS - 1989 C.
PRIOR LOCA MODEL ASSESSMENT - 1990 hPCT~
+
OoF hPCT~
+
OoF PCT=
2162oF D.
PRIOR LOCA MODEL ASSESSMENTS - 1991 PRIOR LOCA MODEL ASSESSMENTS - 1992 PRIOR LOCA MODEL ASSESSMENTS - 1993 1994 10CFR50.46 MODEL ASSESSMENTS dPCT~
-6oF hPCT~
OoF hPCT
+
20 F hPCT~
-117oF H.
LICENSING BASIS PCT
+ PERMANENT ASSESSMENTS PCT 205 9oF
Attachment 2 to AEP:NRC:1118E Page 2
LARGE BREAK LOCA PLANT NAME:
DONALD C.
COOK UNIT 1 Comments:
Evaluation Model:
BASH FQT=2.15, FdH 1.55, SGTP=15%,
Other:
RHR Cross Tie Valve Open, 3413 MWt Reactor Power A.
ANALYSIS OF RECORD B.
PRIOR LOCA MODEL ASSESSMENTS
- 1989 C.
PR1OR LOCA MODEL ASSESSMENTS
- 1990 D.
PRIOR LOCA MODEL ASSESSMENTS
" 1991 E.
PRIOR LOCA MODEL ASSESSMENTS
- 1992 F.
PRIOR LOCA MODEL ASSESSMENTS
- 1993 G.
1994 10CFR50.46 MODEL ASSESSMENTS hPCT~
+
OoF hPCT=
+
0' hPCT=
+
30'F EPCT=
-25 F dPCT=
6oF LPCT=
OoF PCT
~
2181oF H.
OTHER MARGIN ALLOCATIONS (Use of PCT Mazgin):
1.
ANALYSIS MARGINS USED:
Power Margin hPCT~
94oF Z.
LICENSING BASIS PCT + PERMANENT ASSESSMENTS
& POWER MARGIN PCT 2086oF
Attachment 2 to AEP:NRC:1118E Page 3
JUSTIFICATION FOR USE OF POWER MARGIN IN DONALD C.
COOK NUCLEAR PLANT UNIT 1 LARGE BREAK PCT RACK UP The analysis peak clad temperature (PCT) for Donald C. Cook Unit 1 at 3413 MW~ with the RHR cross tie valve open is 2181~F.
When the 1991 LOCA model assessment of 30 F was
- added, the resulting PCT exceeded 2200 F.
The following calculation shows that power margin exists for Cook Nuclear Plant Unit 1 since the core is currently licensed at 3250 MW~ versus the analysis power level of 3413 MW~.
A sensitivity to power was previously determined for the Donald C. Cook Nuclear Plant Unit 2
large break analysis. It was conservatively demonstrated that a reduction of 20 F~/%
Power could be applied for reduced power.
This sensitivity is conservative since it only accounts for the assumed power reduction in the LOCBART run.
A similar reduction in the assumed power for the SATAN run produces an added benefit to PCT during the blowdown portion of the transient.
A reduction in power in the blowdown portion of the transient (i.e.,
SATAN) would be an added benefit which was not accounted for in this sensitivity.
Since both Cook Nuclear Plant Unit 1 and Unit 2 are 4
loop ice condenser
- plants, this sensitivity will be applied to the reduction in power from the Unit 1 analysis power of 3413 MW~ to the licensed operating condition of 3250 MW~ (a 4.7% reduction in power):
(20 Fp~/0 Power)
(4.7% Power) 94 F When this 94~F margin is applied to the Unit 1, 3413 MW~ analysis with RHR cross tie valves open, the 10 CFR 50.46 PCT limit is not exceeded.
Attachment 2 to AEP:NRC:1118E Page 4
SMALL BREAK LOCA PLANT NAME:
DONALD C.
COOK NUCLEAR PLANT UNIT 1 Comments:
Evaluation Model:NOTRUMP, FQ 2.32, FaH=1.55, SGTP 15%
Other:
HHSZ Cross Tie Valve Closed, 3250 MWt Reactor Power A.
ANALYSIS OF RECORD PCT~
1951oF B.
PRIOR LOCA MODEL ASSESSMENTS - 1992 hPCT~
+
3oF1 PRIOR LOCA MODEL ASSESSMENTS
- March 1994 hPCT=
-16 F D.
PRIOR LOCA MODEL ASSESSMENTS
- December 1994 hPCT~
-223~F E.
Burst and Blockage/Time in Life LICENSING BASIS PCT + PERMANENT ASSESSMENTS hPCT=
+
15'F'CT~
1730 F The 1992 assessment for 15x15 hydraulic test results was not included in the new analysis of record.
- However, the drift flux flow regime error was incorporated.
2.
It should be noted that the burst and blockage assessment is subject to change as other model assessments are made because the magnitude of the burst and blockage assessments depends on the PCT without burst and blockage.
Attachment 2 to AEP:NRC:1118E Page 5
SMALL BREAK LOCA PLANT NAME:
DONALD C.
COOK NUCLEAR PLANT UNIT 1 Comments:
Evaluation Model:NOTRUMP, FQ=2.32, Fu.H=1.55, SGTP 15%
Other:
HHSI Cross Tie Valve
~O en, 3588 MHt Reactor Power B.
C.
D.
ANALYSIS OF RECORD PRIOR LOCA MODEL ASSESSMENTS
- October 1993 PRIOR LOCA MODEL ASSESSMENTS
- January 1994 PRIOR LOCA MODEL ASSESSMENTS
- March 1994 PRIOR LOCA MODEL ASSESSMENTS
- December 1994 LICENSING BASIS PCT
+ PERMANENT ASSESSMENTS PCT=
1570 F hPCT~
-16 F EPCT=
-86~F PCT~
1552 F
dPCT=
+
97~F
Attachment 2 to AEP:NRC:1118E Page 6
LARGE BREAK LOCA PLANT NAME:
DONALD C.
COOK NUCLEAR PLANT UNIT 2 Comments:
Evaluation Model:BASH, FQT~2.335, FdH=1.644, SGTP 15%,
Other:
RHR Cross Tie Valve Closed, 3413 MWt Reactor Power A.
ANALYSIS OF RECORD PCT~
2090oF PRIOR LOCA MODEL ASSESSMENTS
" 1989 (Analysis of record was completed in january 1990.
No prior LOCA Model assessments were made.)
PCT~
+
NAoF C.
PRIOR LOCA MODEL ASSESSMENTS
- 1990 D.
PRIOR LOCA MODEL ASSESSMENTS - 1991 E.
PRIOR LOCA MODEL ASSESSMENTS
- 1992 F.
PRIOR LOCA MODEL ASSESSMENTS
- 1993 G.
1994 10CFR50.46 MODEL ASSESSMENTS hPCT~
+
hPCT=
+
hPCT~
JKPCT=
hPCTa 00F 30oF 25oF 60F 00F H.
LICENSING BASIS PCT
+ PERMANENT ASSESSMENTS PCT~
2089oF
C
Attachment 2 to AEP:NRC:1118E Page 7
LARGE BREAK LOCA PLANT NAME:
DONALD C.
COOK NUCLEAR PLANT UNIT 2 Comments:
Evaluation Model:BASH, FQT=2.22, FdH~1.62, SGTP=15%,
Other:
RHR Cross Tie Valve Open, 3588 MWt Reactor Power A.
ANALYSIS OF RECORD PCT~
2140 F PRIOR LOCA MODEL ASSESSMENTS
- 1989 (Analysis of record was completed in january 1990.
No prior LOCA model assessments were made.)
hPCT=
+
NA F D.
F.
PRIOR LOCA MODEL ASSESSMENTS
- 1990 PRIOR LOCA MODEL ASSESSMENTS
- 1991 PRIOR LOCA MODEL ASSESSMENTS
- 1992 PRZOR LOCA MODEL ASSESSMENTS - 1993 1994 10CFR50.46 MODEL ASSESSMENTS hPCT
+
hPCT~
+
EPCT=
hPCT~
hPCT~
0'F 30oF 25oF 6oF O'
H.
OTHER MARGIN ALLOCATIONS 1.
Power Margin hPCT~
-98~F~
Z.
LICENSING BASIS PCT + PERMANENT ASSESSMENTS PCT~
2041 F This value was obtained by temporarily allocating 4.9% of power margin using a sensitivity of 20 F/0 power.
See the Unit 1 justification for the use of power margin in the Donald C.Cook Nuclear Plant Unit 1 Large Break PCT Rack up on page 3 of this attachment.
kp
Attachment 2 to AEP:NRC:1118E Page 8
SMALL BREAK LOCA PLANT NAME:
DONALD C.
COOK NUCLEAR PLANT UNIT 2 Comments:
Evaluation Model:NOTRUMP, FQ~2.45, F~H=1.666, SGTP=15%
Other:
HHSI Cross Tie Valve Closed, 3250 MWt Reactor Power A.
ANALYSIS OF RECORD PCT=
1956 F D.
PRIOR LOCA MODEL ASSESSMENTS
- October 1993 PRIOR LOCA MODEL.ASSESSMENTS
- March 1994 PRIOR LOCA MODEL ASSESSMENTS
- December 1994 Burst and Blockage/Time in Life hPCT~
-13~F hPCT~
-16~F hPCT
+
69 F hPCT=
+
0'F'.
LICENSING BASIS PCT + PERMANENT ASSESSMENTS PCT~
19960F It should be noted that the buxst and blockage assessment is subject to change as other model assessments are made because the magnitude of the buxst and blockage assessments depends on the PCT without burst and blockage.
Attachment 2 to AEP:NRC:1118E Page 9
SMALL BREAK LOCA PLANT NAME:
DONALD C.
COOK NUCLEAR PLANT UNIT 2 Comments:
Evaluation Model:NOTRUMP, FQ=2.44, F~H=1.644, SGTP 15%
Other:
HHSI Cross Tie Valve Closed, 3413 MWt Reactor Power A.
ANALYSIS OF RECORD B.
PRIOR LOCA MODEL ASSESSMENTS
- October 1993 C.
PRIOR LOCA MODEL ASSESSMENTS - March 1994 D.
PRIOR LOCA MODEL ASSESSMENTS - December 1994 E.
Burst and Blockage/Time in Life F.
LICENSING BASIS PCT + PERMANENT ASSESSMENTS PCT=
1947oF dPCT-"
130F dPCT~
hPCT~
-16 F 33oF hPCT=
+
58oF1 PCT~
1943oF It should be noted that the burst and blockage assessment is subject to change as other model assessments are made because the magnitude of the burst and blockage assessments dePends on the PCT without burst and blockage.
Attachment 2 to AEP:NRC:1118E Page 10 SMALL BREAK LOCA PLANT NAME:
DONALD C.
COOK NUCLEAR PLANT UNIT 2 Comments:
Evaluation Model:NOTRUMP, FQ~2.32, Fa.H=1.62,SGTP 15%,
Other:
HHSI Cross Tie Valve ~Oen, 3588 MWt Reactor Power A.
ANALYSIS OF RECORD PCTa 1531+F B.
PRIOR LOCA MODEL ASSESSMENTS - October 1993 dPCT~
13oF C.
D.
PRIOR LOCA MODEL ASSESSMENTS - March 1994 hPCT~
-16~F PRIOR LOCA MODEL ASSESSMENTS - December 1994 hPCT=
+
35 F E.
LICENSING BASIS PCT
+ PERMANENT ASSESSMENTS PCT 1537oF