ML20094S370
| ML20094S370 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 04/07/1992 |
| From: | William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TXX-92175, NUDOCS 9204150005 | |
| Download: ML20094S370 (3) | |
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"1""fT."a Log i TXX-92175 File i 10010 915.6 Ref. I 10CFR50.46 itlELEC1RIC April 7, 1992 William.*. CoMit, J r.
o, +, r.,nr i
U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C.
20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NOS. 50-445 AND 50-446 PEAK CLADDING TEMPERATURE CHANGES GREA1ER THAN 50'f REF:
1)
TU Electric Letter logged TXX-91?'O from William J. Cahill, Jr. to the NRu dated July 31, 1991
- 2) TV Electric Letter logged TXX-91270 from William J. Cahill, Jr. to the NRC dated July 31, 1991 Gentlemen:
Westinghouse Electric Corporation notified 10 Electric of errors in the i
CPSES Unit 1 small break LOCA calculation on March 9, 1992.
The peak fuel u
cladding temperature (PCT) for CPSES Unit 1 small break LOCA analysis m; calculated usin:) the WFLASH model. The most recent notification of PC, penalty from Westinghouse was for removal of credit for the turbine driven auxiliary feedwater pump from the sell break LOCA analysis with a value of 99.1'F.
Each change / error is identified in an attachment to this letter along with the resultant change in peak cladding temperature.
Utilizing the attached list of changes to the Unit 1 PCT conservatively, the maximum updated value for the Unit 1 PCT is 2133.65'F. This updated value remains below the 2200*F limiting value establ.shed by Part 50.46(b)(1).
Therefore, the current analysis cutinues to demonstrate CPSES Unit I compliance with 10Cfk50.46.
This report provides notice of changing the limiting transient for Unit 1 from the large break LOCA to the small break LOCA.
The Unit 2 limiting transient remains as iaentified in Reference 2.
Currently, all ECCS evaluation model changes / errors for Units 1 and 2 have been included in FSAR updates except for the most recent PCf penalty.
The absolute magnitude of these changes total greater than 50*F and in accoldancewith10CFR50.46(a)(3)(i),havebeenclassifiedassignificant.
This letter is TV Electric's 30 day report of changes or errors discovered in the ECCS calculations of PCT as required by 10CFR50.46(a)(3)(ii).
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'TXX-92175 Page 2 of 2 TV Electric provided schedules for reanalysis of the large break LOCA analysis for Unit 1 and Unit 0 5 Reference 1 and Reference 2, respectively.
During a telephone conver d W with the NRC staff on November 21, 1991. TV Electric agreed to provide W 4 reanalysis schedules, lh6 schedules for reanalysis are being revise e, oe consistent with the current schedule for useofSiemensfuel(Cycle 4forUnit1andCycle3forUnit2). The schedela for completion and submitta~. of'the reanalysis for the large break LOCA and small break LOCA for Unit 1 is May 31, 1993 (Cycle 4).
The schedule for completion and submittal of the retnalysis of the large break LOCAforUnit2isMay31,1995(Cycle 3),
if you have any questions, please contact Mr. J. D. Seawright at (214) 812-4375.
Sincerely, he$-
<td 1111am J b hill. Jr. /
JDS/gj c - Mr. R. D. Martin, Region !V Residentinspectors,CPSES(2)
Mr. T. A. Bergman, NRR Mr. B. E. Holian, NRR t
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' Attachment to TXX-92175 Page 1 of 1 CPSES Unit 1 Small Break LOCA Peak Cladding Temperature Changes / Errors its Chance in PCT (*F) 4.4% shortfall in 51 flow delivered 88.0 over time period of interest.
increased the signal processing 9.0 delay time from 1 sec, to 2 sec.
i increased the AFW purge volume used to calculate the 53.0 time to switchover to the lower enthalpy.
Comanche Peak Steam Electric Station Setpoint Study 2.0 Information.
Pressurizer low Pressure Si at 1700 psig.
Automatic AFW Controller Safety Evaluation 75.5 Revised Charging Flow Evaluation.
84.0 Reevaluation of the effect on small break LOCA break
-126.0 LOCA for reductions in Charging $1 and HHSI.
Increased AFW purge volumes due to check 19.2 valve back leakage.
Revised AFW purge volumes.
0.5 IncreaseintheAuxiliaryFeedwaterflowratefrom625 ppm
-25.0 to 1225.5 gpm. entire purge volume assumed to be at 440 F.
Adjustment to the small break analysis results 2.0 for the correction to the Zirc/ Water error.
ECCS Flow changes to prevent runout of the 64.85 Charging /SI and HHS1 during post-LOCA recirculation.
l Removal of the credit for TDAFW delivery from 99.10 LOCA analysis.
Total PCT penalty fer 10CFR50.59 changes and 346.15'F permanent ECCS model changes.
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-Limiting Case PCT 1787.5'F Total Limiting Case PCT 2133.65'F
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