ML20133H384
| ML20133H384 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 01/13/1997 |
| From: | Terry C TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TXX-97013, NUDOCS 9701170156 | |
| Download: ML20133H384 (2) | |
Text
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e N-Log # TXX 97013 llllllll" =
File # 10010 L
2 915 1
Ref. # 10CFR50.46 1UELECTRIC' 1
January 13, 1997 C. Iance Terry i
Gnmp Mce President U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NOS. 50-445 AND 50 446 LARGE BREAK LOCA ANALYSIS 10CFR50.46 REPORT REF:
1.
Letter from R. A. Copeland (SPC) to Director of Nuclear Reactor Regulation, " Annual Reporting of Changes and l
Errors in ECCS Evaluation Models, RAC:94:019,* dated February 14, 1994.
1 2.
Letter logged TXX-96517, dated November 27, 1996, from l
C. L. Terry to the Nuclear Regulatory Cc.uission.
Gentlemen:
i On February.14, 1994 Siemens Power Corporation (SPC) reported an error in 1
the Z equivalent parameter used in the FCTF correlation present in one of i
the large break LOCA analysis codes (T00DEE2) in an annual report to the NRC (see Reference 1) and elected not to correct it.
On December 12, 1996, TU Electric determined that the error in the Z equivalent parameter used in the FCTF correlation vould change the calculated peak clad temperatures (PCT) by more than 50'F and is therefore significant and reportable for both CPSES Units 1 and 2.
Pursuant to 10CFR50.46. TU Electric herein reports a significant error in the large break LOCA analyses for Units 1 and 2.
The (Z equivalent) scror itself was discussed in Reference 1.
The error is in the conservative direction and correcting it would lower the PCTs for both units. TV Electric is not correcting the error in the methodology at this time because the error is in the conservative direction and SPC is developing methodology improvements that address this issue which will be available to TV Electric.
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TXX 97013 Page 2 of 2 As a result, the current, previously reported PCTs remain unchanged and 1
therefore include this error as a penalty (see Reference 2).
The current LBLOCA PCTs of record for CPSES Units 1 and 2 are 2013*F and 2072*F, respectively. Based on preliminary evaluations, the PCTs with a corrected T00DEE2 code would have resulted in a decrease cf 100*F for Unit 1 and 53*F for Unit 2.
TU Electric accepts the penalties associated with using the uncorrected T00DEE2 code and no reduction in PCT w!il be credited as a result of this error. Therefore, the values for PCT for CPSES Units 1 and 2 remain at 2013'F and 2072'F respectively, and the conclusion of the analyses presented in FSAR Section 15.6.5 remains valid.
Since the error in the large break LOCA methodology is conservative for CPSES Units 1 and 2, TU Electric plans to continue use of this methodology without corrections until the NRC approves the SPC methodology improvements to the. large break LOCA analysis.
TV Electric proposes to reanalyze the large break loss of coolant accident for Units 1 and 2 within one year following the NRC approval of the SPC methodology improvements.
Should you have any questions concerning this report, please contact Mr. J. D. Seawright at (817) 897 0140.
i Sincerely, C. L. Terry By[J. S. Marshall Generic Licensing Manager JDS/grp c-Mr. L. J. Callan, Region IV Ms. J. I. Tapia, Region IV Resident Inspectors, CPSES i
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