TXX-9127, Forwards 30 Day Rept of Changes or Errors Discovered in ECCS Calculations of Peak Cladding Temp.Updated Value Remains Below 2200 F Limiting Value & Continues to Demonstrate Compliance w/10CFR50.46

Forwards 30 Day Rept of Changes or Errors Discovered in ECCS Calculations of Peak Cladding Temp.Updated Value Remains Below 2200 F Limiting Value & Continues to Demonstrate Compliance w/10CFR50.46

ML20091B795
Person / Time
Site:	Comanche Peak
Issue date:	07/31/1991
From:	William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
TXX-91270, NUDOCS 9108020152
Download: ML20091B795 (3)

Text

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. Log # TXX-91270

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File # 10010 915.6 Ref. # 10CFR50.46 7UELECTRIC William J. Cahill, Jr. Ju1y 31, 1991 Emerve Vke Frenlmi U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555

SUBJECT:

C0HANCHE PEAK STEAM ELECTRIC STATION (CPSES) - UNIT 2 DOCKET NO. 50-446 PEAK CLADDING TEMPERATURE CHANGES GREATER THAN 500F REF: 1) Letter logged TXX-6444, dated May 18, 1987, from.

W. G. Counsil to the NRC Gentlemen:

Westinghouse Electric Corporation notified TU Electric of errors in the CPSES Unit 2 emergency core cooling system (ECCS) calculation on July 1, 1991. The peak fuel cladding temperature (PCT) for CPSES Unit 2 was calculated using the 1981 version of the Westinghouse ECCS evaluation model as identified in the letter logged TXX-6444, Reference 1, and Supplemental Safety Evaluation Reports 21 and 24 to NUREG 0797. Each change / error is identified in an attachment to this letter along with the resultant change in peak cladding temperature.

The absolute magnitude of these changes total greater than 500F and in accordance with 10CFR50.46(a)(3)(i), have been classified as significant. This letter is TU Electric's 30 day report of changes or errors discovered in the ECCS calculations of PCT as required by 10CFR50.46(a)(3)(ii). Therefore, the informaLion required by 10CFR50.46 is provided below.

Utilizing the attached list of changes to the Unit 2 PCT conservatively, the maximum updated value for the Unit 2 PCT is 18810F. This updated value remains well below the 22000F limiting value established by Part 60.46(b)(1).

Therefore, the current analysis continues to demonstrate CPSES t2 compliance with 10CFR50.46.

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r TXX-91270 Page 2 of 2 Furthermore, TU Electric is applying Advanced Nuclear Fuels methodology to perform a large Break LOCA analysis for CPSES Unit 2, Cycle 1. The schedule for completion and submittal of the CPSES Unit 2. Cycle 1 analysis is August 1, 1992.

If you have any questions, please contact Mr. J. D. Seawright at (214) 812-4375.

Sincerely, f _' 0 l William J. Cahill. Jr.

JDS/grp Attachment c - Mr. R. D. Hartin Region IV Resident Inspectors, CPSES (2)

Mr. H. B. Fields. NRR r

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Attachment to TXX-91270 Page 1 of 1 CPSES Unit 2 Peak Cladding Temperature Changes / Errors 11gm Chance in PCT (OF1 Allowance for WREFLOOD errors per NRC 12 Generic Letter 86-16 (6 to 120F)

Steam generator tube collapse due to 20 concurrent seismic and LOCA loads Fuel Rod Initial Coldition inconsistency 41 Total Change 73 Base Calculation 18080F (1981 version of the Westinghouse ECCS evaluation model)

Total Peak Clad Temperature 18810F l

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