TXX-9136, Discusses Applicability of Unit 1 Testing & Validation Under Guidance of Position 4 of Branch Technical Position PSB-1 for Unit 2 Re Derived Voltage Values Vs Measured Test Results,Per Sser 22 (NUREG-0797) & Sser 7 (NUREG-0781)

Discusses Applicability of Unit 1 Testing & Validation Under Guidance of Position 4 of Branch Technical Position PSB-1 for Unit 2 Re Derived Voltage Values Vs Measured Test Results,Per Sser 22 (NUREG-0797) & Sser 7 (NUREG-0781)

ML20085N063
Person / Time
Site:	Comanche Peak
Issue date:	11/06/1991
From:	William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RTR-NUREG-0781, RTR-NUREG-0797, RTR-NUREG-781, RTR-NUREG-797 TXX-91366, NUDOCS 9111140037
Download: ML20085N063 (3)

Text

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- ,, tog # TXX 91366 File # 10010 908.2 7UELECTRIC Ref. #$FR2.102(a)

M IHiem J. CahlH, Jr.

o.w u r , r,,,"'"

November 6, 1991 U. S. Nuclear Regulatory Commission Attn: Document Control Desk -

Washington, D. C. 205S5

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATIO!! (CPSES) -

UNIT 2 DOCKET t10. 50 446 APPLICABill1Y Of UNIT 1 TESTING AND VAL 10AT10N UNDER .

THE GUIDANCE OF POSITION 4 0F BRANCH TECHNICAL POSIT 10!i PSB 1 FOR Utill 2 REF: 1) 10 Electric letter logged. TXX 89147, f rom W. J. Cahill, Jr. , to the NRC, dated March 17, 1989

2) TV Electric letter logged. TXX 89625, f rom W. J. Cahill, Jr., to the NRC, dated August 28, 1989

3) HRC NUREG 0797, CPSES, SER Supplement 22, Section 8.2.4 dated January 1990

4) HRC NUREG 0781 SOUTH TEXAS PROJECT, SER Supplement 7, Section 8.3, dated March 1989 Gentlement -

In Reference 1, TV Electric responded to Position 4 of Branch Technical Position (BTP) PSB-1. The response _ indicated that Unit 1 would perform testing to obtain ESF bus voltage levels for comparison with the design analysis, in Reference 2. TV Electric provided the NRC Staff a comparison of the analytically ocrived voltage values and the measured test results. The comparison confirmed that the analytical techniques and assumptions used adequately predict electrical system voltages f or the expected CPSES supply voltage and system loading conditions. The analytical voltage values for selected ESF busses were more conservative than the measured test voltage values for Unit 1. This test was performed in accordance with the guidance of Position 4 of Branch Technical Position (BTP) PSB 1 (llVREG 0800). The NRC Staff stated in Reference-3 that the verification test results were satisfactory. However, Reference 3 is unclear regarding the necessity of performing the same test for linit 2.

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TXX 91366 Page 2 of 3 On July 19, 1991. Ms. V. P. Cornell of 10 Electric, discussed the need for testing on Unit 2 under the guidance of CTP PSB 1 with Mr. H. B. Fields of NRR. Mr. Fields stated that the NRC's interpretation of TV Electric's commitment and the NRC's conclusions in Reference 3, were that testing is required for Unit 2.

Reference 1 stated the following HRC Ouestions on FSAR Chapter 8 '

1) 'During preoperational testing, voltage levels of the ESF buses will be verified as the buser. e*e loaded. Transformer taps are set in accordance with tbt piant voltage analyses to obtain optimum voittye levels from noload to fully loaded conditions. Voltage levels will be compared with design enalysis. The staff requests the applicant to provide, when available, a comparison of the analytically derived voltages to the test results to confirm that the analytical techniques and assumptions used can adequately predict electrical system voltages for expected supply voltage and 5,1 tem loading conditions. Please provide a schedule -for submitting _ this comparison."

JU Electric Resoonse

1) " Based on the current preoperational testing schedule, a comparison of the analytically derived voltages to the preoperational test results will be submitted by August 31, 1989.*

Af ter further review of BTP PSB 1, the CPSES test methodology, and the CPSES test results. TV Electric has concluded that the similarities between Units .

allow the results of the Unit I verification test results to apply also to Unit 2.

The technical _ justifications for TV Electric's position are as follows:

1) The same mathematical model is being used for both units.

2) The power system capacity and voltages are essentially identical for-both Units.

3) The transformers for both units have been purchased under the same specification with the same impedances.

4) The physical layout of the_ equipment for both Units have a high_ degree of similarity resulting in essentially similar cable lengths for both Units.

5) The loads for both units are basically the same.

-.. . = . . - - . - . -

TXX-91366 Page 3 of 3 Precedence exists for TV Electric's proposed method of satisfying BTP PSB 1 for CPSES Unit 2. The NRC evaluated Houston Lighting and Power's program and noted the following in Reference 4.

'The NRC staff concludes that the mathematical model, design and physical layout for Unit 2 are basically identical to those for Unit 1, and therefore, the successful verification tests conducted satisfy the requirements for BTF PSB 1 regarding voltage verification testing for South Texas Project Unit 1 and 2.*

Based on the above CPSES technical justifications, and the Houston Lighting &

+

Power precedent, TV Electric believes that the voltage verification testing

- performed on Unit 1-is representative for Unit 2. Unit 2 results would be enveloped by the mathematical model, and that additional testing is not necessary.

TV Electric requests that the NRC perform an expedited review of the above position, in addition, TV Electric requests that a verbal or written response regarding NRC concurrence with the position prior to December 6, 1991.

If there are any questions regarding this submittal, contact Veronica Cornell at (214) 812 8886.

Sincerely, William J. Cahill, .ir.

- By t in D. R. Woodlan Docket Licensing Manager RHS/fds c - Mr. R. D. Martin. Region IV '

Resident Inspectors. CPSES (2)

Mr.-H. B. Fields (NRR)

-l l

1 4 1

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