ML20203H807
| ML20203H807 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 07/30/1986 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.K.3.31, TASK-TM GL-85-35, NUDOCS 8608050099 | |
| Download: ML20203H807 (2) | |
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w TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 374o1 SN 157B Lookout Place JUL 30 886 Director of Nuclear Reactor Regulation Attention:
Mr. B. Youngblood, Project Director PWR Project Directorate No. 4 Division of Pressurized Water Reactors (PWR)
Licensing A U.S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear Mr. Youngblood:
In the Matter of
)
Docket Nos. 50-327 Tennessee Valley Authority
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50-328
References:
1.
Tennessee Valley Authority, Docket No. 50-328, Sequoyah Nuclear Plant Unit 2, Facility Operating License (No. DPR-79) 2.
NRC Generic Letter 83-35 from D. G. Eisenhut, " Clarification of TMI Action Plan Item II.K.3.31," November 2, 1983 l
3.
L. D. Butterfield letter to J. Lyons, " Westinghouse Owners' Group Transmitting of WCAP-ll145, OG-190," June 11, 1986 The Sequoyah Nuclear Plant (SQN) operating license (reference 1) contains a license condition that requires TVA to submit a plant specific analysis utilizing the new NRC approved NOTRUMP Small Break LOCA (SBLOCA) Evaluation Model (EM), as required by TMI Action Plan Item II.K.3.31.
In reference 2, the NRC staff indicated that the resolution of TMI Action Plan Item II.K.3.31 may be accomplished by generic analyses to demonstrate that the previous NRC approved WFLASH SBLOCA EM results were conservative when compared with the new NOTRUMP SBLOCA EM.
Such generic studies were undertaken by the Westinghouse Owners' Group (WOG) of which TVA is a participating member. The WOG has completed these generic studies and has submitted the results of the analyses to NRC in the topical report WCAP-ll145 (reference 3).
The purpose of this letter is to inform you that TVA is referencing topical report WCAP-lll45 in order to satisfy the requirements of TMI Action Item II.K.3.31 for SQN in a generic fashion in accordance with reference 2.
Topical report WCAP-lll45 documents the results of a series of SBLOCA analyses performed with the NRC approved NOTRUMP SBLOCA EM.
Cold leg break spectrum analyses were performed for the limiting SBLOCA plant from each of the Westinghouse 4-loop 4-loop Upper Heat Injection (UHI), 3-loop, and 2-loop plant categories. The limiting SBLOCA plant in each category was defined on the basis of previous SBLOCA analyses which were performed witn the NRC approved WFLASH SBLOCA EM.
In addition to the cold leg break spectrums, a hot leg and pump suction break were performed as part of the 4-loop plant analysis, confirming that the cold leg was still the worst break location.
Comparison of the NOTRUMP cold leg break spectrum results with the previously 8608050099 860730 PDR ADOCK 05000327 P
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(E) *~ Director of Nuclear Reactor Regulation JUL 301335 generated WFLASH results, showed that the WFLASH results were conservative for all plant categories.
For SQN, the 4-loop UHI plant category results showed that the NOTRUMP SBLOCA EM calculated no core uncovery for any of the SBLOCA transients analyzed, whereas the previous WFLASH analysis calculated partial core uncovery with a limiting Peak Clad Temperature (PCT) of 1,499 degrees Fahrenheit. The generic results documented in WCAP-11145, demonstrate that a plant specific reanalysis of the 4-loop UHI SQN plant with the NOTRUMP SBLOCA EM would result in the calculation of a limiting PCT which would be significantly lower than the 1,486 degrees Fahrenheit PCT currently calculated with the WFLASH SBLOCA EM.
Hence, the WFLASH SBLOCA EM results which currently form the licensing basis for SQN are conservative and still valid for demonstrating the adequacy of the Emergency Core Cooling System to mitigate the consequences of a SBLOCA, as required by 10 CFR 50.46.
It is, therefore, concluded that a plant specific analysis is not needed in order for SQN to comply with TMI Action Plan Item II.K.3.31.
Rather, TVA references WCAP-lll45 in order to comply with Item II.K.3.31 on a generic basis, in accordance with reference 2.
This should satisfy the license condition 2.C.16.p of SQN Operating License DPR-79.
Note that there was no comparable license condition for SQN operating license DPR-77 (unit 1).
If you have any questions, please get in touch with M.
R. Harding at (615) 870-6422.
Very truly yours, TENNESSEE VALLE AUTHORITY R. Ce dley, Dir ctor Nuclear Safety'and Licensing cc:
U.S. Nuclear Regulatory Commission Region II Attn:
Dr. J. Nelson Crace, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. Carl Stahle Sequoyah Project Manager U.S. Nuclear Regulatory Commission 7920 Norfolk Avenue Bethesda, Maryland 20814 l
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