ML20207K771
| ML20207K771 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 12/31/1986 |
| From: | Leblond P COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.K.3.31, TASK-TM 2566K, NUDOCS 8701090515 | |
| Download: ML20207K771 (2) | |
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Commonwealth Edloon
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Address Reply to: Post Office Box 767
\\s! Chicago, lHinois 60690 0767 December 31, 1986 Mr. Harold R. Denton U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, DC. 20555
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Subject:
Zion Nuclear Power Station Units 1 and 2 NUREG-0737 Item II.K.3.31 NRC Docket Nos. 50-295 and 50-304
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References:
(a) June 11, 1986 letter from L.D. Butterfield to J. Lyons l
(b) July 8, 1986 letter from P.C. LeBlond to H.R. Denton
Dear Mr. Denton:
Reference (a) transmitted WCAP 11145 to the NRC staff for review and approval. That document contains the results of studies undertaken by the Westinghouse owner's Group (WOG) to demonstrate that the new NOTRUMP Small Break Loss of Coolant Accident Evaluation Model (SBLOCA EM) was conservatively bounded by the previous SBLOCA EM, WFLASH. Reference (b) notified the NRC staff that Commonwealth Edison Company intended to utilize WCAP 11145 to satisfy the requirements of NUREG 0737. Item II.K.3.31 for Zion Station.
In addition, Commonwealth Edison committed to independently verifying the applicability of WCAP 11145 to Zion Station. This submittal is transmitting the results of that review.
Topical Report WCAP-11145 documents the results of a series of Small Break LOCA (SBLOCA) analyses performed with the NRC approved NOTRUMP SBLOCA Evaluation Model. Cold leg break spectrum analyses were performed for the limiting SBLOCA plant from each of the Westinghouse 4-loop, 4-loop Upper Head 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 with 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 analyses, confirming that the cold leg was still the worst break location.
Comparison of the NOTRUMP cold leg break spectrum
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results with the previously generated WFLASH results, showed that the We' LASH results were conservative for all plant categories.
In particular, the 4-loop plant category results showed that the NOTRUMP SBLOCA EM calculated a limiting Peak Clad Temperature (FCT) which was 5370F lower than that previously calculated by the WFLASH SBLOCA EM.
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, The generic results documented in WCAP-11145, demonstrate that a plant specific reanalysis of Zicn Station with the NOTRUMP SBLOCA EM would result in the calculation of a limiting PCT which would be significantly lower than the 1747oF PCT currently calculated with the WFLASH SBLOCA EM.
- Hence, the WFLASH SBLOCA EM results which currently form the licensing basis for Zion are consorvative and still valid for demonstrating the adequacy of the Emergency Core Cooling System to mitigate the consequences of a SBLOCA, as required by 10CFR 50.46.
It is therefore concluded that a plant specific analysis is not needed in order for Zion Station to comply with TMI Action Item II.K 3.31.
If any further questions arise regarding this matter, please direct them to this office.
Very truly yours, h
P.C. LeBlond Nuclear Licensing Administrator
/klj cc: Resident Inspector-Zion J.A. Norris-NRR 2566K