ML20207K572
| ML20207K572 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, 05000000 |
| Issue date: | 12/24/1986 |
| From: | Hunsader S COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0876, RTR-NUREG-876, TASK-2.K.3.31, TASK-TM 2509K, GL-85-35, NUDOCS 8701090454 | |
| Download: ML20207K572 (2) | |
Text
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/.4 Jdress Reply to: Post Omco Box 767
. * ' Nd Chicago, Illinois 60690 - 0767 December 24, 1986 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Byron Station Units 1 and 2 Braidwood Station Units 1 and 2 TMI Action Item II.K.3.31 NRC Docket Nos. 50-454/455 & 50-456/457 References (a)* NUREG-0876, Safety Evaluation Report, dated February, 1982.
(b): NRC Generic Letter 85-35 from D. G. Eisenhut
" Clarification of TMI Action Plan Item II.K.3.31 - dated November 2, 1983."
(c): May 25, 1985, B. J. Youngblood letter to D. L. Parrar.
(d): June 11, 1986, L. D. Butterfield letter to J. Lyons.
Dear Mr. Denton:
Reference (a) provided the commitment to provide plant-specific analyses 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 (b) 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 Commonwealth Edison is a participating member. The WOG has completed these generic studies and, via reference (d), has submitted the results of the analyses to the NRC in the Topical Report WCAP-11145. The purpose of this letter is to inform you that commonwealth Edison is referencing Topical Report WCAP-11145 in order to satisfy the requirements of TMI Action Item II.K.3.31 for Byron and Braidwood Stations in a generic fashion, in accordance with Reference (b).
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r Mr. H. R. Denton December 24, 1986 Topical Report WCAP-11145 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 Head Injection (UNI), 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 results with the previously generated WFLASH results, showed that the WFLASH 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.(PCT) which was 5370F lower than that previously calculated by the WFLASH SBLOCA EM.
The generic results documented in WCAP-11145 demonstrate that a plant-specific reanalysis of the 4-loop Byron /Braidwood plant with the NOTRUMP SBLOCA EM would result in the caluclation of a limiting PCT which would be significantly lower than the 1777.5'F PCT currently calculated with the WFLASH SBLOCA EM.
Hence, the WFLASH SBLOCA EM results which currently form the licensing basis for Byron and Braidwood 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 Byron and Braidwood to comply with TMI Action Item II.K.3.31.
- Rather, Commonwealth Edison references WCAP-11145 in order to comply with TMI Action Item II.K.3.31 on a generic basis, in accordance with Reference (b). This should satisfy the appropriate licensing conditions of Byron Operating Licenses NPF-37 and 60, and Braidwood Operating License NPF-59.
If there are any questions regarding this matter, please contact this office.
One signed original and fifteen copies of this letter are provided for your review.
Very truly yours, 6
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S. C. Hunsader Nuclear Licensing Administrator in cc:
J. Stevens - NRR L. Olshan - NRR 2509K
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