ML19312C277
| ML19312C277 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 07/11/1977 |
| From: | Parker W DUKE POWER CO. |
| To: | Case E, Schwencer A Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7912120851 | |
| Download: ML19312C277 (2) | |
Text
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NRC Pomu 195 u.c. NUCUIAR REGULATOMY C JISSioN yET NU u-758
.3 O A10-M 7 NHC DISTRll:lUTION Pon PART 50 DOCKET MATERIAL TO:
FROM:
oATE or coCuMENT Mr! Edson G. Case Duke Power Co.
n7 11_77 Charlotte, N. C.
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s,. w ed CESCRIPTIC.*4 ENCLoSu RE Ltr.CConcluding that the current Tech Specs limits for Oconee Unit 1,22, C 3 and the proposed Tech Spec. changes for Oconee 1 Cycle 4 and Oconnee 2 Cycle 3 are conservativelyr valic'...
ACKNOWLEDGED
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PLANT NAME: 0CONEE UNITS 1, 2, C 3 jcm 07/18/77 i
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DUKE POWER COMPANY Powra Bt:st.niwo 42c SouTn Curacu SrazzT, CiuntoTTr. N. C. ae24a w wm o. ea a a c a. s a.
July 11, 1977 Vict Potsiorm?
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?. :ne % ecv? woe 3 7 3-d M 3 Mr. Edson G. Case, Acting Director Office of Nuclear Reactor Regulation
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'O 4 9 Attention:
Mr. A. Schwencer, Chief
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Reference:
Oconee Nuclear Station 4
j Docket Nos. 50-269, -270, -287 Nt g Regulatory Docket File
Dear Sir:
The B&W Topical Report BAW-10103, "ECCS Analysis of B&W's 177 FA Lowered-Loop NSS", contains the ECCS analysis applicable to Oconee Units 1, 2 and 3.
Recently, a discrepancy has been identified in the value of the flow resistance factor associated with the reactor vessel inlet U-baffle assumed in the bah iO103 analysis. The dis-crepancy relates to the fact that the BAW-10103-assumed values of these flow resistance factors were based on the original design characteristics of the U-baffle and did not take into account the modification of the U-baffle structure that was made since the original design. This was reported by letter dated June 10, 1977 which transmitted Reportable Occurrence Report R0-269/77-18.
A re-analysis of the ECCS performance has now been completed by B&W for the Oconee class reactors using the corrected flow resistance factors and utilizing the approved B&W ECCS Evaluation Model. This re-analysis is documented in a letter from Mr. James H. Taylor of B&W to Dr. R. L. Baer of the NRC, dated July 8, 1977. The analysis indicates that the ECCS evaluation results reported in BAW-10103 are conservative with respect to the re-analysis using the corrected flow resistance factors.
The Oconee Nucleer Station Technical Specifications include certain specified limits on core power distribution parameters which have been based on the linear heat rate limits established in BAW-10103.
Since the ECCS evaluation results contained in BAW-10103 are found to be conservative compared to the results of the analysis using the corrected flow resistance factors, it is concluded that the current Technical Specifications limits for Oconee Unit 1, 2, and 3 and the proposed Technical Specification changes for Oconee 1 Cycle 4 and Oconee 2 Cycle 3 are conservatively valid.
Ve y'truly yourg, s
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William O. Parker, 771990129 PMA:ge cc:
Mr. N. C. Moseley
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