ML19289D927
| ML19289D927 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 02/08/1979 |
| From: | Check P Office of Nuclear Reactor Regulation |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7903190431 | |
| Download: ML19289D927 (2) | |
Text
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At*h4.0 hIlu mr a-e s
t FEB o 81979 Docket Number: 50-346 I
EHORANDUM FOR: Robert W. Reid, Chief, Operating Reactor Branch #4, Division of. Operating Reactors FROM:
Paul S. Check, Chief, Reactor Safety Branch, Division of Operating Reactors
SUBJECT:
TECHNICAL SPECIFICATION CHANGE REQUEST TO REFLECT THE AS-MEASURED RCP CHARACTERISTICS AND ITS EFFECT ON THE REACTOR CORE SAFETY LIMITS AND RPS TRIP SETPOINTS PLANT NAME: Davis Besse - 1 DOCKET NUMBER: 50-346 RESPONSIBLE BRANCH & PROJECT MANAGER: ORB-4, G. Vissing REVIEW BRANCH: Reactor Safety REVIEW STATUS: Complete The Reactor Safety Branch has completed its review of the subject Technical Specification Change Request. The licensee requests changes in the Reactor Core Safety Limit (RCSL) curve and the Reactor Protection System Instrumentation Trip Setpoints (RPSITS) to reflet the as-measured one Reactor Coolant Pump (RCP) coastdown curve which is steeper than the design one RCP coastdown curve presented in the FSAR. After re-viewing Reference 1* we concluded that the requested change is acceptable.
i The licensee has stated that the as-measured RCP characteristics indicate a 14.6% excess flow and a steeper-than-design one RCP coastdown curve.
The RCP excess flow was partially used (by an earlier submittal by' the licensee) to offset the DNBR penalty due to Rod Bow effect, and partially used to compensate for the steeper coastdown curve in case of a Loss of Flow Accident (LOFA). In the spring of 1978, the licensee removed all BPRAs and all but two ORAs. One result of BPRA and ORA removal is a
- For clarification and follow up, two telephone conversations were held with the licenseee (Mr. Ray Sund) on 01/09/79 and 01/10/79.
Contact:
S. Diab, RS/00R 90431-28285 orrie s e summa us e oars >
t Form AZC 318 (Rev. 9 53) AECM 0240
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Robert W. Reid reduced coolant flow along the fuel rod assemblies, a situation which could produce a DNB in case of a LOFA. In May,1978, B&W analysis showed that the excess flow provided adequate cooling in case of a LOFA. However, B&W discovered an error in their Hay,1978 analysis, and subsequently reanalysed the transient. This LOFA transient reanalysis has resulted in the proposed changes to the RCSL and RPSITS and their associated bases. The B&W reanalysis was performed using i
RADAR, an NRC-approved code for the loss of flow transient.
l Since the requested changes preserve the DNB ratio margin for the loss of flow tvansient we find them acceptable.
Paul S. Check, Chief 3
Reactor Safety Branch Division of Operating Reactors cc:
V. Stello Jr./D. Eisenhut R. Vollmer C. Berlinger F. Coffman S. Weiss G. Vissing K. Kniel Section C, RS/ DOR S. Diab 4
I, i
Reference:
Letter from L. E. Roe, Toledo Edison Co. to the Director, Office of Nuclear Reactor Regulation, USNRC, November 23, 1978.
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