ML20046A468
| ML20046A468 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 07/20/1993 |
| From: | Hunger G VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-89-10, NUDOCS 9307280150 | |
| Download: ML20046A468 (2) | |
Text
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PHILADELPIIIA ELECTRIC COMPANY NUCLEAR GROUP HEADQUARTERS 955-65 CHESTERBROOK BLVD.
WAYNE, PA 19087-5691 a15) Mo-am STADON SUPPORT DEPARTMENT July 20, 1993 Docket Nos. 50-352 50-353 License Nos. NPF-39 NPF-85 Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
Subject:
Limerick Generating Station, Units 1 and 2 Change in Commitment Regarding Motor-0perated Valve Design Basis Reviews for the Reactor Water Cleanup System Identified in NRC Inspection Report Nos.
50-352/92-80 and 50-352/92-80 Gentlemen:
By letter dated February 14, 1992, the NRC issued Inspection Report Nos. 50-352/92-80 and 50-353/92-80 for Limerick Generating Station, Units 1 and 2.
This report summarized the results of the inspection conducted on January 13-17, 1992, that evaluated the adequacy of the program Philadelphia Electric Company developed to assure the reliability of motor-operated valves (MOVs) in response to NRC Generic letter (GL) 89-10, " Safety-Related Motor-0perated Valve Testing and Surveillance."
In Section 2.2, " Design Basis Reviews," of this inspection report, the NRC noted that we used the methodology described in the Boiling Water Reactor Owners' Group (BWROG) reports on the operational design basis of selected safety-related MOVs for design basis reviews performed in response to GL 89-10.
Furthermore, the NRC noted that the design basis reviews generally used the lowest reactor pressure vessel (RPV) safety relief valve setpoint for reactor vessel pressure when performing differential pressure calculations; however, normal operating RPV pressure was used in calculations for MOVs in the Reactor Water Cleanup (RWCU) system. As stated in this inspection report, we indicated that the design basis reviews for the applicable RWCU system MOVs would be revised to use the lowest RPV safety relief valve setpoint pressure as the reactor vessel pressure for performing differential pressure calculations.
270 E l 0
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U.S. Nuclear Regulatory Commission July'20, 1992 Document Control Desk Page 2 Initially, as documented in NEDC-31871, "BWR Owners' Group Report on Operational Design Basis of Selected bafety Related Motor Operated Valves in Response to Generic Letter 89-10," dated November 1990, the BWROG defined the reactor vessel pressure term to be used in performing the RWCU system differential pressure calculations as the RPV safety relief valve spring setpoint. However, after further review of the design basis accident scenarios the BWROG determined that the RPV full power pressure could be used in lieu of the RPV safety relief valve spring setpoint. The NRC, in an internal memorandum from James E. Richardson, " Guidance for Inspections of Programs in Response to Generic Letter 89-10," dated April 30, 1993, recognized the assumption provided by the BWROG that a pressure lower than the safety relief valve setpoint may be used for RWCU system differential pressure calculations provided the licensee justify their design-basis parameters.
Therefore, as a result of this clarification by the BWROG, we will use the RPV full power pressure and not the lowest RPV safety relief valve spring setpoint for performing differential pressure calculations for the RWCU system suction and discharge valves as previously committed.
Use of the RPV full power pressure is based on the design of the RWCU system suction and discharge valves to close for protection against a rupture of the system piping external to containment. The design basis conditions for a RWCU high energy line break scenario postulates the accident initiation from reactor operation at 100% rated power and corresponding RPV pressure.
If you have any questions or require additional information, please do not hesitate to contact us.
Very truly yours, fl G.' A. Hunger, Jr.
Director Licensing Section cc:
T. T. Martin, Administrator, Region I, USNRC N. S. Perry, USNRC Senior Resident Inspector, LGS