ML20065H038
| ML20065H038 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 10/15/1990 |
| From: | Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737 90-606, NUDOCS 9010250133 | |
| Download: ML20065H038 (2) | |
Text
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1 l-VinoNIA Ex.nrinic ann Pownu COMPANY Hiruxoxts, h otnir canot Oc',ober 15,1990 U.S. Nuclear Regulatory Commission Serial No.
90 606 Attention: Document Control Desk NL&P/RMN Washington, D.C. 20555 Docket Nos.
50 338 50 339 License Nos. NPF 4 NPF 7 Gentlemen:
i VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA. POWERfsTATION UNITS 1 AND 2 NUREG-0737. ITEM ll.D.1 PORV AND BLOCK VALVE QUALIFICATION in your March 21,1989 letter on NUREG 0737 Item II.D.1, " Performance Testing of Relief and Safety Valves," you found that we had met the requirements of item II.D.1 except where deficiencies were noted. The one noted deficiency pertained to the environmental qualification of the PORV control circuits and block valves. You requested that we take appropriate actions to resolve the noted deficiencies. In response, Virginia Electric and Power Company had ordered and scheduled for replacement environmentally qualified motor operators for the block valves.
On June 25,1990, you issued Generic Letter 90 06 " Resolution of Generic issue 70,
' Power Operated Relief Valve.and Block Valve Reliability'; and Generic issue 94
'Additiona! Low-Temperature Overpressure Protection for Light Water Reactors.'" In
.the generic letter, you stated that it is not cost effective to make the PORVs and block valves safety related. The requirements for. safety re'ated. systems were listed including environmental qualification. The letter also referenced a Brookhaven National Laboratory study that showed only a relatively insignificant contribution to.
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core melt probabilit 'due to PORV and block valve improvements. The BNL study did not consider blee and. feed cnpability, which the letter referred to as a valuable option. As a result, you have proposed various maintenance and testing techniques in lieu of design modifications in ' order to affect reliability. Improvements. We therefore interpret Generic Letter 90 06 to mean that block valve operators and the PORVs need not be upgraded with environmentally qualified components.
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Based on this interpretation, it is our intent to take no further actions to address the
- noted deficiency in your Maich 21, 1989 letter and to comply with the guidance in Generic Letter 90 06.
If you have any questions or require additionalinformation, please contact us.
Very truly yours, k
l W. L. Stewart r
Senior Vice President Nuclear i
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U.S. Nuclear Regulatory Commission Region ll 101 Marietta Street, N.W.
Suite 2900
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Atlanta, Georgia 30323 i
Mr. M. S. Lesser l
NRC Senior Resident inspector.
North Anna Power Station i
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