ML20141B751
| ML20141B751 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 06/19/1997 |
| From: | Hill W NORTHERN STATES POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEIN-96-007, IEIN-96-7, NUDOCS 9706240132 | |
| Download: ML20141B751 (2) | |
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Northem States Power Company Monticello Nuclear Generating Plant 2007 West Hwy 75 Monticello, Minnesota 55362 9637 June 19,1997 U S Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22 Update on Dual ASCO Scram Pilot Valve issue On February 18,1997 a telecon was held between the Boiling Water Reactor Owners Group (BWROG) and the NRC to discuss closure of the Scram Solenoid Pilot Valve (SSPV) diaphragm materialissue identified in NRC Information Notice 96-07. During this call, the NRC requested that utilities inform the NRC of their i.itentions for resolution of this issue. With this letter, Northern States Power is updating the NRC regarding this request.
During Monticello's 1994 refueling outage, all SSPV Buna-N diaphragms were replaced with the Viton A material which later was determined to experience sticking of the diaphragm to the SSPV seat resulting in slow scram insertion times. To resolve the problem, General Electric (GE) developed and qualified a replacement material called Viton 515AB.
As a test, Monticello recently replaced four Viton A SSPV #118 exhaust valve diaphragms with the new Viton 515AB material. For the remainder of this cycle, Monticello will monitor the scram time performance of these four valves as we have been doing with the Viton A valves.
Performance of the Viton 515AB diaphragms will be monitored and final action determined accordingly.
Monticello will continue to monitor the scram times for the SSPV's with Viton A diaphragms, as committed to in our May 10,1996 letter.
Please contact Sam Shirey at 612-295-1449 if you have any questions related to this submittal.
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USNRC June 19,1997 Page 2 c:
Regional Administrator-lil, NRC NRR Project Mgr., NRC NRC Resident inspector State of Minnesota Attn: Kris Sanda J E Silberg
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