ML20059J849
| ML20059J849 | |
| Person / Time | |
|---|---|
| Issue date: | 01/06/1994 |
| From: | Hodges M Office of Nuclear Reactor Regulation |
| To: | Hall W NUCLEAR ENERGY INSTITUTE (FORMERLY NUCLEAR MGMT & |
| References | |
| NUDOCS 9402010220 | |
| Download: ML20059J849 (1) | |
Text
M 0 6194]
Mr. Warren J. Hall, Manager Operations, Management and Support Services Division Nuclear Management and Resources Council 1776 Eye Street, N.W., Suite 300 Washington, D.C., 20006-3706
Dear Mr. Hall:
SUBJECT:
PRESSURE LOCKING AND THERMAL BINDING OF GATE VALVES Based on a review of the operating experience of nuclear power plants, the staff concluded that pressure locking and thermal binding could occur in gate valves used in safety-related systems of both PWR and BWR plants and that such occurrences pose a common mode failure mechanism that could render multiple safety systems inoperable.
In a letter dated February 8, 1993, the NRC staff asked the Nuclear Management and Resources Council (NUMARC) to look into developing specific guidance on approaches to analyze and resolve the problem of pressure locking and thermal binding of gate valves.
During a meeting on October 4,1993, and in your letter dated December 22, 1993, you stated that NUMARC did not believe that there was a need to provide additional guidance on this issue. However, the staff still considers that additional action is important to provide assurance that pressure locking and t
thermal binding do not prevent gate valves from performing their safety functions.
t The NRC has scheduled a public workshop for February 4,1994, to discuss industry's activities to address the issue of pressure locking and thermal l
binding of gate valves and possible generic communications by the staff.
Licensees have also been invited to discuss these issues at the workshop.
In your letter, you noted that the Institute of Nuclear Power Operations (INPO) agreed to evaluate the problems associated with the pressure locking and thermal binding issue. The staff would welcome a presentation by INP0 on the status of its review at the workshop scheduled for February 4,1994.
Please contact James A. Norberg, Chief, Mechanical Engineering Branch, NRR, at (301) 504-3288 for interest and participation of NUMARC and INP0 in the workshop.
Orioinnistonedby M. Wayne Hodges, Acting Director Division of Engineering
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