Results of the Public Workshops (Generic Letter 89-10, Supplement 1)
June 13, 1990 TO: ALL LICENSEES OF OPERATING NUCLEAR POWER PLANTS AND HOLDERS OF CONSTRUCTION PERMITS FOR NUCLEAR POWER PLANTS, AND INDIVIDUALS ON THE ATTACHED DISTRIBUTION LIST SUBJECT: SUPPLEMENT 1 TO GENERIC LETTER 89-10: RESULTS OF THE PUBLIC WORKSHOPS In September 1989, the NRC staff held three public workshops to discuss Generic Letter 89-10, "Safety-Related Motor-Operated Valve Testing and Surveillance." This generic letter, issued on June 28, 1989, requests holders of nuclear power plant operating licenses and construction permits to establish a program to provide for the testing, inspection, and maintenance of safety-related motor-operated valves (MOVs) and certain other MOVs in safety-related systems. Attached for the use of licensees and construction permit holders are the results of the public workshops. This supplement to Generic Letter 89-10 includes the opening remarks by NRC representatives and the responses provided by the NRC staff to all significant questions. These responses reflect the best information currently available to the staff from research and operating experience regarding the operability of MOVs under design-basis conditions. For example, the staff believes that, at the present time, the most reliable means of demonstrating operability of an MOV under design-basis conditions is to perform a test of the MOV in situ under those conditions. Such testing in situ, however, will not be practicable for some MOVs within the scope of Generic Letter 89-10. For those instances, the staff indicated in the generic letter that alternatives to testing the MOV in situ may be developed by the licensee or permit holder. The staff discussed several possible alternatives at the workshops, including potential problems and limitations associated with those alternatives, and various factors that should be considered when a licensee or permit holder intends to use one of those alternatives. This generic letter supplement has been prepared to assist licensees and permit holders in developing programs that will provide assurance of MOV operability under design-basis conditions. Because the workshops were held to answer specific questions on the generic letter, the supplement does not contain all of the information necessary to develop and implement such programs. Therefore, licensees and permit holders, together with the Nuclear Management and Resources Council (NUMARC), should coordinate their efforts in developing and implementing MOV programs. In this regard, NUMARC is preparing guidelines for use by licensees and permit holders in implementing the generic letter. NUMARC is also working with the Electric Power Research Institute to establish a research program aimed, in part, at determining the relationship between MOV performance characteristics. The NRC staff will also provide the industry with additional information on MOV operability as it becomes available. 9006070427 . Generic Letter 89-10 - 2 - Supplement No. 1 Licensees and permit holders should review the entire package because the staff guidance in the generic letter supplement should be considered in the context of all questions and responses. This supplement has been approved in accordance with NRC procedures for generic guidance and reflects the current staff positions concerning the implementation of the generic letter. Staff positions expanded, clarified, or modified following the workshops are identified in the supplement. For example, the staff position on the scope of the generic letter, provided in the response to Question 3, has been modified with respect to dampers and other MOVs not located in piping systems. In addition, as discussed in the response to Question 9, the prevention of inadvertent MOV operation within the context of the generic letter has been limited to the potential for MOV mispositioning from the control room. As a result of operating experience and research results, the NRC staff determined that MOV tests beyond those acceptable in the past are necessary to satisfy the NRC regulations. This determination constitutes backfitting. Consequently, the staff guidance in Generic Letter 89-10 contains provisions that were approved as backfits. Those provisions include MOV testing beyond Section XI of the ASME Boiler and Pressure Vessel Code; consideration of the operability of position-changeable MOVs located in safety-related systems; testing of MOVs under design-basis conditions, where practicable, because of uncertainties regarding industry sizing equations, and the extrapolation and application of MOV test data; preparation or revision of procedures to ensure correct MOV switch settings; and maintenance of records of test methods, MOV failures, and corrective action (including trending). In hindsight, the discussion in the generic letter should have referenced 10 CFR 50.109 and also should have stated that licensees and construction permit holders were required to advise the NRC "if" the provisions of the generic letter would be met. Nevertheless, the staff considers Generic Letter 89-10 to be a backfit and prepared the generic letter in accordance with NRC procedures for the issuance of staff guidance containing backfit provisions. Please direct questions or comments regarding this generic letter supplement to the appropriate NRC project manager. James G. Partlow Associate Director for Projects Office of Nuclear Reactor Regulation Enclosure: As stated
Page Last Reviewed/Updated Tuesday, March 09, 2021
Page Last Reviewed/Updated Tuesday, March 09, 2021