Addressees All holders of operating licenses (except those licenses that have been amended to possession-only status) or construction permits for nuclear power reactors. Purpose The U.S. Nuclear Regulatory Commission (NRC) is issuing this generic letter to (1) discuss the periodic verification of the capability of safety-related motor-operated valves (MOVs) to perform their safety functions consistent with the current licensing bases of nuclear power plants, (2) request that addressees implement actions described herein, and (3) require that addressees provide to the NRC a written response to this generic letter relating to implementation of the requested actions. Background NRC regulations require that components that are important to the safe operation of a nuclear power plant, including MOVs, be treated in a manner that provides assurance of their performance. Appendix A, "General Design Criteria for Nuclear Power Plants," and Appendix B, "Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants," to Part 50 of Title 10 of the Code of Federal Regulations (10 CFR Part 50) include broad- based requirements in this regard. In 10 CFR 50.55a(f), the NRC requires licensees to comply with Section XI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code). Nuclear power plant operating experience, valve performance problems and MOV research have revealed that the focus of the ASME Code on stroke time and leak-rate testing for MOVs was not sufficient in light of the design of the valves and the conditions under which they must function. For this reason, on June 28, 1989, the NRC staff issued Generic Letter (GL) 89-10, "Safety-Related Motor-Operated Valve Testing and Surveillance." In GL 89-10, the staff requested that licensees and permit holders ensure the capability of MOVs in safety-related systems to perform their intended functions by reviewing MOV design bases, verifying MOV switch settings initially and periodically, testing MOVs under design-basis conditions where practicable, improving evaluations of MOV failures and necessary corrective action, and trending MOV problems. The staff requested that licensees complete the GL 89-10 program within approximately three refueling outages or 5 years from the issuance of the generic letter. Permit holders were requested to complete the GL 89-10 program before plant startup or in accordance with the above schedule, whichever was later. Recommendation "d" of GL 89-10 requested that licensees and permit holders prepare procedures to ensure that correct MOV switch settings are maintained throughout the life of the plant. GL 89-10 stated that it may become necessary to adjust MOV switch settings because of wear or aging and that additional measures beyond ASME Code stroke-time testing should be taken to adequately verify that the switch settings ensure MOV operability. Recommendation "j" of GL 89-10 stated that licensees should periodically verify MOV capability every 5 years or every 3 refueling outages. Recommendation "h" of GL 89-10 requested that licensees evaluate trends in MOV performance every 2 years or at each refueling outage. The staff issued seven supplements to GL 89-10 that provided additional guidance and information on GL 89-10 program scope, design-basis reviews, switch settings, testing, periodic verification, trending, and schedule extensions. Supplement 6 to GL 89-10 stated that no licensee had adequately justified the use of static test data as the sole basis for periodically ensuring MOV design-basis capability. GL 89-10 and its supplements provide only limited guidance regarding periodic verification and the measures appropriate to assure preservation of design- basis capability. This generic letter provides more complete guidance regarding periodic verification of safety-related MOVs and supersedes GL 89-10 and its supplements with regard to MOV periodic verification. Although this guidance could have been provided in a supplement to GL 89-10, the staff has prepared this new generic letter to allow closure of the staff review of GL 89-10 programs as promptly as possible. Discussion Nuclear power plant utilities are nearing completion of the verification of the design-basis capability of their GL 89-10 MOVs. The NRC staff has been closing its review of individual GL 89-10 programs on the basis of the completion of the design-basis verification of safety-related MOVs at each nuclear power plant and the utility establishment of a program for periodic verification of MOV design-basis capability and for the trending of MOV problems. The staff may conduct a more complete review of licensee programs for MOV periodic verification as part of the implementation of this generic letter. The staff believes that various approaches can be taken by licensees to establish a periodic verification program that provides confidence in the long-term capability of MOVs to perform their design-basis safety functions. With each approach, the licensee should address potential degradation that can result in (1) the increase in thrust or torque requirements to operate the valves and (2) the decrease in the output capability of the motor actuator. The staff has long recognized the limitations of using stroke-time testing as a means of monitoring the operational readiness of MOVs (see GL 89-04, Supplement 1, "Guidance on Developing Acceptable Inservice Testing Programs") and has supported industry efforts to improve MOV periodic monitoring under the inservice testing (IST) program and GL 89-10. As such, the staff would consider a periodic verification program that provides an acceptable level of quality and safety as an alternative to the current IST requirements for stroke-time testing and could authorize such an alternative, upon application by a licensee, pursuant to the provisions of 10 CFR 50.55a(a)(3)(i). Guidance in this generic letter and GL 89-04 (Supplement 1) could be used by a licensee in determining whether its periodic verification program provides an acceptable level of quality and safety. The staff believes that various approaches can be taken by licensees to establish a periodic verification program that provides confidence in the long-term capability of MOVs to perform their design-basis safety functions. With each approach, the licensee should address potential degradation that can result in (1) the increase in thrust or torque requirements to operate the valves and (2) the decrease in the output capability of the motor actuator. The staff has long recognized the limitations of using stroke-time testing as a means of monitoring the operational readiness of MOVs (see GL 89-04, Supplement 1, "Guidance on Developing Acceptable Inservice Testing Programs") and has supported industry efforts to improve MOV periodic monitoring under the inservice testing (IST) program and GL 89-10. As such, the staff would consider a periodic verification program that provides an acceptable level of quality and safety as an alternative to the current IST requirements for stroke-time testing and could authorize such an alternative, upon application by a licensee, pursuant to the provisions of 10 CFR 50.55a(a)(3)(i). Guidance in this generic letter and GL 89-04 (Supplement 1) could be used by a licensee in determining whether its periodic verification program provides an acceptable level of quality and safety. The staff believes that various approaches can be taken by licensees to establish a periodic verification program that provides confidence in the long-term capability of MOVs to perform their design-basis safety functions. With each approach, the licensee should address potential degradation that can result in (1) the increase in thrust or torque requirements to operate the valves and (2) the decrease in the output capability of the motor actuator. The staff has long recognized the limitations of using stroke-time testing as a means of monitoring the operational readiness of MOVs (see GL 89-04, Supplement 1, "Guidance on Developing Acceptable Inservice Testing Programs") and has supported industry efforts to improve MOV periodic monitoring under the inservice testing (IST) program and GL 89-10. As such, the staff would consider a periodic verification program that provides an acceptable level of quality and safety as an alternative to the current IST requirements for stroke-time testing and could authorize such an alternative, upon application by a licensee, pursuant to the provisions of 10 CFR 50.55a(a)(3)(i). Guidance in this generic letter and GL 89-04 (Supplement 1) could be used by a licensee in determining whether its periodic verification program provides an acceptable level of quality and safety. In Attachment 1 to this generic letter, the staff discusses industry and regulatory activities and programs related to maintaining long-term capability of safety-related MOVs and provides the staff position regarding American Society of Mechanical Engineers (ASME) Code Case OMN-1. The staff also identifies attributes of periodic verification programs that the staff considers to be effective and an example approach in implementing those attributes. Additionally, as discussed in Attachment 1, certain licensees developed MOV periodic verification programs that the staff found acceptable during the closure of its review of GL 89-10 programs. Licensees may consolidate long-term MOV periodic verification and trending activities as part of their programs to meet the Maintenance Rule (10 CFR 50.65) and other applicable regulations. Requested Actions Each addressee of this generic letter is requested to establish a program, or to ensure the effectiveness of its current program, to verify on a periodic basis that safety-related MOVs continue to be capable of performing their safety functions within the current licensing bases of the facility. The program should ensure that changes in required performance resulting from degradation (such as those caused by age) can be properly identified and accounted for. Addressees that have developed periodic verification programs in response to GL 89-10 should review those programs to determine whether any changes are appropriate in light of the information in this generic letter. Required Response All addressees are required to submit the following written responses to this generic letter: - Within 60 days from the date of this generic letter, a written response indicating whether or not the addressee will implement the action(s) requested herein. If the addressee intends to implement the requested action(s), the addressee shall submit a schedule for completing implementation. If an addressee chooses not to implement the requested action(s), the addressee shall submit a description of any proposed alternative course of action, the schedule for completing the alternative course of action (if applicable), and the safety basis for determining the acceptability of the planned alternative course of action.
- Within 180 days from the date of this generic letter, or upon notification to NRC of completion of GL 89-10 (whichever is later), the addressee shall submit a written summary description of its MOV periodic verification program established in accordance with the Requested Actions paragraph or the alternative course of action established by the addressee in response to item 1 above.
All addressees shall submit the required written reports to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, D.C. 20555- 0001, under oath or affirmation under the provisions of Section 182a, Atomic Energy Act of 1954, as amended, and 10 CFR 50.54(f). In addition, a copy of the report shall be submitted to the appropriate Regional Administrator. Backfit Discussion 10 CFR Part 50 (Appendix A, Criteria 1 and 4) and plant licensing safety analyses require and/or commit that the addressees design and test components and systems to provide adequate assurance that those systems can perform their safety functions. Other individual criteria in Appendix A to 10 CFR Part 50, or commitments made by licensees in their Final Safety Analysis Reports, apply to specific systems. In accordance with those regulations and licensing commitments, and under the additional provisions of Criterion XVI of Appendix B to 10 CFR Part 50, licensees are required to take actions to ensure that safety-related MOVs are capable of performing their required safety functions. Recommendation "d" of GL 89-10 requested that licensees and permit holders prepare procedures to ensure that correct MOV switch settings are maintained throughout the life of the plant. GL 89-10 stated that it may become necessary to adjust MOV switch settings because of wear or aging and that additional measures beyond ASME Code stroke-time testing should be taken to adequately verify that the switch settings ensure MOV operability. The NRC staff issued GL 89-10 as a compliance backfit as defined in 10 CFR 50.109. The actions requested in this generic letter are considered compliance backfits, under the provisions of 10 CFR 50.109 and existing NRC procedures, to ensure that safety-related MOVs are capable of performing their intended safety functions. In accordance with the provisions of 10 CFR 50.109 regarding compliance backfits, a full backfit analysis was not performed for this proposed action; but the staff performed a documented evaluation, which stated the objectives of and reasons for the requested actions and the basis for invoking the compliance exception. A copy of this evaluation will be made available in the NRC Public Document Room. Federal Register Notification This generic letter was issued for a 60-day public comment period on February 20, 1996. Paperwork Reduction Act Statement This generic letter contains information collections that are subject to the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.). These information collections were approved by the Office of Management and Budget, approval number 3150-0011, which expires July 31, 1997. The public reporting burden for this collection of information is estimated to average 75 hours per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. The U.S. Nuclear Regulatory Commission is seeking public comment on the potential impact of the collection of information contained in the generic letter and on the following issues: - Is the proposed collection of information necessary for the proper performance of the functions of the NRC, including whether the information will have practical utility?
- Is the estimate of burden accurate?
- Is there a way to enhance the quality, utility, and clarity of the information to be collected?
- How can the burden of the collection of information be minimized, including the use of automated collection techniques?
Send comments on any aspect of this collection of information, including suggestions for reducing this burden, to the Information and Records Management Branch, T-6 F33, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202 (3150-0011), Office of Management and Budget, Washington, DC 20503. The NRC may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB control number. If you have any questions about this matter, please contact the technical contact or the lead project manager listed below, or the appropriate Office of Nuclear Reactor Regulation (NRR) project manager. |