ML21162A122
| ML21162A122 | |
| Person / Time | |
|---|---|
| Issue date: | 06/11/2021 |
| From: | Thomas Scarbrough, Robert Wolfgang NRC/NRR/DEX/EMIB |
| To: | |
| Ian H Tseng 301-415-7964 | |
| References | |
| Download: ML21162A122 (22) | |
Text
Valve Position Indication Requirements Public Meeting Thomas G. Scarbrough Robert J. Wolfgang U.S. Nuclear Regulatory Commission June 14, 2021
2 Agenda
- Purpose
- Background
- Risk Insights
- §50.55a Alternative Requests
- Summary
- Q&A
3 Purpose The purpose of this public meeting is to discuss:
- Supplemental requirements in §50.55a
- Alternative requests related to valve position indication.
4 Obturator Motion in Basic Valve Types
5 Valves with remote position indicators shall be observed locally at least once every 2 yr to verify that valve operation is accurately indicated.
Where practicable, this local observation should be supplemented by other indications such as use ASME OM Code of flow meters or other suitable instrumentation ISTC-3700 to verify obturator position. These observations need not be concurrent. Where local observation is not possible, other indications shall be used for verification of valve operation. Position verification for active MOVs shall be tested in accordance with Mandatory Appendix III of this Division.
- ASME OM Code, ISTC-3700 (2017 Edition)
6
- Beginning in 1995, NUREG-1482, Guidelines for Inservice Testing at Nuclear Power Plants, emphasized the ASME OM Code requirements for valve position indication.
- Most recently, NUREG-1482 (Revision 3) indicates that ASME OM Code allows flexibility to licensees in verifying that NUREG-1482 operation of valves with remote position indicators is accurately indicated.
- NUREG-1482 refers to various methods to verify valve operation, such as nonintrusive techniques, flow initiation or absence of flow, leak testing, and pressure testing.
7
- Over many years, operating experience revealed that some licensees were not implementing ISTC-3700 in a manner that provides reasonable assurance that the remote indicating lights for valves within the scope of their IST Program Operating are accurately verifying the position of the valve obturator.
Experience
- IN 2017-03, Anchor/Darling Double Disc Gate Valve Wedge Pin and Stem-Disc Separation Failures, dated June 15, 2017 (ADAMS Accession No. ML17153A053).
8 What can happen?
- Stem-disc separation and other causes of inaccurate position indication have occurred.
How likely is it?
- Some valve designs are more susceptible to stem-disc separation than others.
What are the consequences?
Risk Insights
- Unexpected loss of valve function when called upon. The safety consequences differ based on application.
Review should be commensurate with safety significance.
9 In 2017, the NRC added 10 CFR 50.55a(b)(3)(xi) as follows:
When implementing paragraph ISTC-3700, Position Verification Testing, in the ASME OM Code, 2012 Edition through the latest edition and addenda of the ASME OM Code incorporated by reference in OM Condition: paragraph (a)(1)(iv) of this section, licensees shall verify that valve operation is accurately indicated by Valve Position supplementing valve position indicating lights with Indication in other indications, such as flow meters or other suitable
§50.55a(b)(3)(xi) instrumentation to provide assurance of proper obturator position for valves with remote position indication within the scope of Subsection ISTC including its mandatory appendices and their verification methods and frequencies.
10 Federal Register Notice and NRC Response to Public Comments:
§50.55a(b)(3)(xi) to emphasize the provisions in OM Code, 2012 Edition, Subsection ISTC-3700, Position Verification Testing, to verify that valve obturator position is accurately indicated.
The NRC is requiring this condition for the implementation of the 2012 Edition of the OM Code for the 120-month IST interval OM Condition: in order to allow additional time for licensees to comply with Valve Position this condition. (82 FR 32934)
Indication in In NRC Response to Proposed Rule Public Comments (ADAMS Accession No. ML16130A531):
§50.55a(b)(3)(xi)
- NRC stated that this condition is not a backfit.
- NRC declined to allow an additional 24 months beyond implementation of ASME OM Code (2012 Edition) to perform valve position indication tests.
- NRC indicated that licensees may submit alternative requests if needed.
11
- IN 2021-01 alerts licensees to lessons learned from recent NRC inspections of the design-basis capability of power-operated valves (POVs) at nuclear power NRC plants.
Information
- IN 2021-01 addresses implementation of
§50.55a(b)(3)(xi) in addition to other POV inspection Notice lessons learned.
2021-01
- NRC staff held public meetings in December 2020 and January 2021 to discuss the POV inspection lessons learned, including the schedule for implementing
§50.55a(b)(3)(xi).
12 On March 26, 2021, the NRC issued a proposed rule in the Federal Register (86 FR 16087) to incorporate by reference the 2020 Edition of the ASME OM Code into §50.55a.
Proposed Proposed modification to §50.55a(b)(3)(xi) states:
Modification of OM Condition: For valves not susceptible to stem-disk separation, position verification testing specified in ISTC-3700 Valve Position may be performed on a 10-year interval where the Indication in licensee documents a justification, which is made available for NRC review, demonstrating that the
§50.55a(b)(3)(xi) stem-disk connection is not susceptible to separation based on the internal design and evaluation of the stem-disk connection using plant-specific and industry operating experience and vendor recommendations.
13 (z) Alternatives to codes and standards requirements.
Alternatives to the requirements of paragraphs (b) through (h) of this section or portions thereof may be used when authorized by the Director, NRR. A proposed alternative must be submitted and authorized prior to implementation. The applicant or licensee must demonstrate that:
(1) Acceptable level of quality and safety. The Alternatives proposed alternative would provide an acceptable level of quality and safety; or via 50.55a(z) (2) Hardship without a compensating increase in quality and safety. Compliance with the specified requirements of this section would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
14 NRC has authorized alternative requests to extend the initial implementation of §50.55a(b)(3)(xi) following the IST Program 10-year update :
- Ginna Verbal Authorization 4/26/2021 Alternative (ML21117A031)
Requests for the
- Perry VR-6 SE 5/5/2021 (ML21123A217)
Initial NRC review considered:
- Basis for assuming that the remote indicating lights Implementation for each valve properly indicate the open and close of obturator position (such as by previous opening for
§50.55a(b)(3)(xi) flow and closing for leakage testing) to justify the requested extension of initial implementation of
§50.55a(b)(3)(xi).
§50.55a(b)(3)(xi) when implemented.
15 NRC has authorized requests for extensions of the OM Code required test interval on a plant-specific basis:
- Palo Verde VRR-01 SE 11/13/2019 (ML19310F679)
- Fermi 2 VRR-004 SE 7/8/2020 (ML20169A652)
- Fermi 2 VRR-012 SE 3/7/2018 (ML17354B002)
NRC review considered:
Extension of
- Justification for the extended interval based on the successful history of remote indicating lights for the ISTC-3700 2- applicable valves to properly indicate the open and Year Interval close obturator position (such as flow and leakage testing) to support the proposed test interval.
§50.55a(b)(3)(xi) when valve position verification is conducted for the remote position indicating lights at the proposed interval.
16
- The NRC staff has accepted the use of ASME OM Code Cases in alternative requests in advance of generic acceptance where all aspects of a code case will be implemented.
- Code Case OMN-28 addresses the extension of the 2-year ISTC-3700 test interval and testing Code Cases in activities for valves determined to have a stem-disk connection not susceptible to separation.
Alternative
- NRC staff is reviewing OMN-28 for Requests incorporation into a future revision to Regulatory Guide 1.192.
- For valves outside the scope of OMN-28, licensees will need to follow ISTC-3700 as supplemented by §50.55a(b)(3)(xi) or be addressed in a valve-specific alternative request.
17
- If licensees provide the necessary information to meet §50.55a(z), the NRC staff will be able to promptly and thoroughly review the alternative request for valve position indication requirements in a timely manner.
- Recommend that licensees contact NRC Project NRC Review Manager to alert the NRC staff that an alternative request for the valve position of Alternative indication requirements will be submitted.
- Licensees may explore submitting alternative Requests requests through the Web-Based Relief Request (WRR) Portal (https://wrr.nrc-gateway.gov) to improve the efficiency of the process.
For more information contact:
Web-BasedReliefRequests.Resource@nrc.gov
18 Web-based Relief Requests
19
- NRC staff is evaluating whether a recent EPRI report can be reviewed for acceptance to help with this issue.
- EPRI Technical Report 3002019621, Susceptibility of EPRI Valve Applications to Failure of the Stem-to-Disk Connection, provides guidance for licensees to Technical implement ISTC-3700 as supplemented by proposed modification to §50.55a(b)(3)(xi) or request use of Report ASME OM Code Case OMN-28.
3002019621
- EPRI describes its review of various valve stem-disk connection designs, and its evaluation of industry operating experience to determine the susceptibility of these stem-disk connection designs to separation under applicable operating conditions.
20
- ISTC-3700 as supplemented by
§50.55a(b)(3)(xi) specifies requirements for valve position indication.
- Licensees may submit an alternative request for valve position indication testing in accordance with §50.55a(z).
- Alternative requests may specify the use of Code Case OMN-28 or describe plant-specific Summary approaches.
- NRC staff will be able to review alternative requests promptly and thoroughly in a timely manner if necessary information is provided in the submittal.
21 Questions or Comments?
22 Acronyms ASME American Society of Mechanical Engineers CFR Code of Federal Regulations EPRI Electric Power Research Institute FRN Federal Register Notice IN Information Notice IST Inservice Testing OM Operation and Maintenance of Nuclear Power Plants OMN-28 Alternative Valve Position Verification Approach to Satisfy ISTC-3700 for Valves Not Susceptible to Stem-Disk Separation NRC U.S. Nuclear Regulatory Commission NRR Office of Nuclear Reactor Regulation