ML20090B410

Issuance of Relief Request GVRR-9 Associated with Pandemic-Related Issues - Inservice Testing Interval Extension for Motor Operated Valves (EPID L-2020-LLR-0046 (COVID-19))

ML20090B410
Person / Time
Site:	Limerick
Issue date:	06/02/2020
From:	James Danna Plant Licensing Branch 1
To:	Bryan Hanson Exelon Generation Co, Exelon Nuclear
Sreenivas V, NRR/DORL/LPLI, 415-2597
References
EPID L-2020-LLR-0046
Download: ML20090B410 (8)

Text

June 2, 2020 Mr. Bryan C. Hanson Senior Vice President Exelon Generation Company, LLC President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

LIMERICK GENERATING STATION, UNIT 1 - ISSUANCE OF RELIEF REQUEST GVRR-9 ASSOCIATED WITH PANDEMIC RELATED ISSUES -

INSERVICE TESTING INTERVAL FOR MOTOR-OPERATED VALVES (EPID L-2020-LLR-0046 [COVID-19])

Dear Mr. Hanson:

By letter dated March 29, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20089A008), Exelon Generation Company, LLC (the licensee) proposed an alternative to specific inservice sesting (IST) program requirements in the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code), Division 1: Section IST, 2012 Edition, for Limerick Generating Station, Unit 1 (Limerick Unit 1).

Specifically, pursuant to the requirements of Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(z)(2), the licensee requested a one-time IST program interval extension for diagnostic testing of 17 motor-operated valves (MOVs) at Limerick Unit 1 listed in the request from the refueling outage scheduled for the spring of 2020 to the next refueling outage in the spring of 2022. In its submittal, the licensee requested use of the proposed alternative described in relief request GVRR-9 for the 17 specified MOVs at Limerick Unit 1 on the basis that compliance with the MOV diagnostic testing requirement during the spring 2020 refueling outage would result in a hardship without a compensating increase in the level of quality and safety in accordance with 10 CFR 50.55a(z)(2).

On March 31, 2020, the U.S. Nuclear Regulatory Commission (NRC) provided a verbal authorization (ADAMS Accession No. ML20090A652) of the proposed alternative in request GVRR-9 for the one-time extension of the diagnostic testing interval for the MOVs at Limerick Unit 1.

The NRC staff has determined that the proposed alternative for a one-time extension of the diagnostic testing interval to the next refueling outage in the spring of 2022 for the specified 17 MOVs at Limerick Unit 1 is acceptable in accordance with 10 CFR 50.55a(z)(2). The proposed alternative will provide reasonable assurance that the MOVs will be operationally ready to perform their safety functions until the next refueling outage currently scheduled for the spring of 2022.

All other ASME OM Code requirements for which relief was not specifically requested and approved remain applicable.

B. Hanson If you have any questions, please contact the Limerick Project Manager, V. Sreenivas, at 301-415-2597 or V.Sreenivas@nrc.gov.

Sincerely, Digitally signed by James James G. G. Danna Date: 2020.06.02 Danna 11:31:38 -04'00' James G. Danna, Chief Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-352

Enclosure:

Safety Evaluation cc: Listserv

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION GVRR-9 ASSOCIATED WITH PANDEMIC RELATED ISSUES -

INSERVICE TESTING INTERVAL FOR MOTOR-OPERATED VALVES EXELON GENERATION COMPANY, LLC LIMERICK GENERATING STATION, UNIT 1 DOCKET NO. 50-352

1.0 INTRODUCTION

By letter dated March 29, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20089A008), Exelon Generation Company, LLC (the licensee) proposed an alternative to specific inservice testing (IST) program requirements in the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code), Division 1: Section IST, 2012 Edition, for Limerick Generating Station, Unit 1 (Limerick Unit 1), pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Section 55a, Codes and standards.

In particular, the licensee submitted Relief Request GVRR-9 Associated with Pandemic Related Issues - Inservice Testing Interval Extension for Motor Operated Valves on March 29, 2020, requesting authorization by the U.S. Nuclear Regulatory Commission (NRC) for a one-time IST program interval extension for diagnostic testing of 17 motor-operated valves (MOVs) at Limerick Unit 1 listed in the request from the refueling outage scheduled for the spring of 2020 to the next refueling outage in the spring of 2022. In its submittal, the licensee requested use of a proposed alternative described in relief request GVRR-9 for the 17 specified MOVs at Limerick Unit 1 on the basis that compliance with the MOV diagnostic testing requirement during the spring 2020 refueling outage would result in a hardship without a compensating increase in the level of quality and safety in accordance with 10 CFR 50.55a(z)(2).

On March 31, 2020, the NRC provided a verbal authorization (ADAMS Accession No. ML20090A652) of the proposed alternative in request GVRR-9 for the one-time extension of the diagnostic testing interval for the MOVs at Limerick Unit 1 specified in the licensees submittal dated March 29, 2020. The verbal authorization documentation provides a summary of the NRC staffs evaluation for this proposed alternative. This safety evaluation (SE) provides the details of the NRC staffs review of proposed alternative in request GVRR-9.

Enclosure

2.0 REGULATORY EVALUATION

The NRCs regulations in 10 CFR 50.55a(f)(4), Inservice testing standards requirement for operating plants, state, in part, that throughout the service life of a boiling or pressurized water-cooled nuclear power facility, pumps and valves that are within the scope of the ASME OM Code must meet the IST requirements (except design and access provisions) set forth in the ASME OM Code and addenda that become effective subsequent to editions and addenda specified in 10 CFR 50.55a(f)(2) and (3) and that are incorporated by reference in 10 CFR 50.55a(a)(1)(iv) to the extent practical, within the limitations of design, geometry, and materials of construction of the components.

The NRCs regulations in 10 CFR 50.55a(z) state, in part, that alternatives to the requirements of 10 CFR 50.55a(f) may be used, when authorized by the NRC, if the licensee demonstrates (1) the proposed alternatives would provide an acceptable level of quality and safety, or (2) compliance with the specified requirements would result in hardship or unusual difficulty, without a compensating increase in the level of quality and safety.

The applicable ASME OM Code of record for the IST program at Limerick Unit 1 for the fourth 10-year IST program interval, which began on January 8, 2020, and is currently scheduled to end on January 7, 2030, is the 2012 Edition of the ASME OM Code, as incorporated by reference in 10 CFR 50.55a.

3.0 TECHNICAL EVALUATION

3.1 Licensees Alternative Request GVRR-9 The IST requirements of the ASME OM Code, as incorporated by reference in 10 CFR 50.55a related to this alternative request are as follows:

ASME OM Code (2012 Edition), Mandatory Appendix III, Preservice and Inservice Testing of Active Electric Motor Operated Valve Assemblies in Light-Water Reactor Power Plants, paragraph III-3310, Inservice Test Interval, subparagraph (c), states that The maximum inservice test interval shall not exceed 10 yr [years]. MOV inservice tests conducted per para. III-3400 may be used to satisfy this requirement.

ASME OM Code (2012 Edition), Mandatory Appendix III, paragraph III-3722, LSSC MOVs, subparagraph (d), states that LSSC [Low Safety-Significant Component] MOVs shall be inservice tested at least every 10 yr in accordance with para. III-3310.

In its submittal, the licensee requests an extension of the diagnostic test interval for the following 17 active safety-related MOVs at Limerick Unit 1:

Table 1 Code OM Valve ID Function Class Category HV-013-106 Reactor Enclosure Cooling Water 2 A HV-013-108 Reactor Enclosure Cooling Water 2 A HV-013-111 Reactor Enclosure Cooling Water 2 A HV-041-130B Nuclear Boiler 1 A

HV-041-140 Nuclear Boiler NC B HV-046-125 Control Rod Drive Hydraulic NC B HV-048-1F006B Standby Liquid Control 1 A/C HV-051-1F008 Residual Heat Removal 1 A HV-051-1F009 Residual Heat Removal 1 A HV-057-162 Containment Atmospheric Control 2 A HV-057-163 Containment Atmospheric Control 2 A HV-059-101 Primary Containment Instrument Gas 2 A HV-059-151A Primary Containment Instrument Gas 2 A HV-059-151B Primary Containment Instrument Gas 2 A HV-087-120A Drywell Chilled Water NC A HV-087-121B Drywell Chilled Water NC A HV-087-123 Drywell Chilled Water 2 A

Reason for Request

In its submittal dated March 29, 2020, the licensee indicated that Limerick Unit 1 was scheduled to begin a refueling outage in the spring of 2020. The licensee reported that the MOVs listed in its request were required by the ASME OM Code, Appendix III, to be diagnostically tested.

These MOVs were scheduled to be tested during the refueling outage in the spring of 2020.

Due to occupational health and safety concerns associated with the Coronavirus Disease 2019 (COVID-19) pandemic, the licensee stated that the performance of diagnostic testing of the 17 MOVs listed in Table 1 of this SE during the spring 2020 refueling outage at Limerick Unit 1 would represent a hardship, without a compensating increase in the level of quality and safety in accordance with 10 CFR 50.55a(z)(2), because performing the MOV diagnostic tests would require work in close spaces, which could be detrimental to the occupational health and safety of plant personnel and result in the potential to spread the virus. Additionally, the licensee may experience critical shortages of specially trained and qualified personnel due to illness, which would greatly affect completion of these required tests during the current refueling outage.

Proposed Alternative The licensee proposed a one-time extension of the IST program diagnostic test intervals for the MOVs listed in Table 1 of this SE to the next refueling outage for Limerick Unit 1 currently scheduled for the spring of 2022.

In its submittal, the licensee provided the calculated MOV functional margin after accounting for uncertainties and degradation factors based on the most current MOV test for each of the MOVs within the scope of its request. The licensee reported that each of these MOVs has a functional margin of high (> 10 percent and < 20 percent) or very high (> 20 percent), indicating that there is existing safety margin to assure reliable operation of these MOVs. The licensee also stated that its evaluation to support this request included a review of the maintenance history of each MOV. The licensee reported that no deficiencies, adverse trends, or open maintenance work orders were identified that would impact or degrade each valves performance capability and exclude it from this test interval extension request. The licensee stated that each MOV in the scope of this request is currently on a standard testing interval with acceptable performance.

Considering the MOVs current acceptable performance and the high or very high MOV functional margin, the licensee considered that there is reasonable assurance that each MOV will continue to be capable of performing its design function during the use of this proposed alternative.

In summary, the licensee asserted that extending the MOV diagnostic testing interval for each MOV in the scope of its request to the next refueling outage scheduled for the spring of 2022 would not adversely impact the function of the MOV or result in a reduction in plant safety. In the current pandemic environment, the licensee considered that performing the required tests would result in an increased risk of virus exposure to plant personnel and a reduction in occupational health and safety without a compensating benefit. Therefore, the licensee stated that this request met the criteria for an alternative to the ASME OM Code requirements on the basis that compliance would result in hardship or unusual difficulty, without a compensating increase in level of quality or safety during the current pandemic.

3.2 NRC Staff Evaluation ASME OM Code (2012 Edition), Mandatory Appendix III, as incorporated by reference in 10 CFR 50.55a, requires active safety-related MOVs to be periodically diagnostic tested at an interval not to exceed 10 years to demonstrate their capability to perform the specific safety functions. When determining the proper diagnostic test interval, the MOV program engineer at a nuclear power plant considers all potential performance-related degradations that could impact the capability of each MOV to perform its safety functions. The diagnostic test interval needs to be established such that the MOV functional margin does not decrease below the acceptance criteria for demonstrating its design-basis capability.

The MOVs listed in Table 1 of this SE are currently being tested at the specified 10-year interval and were due to be tested during the spring 2020 refueling outage. Due to current circumstances of the nation being in a pandemic situation, the licensee was concerned that compliance with the performance of these required tests would involve activities that would be detrimental to the occupational health and safety of the workforce and have the potential to spread the COVID-19 virus. As a result, the licensee requested to extend the diagnostic testing of these MOVs until the next refueling outage currently scheduled for the spring of 2022. The licensee considered that justification for the extension of the diagnostic testing interval for the specific MOVs is the excellent performance history of each MOV, and the determination that all MOVs listed in Table 1 of this SE have adequate margin to perform their safety function.

In its submittal, the licensee stated that the performance of diagnostic testing of the 17 specified MOVs during the spring 2020 refueling outage at Limerick Unit 1 would represent a hardship during the COVID 19 outbreak because performing the MOV diagnostic tests would require work in close spaces, which could be detrimental to the occupational health and safety of plant personnel. To support its request for a one-time extension of the diagnostic testing interval for these MOVs until the next refueling outage in the spring of 2022, the licensee provided the calculated functional margin after accounting for uncertainties and degradation factors for each specific MOV based on the most current diagnostic test data. The licensees calculations indicate that each of the MOVs has a functional margin of at least 10 percent. The licensee reported that its evaluation in preparing the alternative request included a review of the maintenance history of each MOV.

The licensee stated that no deficiencies, adverse trends, or open maintenance work orders were identified that would impact or degrade the performance capability of these MOVs. The licensee reported that each MOV is undergoing the standard testing interval with acceptable performance. The licensee considered that the current acceptable performance and high functional margin support reasonable assurance that each MOV will continue to be capable of performing its design function during the time interval of this alternative request.

In response to the licensees request, the NRC staff reviewed the historical performance data of the MOVs listed in Table 1 of this SE and performed a review of MOV operating experience for the last 20 years using the Industry Reporting Information System (IRIS) database established by the Institute of Nuclear Power Operations (INPO). The staff did not identify any significant MOV malfunctions in IRIS, and only minor events were identified during normal work activities.

The staff determined that the MOVs listed in Table 1 of this SE have sufficient margin and excellent performance history to justify extending the MOV diagnostic test interval to the next refueling outage. The NRC staff determined that requiring the MOVs listed in Table 1 of this SE to be diagnostically tested within the specified 10-year interval with limited personnel resources represents a hardship or unusual difficulty, without a compensating increase in the level of quality and safety.

Based on the information provided by the licensee for the 17 specific MOVs at Limerick Unit 1 identified in its submittal, the NRC staff found that (1) previous diagnostic testing of those MOVs indicates their acceptable historical performance, (2) ongoing IST activities have not identified MOV performance concerns, (3) periodic maintenance activities will continue, and (4) a hardship exists for the performance of diagnostic testing of these MOVs during the spring 2020 refueling outage that would be contrary to the health and safety of plant personnel. Therefore, the NRC determined that the licensees proposed alternative for a one-time extension of the diagnostic testing interval to the next refueling outage in the spring of 2022 for the specified 17 MOVs at Limerick Unit 1 is acceptable, in accordance with 10 CFR 50.55a(z)(2). The proposed alternative will provide reasonable assurance that the MOVs will be operationally ready to perform their safety functions until the next refueling outage currently scheduled for the spring of 2022.

4.0 CONCLUSION

As set forth above, the NRC staff determines that complying with the specified requirement would result in hardship or unusual difficulty, without a compensating increase in the level of quality and safety. Accordingly, the NRC staff concludes that the licensee has adequately addressed the regulatory requirements set forth in 10 CFR 50.55a(z)(2). Therefore, the NRC staff authorizes the proposed alternative at Limerick Unit 1 for the fourth 10-year IST program interval, which began on January 8, 2020, and is currently scheduled to end on January 7, 2030.

All other ASME OM Code requirements for which relief was not specifically requested and approved remain applicable.

Principal Contributor: M. Farnan Dated: June 2, 2020

ML20090B410 *by e-mail OFFICE NRR/DORL/LPL1/PM NRR/DORL/LPL1/LA NRR/DEX/EMIB/BC/(A)*

NAME VSreenivas LRonewicz TScarbrough DATE 05/12/2020 05/11/2020 04/07/2020 OFFICE NRR/DORL/BC NRR/DORL/LPL1/PM NAME JDanna VSreenivas DATE 06/02/2020 06/02/2020