ML17122A157

Request for Alternative to Use Code Case OMN-20 for the Fifth 10-Year Inservice Testing Interval

ML17122A157
Person / Time
Site:	Monticello
Issue date:	05/15/2017
From:	David Wrona Plant Licensing Branch III
To:	Gardner P Northern States Power Company, Minnesota
Kuntz R
References
CAC MF8216
Download: ML17122A157 (10)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 May 15, 2017 Mr. Peter A. Gardner Site Vice President Monticello Nuclear Generating Plant Northern States Power Company - Minnesota (NSPM) 2807 West County Road 75 Monticello, MN 55362-9637

SUBJECT:

MONTICELLO NUCLEAR GENERATING PLANT - REQUEST FOR ALTERNATIVE TO USE CODE CASE OMN-20 FOR THE FIFTH 10-YEAR INSERVICE TESTING INTERVAL (CAC NO. MF8216)

Dear Mr. Gardner:

By letter dated July 28, 2016, as supplemented by letter dated January 4, 2017, the Northern States Power Company- Minnesota (NSPM or the licensee) submitted Request for Alternative PR 07 for the fifth 10-year inservice testing (IST) interval for Monticello Nuclear Generating Plant (MNGP) to use American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance (OM) 2004 Edition through the 2006 Addenda, Code Case OMN-20, "lnservice Test Frequency." The proposed duration of this alternative is for the current 10-year IST interval or until the Code Case OMN-20 is incorporated in Title 10 of the Code of Federal Regulations (10 CFR) 50.55a.

Specifically, pursuant to 10 CFR 50.55a(z)(2), the licensee requested to use the proposed alternative, Code Case OMN-20, on the basis that it provides reasonable assurance that the components are operationally ready and that compliance with the ASME OM Code requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

The U.S. Nuclear Regulatory Commmission (NRC) staff reviewed the proposed alternative and determined, as set forth in the enclosed safety evaluation, that for request PR 07 (use Code Case OMN-20), the proposed alternative provides reasonable assurance that the affected components are operationally ready, and complying with the ASME OM Code requirements 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 all of the regulatory requirements set forth in 10 CFR 50.55a(z)(2).

Therefore, the NRC staff authorizes alternative request PR 07 for the MNGP current 10-year IST interval which ends May 31, 2022, or until Code Case OMN-20 is incorporated into 10 CFR 50.55a. All other ASME OM Code requirements for which relief was not specifically requested and approved in the subject request remain applicable.

P. Gardner If you have any questions, please contact Robert Kuntz at 301-415-3733, or via e-mail at Robert. Kuntz@nrc.gov.

Sincerely, c)~J 9 v* I David J. Wrona, Chief Plant Licensing Branch Ill Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-263

Enclosure:

Safety Evaluation cc w/enclosure: Distribution via ListServ

ML17122A157 *by e-mail OFFICE DORL/LPL3/PM DORL/LPL 1-1/LA DE/EVIB/BC DORL/LPL3-1 /PM NAME RKuntz SRohrer DAiiey* DWrona DATE 05/02/17 05/02/17 04/26/17 05/15/17 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REQUEST FOR ALTERNATIVE PR 07 TO USE CODE CASE OMN-20 FOR THE FIFTH 10-YEAR INSERVICE TESTING INTERVAL NORTHERN STATES POWER COMPANY - MINNESOTA MONTICELLO NUCLEAR GENERATING PLANT DOCKET NO. 50-263

1.0 INTRODUCTION

By letter dated July 28, 2016 (Agencywide Documents and Access Management System (ADAMS) Accession No. ML 1621 OA030), as supplemented by letter dated January 4, 2017 (ADAMS Accession No. ML17004A208), Northern States Power Company (NSPM, or the licensee), doing business as Xcel Energy, submitted request for relief to the U.S. Nuclear Regulatory Commission (NRC), proposing alternatives to certain requirements of the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code), for the current inservice testing (IST) programs at Monticello Nuclear Generating Plant (MNGP).

Request No. PR 07 proposes an alternative for the fifth 10-year IST interval for MNGP to use ASME OM Code 2004 Edition through the 2006 Addenda, Code Case OMN-20, "lnservice Test Frequency." The proposed duration of this alternative is for the current 10-year IST interval or until the Code Case OMN-20 is incorporated in Title 1O of the Code of Federal Regulations (10 CFR) 50.55a.

Specifically, pursuant to 10 CFR 50.55a(z)(2), the licensee requested to use the proposed alternative Code Case OMN-20 in Relief Request No. PR 07 on the basis that it provides reasonable assurance that the components are operationally ready and that compliance with the ASME OM Code requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

2.0 REGULATORY EVALUATION

10 CFR 50.55a(f), "lnservice Testing Requirements," requires, in part, that the IST of certain ASME Code Class 1, 2, and 3 components must meet the requirements of the ASME OM Code Enclosure

and applicable addenda, except where alternatives have been authorized by the NRC pursuant to 10 CFR 50.55a(z)(1) or 10 CFR 50.55a(z)(2).

The regulations in 10 CFR 50.55a(z), state, in part, that alternatives to the requirements of 10 CFR 50.55a(f) may be authorized by the NRC if the licensee demonstrates that: (1) the proposed alternative provides an acceptable level of quality and safety (10 CFR 50.55a(z)(1 )),

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 (10 CFR 50.55a(z)(2)).

Based on the above, and subject to the following technical evaluation, the NRC staff finds that regulatory authority exists for the licensee to request and the NRC to grant the relief requested by the licensee.

3.0 TECHNICAL EVALUATION

3.1 Licensee's Alternative Request No. PR 07 for the Use of Code Case OMN-20 3.1.1 Applicable Code Requirements This request applies to the frequency specifications of the ASME OM Code. The frequencies for tests given in the ASME OM Code include the following but do not include a tolerance band:

ISTA-3120, "lnservice Test Interval," (a) states, 'The frequency for inservice testing shall be in accordance with the requirements of Section IST."

ISTB-3400, "Frequency of lnservice Tests," states, "An inservice test shall be run on each pump as specified in Table ISTB-3400-1."

Table ISTB-3400-1, "lnservice Test Frequency," notes that Group A and Group B pump tests are to be conducted quarterly and comprehensive pump tests are to be conducted biennially.

ISTC-3510, "Exercising Test Frequency," states, "Active Category A, Category B, and Category C check valves shall be exercised nominally every 3 months, except as provided by ISTC-3520, ISTC-3540, ISTC-3550, ISTC-3570, ISTC-5221, and ISTC-5222. Power-operated relief valves shall be exercise tested once per fuel cycle."

ISTC-3540, "Manual Valves," states, "Manual valves shall be full-stroke exercised at least once every 2 years, except where adverse conditions may require the valve to be tested more frequently to ensure operational readiness. Any increased testing frequency shall be specified by the Owner. The valve shall exhibit the required change of obturator position."

ISTC-3630, "Leakage Rate for Other Than Containment Isolation Valves," (a) "Frequency,"

states, "Tests shall be conducted at least once every 2 years."

ISTC-3700, "Position Verification Testing," states, in part, "Valves with remote position indicators shall be observed locally at least once every 2 years to verify that valve operation is accurately indicated."

ISTC-5221, "Valve Obturator Movement," (c)(3), states, "At least one valve from each group shall be disassembled and examined at each refueling outage; all valves in each group shall be disassembled and examined at least once every 8 years."

Mandatory Appendix I, "lnservice Testing of Pressure Relief Devices in Light-Water Reactor Nuclear Power Plants," 1-1320, "Test Frequencies, Class 1 Pressure Relief Valves," (a), "5-Year Test Interval," states, in part, "Class 1 pressure relief valves shall be tested at least once every 5 years, starting with initial electric power generation."

Mandatory Appendix I, 1-1330, "Test Frequency, Class 1 Nonreclosing Pressure Relief Devices,"

states, "Class 1 nonreclosing pressure relief devices shall be replaced every 5 years unless historical data indicates a requirement for more frequent replacement."

Mandatory Appendix I, 1-1340, Test Frequency, Class 1 Pressure Relief Valves That Are Used for Thermal Relief Application," states, "Tests shall be performed in accordance with 1-1320, Test Frequencies, Class 1 Pressure Relief Valves."

Mandatory Appendix I, 1-1350, "Test Frequency, Classes 2 and 3 Pressure Relief Valves," (a),

"10-YearTest Interval," states, in part, "Class 2 and 3 pressure relief valves, with the exception of PWR [pressurized water reator] main steam safety valves, shall be tested every 10 years, starting with initial electric power generation."

Mandatory Appendix I, 1-1360, "Test Frequency, Classes 2 and 3 Nonreclosing Pressure Relief Devices," states, "Classes 2 and 3 nonreclosing pressure relief devices shall be replaced every 5 years, unless historical data indicates a requirement for more frequent replacement."

Mandatory Appendix I, 1-1370, Test Frequency, Classes 2 and 3 Primary Containment Vacuum Relief Valves," states, "(a) Tests shall be performed on all Classes 2 and 3 containment vacuum relief valves at each refueling outage or every 2 years, whichever is sooner, unless historical data requires more frequent testing. (b) Leak tests shall be performed on all Classes 2 and 3 containment vacuum relief valves at a frequency designated by the Owner in accordance with Table ISTC-3500-1."

Mandatory Appendix I, 1-1380, Test Frequency, Classes 2 and 3 Vacuum Relief Valves, Except for Primary Containment Vacuum Relief Valves," states, "All Classes 2 and 3 vacuum relief valves shall be tested every 2 years, unless performance data suggest the need for a more appropriate test interval."

Mandatory Appendix I, 1-1390, "Test Frequency, Classes 2 and 3 Pressure ReliefDevices That Are Used for Thermal Relief Application," states, "Tests shall be performed on all Classes 2 and 3 relief devices used in thermal relief application every 10 years, unless performance data indicate more frequent testing is necessary. In lieu of tests the Owner may replace the relief devices at a frequency of every 10 years, unless performance data indicate more frequent replacements are necessary."

Mandatory Appendix 11, "Check Valve Condition Monitoring Program," 11-4000, "Condition-Monitoring Activities," (a), "Performance Improvement Activities," (1 ), states, in part, "If sufficient information is not currently available to complete the analysis required in 11-3000, or if this analysis is inconclusive, then the following activities shall be performed at sufficient intervals over an interim period of the next 5 years or two refueling outages, whichever is less, to determine the cause of failure or the maintenance patterns."

Mandatory Appendix II, 11-4000, (b), "Optimization of Condition-Monitoring Activities," (1 )(e),

states, "Identify the interval of each activity. Interval extensions shall be limited to one fuel cycle per extension. Intervals shall not exceed the maximum intervals shown in Table 11-4000-1. All valves in a group sampling plan must be tested or examined again, before the interval can be extended again, or until the maximum interval would be exceeded. The requirements of ISTA-120, lnservice Test Interval, do not apply."

In summary, ASME OM Code, Division 1, Section IST, 2009 Edition through OMa-2011 Addenda and all earlier editions and addenda specify component (pump and valve) test frequencies based either on elapsed time periods (e.g., quarterly, 2 years, etc.) or on the occurrence of plant conditions or events (e.g., cold shutdown, refueling outage, upon detection of a sample failure, following maintenance, etc.) without any tolerance.

3.1.2 Applicable Code Edition and Addenda The Code of Record for MNGP fifth 10-year IST program is the 2004 Edition through 2006 Addenda of ASME OM Code. The MNGP current (fifth) 10-year IST interval ends May 31, 2022.

3.1.3 Components for which Alternative Relief is Requested All pumps and valves contained within the MNGP IST program's scope.

3.1.4 Licensee's Reason for Requesting Relief ASME OM Code Section IST establishes the inservice test frequency for all components within the scope of the code. The frequencies (e.g., quarterly) have always been interpreted as "nominal" frequencies (generally as defined in the Table 3.2 of NUREG-1482, Revision 2) and owners routinely applied the surveillance extension time period (i.e., grace period) contained in the plant technical specification (TS) surveillance requirements (SRs). The TSs typically allow for a less than or equal to 25 percent extension of the surveillance test interval to accommodate plant conditions that may not be suitable for conducting a TS surveillance (SR 3.0.2). However, Regulatory Issue Summary (RIS) 2012-10, "NRC Staff Position on Applying Surveillance Requirements 3.0.2 and 3.0.3 to Administrative Controls Program Tests," states that SRs 3.0.2 and 3.0.3 cannot be applied to TS 5.5, "Programs and Manuals," for tests that are not associated with a TS SR The lack of a tolerance band on the ASME OM Code IST frequency restricts operational flexibility. The NRC recognized this potential issue in the TSs by allowing a frequency tolerance as described in TS SR 3.0.2. The lack of a similar tolerance applied to the ASME OM Code

testing places an unusual hardship on the plant to adequately schedule work tasks without operational flexibility.

With the TS-required surveillance testing, some tolerance is needed to allow adjusting ASME OM Code testing intervals to suit the plant conditions and other maintenance and testing activities. This assures operational flexibility when scheduling IST that would minimize the conflicts between the need to complete the testing and plant conditions.

3.1.5 Licensee's Proposed Alternative The licensee proposed to perform IST per ASME OM Code Case OMN-20, repeated below, for determining acceptable tolerances for pump and valve test frequencies. This Code Case was approved by the ASME OM Code Standards Committee in February 2012, and subsequently published in the 2012 Edition through 2015 Edition of the ASME OM Code. The proposed alternative will be used for the current 10-year IST intervals at MNGP and will apply to the various frequency specifications of the ASME OM Code for all pumps and valves contained within the IST Program scope.

ASME OM Code Case OMN-20, "lnservice Test Frequency" ASME OM Code Case OMN-20 states the following:

ASME OM, Division 1, Section IST and all earlier editions and all addenda [of ASME OM Code] specify component test frequencies based either on elapsed time periods (e.g., quarterly, 2 yr [years], etc.) or on the occurrence of plant conditions or events (e.g., cold shutdown, refueling outage, upon detection of a sample failure, following maintenance, etc.).

(a) Components whose test frequencies are based on elapsed time periods shall be tested at the frequencies specified in Section IST with a specified time period between tests as shown in the Table 1. The specified time period between tests may be reduced or extended as follows:

(1) For periods specified as less than 2 yr, the period may be extended by up to 25% for any given test.

(2) For periods specified as greater than or equal to 2 yr, the period may be extended by up to 6 months for any given test.

(3) All periods specified may be reduced at the discretion of the owner (i.e.,

there is no minimum period requirement).

Period extension is to facilitate test scheduling and considers plant operating conditions that may not be suitable for performance of the required testing (e.g.,

performance of the test would cause an unacceptable increase in the plant risk profile due to transient conditions or other ongoing surveillance, test, or maintenance activities). Period extensions are not intended to be used

repeatedly but merely as an operational convenience to extend test intervals beyond those specified.

Period extensions may also be applied to accelerated test frequencies (e.g.,

pumps in alert range) and other fewer than 2-yr test frequencies not specified in Table 1.

Period extensions may not be applied to the test frequency requirements specified in Subsection ISTD, Preservice and lnservice Examination and Testing of Dynamic Restraints (Snubbers) in Light-water Reactor Nuclear Power Plants, as Subsection ISTD contains its own rules for period extensions.

(b) Components whose test frequencies are based on the occurrence of plant conditions or events may not have their period between tests extended except as allowed by the ASME OM Code.

Table 1 Specified Test Frequencies Frequency Specified Time Period Between Tests Quarterly 92 days (or everv 3 months)

Semiannually 184 days (or everv 6 months)

Annually 366days (or everv vear}

x calendar years x Years where 'x' is a whole number of vears :.:: 2 3.1.5 NRC Staff Evaluation Historically, licensees have applied and the NRC staff has accepted, the standard TS definitions for IST intervals (including allowable interval) extensions to ASME OM Code required testing (reference NUREG-1482 Revision 2, Section 3.1.3). Recently, the NRC staff reconsidered the allowance of the TS testing intervals and interval extensions for IST not associated with TS SRs. As noted in RIS 2012-10, the NRC determined that programmatic test frequencies can't be extended in accordance with the TS SR 3.0.2. This includes all IST described in the ASME OM Code not specifically required by the TS SRs.

The lack of a tolerance band on the ASME OM Code IST frequency restricts operational flexibility. The NRC staff recognized that, just as with TS required surveillance testing, some tolerance is needed to allow adjusting ASME OM Code testing intervals to suit the plant conditions and other maintenance and testing activities. To provide operational flexibility when scheduling an IST that minimize the conflicts between the need to complete the testing and plant conditions, the NRC staff sponsored and co-authored an ASME OM Code inquiry and Code Case to modify the ASME OM Code to include TS-like test interval definitions and interval extension criteria. The resultant ASME-Approved Code Case OMN-20, as shown above, was

approved by the ASME Operation and Maintenance Standards Committee on February 15, 2012, with the NRC representative voting in the affirmative. Code Case OMN-20 was subsequently published in conjunction with the 2012 Edition through 2015 Edition of the ASME OM Code.

Requiring the licensee to meet the ASME OM Code requirements, without an allowance for defined frequency and frequency extensions for IST of pumps and valves, results is a hardship without a compensating increase in the level of quality and safety. Based on the licensee's proposal to adopt the ASME-Approved Code Case OMN-20 in its entirety and prior acceptance of the similar TS test interval definitions and interval extension criteria, the NRC staff finds that implementation of the ASME-approved OM Code Case OMN-20 provides reasonable assurance of operational readiness of pumps and valves subject to the IST requirements of ASME OM Code.

4.0 CONCLUSION

As set forth above, the NRC staff determines that for request PR 07 (use Code Case OMN-20),

the proposed alternative provides reasonable assurance that the affected components are operationally ready, and complying with the ASME OM Code requirements 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 all of the regulatory requirements set forth in 10 CFR 50.55a(z)(2).

Therefore, the NRC staff authorizes alternative request PR 07 for the MNGP current 10-year IST interval which ends May 31, 2022, or until Code Case OMN-20 is incorporated into 10 CFR 50.55a. All other ASME OM Code requirements for which relief was not specifically requested and approved in the subject request remain applicable.

Principal Contributor: Gurjendra S. Bedi Date of issuance: May 15, 2017