ML17145A552
| ML17145A552 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 08/11/2017 |
| From: | Undine Shoop Plant Licensing Branch II |
| To: | James Shea Tennessee Valley Authority |
| Saba F DORL/LPL2-2 301-415-1447 | |
| References | |
| CAC MF9087, CAC MF9088, CAC MF9089 | |
| Download: ML17145A552 (9) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 August 11, 2017 Mr. Joseph W. Shea, Vice President Nuclear Regulatory Affairs and Support Services Tennessee Valley Authority 1101 Market Street, LP 3R-C Chattanooga, TN 37 402-2801
SUBJECT:
BROWNS FERRY NUCLEAR PLANT, UNITS 1, 2, AND 3 - ALTERNATIVE REQUEST NO. IST-RR-1 FOR THE FOURTH 10-YEAR INSERVICE TESTING INTERVAL AT BROWNS FERRY NUCLEAR PLANT UNITS 1, 2, AND 3 (CAC NOS. MF9087, MF9088, AND MF9089)
Dear Mr. Shea:
By letter dated January 17, 2017, Tennessee Valley Authority (the licensee) submitted a request to the Nuclear Regulatory Commission (NRG), for the use of 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 programs at Browns Ferry Nuclear Plant (Browns Ferry), Units 1, 2, and 3.
Specifically, pursuant to Title 1 O of the Code of Federal Regulations (1 O CFR) 50.55a(z)(2), the licensee requested to use the proposed alternative Code Case OMN-20 in Relief Request No IST-RR-1 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 NRG staff reviewed the subject request and determined that for Relief Request No. IST-RR-1 (use of Code Case OMN-20), the proposed alternative provides reasonable assurance that the affected components are operationally ready and that 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 NRG staff concludes that the licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(z)(2).
Therefore, the NRG staff authorizes alternative request IST-RR-1 for the Browns Ferry, Units 1, 2, and 3, fourth 10-year inservice testing interval program. All other ASME Code,Section XI requirements for which relief was not specifically requested and approved remain applicable, including third-party review by the Authorized Nuclear lnservice Inspector.
J.Shea If you have any questions, please contact the Project Manager, Farideh Saba, at (301) 415-1447 or farideh.saba@nrc.gov.
Docket Nos. 50-259, 50-260, and 50-296
Enclosure:
Safety Evaluation cc w/encl: Distribution via Listserv Sincerely,
~~
Undine Shoop, Chief Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELIEF REQUEST NO. IST-RR-1 REGARDING ALTERNATIVE TO THE FOURTH 10-YEAR INSERVICE TESTING INTERVAL TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT, UNITS 1, 2, AND 3 DOCKET NOS. 50-259, 50-260, AND 50-296
1.0 INTRODUCTION
By letter dated January 17, 2017, Tennessee Valley Authority (the licensee) submitted a request to the Nuclear Regulatory Commission (NRC), for the use of 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 programs at Browns Ferry Nuclear Plant (Browns Ferry), Units 1, 2, and 3.
Specifically, pursuant to Title 1 O of the Code of Federal Regulations (1 O CFR) 50.55a(z)(2), the licensee requested to use the proposed alternative Code Case OMN-20 in Relief Request No IST-RR-1 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
The regulations in 10 CFR 50.55a(f), "lnservice Testing Requirements," require that the IST of certain ASME Code Class 1, 2, and 3 components must meet the requirements of the ASME OM Code and applicable addenda, except where alternatives have been authorized by the NRC pursuant to 10 CFR 50.55a(z)(1) or 1 O CFR 50.55a(z)(2).
The regulations in 1 O CFR 50.55a(z) state that alternatives to the requirements of 1 O CFR 50.55a(f) may be authorized by the NRG 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 authorize the alternative proposed by the licensee.
Enclosure 3.0 Technical Evaluation Applicable Code Requirements This request applies to the frequency specifications of the ASME OM Code for all pumps and valves testing contained within the IST program scope. 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 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-Year Test Interval," states, in part, "Class 2 and 3 pressure relief valves, with the exception of PWR main steam safety valves, shall be tested every 1 O 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 non-reclosing 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 Relief Devices 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 1 O 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 1 O years, unless performance data indicate more frequent replacements are necessary."
Mandatory Appendix II, "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-3120, "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) or on the occurrence of plant conditions or events (e.g., cold shutdown, refueling outage, upon detection of a sample failure, following maintenance) without any tolerance.
Applicable Code Edition and Addenda
The Code of Record for Browns Ferry, Units 1, 2 and 3, fourth 10-year IST program is the 2004 Edition through 2006 Addenda of the ASME OM Code.
Components for Which Alternative Relief is Requested All pumps and valves contained within the Browns Ferry, Units 1, 2, and 3, fourth 10-year IST interval program scope.
Reason for Request
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 2012-10, "NRC Staff Position on Applying Surveillance Requirements 3.0.2 and 3.0.3 to Administrative Controls Program Tests" (ADAMS Accession No. ML12079A393), states that SAs 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 for TS SRs as described in TS SR 3.0.2. The lack of a similar tolerance in the ASME OM Code testing intervals places an unusual hardship on the plant by requiring them to perform the tests when the plant conditions may not be ideal and challenging the ability to schedule other maintance and testing activities.
Allowing a testing frequency range would assure operational flexibility when scheduling IST that would minimize the conflicts between the need to complete the testing and plant conditions.
Proposed Alternative The licensee proposed to perform the IST per ASME OM Code Case OMN-20 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 utilized at Browns Ferry, Units 1, 2 and 3, for the fourth 10-year IST interval until Code Case OMN-20 is incorporated into 10 CFR 50.55a. This proposed alternative at Browns Ferry, Units 1, 2, and 3, 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, Division 1, Section IST, and earlier editions and addenda of the ASME OM Code, specify component 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.).
(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 below.
Frequency Specified Time Period Between Tests Quarterly 92 days (or every 3 months)
Semiannually 184 days (or every 6 months)
Annually 366 days (or every year) x Years x calendar years L
where x rs a whole number of years ~ 2 The specified time period between tests may be reduced or extended as follows:
(1)
For periods specified as less than two years, the period may be extended by up to 25 percent for any given test.
(2)
For periods specified as greater than or equal to two years, 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 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 less than 2-year test frequencies not specified in the table above.
Period extensions may not be applied to the test frequency requirements specified in ASME OM Code 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.
A similar alternative request was authorized for the Grand Gulf Nuclear Station, Unit 1, by the NRC in a letter dated June 16, 2016 (ADAMS Accession No. ML16160A092).
NRC Staff Evaluation
Historically, licensees have applied, and the NRC staff has accepted, the Standard Technical Specificaiton definitions for IST intervals (including allowable interval) extensions to ASME OM Code-required testing (Reference NUREG-1482, Revision 2, Section 3.1.3). As noted in Regulatory Issue Summary 2012-10, the NRC determined that programmatic test frequencies can not be extended in accordance with 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. However, the NRC staff recognizes that some tolerance is needed to allow adjusting the ASME OM Code testing intervals. To provide operational flexibility when scheduling 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. 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 acceptanGe 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 the ASME OM Code.
4.0 CONCLUSION
As set forth above, the NRC staff determined that the proposed alternative in Relief Request No. IST-RR-1 (use of Code Case OMN-20), provides reasonable assurance that the affected components are operationally ready, and that 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 IST-RR-1 for the Browns Ferry, Units 1, 2, and 3, fourth 10-year IST interval program. 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: August 11, 2017
SUBJECT:
BROWNS FERRY NUCLEAR PLANT, UNITS 1, 2, AND 3-ALTERNATIVE REQUEST IST-RR-1 FOR THE FOURTH 10-YEAR INSERVICE TESTING INTERVAL AT BROWNS FERRY NUCLEAR PLANT UNITS 1, 2, AND 3 (CAC NOS. MF9087, MF9088, AND MF9089) DATED AUGUST 11, 2017 DISTRIBUTION:
PUBLIC LPL2-2 r/f RidsNrrDorllpl2-2 Resource RidsACRS_MailCTR Resource RidsN rrPMBrownsFerry Resource JBowen, OEDO GBedi, NRA RidsNrrDeEpnb Resource RidsNrrLABClayton Resource RidsRgn2MailCenter Resource ADAMS A ccess1on N ML17145A552 o.:
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- 1 1y e-ma1 OFFICE NRR/DORULPL2-2/PM NRR/DORULPL2-2/LA NRR/DE/EPNB/BC*
NAME FSaba BClayton DAiiey (LRonewicz for)
DATE 06/29/2017 06/28/2017 05/11/2017 OFFICIAL RECORD COPY NRR/DORULPL2-2/BC US hoop 08/11/2017