ML20169A652
| ML20169A652 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 07/08/2020 |
| From: | Robert Kuntz Plant Licensing Branch III |
| To: | Peter Dietrich DTE Electric Company |
| Arora S, NRR/DORL, 415-1421 | |
| References | |
| EPID L-2019-LLR-0098 | |
| Download: ML20169A652 (12) | |
Text
July 8, 2020 Mr. Peter Dietrich, Senior Vice President and Chief Nuclear Officer DTE Energy Company Fermi 2 - 260 TAC 6400 North Dixie Highway Newport, MI 48166
SUBJECT:
FERMI 2 - REVISED VALVE TESTING RELIEF REQUEST VRR-004 FOR THE INSERVICE TESTING PROGRAM FOURTH 10-YEAR INTERVAL (EPID L-2019-LLR-0098)
Dear Mr. Dietrich:
By letter dated October 8, 2019 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML19281C656), DTE Energy Company (DTE, the licensee), submitted relief request VRR-004 to the U.S. Nuclear Regulatory Commission (NRC). The licensee requested an alternative test plan in lieu of certain inservice testing (IST) requirements of the 2012 Edition of the American Society of Mechanical Engineers (ASME) Operation and Maintenance of Nuclear Power Plants (OM Code) at Fermi 2.
Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Section 50.55a(z)(1), the licensee requested to use proposed alternatives VRR-004 on the basis that the alternatives provide an acceptable level of quality and safety.
The NRC staff has reviewed the subject request and concludes that the proposed alternatives described in request VRR-004 provides an acceptable level of quality and safety for components listed in Table 1 of the enclosed safety evaluation. Accordingly, the NRC staff concludes that DTE has adequately addressed all the regulatory requirements set forth in 10 CFR 50.55a(z)(1).
All other ASME OM Code requirements for which relief was not specifically requested and approved in the subject requests for relief remain applicable.
P. Dietrich
If you have any questions, please contact the Project Manager, at 301-415-1421 or e-mail at Surinder.Arora@nrc.gov.
Sincerely, Nancy L. Salgado, Chief Plant Licensing Branch III Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-341
Enclosure:
Safety Evaluation cc: ListServ Robert F.
Kuntz Digitally signed by Robert F. Kuntz Date: 2020.07.08 08:27:22 -04'00'
Enclosure SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION 10 CFR 50.55a REQUEST VRR-004, REVISION 1 PROPOSED ALTERNATIVE TO CONFIRM OBTURATOR POSITION AT SEAT LEAKAGE TESTING FREQUENCY FOURTH 10-YEAR INSERVICE TESTING INTERVAL DTE ELECTRIC COMPANY FERMI 2 DOCKET 50-341
1.0 INTRODUCTION
By letter dated June 14, 2019 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML19165A134), DTE Energy Company (DTE, the licensee), submitted requests VRR-004 and VRR-007 for the fourth 10-year inservice testing (IST) program interval for the Fermi (Fermi 2) to the U.S. Nuclear Regulatory Commission (NRC). By letter dated July 30, 2019 (ADAMS Accession No. ML19197A287), the NRC indicated additional information was needed to begin its detailed technical review of the requests. Following a clarification call between DTE and the NRC staff on July 24, 2019, DTE further reviewed the testing activities associated with each of the components listed in requests VRR-004 and VRR-007. DTE determined that existing activities performed at Fermi 2 would meet the requirements for some of the valves without the need for an alternative. For the subset of valves that remained in scope and where an alternative was still necessary, DTE indicated that additional information would need to be gathered to address the information requested by the NRC in its letter. DTE submitted a follow-up letter to withdraw VRR-004 and VRR-007, dated August 7, 2019 (ADAMS Accession No. ML19219A104), which the NRC acknowledged by letter dated August 14, 2019 (ADAMS Accession No. ML19219A775).
By letter dated October 8, 2019 (ADAMS Accession No. ML19281C656), DTE submitted request VRR-004, Revision 1, which reduced the scope of components in the request, and addressed the information requested by the NRC in letters dated July 30, 2019, and August 14, 2019. In response to a clarification call on February 27, 2020, the licensee submitted an e-mail (ADAMS Accession No. ML20073E422) to supplement its October 8, 2019, submittal. In its revised request, the licensee proposed an alternative to the required verification of valve obturator position by using seat leakage testing at the determined seat leakage testing frequency.
2.0 REGULATORY EVALUATION
The NRC regulations in Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Section 55a, paragraph (f)(4)(ii), Applicable IST Code: Successive 120-month intervals, state that ISTs to verify operational readiness of pumps and valves, whose function is required for safety, conducted during successive 120-month intervals must comply with the requirements of the latest edition and addenda of the American Society of Mechanical Engineers (ASME)
Operation and Maintenance of Nuclear Power Plants, Division 1, OM Code: Section IST (OM Code), incorporated by reference in 10 CFR 50.55a(a)(1)(iv) 12 months before the start of the 120-month interval (or the optional ASME Code Cases listed in NRC Regulatory Guide (RG) 1.147, Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1 (ADAMS Accession No. ML16321A336), or RG 1.192, Operation and Maintenance Code Case Acceptability, ASME OM Code, Revision 3 (ADAMS Accession No. ML19128A261), as incorporated by reference in 10 CFR 50.55a(a)(3)(ii) and (iii), respectively), subject to the conditions listed in 10 CFR 50.55a(b).
The regulation under 10 CFR 50.55a(z) states, 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.
Appendix J, Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors, Option B, Performance-Based Requirements, to 10 CFR Part 50 identifies performance-based requirements and criteria for preoperational and subsequent periodic leakage-rate testing for primary reactor containments. The performance-based testing program includes determination of appropriate leakage testing intervals. The NRC staff provides guidance in NUREG-1482, Revision 2, Guidance for Inservice Testing at Nuclear Power Plants (ADAMS Accession No. ML13295A020), for preparing requests for alternatives to the ASME OM Code requirements.
NRC Information Notice (IN) 2012-14, Motor-Operated Valve Inoperable Due to Stem-Disc Separation, highlights the need to supplement valve position indicating lights with other indications to provide assurance of proper obturator position.
2.1 Applicable ASME OM Code Requirements as Incorporated by Reference in 10 CFR 50.55a The 2012 Edition of the ASME OM Code, applies to the fourth interval of the Fermi 2 IST program. The Fermi 2 fourth 10-year IST program interval commenced on February 17, 2020, and ends on February 16, 2030.
The regulation under 10 CFR 50.55a(b)(3)(xi) states:
OM condition: Valve Position Indication. When implementing ASME OM Code, 2012 Edition, Subsection ISTC-3700, Position Verification Testing, licensees shall verify that valve operation is accurately indicated by supplementing valve position indicating lights with other indications, such as flow meters or other suitable instrumentation, to provide assurance of proper obturator position.
ASME OM Code (2012 Edition), Subsection ISTC, Inservice Testing of Valves in Light-Water Reactor Nuclear Power Plants, paragraph ISTC-3700, Position Verification Testing, states:
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 position indication observation should be supplemented by other indications such as use of flow meters or other suitable instrumentation 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 (2012 Edition), Mandatory Appendix III, Preservice and Inservice Testing of Active Electric Motor Operated Valve Assemblies in Light-Water Reactor Power Plants, paragraph III-3300, Inservice Test, subparagraph (e), states:
Remote position indication shall be verified locally during inservice testing or maintenance activities.
ASME OM Code (2012 Edition), Mandatory Appendix III, paragraph III-3310, Inservice Test Interval, states:
The inservice test interval determination shall include the following:
(a) The inservice test interval shall be determined in accordance with para. III-6440.
(b) If insufficient data exist to determine the inservice test interval in accordance with para. III-6400, then MOV inservice testing shall be conducted every two refueling cycles or 3 yr (whichever is longer) until sufficient data exist, from an applicable MOV or MOV group, to justify a longer inservice test interval.
(c) The maximum inservice test interval shall not exceed 10 yr. MOV inservice tests conducted per para. III-3400 may be used to satisfy this requirement.
3.0 TECHNICAL EVALUATION
3.1 List of Affected Components Table 1: List of Affected Components Valve ID Function ASME Code Class ASME OM Category Proposed Obturator Verification Frequency B2100F076A Feedwater Supply Check Air Operated Valve (AOV) 1 A/C Appendix J, Option B B2100F076B Feedwater Supply Check AOV 1
A/C Appendix J, Option B C4100F006 Standby Liquid Control (SLC)
Outboard Check Valve 1
A/C Appendix J, Option B
Valve ID Function ASME Code Class ASME OM Category Proposed Obturator Verification Frequency E1150F022 Residual Heat Removal (RHR)
Reactor Pressure Vessel (RPV) Head Spray Inboard and Outboard Containment Isolation Motor Operated Valve (MOV) 2 A
Appendix J, Option B E1150F023 RHR RPV Head Spray Inboard and Outboard Containment Isolation MOV 2
A Appendix J, Option B E4150F007 High Pressure Coolant Injection (HPCI) or Reactor Core Isolation Cooling (RCIC) Pump Discharge Isolation MOV 2
A Appendix J, Option B E5150F012 HPCI or RCIC Pump Discharge Isolation MOV 2
A Appendix J, Option B G1100F003 Radwaste Drywell Sump Pumps Outboard Containment Isolation AOV 2
A Appendix J, Option B G1100F019 Radwaste Drywell Sump Pumps Outboard Containment Isolation AOV 2
A Appendix J, Option B T2300F409 Primary Containment Suppression Chamber Reactor Building Vacuum Breaker Valves 2
A Appendix J, Option B T2300F410 Primary Containment Suppression Chamber Reactor Building Vacuum Breaker Valves 2
A Appendix J, Option B T4600F420 Standby Gas Treatment System (SGTS) Torus Hardened Vent Secondary Containment Inboard and Outboard Isolation AOV 2
A 3 Cycles T4600F421 SGTS Torus Hardened Vent Secondary Containment Inboard and Outboard Isolation AOV 2
A 3 Cycles T4800F416 Containment Atmospheric Control (CAC) N2 Inerting to Vacuum Breaker Valves (T2300F400A - T2300F400M)
N2 Supply Isolation AOV 2
A Appendix J, Option B T4800F417 CAC N2 Inerting to Vacuum Breaker Valves (T2300F400A - T2300F400M)
N2 Supply Isolation AOV 2
A Appendix J, Option B T4800F418 CAC N2 Inerting to Vacuum Breaker Valves (T2300F400A - T2300F400M)
N2 Supply Isolation AOV 2
A Appendix J, Option B T4800F419 CAC N2 Inerting to Vacuum Breaker Valves (T2300F400A - T2300F400M)
N2 Supply Isolation AOV 2
A Appendix J, Option B
Valve ID Function ASME Code Class ASME OM Category Proposed Obturator Verification Frequency XXT4800F420 CAC N2 Inerting to Vacuum Breaker Valve (T2300F400A - T2300F400M)
N2 Supply Isolation AOV 2
A Appendix J, Option B TXX4800F421 CAC N2 Inerting to Vacuum Breaker Valves (T2300F400A - T2300F400M)
N2 Supply Isolation AOV 2
A Appendix J, Option B T4X800F422 CAC N2 Inerting to Vacuum Breaker Valves (T2300F400A - T2300F400M)
N2 Supply Isolation AOV 2
A Appendix J, Option B T48X00F423 CAC N2 Inerting to Vacuum Breaker Valves (T2300F400A - T2300F400M)
N2 Supply Isolation AOV 2
A Appendix J, Option B T4800F424 CAC N2 Inerting to Vacuum Breaker Valves (T2300F400A - T2300F400M)
N2 Supply Isolation AOV 2
A Appendix J, Option B T4800F425 CAC N2 Inerting to Vacuum Breaker Valves (T2300F400A - T2300F400M)
N2 Supply Isolation AOV 2
A Appendix J, Option B T4800F426 CAC N2 Inerting to Vacuum Breaker Valves (T2300F400A - T2300F400M)
N2 Supply Isolation AOV 2
A Appendix J, Option B T4800F427 CAC N2 Inerting to Vacuum Breaker Valves (T2300F400A - T2300F400M)
N2 Supply Isolation AOV 2
A Appendix J, Option B T4800F456 CAC N2 Inerting to SGTS N2 Supply Bypass AOV 2
A Appendix J, Option B T4800F457 CAC N2 Inerting to SGTS N2 Supply Bypass AOV 2
A Appendix J, Option B T4800F458 CAC N2 Inerting to SGTS N2 Supply Bypass AOV 2
A Appendix J, Option B T4804F601A H2 Recombiner Isolation Valves 2
A Appendix J, Option B T4804F601B H2 Recombiner Isolation Valves 2
A Appendix J, Option B T4804F602A H2 Recombiner Isolation Valves 2
A Appendix J, Option B T4804F602B H2 Recombiner Isolation Valves 2
A Appendix J, Option B T4804F603A H2 Recombiner Isolation Valves 2
A Appendix J, Option B T4804F603B H2 Recombiner Isolation Valves 2
A Appendix J, Option B
Valve ID Function ASME Code Class ASME OM Category Proposed Obturator Verification Frequency T4804F604A H2 Recombiner Isolation Valves 2
A Appendix J, Option B T4804F604B H2 Recombiner Isolation Valves 2
A Appendix J, Option B T4804F605A H2 Recombiner Isolation Valves 2
A Appendix J, Option B T4804F605B H2 Recombiner Isolation Valves 2
A Appendix J, Option B T4804F606A H2 Recombiner Isolation Valves 2
A Appendix J, Option B T4804F606B H2 Recombiner Isolation Valves 2
A Appendix J, Option B T4901F465 Primary Containment (PC) Pneumatic Supply Outboard PC Isolation AOV 2
A Appendix J, Option B T4901F468 PC Pneumatic Supply Outboard PC Isolation AOV 2
A Appendix J, Option B T4901F601 PC Pneumatic Supply Inboard PC Isolation MOV 2
A Appendix J, Option B T4901F602 PC Pneumatic Supply Inboard PC Isolation MOV 2
A Appendix J, Option B T5000F420A Primary Containment Atmosphere Monitoring (PCAM) Outboard Sample Valves 2
A Appendix J, Option B T5000F420B Primary Containment Atmosphere Monitoring (PCAM) Outboard Sample Valves 2
A Appendix J, Option B T5000F455 PCAM PC Radiation Monitor Rack H21P284 Secondary Isolation AOV 2
A Appendix J, Option B 3.2 Proposed Alternative The licensee is proposing an alternative to perform the required verification of valve obturator position using seat leakage testing at the seat leakage testing interval specified by the 10 CFR Part 50, Appendix J, program, or for two specific valves (T4600F420 and T4600F421) once every three operating cycles. The valves applicable to this request are listed in Table 1 of this safety evaluation (SE). The licensee states that the frequency of valve obturator position verification will be aligned to the frequency of the seat leakage testing commensurate with the 10 CFR Part 50, Appendix J, Option B, performance-based leakage testing program at Fermi 2, which incorporates the guidance in Nuclear Energy Institute (NEI) 94-01, Revision 3-A, Industry Guideline for Implementing Performance-Based Option of 10 CFR Part 50, Appendix J (ADAMS Accession No. ML12221A202), and the conditions and limitations specified in NEI 94-01, Revision 2-A (ADAMS Accession No. ML100620847).
3.3
NRC Staff Evaluation
The ASME OM Code, Subsection ISTC, requires active and passive valves to be periodically tested in accordance with paragraph ISTC-3500, Valve Testing Requirements. Active valves are exercised at a frequency determined by paragraph ISTC-3510, Exercising Test Frequency.
Valves are nominally exercised every 3 months except where the exercise is not practicable when the plant is operating. During valve exercising, valve obturator movement is verified consistent with paragraph ISTC-3530, Valve Obturator Movement, which allows the use of remote position indicating lights that signal the change of obturator position to complete this test. However, the use of remote position indicating lights does not provide a positive verification that the valve operation is accurately achieved. To provide positive verification of valve obturator movement, the ASME OM Code, paragraph ISTC-3700, requires local observation of the valve exercise test every 2 years to verify that valve operation is accurately indicated. The ASME OM Code does not specify how positive verification of valve obturator movement is required to be completed. To supplement paragraph ISTC-3700, the NRC regulations in 10 CFR 50.55a(b)(3)(xi) require that the position verification test be supplemented with other indications, such as flow meters or other suitable instrumentation, to provide assurance of proper obturator position and valve operation.
Both the open and closed positions of the valve need to be verified to satisfy the obturator position verification requirement. For Fermi 2, the licensee discussed its capability to verify the open and close obturator position for each of the valves within the scope of its alternative request. For example, the licensee discussed pump operations or testing to provide flow to demonstrate the open position of the obturator for several valves. Where plant operations are not available to verify the open valve obturator position, the licensee requested to perform this verification as part of the closed valve obturator position activities.
For verification of the closed valve obturator position, the licensee described the need for an alternative for the specific valves within the scope of its request. In particular, the licensee asserts that for all 47 valves in its request, utilizing existing seat leakage testing is the only practical method to verify the closed valve obturator position. As detailed in its submittal, the licensee states that verification of the open position for 14 of the 47 valves will be performed during other plant operations or testing, and thus an alternative is not needed to verify the open obturator position for those valves. For the remaining 33 valves, the licensee asserts that there is no practical method to use process indications or system parameters to verify the open valve obturator position, so the verification of the open position will be performed using seat leakage testing activities at the same interval as the verification for the closed valve position.
The NRC staff considers the proposed use of seat leakage testing to be an acceptable method to verify the obturator closed position, which provides reasonable assurance that the stem and disc assembly is intact and that the valve can be relied upon to perform its closed safety function. The staff considers leakage testing to satisfy the requirements of paragraph ISTC-3700 and 10 CFR 50.55a(b)(3)(xi) to verify the closed obturator position of the valve. Where process indications or system parameters are not available to verify the open valve obturator position, the licensee is permitted to develop a means to demonstrate that the valve obturator moves to the open position as part of the leakage testing activities.
In its request, the licensee proposed alternative test frequencies in lieu of the 2-year interval specified in ASME OM Code, Subsection ISTC, paragraph ISTC-3700, as supplemented by 10 CFR 50.55a(b)(3)(xi), for the valves listed in Table 1 of this SE. Specifically, for 45 out of the 47 subject valves, the licensee proposes to functionally test and verify valve operation is
accurately indicated on a schedule consistent with its 10 CFR Part 50 Appendix J, Option B, program, which the NRC approved for Fermi 2 in 1996 (ADAMS Accession No. ML020730597).
By the licensees proposed alternative, the valves would initially be tested at an interval currently every refueling outage (RFO) or 2 years as specified by paragraph ISTC-3700.
Thereafter, valves that have demonstrated good performance for two consecutive cycles could have their test interval extended, not to exceed 75 months. The licensee indicates that any valve position indication verification test failure would require the component to return to the initial interval of every RFO or 2 years until good performance can again be established.
The licensee noted that two out of the 47 subject valves would not use the 10 CFR Part 50, Appendix J, Option B, program schedule. For these two valves, Standby Gas Treatment System (SGTS) Torus Hardened Vent Secondary Containment Inboard and Outboard Isolation Air Operated Valves (T4600F420 and T4600F421), the licensee proposed leak rate testing as follows: (1) prior to first declaring the system functional; (2) once every three operating cycles thereafter; and (3) after restoration of any breach of system boundary within buildings. This proposal is similar to guidance provided in NEI 13-02, Industry Guidance for Compliance with Order EA-13-109: BWR Mark I & II Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (ADAMS Accession No. ML15054A355). In the scope of this safety review, the NRC staff did not review NEI 13-02 for acceptability and is only basing its decision on the assumption that the frequency of obturator position verification, by way of leak rate testing, will be conducted at least once every three operating cycles.
The NRC staff reviewed the operational history of valves listed in Table 1 of this SE in NRC staff-maintained databases and found no occurrences of valve stem-disc separation.
Additionally, all of the valves listed in Table 1 will continue to have a combination of at least two of the following activities on a regularly scheduled basis: (1) scheduled actuator maintenance, (2) stroke timing testing, (3) position indication testing, (4) exercise test, and (5) diagnostic testing, which provides further assurance that any potential degradation of the valves is detectable. Maintenance that is performed that might affect valve position indication will be followed by applicable post-maintenance testing, including position indication testing and obturator verification. The NRC staff considers that an extension of the valve position verification test interval based on good performance is acceptable for a well-implemented performance-based valve program.
In summary, the NRC staff finds for the valves in Table 1 of this SE, that plant operations and testing to verify the open valve obturator position, where available, and seat leakage testing performed on the 10 CFR Part 50, Appendix J, Option B, program schedule, or once every three cycles for valves T4600F420 and T4600F421, in addition to periodic maintenance and testing, to verify the close valve obturator position (with supplemental activities for open valve obturator verification as necessary) provide reasonable assurance that potential degradation of the stem and disc assembly will be identified for repair prior to failure of the valve stem-disc connection.
4.0 CONCLUSION
Based on the above evaluation, the NRC staff finds that request VRR-004, Revision 1, for Fermi 2 specifies a proposed alternative testing methodology and schedule for obturator position testing for the valves specified in the request that will provide reasonable assurance that the stem and disc connection assembly in the valves will be maintained. Therefore, the NRC staff concludes that request VRR-004, Revision 1, for Fermi 2 may be authorized in accordance with 10 CFR 50.55a(z)(1) by providing an acceptable level of quality and safety in lieu of the requirements in the ASME OM Code as supplemented by 10 CFR 50.55a(b)(3)(xi) for
valve obturator position verification by providing reasonable assurance that the specified valves are operationally ready to perform their safety functions. All other ASME OM Code requirements for which relief or an alternative was not specifically requested and approved as part of this subject request remain applicable. The NRC authorizes request VRR-004, Revision 1, for the fourth 10-year IST program interval at Fermi 2, which commenced on February 17, 2020, and ends on February 16, 2030.
Principal Contributor: I. Tseng Date: July 8, 2020
ML20169A652 *- By email OFFICE NRR/DORL/LPL3/PM NRR/DORL/LPL3/LA NRR/DEX/EMIB/BC*
NRR/DORL/LPL3/BC NAME SArora SRohrer ABuford NSalgado (RKuntz for)
DATE 06/ 12 /2020 06/ 18 /2020 06/ 19 /2020 07/8/2020