ML13297A246
| ML13297A246 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 10/30/2013 |
| From: | Travis Tate Plant Licensing Branch III |
| To: | Pacilio M Plant Licensing Branch III |
| Brenda Mozafari, NRR/DORL 415-2020 | |
| References | |
| TAC ME9867, TAC ME9868 | |
| Download: ML13297A246 (9) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 October 30, 2013 Mr. Michael J. Pacilio Senior Vice President Exelon Generation Company, LLC President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3- SAFETY EVALUATION IN SUPPORT OF REQUEST FOR RELIEF RV-02 ASSOCIATED WITH THE FIFTH 10-YEAR INTERVAL INSERVICE TESTING PROGRAM (TAC NOS. ME9867 AND ME9868)
Dear Mr. Pacilio:
By letter dated October 30, 2012, Exelon Generation Company, LLC (EGC), the licensee, submitted Relief Request RV-02 to the U.S. Nuclear Regulatory Commission (NRC). Pursuant to Title 10 of the Code of Federal Regulations 10 CFR 50.55a(a)(3)(i). The licensee requested authorization to use an alternative test instead of the requirements of the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code) for motor-operated valve (MOV) assemblies included in the MOV Program at Dresden Nuclear Power Station (DNPS), Units 2 and 3. The alternative of Relief Request RV-02 is applicable to the fifth 10-year inservice testing (1ST) program interval at DNPS.
The NRC staff has concluded that the proposed alternative RV-02 to implement ASME OMb Code 2006 Addenda Code Case OMN-1, with the conditions specified in Regulatory Guide 1.192 and with the exception that motor-control center test method will not be used, for MOV assemblies included in the MOV programs at DNPS, Unit 2 and Unit 3, provides an acceptable 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(a}{3}{i},
and is in compliance with the ASME OM Code's requirements. Therefore, the NRC staff authorizes the alternative in Relief Request RV-02 for the fifth 1ST interval for DNPS, Unit 2 and Unit 3, which is currently scheduled to start on November 1, 2013.
All requirements for which relief was not specifically requested and approved in the subject requests remain applicable.
M. Pacilio If you have any questions on this action, please contact the NRC Project Manager, Brenda Mozafari, at (301) 415-2020.
Sincerely,
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Travis L. Tate, Chief Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-237 and 50-249
Enclosure:
Safety Evaluation cc w/encl: Distribution via Listserv
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELIEF REQUEST RV-02 FOR THE FIFTH 10-YEAR INTERVAL INSERVICE TESTING PROGRAM EXELON GENERATION COMPANY, LLC DRESDEN NUCLEAR POWER STATION, UNIT NOS. 2 AND 3 DOCKET NOS. 50-237 AND 50-249
1.0 INTRODUCTION
By letter dated October 30, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12305A532), Exelon Generation Company, LLC (EGG, the licensee) submitted Relief Request RV-02 to the U.S. Nuclear Regulatory Commission (NRC).
The licensee requested authorization to use an alternative test instead of the requirements of the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code) for motor-operated valve (MOV) assemblies included in the MOV Program at Dresden Nuclear Power Station (DNPS), Units 2 and 3. Relief Request RV-02 is applicable to the fifth 10-year inservice testing (1ST} program interval at DNPS.
Specifically, pursuant to Title 10 of the Code of Federal Regulations (1 0 CFR) 50.55a(a)(3)(i),
the licensee requested to use ASME OM Code Case OMN-1 from the ASME OMb-2006 Addenda in lieu of meeting the test requirements of the ASME OM Code because the alternative provides an acceptable level of quality and safety for testing MOVs.
2.0 REGULATORY EVALUATION
Section 50.55a(f) of 10 CFR, "lnservice Testing Requirements," requires, in part, that the 1ST 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 pursuant to paragraphs (a)(3)(i) or (a)(3)(ii).
In proposing alternatives, a licensee must demonstrate that the proposed alternatives provide an acceptable level of quality and safety (1 0 CFR 50.55a(a)(3)(i)); or compliance would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety (10 CFR 50.55a(a)(3)(ii)). Section 50.55a allows the NRC to authorize alternatives to ASME OM Code requirements upon making necessary findings.
Enclosure
The DNPS fifth 10-year 1ST interval is currently scheduled to begin on November 1, 2013, and end on October 31, 2023. The applicable ASME OM Code edition and addenda for DNPS, Units 2 and 3, is the 2004 Edition through the 2006 Addenda.
Guidance documents NUREG-1482, Revision 1, "Guidance for lnservice Testing at Nuclear Power Plants," and Regulatory Guide (RG) 1.192, "Operation and Maintenance Code Case Acceptability, ASME OM Code," were applied for this relief request review. The NRC staff's findings with respect to authorizing alternatives to Relief Request RV-02 are given in the Safety Evaluation herein.
3.0 TECHNICAL EVALUATION
3.1 Licensee's Alternative Request RV-02 ISTA-3130 "Application of Code Cases," (b), states that "Code Cases shall be applicable to the edition and addenda specified in the test plan."
ISTC-31 00 "Preservice Testing," (a), states that "Any valve that has undergone maintenance that could affect its performance after the preservice test shall be tested in accordance with ISTC-3310."
ISTC-3310 "Effects of Valve Repair, Replacement, or Maintenance on Reference Values,"
states, in part, that "When a valve or its control system has been replaced, repaired, or has undergone maintenance that could affect the valve's performance, a new reference value shall be determined or the previous reference value be reconfirmed by an inservice test run before it is returned to service or immediately if not removed from service."
ISTC-3510 "Exercising Test Frequency" states, in part, that "Active Category A, Category B, and Category C check valves shall be exercised nominally every 3 months."
ISTC-3521 "Category A and Category B Valves" states, in part, that active Category A and B valves be exercised during cold shutdowns if it is not practicable to exercise the valves at power or that active Category A and B valves be exercised during refueling outages if it not practicable to exercise the valves during cold shutdowns.
ISTC-3700 "Position Verification Testing" states, in part, that "Valves with remote position indicators shall be observed locally at least once every 2 years to verify that valve operation is accurately indicated."
ISTC-5120 "Motor-Operated Valves," (a), states that "Active valves shall have their stroke times measured when exercised in accordance with ISTC-3500."
ASME OM Code Case OMN-1, "Alternative Rules for Preservice and lnservice Testing of Active Electric Motor-Operated Valve Assemblies in Light-Water Reactor (LWR) Power Plants" (2006 Addenda), provides periodic exercising and diagnostic testing for use in assessing the operational readiness of MOVs. RG 1.192 allows licensees to implement
ASME Code Case OMN-1, Revision 0, in accordance with the provisions in the RG as an alternative to the ASME OM Code provisions for MOV stroke time testing in the ASME OM Code 1995 Edition through 2000 Addenda.
The licensee states that:
Reason for Request
Pursuant to 10 CFR 50.55a(a)(3)(i), approval of an alternative is requested to the listed requirements of the OM Code. Section 4.2.5 "Alternatives to Stroke-Time Testing," of NUREG-1482, "Guidelines for lnservice Testing at Nuclear Power Plants," Revision 1, recommends that licensees implement ASME Code Case OMN-1, "Alternative Rules for Preservice and lnservice Testing of Certain Electric Motor-Operated Valve Assemblies in LWR Power Plants," as accepted by the NRC (with certain conditions) in the regulations or RG 1.192, "Operation And Maintenance Code Case Acceptability, ASME OM Code," as an alternative to the MOV stroke-time testing requirements in Subsection ISTC of the OM Code. The periodic exercising and diagnostic testing requirements in Code Case OMN-1 provide an improved method for assessing the operational readiness of MOVs.
In RG 1.192, it states within Table 2, "Conditionally Acceptable OM Code Cases," that the alternative rules of ASME Code Case OMN-1, "Alternative Rules for Preservice and lnservice Testing of Certain Electric Motor-Operated Valve Assemblies in Light-Water Reactor Power Plants," Revision 0, when applied in conjunction with the provisions for leakage rate testing in ISTC-3600, may be applied with the following provisions:
- 1. The adequacy of the diagnostic test interval for each valve must be evaluated and adjusted as necessary but not later than five years or three refueling outages (whichever is longer) from initial implementation of ASME Code Case OMN-1.
- 2. When extending the exercise test intervals for high-risk MOVs beyond a quarterly frequency, licensees shall ensure that the potential increase in core damage frequency and risk associated with the extension is small and consistent with the intent of the Commission's Safety Goal Policy Statement.
- 3. When applying risk insights as part of the implementation of OMN-1, licensees must categorize MOVs according to their safety significance using the methodology described in Code Case OMN-3, "Requirements for Safety Significance Categorization of Components Using Risk Insights for lnservice Testing of LWR Power Plants," with the conditions discussed in RG 1.192 or use other MOV risk-ranking methodologies accepted by the NRC on a plant-specific or industry-wide basis with the conditions in the applicable safety evaluations.
Since RG 1.192 was last published, Code Case OMN-1 has been updated and modified to address and incorporate the RG 1.192 listed provisions. Code Case OMN-1 was revised in the OMb-2006 Addenda to the ASME OMb Code-2004.
Proposed Alternative and Basis for Use:
The licensee proposes to adopt the requirements of Code Case OMN-1 (as delineated in the OMb-2006 Addenda to the ASME OMb Code-2004) at DNPS in lieu of the performance of stroke-time testing and position indication testing as described by ASME OM Code-2004 through OMb-2006 Addenda ISTC paragraphs listed above. DNPS will implement the Code Case in conjunction with the provisions for leakage rate testing in ISTC-3600. The provision to allow for motor-control center (MCC) testing, as contained in Section 6.1 of Code Case OMN-1, is excluded from this request.
The DNPS MOV testing program was developed as a result of NRC Generic Letter (GL) 89-10, "Safety Related Motor Operated Valve Testing and Surveillance," and GL 96-05, "Periodic Verification of Design Basis Capability of Safety Related Motor Operated Valves," utilizing Topical Report MPR-1807, "Joint BWR, Westinghouse and Combustion Engineering Owners' Group Program on Motor-Operated Valve (MOV) Periodic Verification," Revision 2. DNPS is currently utilizing MPR-2524-A, "Joint Owners' Group (JOG) Motor Operated Valve Periodic Verification Program Summary" (November 2006), as guidance for the MOV program. The adoption of Code Case OMN-1 will consolidate testing between the station's 1ST and MOV programs. The following positions describe how EGC interprets and complies with the various requirements of Code Case OMN-1 (ASME OMb-2006 Addenda version).
- 1. Section 3.1 allows for the use of testing that was conducted prior to the implementation of Code Case OMN-1 if it meets the requirements of the Code Case. EGC intends to utilize the testing credited under its GL 89-10/96-05 responses to satisfy the requirement for a one-time test to verify the capacity of each individual or group of MOV's safety-related design basis requirements.
- 2. Section 3.2 requires that each MOV be tested during the preservice test period or before implementing 1ST. EGC intends to utilize the testing credited under its GL 96-05 response to satisfy this requirement.
- 3. OMN-1, Section 3.3(b), states that inservice tests shall be conducted in the as-found condition, and activities shall not be conducted if they might invalidate the as-found condition for 1ST. EGC maintenance activities that would affect the as-found condition of the valve, such as motor operator preventive maintenance or stem lubrication, are typically scheduled to occur in conjunction with the performance of the MOV Periodic Verification Testing, and are performed after as-found testing. Any other activities that could affect the as-found test results are not performed until after the as-found testing has been conducted.
- 4. Section 3.3(c) requires the 1ST program to include a mix of static and dynamic MOV performance testing. EGC has utilized the JOG program's mix of static and dynamic MOV performance testing (i.e., MPR-2524-A) to develop its current MOV testing program.
Additionally, EGC will continue to utilize the existing engineering standards, which are consistent with the JOG standards, to justify any changes to the mix of required MOV performance testing. The use of such an evaluation will serve to ensure EGC continues to meet this requirement.
- 5. Section 3.3(e) requires that remote position indication shall be verified locally during 1ST or maintenance activities. EGC will continue to verify the operability of each MOV's position indication system as part of each MOV's diagnostic test. In addition, the function of each MOV's position indication system will be verified during the performance of maintenance activities affecting remote position indication.
- 6. Section 3.3.1 (b) requires MOV 1ST to be conducted every two refueling cycles or three years, whichever is longer, if insufficient data exists to determine 1ST intervals. EGC has sufficient MOV testing data to justify its current testing intervals, and therefore meets this requirement. If in the future, modification or replacement results in the necessity to re-baseline a valve or group of valves, the requirements of OMN-1, Section 3.3.1 (b) or 3.7.2.2(c), as applicable, will be followed.
- 7. Section 6.4.4 requires that calculations for determining the MOV's functional margin are evaluated to account for potential performance-related degradation. The DNPS MOV program, including EGG's Motor Operated Valve Design Database (MIDAS) Software, or similar updated product, takes into account performance-related degradation, to calculate valve margin.
The licensee determined that using the provisions of this request as an alternative to the listed requirements of ISTC provides a reasonable alternative to the Code requirements based on the determination that the proposed alternative will provide an acceptable level of quality and safety.
Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), EGC requests approval of this alternative to the specific ISTC requirements identified in this request.
The proposed alternative identified in this relief request shall be utilized during the fifth 10-year 1ST interval, which is scheduled to begin November 1, 2013, and conclude on October 31, 2023.
3.2 NRC Staff Evaluation The NRC staff considered Section 4.2.5, "Alternatives to Stroke-Testing," of NUREG-1482, Revision 1, in its review of the licensee's proposed alternative. Section 4.2.5 states in part that "as an alternative to MOV stroke-time testing, ASME developed Code Case OMN-1, which provides periodic exercising and diagnostic testing for use in assessing the operational readiness of MOVs, may be used." Section 4.2.5 recommends that licensees implement ASME Code Case OMN-1 as an alternative to the MOV stroke-time testing. The periodic exercising and diagnostic testing requirements in OMN-1 provide an improved method for assessing operational readiness of MOVs in accordance with NUREG-1482.
Application of code cases is addressed in 10 CFR 50.55a(b )(6) through references to RG 1.192, which lists acceptable and conditionally acceptable code cases for implementation in 1ST programs. RG 1.192, Table 2, conditionally approves the use of Code Case OMN-1 and states that the code is applicable to the 2000 Addenda and earlier editions and addenda of the Code.
Code Case OMN-1 was revised in the 2006 Addenda to the ASME OM Code. Most of the revisions are enhancements such as clarification of valve remote position indication requirements and ball/plug/diaphragm valve test requirements, and the expansion of risk-informed provisions. There is no technical reason for prohibiting the use of Code Case OMN-1 with the 2004 Edition through 2006 Addenda of the OM Code. This is consistent with
the NRC staff position in NUREG-1482, Revision 1, and RG 1.192.
Section 6.1, "Acceptance Criteria," was revised to allow alternative MCC testing provided that a correlation was made with diagnostic test data collected at the MOV. EGC has excluded the provision for MCC testing from this alternative request and will only do testing at the MOV.
Therefore, the MCC test method will not be used as an acceptance criterion to determine the operational readiness of MOVs.
The NRC staff finds that the 2006 Addenda of Code Case OMN-1, with the conditions specified in RG 1.192, provides an acceptable level of quality and safety for testing of MOVs and is an acceptable alternative for use in DNPS, Unit 2 and Unit 3, 1ST programs.
4.0 CONCLUSION
As set forth above, the NRC staff has concluded that the proposed alternative of Relief Request RV-02 to implement ASME OM Code 2006 Addenda Code Case OMN-1, with the conditions specified in RG 1.192, and with the exception that MCC test method will not be used, for MOV assemblies included in the MOV programs at DNPS, Unit 2 and Unit 3, provides an acceptable 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(a)(3)(i), and is in compliance with the ASME OMb Code's requirements. All other ASME OMb Code requirements for which relief was not specifically requested and approved in the subject request for relief remain applicable.
Therefore, the NRC staff authorizes the alternative in Relief Request RV-02 for the fifth 1ST interval for DNPS, Unit 2 and Unit 3, which is currently scheduled to start on November 1, 2013, and conclude on October 31, 2013.
Principle Contributor: Michael Farnan Date of Issuance: October 30, 2013
..* ML13297A246 *email dated NRR-028 OFFICE LPL3-2/PM LPL3-2/LA DE/EPNB/BC* LPL3-2/BC LPL3-2/PM NAME BMozafari SRohrer Tlupold TTate BMozafari DATE 10/29/13 10/29/13 04/22/13 10/30/13 10/30/13