ML25076A656
| ML25076A656 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 04/02/2025 |
| From: | Jason Kozal NRC/RGN-III/DORS/RPB1 |
| To: | Vanfleet J Exelon Generation Co |
| References | |
| EA-24-070, EAF-RIII-2025-007 IR 2024001 | |
| Download: ML25076A656 (1) | |
Text
EA-24-070/EAF-RIII-2025-007 John VanFleet Site Vice President LaSalle County Station 2601 North 21st Road Marseilles, IL 61341-9756
SUBJECT:
DISPUTED NON-CITED VIOLATION REVISED LASALLE COUNTY STATION, UNIT 1 AND 2 INTEGRATED INSPECTION REPORT 05000373, 05000374/2024001 (NCV 05000374/2024001-02: FAILURE TO TEST MOTOR-OPERATED VALVE IN ACCORDANCE WITH INSERVICE TESTING PROGRAM)
Dear John VanFleet:
On June 12, 2024, LaSalle County Station (LSCS) provided a written response (Agencywide Document and Access Management System (ADAMS) Accession No. ML24164A061) to U.S. NRC Inspection Report 05000373/2024001 and 05000374/2024001 (ML24131A151) dated May 13, 2024. The letter contested the Finding and Non-Cited Violation (NCV)05000374/2024001-02 associated with the failure to meet inservice test requirements set forth in the American Society of Mechanical Engineers (ASME) Operations and Maintenance Code and Addenda Code Case OMN-1 after performing maintenance that could affect motor-operated valve (MOV) performance. In the letter, LSCS asserted that their evaluation, which deferred stroke testing under more suitable plant conditions, met the level of testing required by ASME OMN-1, thus challenging the basis of the violation.
The NRC has completed its evaluation of your response to the Non-Cited Violation. The evaluation was conducted by an individual from the Division of Radiological Safety and Security (DRSS), independent from the NRC staff in the Division of Operating Reactor Safety (DORS) who originally identified the violation and issued the inspection report. Based on this independent evaluation, the NRC has determined the original enforcement decision is valid but should be modified to enhance its clarity. Details of the evaluation and the modified violation are provided in the enclosure to this letter.
In summary, while LSCS performed an evaluation using their best engineering judgement to demonstrate the valves safety-related function to close would be maintained, as documented in Inspection Report 2024001, the staff determined the failure to perform testing to provide positive affirmation of the valves continued capability to move after performing maintenance activities was upheld as a performance deficiency.
April 2, 2025
J. VanFleet 2
Furthermore, the reviewer noted safety-related instrumentation remained in the valves circuitry throughout the duration of the backseating activity, which enabled LSCS to provide reasonable assurance that the designed material limits for valve 1B21-F016 were not exceeded, and that the valves capability to close should not be impacted. LaSalle County Station plans to test the valve during the next outage of sufficient duration.
This letter, its enclosures, LaSalle County Stations June 12, 2024, response, and your response (if any) will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with 10 CFR 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely, Jason W. Kozal, Director Division of Operating Reactor Safety Docket Nos. 05000373 and 05000374 License Nos. NPF-11 and NPF-18
Enclosure:
NRC Staff Assessment of Disputed NCV 05000374/2024001-02 cc: Distribution via LISTSERV Signed by Kozal, Jason on 04/02/25
J. VanFleet 3
Letter to John VanFleet from Jason Kozal, dated April 2, 2025.
SUBJECT:
DISPUTED NON-CITED VIOLATION REVISED LASALLE COUNTY STATION, UNIT 1 AND 2 INTEGRATED INSPECTION REPORT 05000373, 05000374/2024001 (NCV 05000374/2024001-02: FAILURE TO TEST MOTOR-OPERATED VALVE IN ACCORDANCE WITH INSERVICE TESTING PROGRAM)
DISTRIBUTION:
Alejandro Alen Arias RidsNrrDorlLpl3 RidsNrrPMLaSalle Resource RidsNrrDroIrib Resource Jack Giessner Mohammed Shuaibi Diana Betancourt-Roldan Harral Logaras Bryan Bergeon David Curtis Jared Heck Eric Brothman R3-DORS ADAMS Accession Number: ML25076A656
SUNSI Review
Non-Sensitive
Sensitive
Publicly Available
Non-Publicly Available OFFICE RIII-DRSS RIII-DORS RIII-OE RIII-EICS RIII-DORS NAME MJones:anm KStoedter JPeralta DBetancourt JKozal DATE 03/24/2025 03/24/2025 03/26/2025 03/27/2025 04/02/2025 OFFICIAL RECORD COPY
NRC STAFF ASSESSMENT OF DISPUTED NCV 05000374/2024001-02 Enclosure The U.S. Nuclear Regulatory Commission (NRC) staff reviewed information provided in the LaSalle County Station \
letter dated June 12, 2024. This review was performed by staff members having relevant technical and regulatory knowledge.
Documents referenced are listed in the Reference Section of this Enclosure.
1.
BACKGROUND In the first quarter of 2024, inspectors identified an NCV of 10 CFR 50.55a(f)(4)(ii) for the failure to meet inservice testing requirements set forth in the American Society of Mechanical Engineers (ASME) Operations and Maintenance Code and Addenda Code Case OMN-1.
Specifically, after performing maintenance that could affect motor-operated valve (MOV) performance, the licensee failed to perform testing on primary containment isolation MOV, 2B21-F016. The maintenance activity involved disconnecting and reconnecting the MOVs control circuitry to allow for backseating the valve using an MOV backseat relay tool.
This violation was described in Inspection Report 05000374/2024001 (ML24131A151).
On June 12, 2024, the licensee disputed this violation in a letter to the NRC (ML24164A061).
The following sections detail the NRCs review of the licensees position.
2.
ORIGINAL ENFORCEMENT DECISION The original enforcement decision as stated in Inspection Report 05000373/2024001 and 05000374/2024001, was:
Title 10 CFR 50.55a(f)(4)(ii), requires, in part, Inservice tests 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 ASME OM Code incorporated by reference in paragraph (a)(1)(iv) of this section 18 months before the start of the 120-month interval (or the optional ASME Code Cases listed in NRC Regulatory Guide 1.192 as incorporated by reference in paragraph (a)(3)(iii) of this section).
LaSalle County Station IST Program Plan - 4th Interval, Revision 0, establishes the Code of Record for the Fourth 10-Year IST Program Interval (October 12, 2017 -
October 11, 2027) as the ASME OM Code, 2004 Edition through 2006 Addenda, as incorporated by reference in 10 CFR 50.55a. LSCS submitted a Valve Relief Request RV-01 to implement the optional ASME Code Case OMN-1 in their Fourth 10-Year IST Program Plan.
ASME OM Code-2006, Code Case OMN-1, Paragraph 3.4, Effect of MOV Replacement, Repair, or Maintenance, states, in part, When an MOV or its control system is replaced, repaired, or undergoes maintenance that could affect the valves performance, new inservice test values shall be determined, or the previously established inservice test values shall be confirmed before the MOV is returned to service.
Contrary to the above, on January 25, 2024, the licensees inservice tests to verify operational readiness of pumps and valves, whose function is required for safety, did not comply with the requirements of the 2004 Edition through the 2006 Addenda of the ASME OM Code as incorporated by reference in 10 CFR 50.55a for the current 10 Year IST program interval at LaSalle County Station effective October 17, 2017.
2 Specifically, the licensee failed to perform any testing on primary containment isolation MOV 2B21-F016, a valve within the scope of the ASME OM Code and Addenda, before returning the valve to service after electrically backseating the valve, which was maintenance that could affect the valves performance.
3.
LICENSEE POSITION The Licensee disagreed with the assessment and conclusions related to the identified violation. The licensee believes the requirements of Code Case OMN-1 and the guidance in NUREG-1482, Section 4.4.2 were met by performing an analysis to defer post-maintenance testing to a more suitable plant condition. The licensee asserts As explicitly stated in OMN-1 Paragraph 3.4, it is the licensees program that defines the level of testing required after replacement, repair, or maintenance.
Furthermore, the licensee stated due to the MOV 2B21-F016 being located in the drywell, cycling of the valve could have led to unacceptable drywell leakage resulting in a forced shutdown of Unit 2, similar to the [LSCS] event in 2009. Therefore, stroking of the valve at power was considered not practical and deferred to a more suitable plant condition. The LSCS IST program and PMT process determined an evaluation was sufficient to justify returning the valve to service while deferring stroking of the valve to plant shutdown which is within the guidance provided in Section 4.4.2 of NUREG-1482.
Lastly, the licensee believes the performance deficiency is predicated on an interpretation that a level of testing as described in the Code Case precludes an analysis justifying deferral even though the Code Case explicitly states the level of testing is determined by the licensees program, further stating the inspection report does not justify this interpretation or refute NUREG-1482s allowance for deferral. Therefore, the licensee concluded the finding and violation for not meeting the requirements of ASME OM Code Case OMN-1, Paragraph 3.4 is unwarranted.
4.
NRC STAFF REVIEW The NRC staff performed an independent review of NRC NCV 05000374/2024001-02 and the LSCS Letter (Reference 1) which provided the licensees position and reasons for disputing the finding and violation. The staff reviewed the information provided in LaSalle Station Integrated Inspection Report 2024001 and found the licensee had disturbed electrical connections within the valves circuitry as part of installing and removing an MOV backseat relay tool for the purpose of electrically backseating valve 2B21-F016. Section ISTC-3310 of the 2004 ASME OM Code with the 2006 Addenda, the licensees Code of Record, provides examples of maintenance1 that could affect a valves performance. The staff reviewed these examples and concluded the disturbing of control system electrical connections for the purpose of adjusting valve 2B21-F016 was maintenance that could affect valve performance as provided in ISTC-3310.
1 Examples of maintenance that could affect valve performance parameters as provided in ISTC-3310 includes adjustments of stem packing, limit switches, or control system valves, and removal of the bonnet, stem assembly, actuator, obturator, or control system components.
NRC STAFF ASSESSMENT OF DISPUTED NCV 05000374/2024001-02 3
NRC staff reviewed excerpts from both ASME OM Code Case OMN-1, Alternative Rules for Preservice and lnservice Testing of Active Electric Motor-Operated Valve Assemblies in Light-Water Reactor Power Plants, (Reference 4) and NUREG-1482, Guidelines for ln-Service Testing at Nuclear Power Plants, Revision 3 (Reference 5). The licensee stated in their review that both the ASME OM Code Case and the applicable NRC NUREG guidance consistently state that post-maintenance testing is required after performing maintenance that could affect valve performance. However, LSCS noted both [documents] also state the licensee determines the level of testing that is required following maintenance. Continuing, the licensee noted, the guidance states that if current plant conditions make testing not practical, an analysis can be performed to justify that the valve will still be able to perform its required function, and testing shall be performed at the first available opportunity when the plant conditions allow.
Items A. and B. below, provide additional context related to the material quoted by the licensee.
A. ASME OM Code Case OMN-1, Alternative Rules for Preservice and lnservice Testing of Active Electric Motor-Operated Valve Assemblies in Light-Water Reactor Power Plants, states the following in Paragraph 3.4, Effect of MOV Replacement, Repair, or Maintenance:
When an MOV or its control system is replaced, repaired, or undergoes maintenance that could affect the valve's performance, new inservice test values shall be determined, or the previously established in service test values shall be confirmed before the MOV is returned to service... This testing is intended to demonstrate that performance parameters, which could have been affected by the replacement, repair, or maintenance, are within acceptable limits. The Owner's program shall define the level of testing required after replacement, repair, or maintenance.2 Deviations between the previous and new inservice test values shall be identified and analyzed. Verification that the new values represent acceptable operation shall be documented as described in section 9, Records and Reports.
The NRC staff reviewed the licensees procedure for post-maintenance testing (PMT)
(Procedure MA-AA-716-012, Post Maintenance Testing, Revision 28) and noted, for a maintenance activity that involved disconnecting and reconnecting a MOVs control circuitry, the required PMT for MOV 2B21-F016 included a rotation and logic check, a control room functional stroke, and an IST operability stroke time test. As such, the reviewer noted that the licensees program prescribed the necessary testing.
2 The underline and bolded text are provided for emphasis.
NRC STAFF ASSESSMENT OF DISPUTED NCV 05000374/2024001-02 4
The NRC staff noted that OMN-1 provides an exception to performing the testing discussed in Paragraph 3.4 when a valve meets one or more of the exclusions set forth under ASME OMN-1, Paragraph 1.2, Exclusions. Specifically, OMN-1, Paragraph 1.2 cites ASME Subsection ISTC-1200, Exemptions, as the defined allowable cases not subject to inservice test requirements of the ASME Code. The NRC staff reviewed ISTC-1200, Exemptions, of Subsection ISTC of the ASME OM Code, Inservice Testing of Valves in Light-Water Reactor Nuclear Power Plants, and found that MOV 2B21-F016 was not one of the excluded valves3.
The NRC staff concluded LaSalle primary containment isolation valve MOV 2B21-F016 did not meet any of the exemptions provided in ISTC-1200 and therefore, did not qualify for an exclusion from the testing requirements discussed in Paragraph 3.4 of OMN-1.
B. NUREG-1482, Guidelines for ln-Service Testing at Nuclear Power Plants, Revision 34 The NRC staff noted the licensee referenced NRC guidance (i.e., NUREG-1482) within their letter contesting the violation. Specifically, the licensee asserted that both ASME Code Case OMN-1 and Section 4.4.2 of NUREG-1482, consistently state that post-maintenance testing is required after performing maintenance that could affect a valves performance; however, both also state that the licensee determines the level of testing that is required following maintenance. Additionally, the licensee asserted that NUREG-1482 states that if the current plant conditions make testing not practical, an analysis can be performed to justify that the valve will still be able to perform its required function, and testing shall be performed at the first available opportunity when plant conditions allow. Therefore, the licensees position was that the requirements of OMN-1 and NUREG-1482, Section 4.4.2 were met by performing an analysis which demonstrated the performance of valve 2B21-F016 was not adversely affected by the maintenance activity and that deferring the valves PMT to a more suitable plant condition was appropriate.
The NRC staff agrees the guidance in NUREG-1482 provides examples where a licensee may conduct an analysis demonstrating the performance of a backseated valve and postpone the required PMT to a later date when plant conditions are deemed suitable. The NRC staff concluded the use of this approach was limited to valves that could not be stroke or leak rate tested under current plant conditions. Specifically, NUREG-1482 states the following:
This guidance applies only to valves that need adjustment during power operation and cannot be fully stroked in the plant operating mode. The guidance does not apply merely as a convenience to the licensee 3 The list of excluded valves included the following: Valves used only for operating convenience such as vent, drain, instrument and test valves; Valves used only for system control, such as pressure regulating valves; Valves used only for system or component maintenance; Skid-mounted valves - provided they are tested as part of the major component and are justified by the Owner to be adequately tested; External control and protection systems responsible for sensing plant conditions and providing signals for valve operation; Category A and Category B safety and relief valves (NOTE: these valve types are only excluded from the specific requirements provided in ISTC-1200; Non-reclosing pressure relief devices (rupture disks) used in boiling water reactor scram accumulators.
4 The guidelines and recommendations provided in NUREG 1482 and its Appendices do not supersede the regulatory requirements specified in 10 CFR 50.55a.
5 However, NUREG-1482 also provides expectations, over and above the analysis discussed above, which must be met to demonstrate continued compliance with the ASME Code and 10 CFR 50.55a. NUREG-1482 specifically states:
Licensees using backseating to stop packing leaks will be expected to stroke the valve stem away from the backseat after the initial backseating operation to demonstrate that the valve stem has not become bound in the backseat by this temporary leakage mitigation method.
The NRC staff reviewed the licensees analysis of the valves parameters as documented in Inspection Report 2024001. As part of this review, the NRC staff interviewed LSCS personnel and confirmed LSCS did not stroke valve 2B21-F016 away from the backseat after the initial backseating operation to demonstrate that the valve stem was not bound in the backseat. The licensee addressed the practicality of performing the partial stroke test on Page 4 of 8 of Reference 1 by stating:
In 2009, a forced shutdown of Unit 2 was required due to elevated drywell leakage from a packing failure on this valve. Due to past operational experience with packing leakage causing a forced shutdown, a partial stroke off the backseat was deemed not practical while at power and it was deferred to a more suitable plant condition.
During interviews of the LSCS staff performed as part of this review, the NRC staff found the 2009 elevated drywell leakage and subsequent plant shutdown was due to packing degradation. Additionally, no assertions were made by the LSCS staff interviewed indicating that valve backseating activities contributed to the packing failure.
Based on the information provided above, the NRC staff concluded the licensee had not fully implemented the guidance provided by NUREG-1482 to demonstrate continued compliance with the ASME Code and 10 CFR 50.55a. Although the licensee had performed an analysis demonstrating the electrical backseating of valve 1B21-F016 had not deformed the valve stem or impacted the valves performance parameters, the licensee failed to partially stroke the valve stem away from the backseat after the initial backseating operation to demonstrate the valve stem had not become bound in the backseat. Additionally, the NRC staff found no comparative language in the ASME Code, available ASME Code interpretations or NRC guidance that would allow a licensee to deem a partial stroke test on a valve allowed to change position during specific operating conditions as not practical following backseating activities.
NRC STAFF ASSESSMENT OF DISPUTED NCV 05000374/2024001-02 6
- 5. CONCLUSION Based on this review, and after consideration of the information provided by LSCS in \
letter dated June 12, 2024, the NRC staff determined the violation of 10 CFR 50.55a(f)(4)(ii)
(LaSalle County Station IST Program Plan - 4th Interval, Revision 0, and ASME OM Code-2006, Code Case OMN-1, Paragraph 3.4) occurred because: 1) backseating the valve involved maintenance activities that could adversely affect the operation of valve 1B21-F016;
- 2) the ASME Code did not provide an allowance to perform a written evaluation in lieu of post-maintenance testing; and 3) the guidance provided in NUREG-1482 was not fully implemented because valve 1B21-F016 was not partially stroked. However, the original NCV is being modified to enhance its clarity as follows:
Title 10 CFR 50.55a(f)(4)(ii), requires, in part, Inservice tests 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 ASME OM Code incorporated by reference in paragraph (a)(1)(iv) of this section 18 months before the start of the 120-month interval (or the optional ASME Code Cases listed in NRC Regulatory Guide 1.192 as incorporated by reference in paragraph (a)(3)(iii) of this section).
LaSalle County Station IST Program Plan - 4th Interval, Revision 0, establishes the Code of Record for the Fourth 10-Year IST Program Interval (October 12, 2017 -
October 11, 2027) as the ASME OM Code, 2004 Edition through 2006 Addenda, as incorporated by reference in 10 CFR 50.55a. LSCS submitted a Valve Relief Request RV-01 to implement the optional ASME Code Case OMN-1 in their Fourth 10-Year IST Program Plan.
ASME OM Code-2006, Code Case OMN-1, Paragraph 3.4, Effect of MOV Replacement, Repair, or Maintenance, states, in part, When an MOV or its control system is replaced, repaired, or undergoes maintenance that could affect the valves performance, new inservice test values shall be determined, or the previously established inservice test values shall be confirmed before the MOV is returned to service.
Contrary to the above, on January 25, 2024, the licensees inservice tests to verify operational readiness of pumps and valves, whose function is required for safety, did not comply with the requirements of the 2004 Edition through the 2006 Addenda of the ASME OM Code as incorporated by reference in 10 CFR 50.55a for the current 10-Year IST program interval at LaSalle County Station effective October 17, 2017.
Specifically, the licensee failed to perform any testing on primary containment isolation MOV 2B21-F016, a valve within the scope of the ASME OM Code and Addenda, before returning the valve to service after performing a maintenance activity that could affect the valves performance. The maintenance activity involved disconnecting and reconnecting the MOVs control circuitry as part of installing and removing the MOV backseat relay tool used to electrically backseat the valve.
NRC STAFF ASSESSMENT OF DISPUTED NCV 05000374/2024001-02 7
==References:
==
1.
Letter from John Van Fleet to U.S. Nuclear Regulatory Commission, Response to NRC LaSalle County Station, Units 1 and 2 Integrated Inspection Report 05000373/2024001 and 05000374/2024001, dated June 12, 2024.
2.
Letter from Robert Ruiz (U.S. Nuclear Regulatory Commission) to David P. Rhoades (Constellation Energy Generation, LLC), LaSalle County Station - Integrated Inspection Report 05000373/2024001 and 05000374/2024001, dated May 13, 2024 (ADAMS Accession No. ML24131A151).
3.
Constellation Energy Generation, LLC, Programs Evaluate the Use Relay Tool for Backseating 2821-F016, ECR 461530, Revision 2, January 26, 2024.
4.
American Society of Mechanical Engineers, Operations and Maintenance Code Case OMN-1, Alternative Rules for Preservice and lnservice Testing of Active Electric Motor Operated Valve Assemblies in Light-Water Reactor Power Plants.
5.
United States Nuclear Regulatory Commission, Guidelines for lnservice Testing at Nuclear Power Plants, NUREG-1482, Revision 3, July 2020 (ADAMS Accession No. ML20202A473).