IR 05000482/2024004
| ML25027A008 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 01/30/2025 |
| From: | Ami Agrawal NRC/RGN-IV/DORS/PBB |
| To: | Reasoner C Wolf Creek |
| References | |
| EA-24-091 IR 2024004 | |
| Download: ML25027A008 (1) | |
Text
January 30, 2025
SUBJECT:
WOLF CREEK GENERATING STATION - INTEGRATED INSPECTION REPORT 05000482/2024004
Dear Cleve Reasoner:
On December 31, 2024, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Wolf Creek Generating Station. On January 07, 2025, the NRC inspectors discussed the results of this inspection with Jaime McCoy, Site Vice President, and other members of your staff. The results of this inspection are documented in the enclosed report.
One finding of very low safety significance (Green) is documented in this report. This finding involved a violation of NRC requirements. We are treating this violation as a non-cited violation (NCV) consistent with Section 2.3.2 of the Enforcement Policy.
If you contest the violation or the significance or severity of the violation documented in this inspection report, you should provide a response within 30 days of the date of this inspection report, with the basis for your denial, to the U.S. Nuclear Regulatory Commission, ATTN:
Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region IV; the Director, Office of Enforcement; and the NRC Resident Inspector at Wolf Creek Generating Station.
If you disagree with a cross-cutting aspect assignment in this report, you should provide a response within 30 days of the date of this inspection report, with the basis for your disagreement, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region IV; and the NRC Resident Inspector at Wolf Creek Generating Station. This letter, its enclosure, 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 Title 10 of the Code of Federal Regulations 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely, Ami N. Agrawal, Chief Reactor Projects Branch B Division of Operating Reactor Safety Docket No. 05000482 License No. NPF-42
Enclosure:
As stated
Inspection Report
Docket No:
05000482
License No:
Report No:
Enterprise Identifier:
I-2024-004-0005
Licensee:
Wolf Creek Nuclear Operating Corp.
Facility:
Wolf Creek Generating Station
Location:
Burlington, KS
Inspection Dates:
October 1 through December 31, 2024
Inspectors:
C. Henderson, Senior Resident Inspector
J. Melfi, Project Engineer
C. Sigel, Resident Inspector
Approved By:
Ami N. Agrawal, Chief
Reactor Projects Branch B
Division of Operating Reactor Safety
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Wolf Creek Generating Station, in accordance with the Reactor Oversight Process. The Reactor Oversight Process is the NRCs program for overseeing the safe operation of commercial nuclear power reactors. Refer to https://www.nrc.gov/reactors/operating/oversight.html for more information.
List of Findings and Violations
Failure to Promptly Identify and Correct a Condition Adverse to Quality Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000482/2024004-01 Open/Closed
[H.13] -
Consistent Process 71111.12 The inspectors reviewed a self-revealed Green finding and associated non-cited violation of 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Actions, for the licensees failure to promptly identify and correct a condition adverse to quality associated with dislocation of the roll pin in the transducer nozzle assembly contained in Masoneilan model 8005N current to pressure converter.
Additional Tracking Items
Type Issue Number Title Report Section Status LER 05000482/2024-001-00 Mode 3 Entry with One Auxiliary Feedwater Pump Train Inoperable Due to Missed Post-Maintenance Testing 71153 Closed LER 05000482/2024-001-01 Mode 3 Entry with One Auxiliary Feedwater Pump Train Inoperable due to Missed Post-Maintenance Testing 71153 Closed LER 05000482/2024-002-00 Technical Specification Required Shutdown Due to Inoperable Auxiliary Feedwater Discharge Valve 71153 Closed LER 05000482/2024-002-01 Technical Specification required Shutdown Due to Inoperable Auxiliary Feedwater Discharge Valve 71153 Closed URI 05000482/2024-003-03 Turbine-Driven Auxiliary Feedwater Pump Turbine Governor Valve Actuator Failure (EA-24-091)71153 Closed
PLANT STATUS
Wolf Creek Generating Station began the inspection period at full power. On October 16, 2024, the licensee reduced power to 70 percent for flexible power operations (based on daily market demand) and returned to full power on October 19, 2024, and remained for the rest of the inspection period.
INSPECTION SCOPES
Inspections were conducted using the appropriate portions of the inspection procedures (IPs) in effect at the beginning of the inspection unless otherwise noted. Currently approved IPs with their attached revision histories are located on the public website at http://www.nrc.gov/reading-rm/doc-collections/insp-manual/inspection-procedure/index.html. Samples were declared complete when the IP requirements most appropriate to the inspection activity were met consistent with Inspection Manual Chapter (IMC) 2515, Light-Water Reactor Inspection Program - Operations Phase. The inspectors performed activities described in IMC 2515, Appendix D, Plant Status, observed risk significant activities, and completed onsite portions of IPs. The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel to assess licensee performance and compliance with Commission rules and regulations, license conditions, site procedures, and standards.
REACTOR SAFETY
71111.01 - Adverse Weather Protection
Impending Severe Weather Sample (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated the adequacy of the overall preparations to protect risk-significant systems from impending severe weather high winds, potential severe weather and tornado activity on October 30, 2024. The following was evaluated:
- engineered safety feature transformers XNB01 and XNB02
- startup transformer
- station blackout diesel generators
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (3 Samples)
The inspectors evaluated the implementation of the fire protection program by conducting a walkdown and performing a review to verify program compliance, equipment functionality, material condition, and operational readiness of the following fire areas:
(1)engineered safety switchgear room 1, fire area C-9, on October 22, 2024 (2)engineered safety switchgear room 2, fire area C-10, on October 22, 2024 (3)switchboard room 1, fire area C-16, on November 18, 2024
71111.06 - Flood Protection Measures
Flooding Sample (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated the security modification impact on external flooding on December 6, 2024.
71111.07A - Heat Exchanger/Sink Performance
Annual Review (IP Section 03.01) (1 Sample)
The inspectors evaluated readiness and performance of:
71111.11Q - Licensed Operator Requalification Program and Licensed Operator Performance
Licensed Operator Performance in the Actual Plant/Main Control Room (IP Section 03.01) (1 Sample)
- (1) The inspectors observed and evaluated licensed operator performance in the control room during:
- control rod parking with an under-instruction reactor operator performing the actions on November 7, 2024
- emergency diesel generator A monthly run on November 12, 2024
- emergency diesel generator A monthly run with an under-instruction reactor operator performing actions on November 14, 2024
- turbine-driven auxiliary feedwater pump post-maintenance run on November 20, 2024
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed and evaluated licensed operator requalification training for faulted steam generator and loss of secondary heat sink on November 12, 2024.
71111.12 - Maintenance Effectiveness
Maintenance Effectiveness (IP Section 03.01) (1 Sample)
The inspectors evaluated the effectiveness of maintenance to ensure the following structures, systems, and components remain capable of performing their intended function:
(1)turbine-driven auxiliary feedwater pump governor valve actuator and discharge header B air-operated isolation valve, ALHV0010, failures on December 10, 2024
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (3 Samples)
The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:
(1)compensatory measures for inoperable train A electrical penetration room cooler (SGL15A) during maintenance operability determination on October 21, 2024 (2)train A emergency diesel generator cooling water jacket water leak operability determination on November 12, 2024 (3)train A essential service water underground piping corrosion operability determination on December 13, 2024
71111.18 - Plant Modifications
Temporary Modifications and/or Permanent Modifications (IP Section 03.01 and/or 03.02) (1 Sample)
The inspectors evaluated the following temporary or permanent modifications:
(1)turbine-driven auxiliary feedwater air-operated flow control current to pressure converter change on November 15, 2024
71111.24 - Testing and Maintenance of Equipment Important to Risk
The inspectors evaluated the following testing and maintenance activities to verify system operability and/or functionality:
Post-Maintenance Testing (PMT) (IP Section 03.01) (3 Samples)
(1)train A emergency diesel generator tornado damper lubrication and maintenance post-maintenance testing on November 4, 2024 (2)north penetration room cooler essential service water supply and return line stem disc separation valve repair post-maintenance testing on December 9, 2024 (3)train A emergency diesel generator post-maintenance testing on December 31,2024
Surveillance Testing (IP Section 03.01) (1 Sample)
(1)train A emergency diesel generator monthly operability surveillance testing on December 31, 2024
Diverse and Flexible Coping Strategies (FLEX) Testing (IP Section 03.02) (1 Sample)
(1)security modification impact on FLEX strategy on December 10,
OTHER ACTIVITIES - BASELINE
===71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:
MS08: Heat Removal Systems (IP Section 02.07)===
- (1) October 1, 2023, through October 31, 2024
MS09: Residual Heat Removal Systems (IP Section 02.08) (1 Sample)
- (1) October 1, 2023, through October 31, 2024
71152A - Annual Follow-up Problem Identification and Resolution Annual Follow-up of Selected Issues (Section 03.03)
The inspectors reviewed the licensees implementation of its corrective action program related to the following issues:
(1)train B component cooling water pump room cooler flowrate less than design and train A centrifugal charging pump room cooler less than design on October 16, 2024 (2)train A and B component cooling water heat exchanger outlet cross-connect header check valves, EGV0036 and EGV0061, inservice testing requirements and inservice testing program extent of condition on November 20, 2024
71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02)
- (1) The inspectors reviewed the licensees corrective action program to identify potential trends in operability determinations that might be indicative of a more significant safety issue.
71153 - Follow Up of Events and Notices of Enforcement Discretion Event Report (IP Section 03.02)
The inspectors evaluated the following licensees event reporting determinations to ensure it complied with reporting requirements.
- (1) LER 05000482/2024-001-00, Mode 3 Entry with One Auxiliary Feedwater Pump Train Inoperable due to Missed Post-Maintenance Testing (Agencywide Documents Access and Management System (ADAMS) Accession No. ML24184C185), and LER 05000482/2024-001-01, Mode 3 Entry with One Auxiliary Feedwater Pump Train Inoperable due to Missed Post-Maintenance Testing, (ML24296A068). The inspectors documented a minor licensee identified violation documented in integrated inspection report 05000482/2024002 (ML24200A177) section 71152S. These LERs are closed.
- (2) LER 05000482/2024-002-00, Technical Specification Required Shutdown Due to Inoperable Auxiliary Feedwater Discharge Valve (ML24295A397), and LER 05000482/2024-002-01, Technical Specification Required Shutdown Due to Inoperable Auxiliary Feedwater Discharge Valve (ML24346A412). The inspectors documented a Green non-cited violation 05000482/2024004-01, "Failure to Promptly Identify and Correct a Condition Adverse to Quality." These LERs are closed.
Notice of Enforcement Discretion (IP Section 03.04) (1 Sample)
- (1) The inspectors evaluated the licensee actions associated with the Unresolved Item URI 05000482/2024003-03 opened in the 3rd quarter integrated inspection report, and related Notice of Enforcement Discretion, EA-24-091, which can be accessed at http://www.nrc.gov/reading-rm/doc-collections/enforcement/notices/noedreactor.html.
The inspectors concluded that the failure was not within the ability of the licensee to foresee or correct the cause discussed in the URI; therefore, no performance deficiency or violation was identified. This URI is closed.
INSPECTION RESULTS
Failure to Promptly Identify and Correct a Condition Adverse to Quality Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000482/2024004-01 Open/Closed
[H.13] -
Consistent Process 71111.12 The inspectors reviewed a self-revealed Green finding and associated non-cited violation of 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Actions, for the licensees failure to promptly identify and correct a condition adverse to quality associated with dislocation of the roll pin in the transducer nozzle assembly contained in Masoneilan model 8005N current to pressure converter.
Description:
On August 21, 2024, the turbine-driven auxiliary feedwater pump air-operated flow control valve to steam generator B (ALHV0010) failed to remain closed with a demand signal during surveillance testing of the turbine-driven auxiliary feedwater pump surveillance testing. This condition resulted in ALHV0010 being unable to perform its safety function to close to isolate auxiliary feedwater to steam generator B in the event of a faulted or ruptured steam generator design basis accident. The licensee was unable to identify and correct the condition which prevented ALHV0010 from performing its safety function in the closed position within the required 72-hour technical specification limited condition of operation. This resulted in a plant shutdown to perform troubleshooting to identify the issue and repair ALHV0010. During the troubleshooting and repair of ALHV0010, the licensee identified and replaced the Masoneilan model 8005N current to pressure (I/P) converter with a different vendor I/P converter. The licensee entered this condition into their corrective action program as Condition Report (CR) 10035961 and performed an equipment performance evaluation and organizational and programmatic investigation and had a third-party vendor perform a hardware failure analysis. The inspectors reviewed the equipment performance evaluation, hardwater failure analysis, and internal and external operating experience associated with Masoneilan model 8005N I/P and identified the following:
- The hardware failure analysis, equipment performance evaluation, and operational and programmatic investigation identified the Masoneilan model 8005N I/P converter failure was caused by the dislocation of the roll pin in the transducer nozzle assembly.
The roll pin was found to be protruding 0.0265 inches beyond the face of the nozzle once the converter was disassembled. The failure mechanism was identified in the NRC Part 21 notification 2019-36-01, and vendor document DA-JX-001, Evaluation of Methods to Determine Operational Readiness of 8005N I/P Transducer, revision A.
Document DA-JX-001 documents the issue and provides the techniques to check for the identified failure of the 8005N I/P converter. The operational and programmatic investigation identified a contributing cause of the Masoneilan model 8005N I/P converters, which had known vulnerabilities with a 2019 NRC Part 21 notification, and partially executed plans to replace the failure prone I/P converters with a new model.
- On August 21, 2018, and January 15, 2020, the licensee initiated CR 126023 and CR 139894 which are associated with the external operating experience of Masoneilan 8005N I/P converts. CR 126023 documented the results of the air-operated valve self-assessment 2018-0139 recommendation. The recommendation was to track the applicability of another stations Masoneilan Part 21 notification 2019-36-01 (CR 139894) and LER 2018-003-00 for the failed nozzle roll pin not being fully inserted during manufacture of the component. The corrective action was to send one of three warehouse spare Masoneilan 8005N I/P converters to the vendor under Purchase Order (PO) 785036 to evaluate the Part 21 notification and LER 2018-003-00. The licensee determined the issue identified in the Part 21 notification and LER 2018-003-00 was not applicable, for the following reasons: 1) It was determined that the worst protrusion of the three warehouse spares would not have caused any issues with the operation of the valve; 2) Masoneilan has not issued any subsequent Part 21s in response to the other stations notifications and maintained their official position that the issue was a onetime event; 3) There have been no additional failures due to roll pin protrusion in the industry. However, the inspectors identified the vendor provided DA-JX-001, revision A, as part of the vendor response to PO 785036. This vendor report was received by the licensee on December 5, 2018. The licensee closed CR 126023 with no further actions taken to evaluate the installed 8005N I/P converts installed in steam generator A, B, C, D air-operated valves turbine-driven auxiliary feedwater pump flow control valves (ALHV0006, 8, 10, and 12) and steam generator atmospheric reliefs valves (ABPV0001, 2, 3, 4).
- On March 12, 2022, the licensee initiated CR 10012832 for ABPV0004 exceeding the stroke time limit during surveillance testing. The licensee determined the most likely cause for the failed surveillance was the degradation of the upper limit switch and Masoneilan 8005N I/P converter calibration drift causing the valve to fail the surveillance testing and became the second issue associated with Masoneilan 8005N I/P converter in the past seven months (reference CR 10008697). In each case the 8005N I/P converter was replaced. Additionally, the licensee initiated CR 10013552 as an enhancement item for component engineering to research a feasible replacement option for the Masoneilan 8005N I/P converters to improve the reliability of the component and was classified as not a condition adverse to quality. The licensee identified two alternate I/P converters for the steam generator atmospheric relief valves and turbine-driven auxiliary feedwater flow control valves and was documented in the following design equivalent change packages:
o DECP 20617, Alternate I/P Transducer for Steam Generator Atmospheric Relief Valve, revision 0 o
DECP 20652, Alternate I/P Transducer for Turbine Driven Auxiliary Feedwater Pump Discharge Valve, revision 0 All four steam generator atmospheric relief valves Masoneilan 8005N I/P converters were replaced in the fall 2022 refueling outage (RF 25), but the turbine-driven auxiliary feedwater pump flow control valves Masoneilan 8005N I/P converters were not.
Additionally, the inspectors did not identify any corrective actions or condition reports generating work orders to replace turbine-driven auxiliary feedwater pump flow control valves Masoneilan 8005N I/P converters prior to ALHV0010 failure on August 21, 2024.
From the above, the inspectors concluded the failure of ALHV0010 was foreseeable and preventable, and the licensee failed to timely identify and correct the condition adverse to quality associated with the Masoneilan 8005N I/P converters.
Corrective Actions: The licensee repaired ALHV0010, performed an extent of condition to determine the remaining installed Masoneilan 8005N I/P converters, and initiated work orders to replace the remaining installed Masoneilan 8005N I/P converters.
Corrective Action References: Condition Reports 10035961, 10038863
Performance Assessment:
Performance Deficiency: The licensees failure to promptly identify and correct a condition adverse to quality associated with the dislocation of the roll pin in the transducer nozzle assembly contained in Masoneilan model 8005N I/P transducer was a performance deficiency.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Equipment Performance attribute of the Mitigating Systems cornerstone and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the failure mechanism of the Masoneilan model 8005N I/P transducer prevented ALHV0010 from performing its closed safety function to isolate a faulted or ruptured steam generator.
Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power.
Specifically, the safety function of ALHV0010 to close to isolate a faulted or ruptured steam generator failed. An NRC senior reactor analyst performed a detailed risk evaluation for this finding. To perform this assessment, the analyst used the Wolf Creek Standardized Plant Analysis Risk (SPAR) Model version 8.81 and SAPHIRE version 8.2.11, which are PRA tools used to evaluate the risk impact of safety functions necessary to prevent core damage from occurring as a result of postulated accident sequences. The analyst assumed that the condition attributable to the performance deficiency would be best represented by setting the basic event AFW-FCV-FC-HV10, SG B Control AOV HV10 From TDP Fails, to TRUE in the Events and Conditions Assessment Workspace with an exposure time of 49 days. The analyst included credit for the use of Diverse and Flexible Coping Strategies Flex by adjusting the basic event FLX-XHE-XE-ELAP, Operators Fail to Declare ELAP When Beneficial, probability to 1.0E-2. The analyst quantified the SPAR model according to the above assumptions to obtain a result of 1.30E-7/year for an increase in average annual core damage frequency (delta-CDF) for both internal and external events. The dominant sequences included: 1) fires in fire areas C9 and C10 with failures of the auxiliary feedwater, main feedwater, and feed-and-bleed functions; 2) feedwater line breaks with failure of the feedwater isolation and feed-and-bleed functions; and 3) a Bin-3 earthquake resulting in a loss of offsite power with anticipated transient without scram and loss of the main feedwater and auxiliary feedwater functions. The finding was also evaluated for risk impact on large early release frequency (LERF). The analyst performed a screening for increase in LERF using Inspection Manual Chapter 0609, Appendix H, Containment Integrity Significance Determination Process, with the finding being treated as a Type A finding. The analyst reviewed all dominant sequences contributing to CDF for any attributes affecting LERF in accordance with Table 6.1 and screened out all dominant sequences. The finding was thus determined to represent no significant increase in risk due to LERF. Based on best estimates of 1.30E-7/year for total delta-CDF and no significant increase in LERF, the analyst concluded that the risk significance of the finding was determined to be very low safety significance (Green).
Cross-Cutting Aspect: H.13 - Consistent Process: Individuals use a consistent, systematic approach to make decisions. Risk insights are incorporated as appropriate. Specifically, the licensee failed to use the corrective action and work management program to ensure actions to replace the turbine-driven AFW pump flow control valves Masoneilan 8005N I/P converters were replaced in a timely manner prior to ALHV0010 failure on August 21, 2024.
Enforcement:
Violation: Title 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Actions, states, in part, that measures shall be established to assure that conditions adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective material and equipment, and nonconformances are promptly identified and corrected.
Contrary to the above, between August 2018 to August 2024, the licensee failed to promptly identify and correct a condition adverse to quality associated with dislocation of the roll pin in the transducer nozzle assembly contained in Masoneilan model 8005N I/P transducer. This condition was identified from another licensees licensing event report, Part 21 notification, and vendor report received by the licensee, but not correctly identified and corrected by the licensee until after subsequent failure of ALHV0010 on August 22, 2024.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Observation: Semiannual Trend Review 71152S The inspectors reviewed the licensees corrective action program, performance indicators, system health reports, and other documentation available to help identify performance trends that might indicate the existence of a more significant safety issue. The inspectors verified that the licensee was taking corrective actions to address the identified adverse trends. The inspectors did not review any cross-cutting themes because none existed at the site.
To verify that the licensee was taking corrective actions to address identified adverse trends that might indicate the existence of a more significant safety issue, the inspectors reviewed the corrective action program documentation associated with a potential adverse in the operability determination process. Specifically, quality of documentation found in condition report operability determinations or technical rigor. The inspectors identify three examples of a lack of documentation in the screening that did not allow an independent reviewer to draw the same documented conclusion in accordance with Procedure AP 26C-004, Operability Determinations and Functionality Assessments, revision 48. Procedure AP 26C-004, step 6.3.4, states in part, adequate documentation is necessary to establish a basis to allow for subsequent independent reviews. Operability determinations should be documented in sufficient detail to allow an individual knowledgeable in the technical discipline associated with the condition to understand the basis for the determination. In response, the licensee initiated Condition Report 10037306 to capture the potential trend and closed it to Condition Report 10030856. Condition Report 10030856 was initiated to capture the licensees Quality Assurance recommendation identified during Audit Report 24-07-OP, Quality Assurance Audit Report Operations, dated August 27, 2024. Audit Report 24-07-OP identified a potential low-level trend in operability determinations. A specific example included the lack of technical rigor and incomplete operability determination. In response to the inspectors observation and Audit Report 24-07-OP, the licensee is developing an action plan to address the low-level trend.
Unresolved Item (Closed)
Turbine-Driven Auxiliary Feedwater Pump Turbine Governor Valve Actuator Failure (EA-24-091)
Description:
On August 20, 2024, at 5:00 a.m. CDT, the licensee entered a planned maintenance outage of the turbine-driven auxiliary feedwater (TDAFW) pump, under Technical Specification (TS) Limiting Condition for Operation (LCO) 3.7.5, action C, which requires the licensee to return the pump to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in Mode 3 within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. While conducting AFW testing, valve AL-HV-10, the AFW flow control for steam generator B, did not respond as expected. The licensee calibrated the valve controller and completed diagnostic valve testing, and no issues were identified, so the licensee concluded that valve AL-HV-10 was operating correctly.
On August 22, 2024, at 3:16 a.m. CDT, during post-maintenance testing activities on valve AL-HV-10, with the TDAFW pump running, the turbine tripped on electronic overspeed. The licensee commenced troubleshooting activities for the turbine trip. The licensee was able to identify that the cause of the turbine trip as a faulty actuator on the turbine speed governing valve, FV-313. The licensee determined that the repairs to correct the condition with the TDAFW pump would exceed the TS 3.7.5 LCO completion time and initiated the notice of enforcement discretion (NOED) process with the NRC by contacting the senior resident inspector.
Based on the NRC staffs evaluation of the licensees request, the staff determined that granting this NOED was consistent with the NRCs Enforcement Policy and staff guidance.
NRC staff independently evaluated the risk insights associated with the requested NOED condition and obtained results consistent with the licensees assertions relative to satisfying the incremental conditional core damage probability and incremental conditional large early release probability criteria referenced above. The NOED request met the criteria specified in NRCs Enforcement Manual, appendix F, sections 2.2 and 2.5. Therefore, as communicated orally to the licensee at 1:05 a.m. CDT on August 23, 2024, the NRC exercised discretion to not enforce compliance with TS 3.7.5 LCO requirements that Wolf Creek Generating Station be in Mode 3 by 11:00 a.m. CDT on August 23, 2024. The NRC extended the Wolf Creek Generating Station Mode 3 entry by 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> to 11:00 p.m. CDT on August 24, 2024, and subsequent Mode changes required by TS 3.7.5 were extended as well. Subsequent to the NRC verbal approval of the NOED request, and prior to entering the period of enforcement discretion, the licensee discovered an additional issue, not related to the NOED, with the AFW system that would require extensive troubleshooting to determine the cause-and-effect repairs. Thus, following the expiration of the 72-hour TS 3.7.5 LCO at 5:00 a.m. CDT, the licensee entered TS 3.7.5, condition D, requiring the plant to be in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 4 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Operators initiated a TS required shutdown at 8:00 a.m. CDT on August 23, 2024, as required by action D of TS 3.7.5 LCO. The licensee completed the shutdown to Mode 3 at 10:24 a.m. CDT, and Mode 4 at 4:51 p.m. CDT on August 23, 2024.
The licensee submitted its written request for enforcement discretion in letter WO 24-0609, Docket No. 50-482: Request for Notice of Enforcement Discretion Regarding Technical Specification 3.7.5, Auxiliary Feedwater (AFW) System, dated August 27, 2024, (ML24240A264). The NOED letter from the NRC staff was sent to the licensee on August 29, 2024 (ML24241A221).
The inspectors reviewed the licensees equipment performance evaluation and hardware failure analysis, documented in Condition Report 10036008, for failure of the FV-313 actuator resulting in an electrical overspeed trip of the TDAFW pump reviewed licensees and industrys operating experience and noted the following:
- The FV-313 actuator that failed was installed during refueling outage 26 due to a time-based preventative maintenance. The actuator was in service for approximately 3 months prior to the failure. Prior to installation, the actuator was in the warehouse since delivery in January 2014. The failure mechanism was not identified, but the component issues experienced shortly after installation suggest a possible parts quality issue.
- No licensee and industry operating experience was identified as failures associated with FV-313 actuator.
The inspectors concluded that the failure was not within the ability of the licensee to foresee and correct given the potential of infant materiality of the component was the potential cause of the failure. Therefore, no performance deficiency was identified for the failure of FV-313 actuator. This disposition closes URI 05000482/2024003-03.
Corrective Action Reference(s): Condition Report
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On January 7, 2025, the inspectors presented the integrated inspection results to Jaime McCoy, Site Vice President, and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Corrective Action
Documents
Condition Report
(CR-)
10037664, 10037667
Corrective Action
Documents
Condition Report
(CR-)
10037259
Corrective Action
Documents
Resulting from
Inspection
Condition Report
(CR-)
10037410, 10037416, 10037622, 10038536
Miscellaneous
WCRE-35
Boundary Matrix
AP 10-103
Fire Protection Impairment Control
41A
AP 10-104
Breach Authorization
Procedures
STN FP-440
Fire Door Visual Inspection
Calculations
XX-C-076
Flood Water Surface Elevation Calculation
Corrective Action
Documents
Condition Report
(CR-)
10029728
DECP 20612
Security Phase III-ESW PAB Tie-in
Engineering
Changes
DECP 20613
Security Phase III - Vehicle Barrier System
EF-M-014
UHS Thermal Analysis-Review for Power Rerate
EF-M-046
UHS Analysis with Initial Lake Temperature Up to 94
degrees F
EF-M-080
UHS Inventory Losses from ESW through the AFW System
Calculations
WR-WC-UH-1A
Elevation-Area-Capacity of Ultimate Heat Sink (UHS)
Corrective Action
Documents
Condition Report
(CR-)
10026742, 10015964, 10036794
Corrective Action
Documents
Resulting from
Inspection
Condition Report
(CR-)
10037308
Miscellaneous
23-000049
Wolf Creek Generating Station June 2023 Hydrographic
Survey of the UHS
06/27/2023
Procedures
STS EF-100A
ESW System Inservice Pump A and ESW A Check Valve
Test
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
STS EF-100B
ESW System Inservice Pump B and ESW B Check Valve
Test
TMP 10-035
Dredging the UHS Channel
Work Orders
ALR 00-018A
NB01 Bus Lockout
Procedures
OFN NB-030
Loss of AC Emergency Bus NB01 (NB02)
Corrective Action
Documents
Condition Report
(CR-)
10036061, 10036066, 10036629, 10013552, 10012832,
10008697, 27871, 132928, 115731, 115389, 115370,
139894, 10037450, 10037502, 126023, 10037553,
10037554, 2008-03616, 10038050
Engineering
Changes
CCP 020652
Alternate IP Transducer for Turbine Driven Auxiliary
Feedwater Pump (TDAFP) Discharge Valve
M-021-00025
TDAFP Failure Modes and Effects Analysis
W01
M-021A
Technical Specification for Auxiliary Feedwater Pump
Turbine Governor Control System Upgrade Wolf Creek
Generating Station (WCGS)
M-021A-00011
Instruction Manual for Terry Turbine Digital Controls
Replacement/Retrofit
W07
PO 785036
Purchase Order
09/12/2019
Miscellaneous
WCRE-34
Fourth 10-Year Interval Inservice Testing Basis Document
AI 23N-001
Air Operated Valve Categorization
ALR 00-127D
CST Lev LOLO2
10A
ALR 00-128E
TD AFP SPD HILO
ALR 00-129C
TD AFP OVSPD/SYS Fault Trip
EMG E-0
Reactor Trip or Safety Injection
EMG E-2
Faulted Steam Generator Isolation
EMG E-3
Steam Generator Tube Rupture
Procedures
STS AL-104
TDAFW ESF Response Time and Flow Path Verification
Work Orders
WO 15964, 21346, 83303, 18-443512-000, 23-486669-000,
23-487739-001, 23-485753-005, 23-483863-001,
23-484353-000
Calculations
AN-97-004
Updated Containment Pressure and Temperature Response
Analysis for Limiting LOCA Scenario, Accounting for
Additional Time Delay for Fan Cooler Activation
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
EF-M-046
UHS Analysis with Initial Lake Temperature Up to 94
degrees F
GL-M-002
SGL15A/B Heat Loads and Tube Plugging
GL-M-005
Electrical Penetration Room Temperature Heat Up with
Inoperable Room Cooler
XX-M-068
Tube Plugging Criteria for Safety-Related Room Cooler
(Aerofin AL6XN) Cooling Coils
Corrective Action
Documents
Condition Report
(CR-)
10033847, 10036649, 10036650, 10036652, 10036654,
10036655, 10036656, 10036657, 10036658, 10036684,
10037075, 10037347, 10037392, 10037395, 10037396,
10037404, 10037410
Corrective Action
Documents
Resulting from
Inspection
Condition Report
(CR-)
10037373
KD-7496
One Line Diagram
Drawings
M-1HX001
Heat Exchanger Tube Sheet Maps
Engineering
Changes
CCP 09816
Compensatory Measures for Inoperable Elec. Pen. Rm.
Coolers
Miscellaneous
EQSD-I
Equipment Qualification Design Basis Document
Operability Determinations and Functionality Assessments
EMG E-0
Reactor Trip or Safety Injection
STS KJ-005A
Manual/Auto Start, Sync & Loading of EDG NE01
075
Procedures
SYS GL-200
Inoperable Penetration Room Cooler
13B
Work Orders
Corrective Action
Documents
Condition Report
(CR-)
10020042, 10014459, 10015266, 10013552, 10001156,
10016875, 10019819
E-13AL05B
Schematic Diagram Aux Feedwater Pumps, Discharge
Control - Air Operated Valves
Drawings
W16
Engineering
Changes
DECP 020652
Alternate IP Transducer for Turbine Driven Auxiliary
Feedwater (TDAFP) Discharge Valve
Instruction Manual for Nuclear Service Control Valves
W57
Miscellaneous
Qualification Report for Current to Pressure Transducer
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Thermo Scientific P/N STD6131-2
INC C-1006
Calibration of Converters
4A
Procedures
INC S-0020
Air Operated Valve (AOV) Diagnostic Testing
Work Orders
WO 83159, 83302, 22-482891-000
Corrective Action
Documents
Condition Report
(CR-)
10033847, 10037113, 10037129, 10037134, 10037136,
10037137, 10037139, 10037200, 10037218, 10037219,
10037220, 10037221, 10037224, 10037225, 10037226,
10037347, 10037392, 10037395, 10037396, 10037404,
10037534, 10037926, 10037954
Corrective Action
Documents
Resulting from
Inspection
Condition Report
(CR-)
10037695, 10037965, 10038440
20612
Security Phase III - ESW PAB Tie-In
Engineering
Changes
20613
Security Phase III - Vehicle Barrier System
FSG-05
Initial Assessment and Flex Equipment Staging
MPE VD-001
M627A Ventilation Damper Maintenance
Procedures
STN PE-037A
ESW Train A Heat Exchanger Flow and DP Trending
2A
Work Orders
WO 45642, 45654, 48831, 66217, 91710, 92312, 92358, 92297,
294, 92648
Miscellaneous
WCNOC-163
Mitigating System Performance Index (MSPI) Basis
Document
71151
Procedures
STS EJ-209A
Train A RHR System Inservice Valve Test
Calculations
GL-M-007
Cooling Load Calculation in Safety Related Pumps Rooms
Corrective Action
Documents
Condition Report
(CR-)
10023021, 10023659, 10035907, 10037007, 10037050,
10037269
Corrective Action
Documents
Resulting from
Inspection
Condition Report
(CR-)
10038184
M-12EG02
Piping and Instrumentation Diagram Component Cooling
Water System
Drawings
M-12EG03
Piping and Instrumentation Diagram Component Cooling
Water System
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
M-12EG04
Piping and Instrumentation Diagram Component Cooling
Water System
WCRE-09-EG
IST Design Basis Document System EG
Miscellaneous
WCRE-19
Third 10-Year Interval Inservice Testing Basis Document
OFN BN-030
Loss of AC Emergency Bus NB01 (NB02)
Procedures
SYS EG-201
Transferring Supply of CCW Service Loop and CCW Train
Shutdown
Corrective Action
Documents
Condition Report
(CR-)
10030856, 10035719, 10035725, 10035726, 10035727,
10035729, 10035730, 10035731, 10035732, 10035733,
10037259, 10037373, 10038305
Corrective Action
Documents
Resulting from
Inspection
Condition Report
(CR-)
10037306
Miscellaneous
24-07-OP
Quality Assurance Audit Response Operations
08/27/2024
AP 21-200
Operational Decision Making
Procedures
Operability Determinations and Functionality Assessments
Corrective Action
Documents
Condition Report
(CR-)
26023, 139894, 10012832, 10013552, 10033418,
10033639, 10034883, 10035961, 10036233, 10037808
AI 28A-100
Condition Report Resolution
AP 28-011
Resolving Degraded or Nonconforming Conditions Impacting
Procedures
Corrective Action Program
27