IR 05000390/2024002
| ML24219A233 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 08/07/2024 |
| From: | Louis Mckown NRC/RGN-II/DRP/RPB5 |
| To: | Jim Barstow Tennessee Valley Authority |
| Shared Package | |
| 19 | List: |
| References | |
| IR 2024002 | |
| Download: ML24219A233 (19) | |
Text
SUBJECT:
WATTS BAR NUCLEAR PLANT - INTEGRATED INSPECTION REPORT 05000390/2024002 AND 05000391/2024002
Dear Jim Barstow:
On June 30, 2024, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Watts Bar Nuclear Plant. On July 31, 2024, the NRC inspectors discussed the results of this inspection with Christopher Reneau, Site Vice President and other members of your staff. The results of this inspection are documented in the enclosed report.
Three findings of very low safety significance (Green) are documented in this report. Three of these findings involved violations of NRC requirements. We are treating these violations as non-cited violations (NCVs) consistent with Section 2.3.2 of the Enforcement Policy.
If you contest the violations or the significance or severity of the violations 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 II; the Director, Office of Enforcement; and the NRC Resident Inspector at Watts Bar Nuclear Plant.
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 II; and the NRC Resident Inspector at Watts Bar Nuclear Plant.
August 7, 2024 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, Louis J. McKown, II, Chief Reactor Projects Branch 5 Division of Reactor Projects Docket Nos. 05000390 and 05000391 License Nos. NPF-90 and NPF-96
Enclosure:
As stated
Inspection Report
Docket Numbers:
05000390 and 05000391
License Numbers:
Report Numbers:
05000390/2024002 and 05000391/2024002
Enterprise Identifier:
I-2024-002-0030
Licensee:
Tennessee Valley Authority
Facility:
Watts Bar Nuclear Plant
Location:
Spring City, Tennessee
Inspection Dates:
April 01, 2024 to June 30, 2024
Inspectors:
W. Deschaine, Senior Project Engineer
M. Donithan, Senior Operations Engineer
J. Hamman, Senior Project Engineer
J. Hickey, Senior Project Engineer
R. Wehrmann, Resident Inspector
Approved By:
Louis J. McKown, II, Chief
Reactor Projects Branch 5
Division of Reactor Projects
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Watts Bar Nuclear Plant, 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
D-A ERCW Failure to start Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000390,05000391/2024002-01 Open/Closed
[P.5] -
Operating Experience 71111.12 A self-revealed finding of very low safety significance (Green) and an associated NCV of Title 10 of the Code of Federal Regulations (CFR) Part 50, Appendix B, Criterion V, Instructions,
Procedures, and Drawings, was identified due to the failure of the licensee to provide adequate maintenance procedures for 6900 Volts Circuit Breaker inspection and overhaul. Specifically, the licensee failed to incorporate required relay armature gap checks identified in applicable operating experience into maintenance procedure steps resulting in the failure to start of the D-A Essential Raw Cooling Water (ERCW) on April 3, 2024.
Failure to assess and manage risk associated with A train essential air header work resulting in loss of shield building.
Cornerstone Significance Cross-Cutting Aspect Report Section Barrier Integrity Green NCV 05000390,05000391/2024002-02 Open/Closed
[H.11] -
Challenge the Unknown 71111.13 A self-revealed Green finding and associated NCV of 10 CFR 50.65(a)(4), for failure to assess and manage the increase in risk that resulted from the maintenance activities. Specifically, the licensee failed to assess the loss of shield building as a probable outcome of the maintenance activity and manage the increase in risk associated with the loss of shield buildings on Unit 1 and Unit 2.
Unit 2 Loss of RHR Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000391/2024002-03 Open/Closed
[H.3] - Change Management 71111.15 A self-revealed Green finding associated with NCV of TS 5.7.1.1.a for failure to follow the plant procedure. Specifically, an operator inadvertently closed the B Train Residual Heat Removal (RHR) Heat Exchanger outlet flow control valve during a planned A Train RHR outage resulted in loss of RHR safety function.
Additional Tracking Items
None.
PLANT STATUS
Unit 1 began the inspection period at or near rated thermal power. On May 24, 2024, the unit was shut down to affect repairs to the main generator current transformers. The unit was returned to rated thermal power on May 29, 2024, and remained at or near rated thermal power for the remainder of the inspection period.
Unit 2 began the inspection period at or near rated thermal power. On June 12, 2024, Unit 2 was down powered to approximately 60% rated thermal power to support switching operations.
The unit was returned to rated thermal power on June 14, 2024, and remained at or near rated thermal power for the remainder 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 on-site 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, tornado warning, on April 2, 2024.
71111.04 - Equipment Alignment
Partial Walkdown Sample (IP Section 03.01) (3 Samples)
The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:
(1)2B-B emergency diesel generator (EDG) on April 24, 2024 (2)2A centrifugal charging pump (CCP) while the 2B CCP was out for maintenance on April 24, 2024
- (3) Unit 1 turbine driven auxiliary feedwater pump (TDAFW) system on April 25, 2024
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (5 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) Auxiliary building, elevation 757' - auxiliary control room, auxiliary instrument rooms, and 125V vital battery board rooms on April 22, 2024
- (2) Auxiliary building elevation 772' - 480V board rooms on April 23, 2024
- (3) Control building, elevation 708' - Unit 1 and 2 auxiliary instrument rooms and computer room on April 23, 2024
- (4) Auxiliary building, elevation 713' - penetration rooms on April 24, 2024
- (5) Auxiliary building corridor, elevation 676' on April 24, 2024
Fire Brigade Drill Performance Sample (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated the onsite fire brigade training and performance during an announced fire drill on April 22, 2024.
71111.07A - Heat Exchanger/Sink Performance
Annual Review (IP Section 03.01) (1 Sample)
The inspectors evaluated readiness and performance of:
(1)1A-A EDG Jacket Water Heat Exchanger 1A1 under work order (WO) 123615466 and Jacket Water Heat Exchanger 1A2 under WO 123615488
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 Unit 1 shutdown and power ascension for forced outage activities on May 25, 2024, and May 28, 2024.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed and evaluated the Licensed Operator Requalification crew simulator set which included a loss of Auxiliary Air, Reactor Trip, and a large break LOCA on May 8, 2024.
71111.12 - Maintenance Effectiveness
Maintenance Effectiveness (IP Section 03.01) (3 Samples)
The inspectors evaluated the effectiveness of maintenance to ensure the following structures, systems, and components (SSCs) remain capable of performing their intended function:
(1)2A-A safety injection pump motor maintenance under WO 123643445 on April 02, 2024
- (2) D-A ERCW pump failed to start on April 03, 2024
- (3) A-A electric board room chiller maintenance under WO 122853550 on May 6, 2024, through May 16, 2024
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (4 Samples)
The inspectors evaluated the accuracy and completeness of risk assessments for the following planned and emergent work activities to ensure configuration changes and appropriate work controls were addressed:
- (1) A Train essential air header repair on May 01, 2024, under WO 121942142
- (2) Unit 1 shutdown Board B swap to alternate source for breaker swap on May 21, 2024
- (3) A Train essential air header modification on June 09, 2024, under WO 124471215 (4)1A-A EDG outage the week of June 24, 2024
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (8 Samples)
The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:
- (1) Loss of control room envelope on April 2, 2024
- (2) Unit 2 TDAFW pump room direct current emergency exhaust fan grounds as documented in Condition Report (CR) 1927836 on April 30, 2024 (3)2-FCV-30-37 failure to close as documented in CR 1928734 on May 2, 2024
- (4) Loss of RHR due to closure of 2-FCV-74-28 and entry into limiting condition for operations (LCO) 3.0.3 as documented in CR 1930872 on May 13, 2024 (5)1-FI-3-147B AFW Flow Indicator to the #3 Steam Generator reading low off-scale in standby as documented in CR 1933494 on June 7, 2024
- (6) WBN-2-MTR-030-0446B-B, 2B Diesel Generator Ventilation Intake Damper found closed as documented in CR 1936490 on June 10, 2024
- (7) WBN-1-ZS-090-0190, Divider Barrier Escape Hatch Door Alarm not functioning as documented in CR 1936966 on June 11, 2024
- (8) Elevated outboard seal leakage on the 2A CCP as documented in CR 1937968 on June 18, 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) (4 Samples)
- (1) Replacement of 2-FSV-67-176-A under WO 123643445, on April 1, 2024
===123621814, on April 1, 2024
- (3) PMT for 2B CCP following a maintenance outage under WO 123621187, on April 23, 2024
- (4) PMT of 0-FCO-31-30A actuator replacement under WO 123989439, on May 6, 2024 Surveillance Testing (IP Section 03.01)===
(1)1-SI-92-31 18 Month Ch Cal Source Range, Intermediate Range under WO
123860979, on May 7, 2024 Inservice Testing (IST) (IP Section 03.01)
- (1) B-A ECRW Pump testing under WO 123647526, on May 13, 2024 (2)1-SI-63-902-A, Valve Full-Stroke Exercising During Plant Operation - Safety Injection System (Train A) on May 14, 2024
Diverse and Flexible Coping Strategies (FLEX) Testing (IP Section 03.02) (1 Sample)
(1)0-SOI-360.003 6900V FLEX Diesel Generator System for the FLEX DG 3B, on June 6, 2024
71114.06 - Drill Evaluation
Required Emergency Preparedness Drill (1 Sample)
- (1) Fire in a condensate pump, anticipated transient without scram, Unit 1 reactor coolant system (RCS) pipe break in A RHR HX room, and fuel failure resulting in a general emergency classification on June 12,
OTHER ACTIVITIES - BASELINE
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 the use of toolpouch maintenance on safety related SSCs that might be indicative of a more significant safety issue.
71153 - Follow Up of Events and Notices of Enforcement Discretion Reporting (IP Section 03.05)
The inspectors evaluated the following licensee event reports (LERs):
- (1) Retraction of event notification56970 This EN was submitted and subsequently retracted by licensee correspondence titled EN 56970 Retraction, dated February 21, 2024. The event was reviewed to determine if reporting requirements were met and should have been reported by the licensee.
INSPECTION RESULTS
D-A ERCW Failure to start Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000390,05000391/2024002-01 Open/Closed
[P.5] -
Operating Experience 71111.12 A self-revealed finding of very low safety significance (Green) and an associated NCV of Title 10 of the Code of Federal Regulations (CFR) Part 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, was identified due to the failure of the licensee to provide adequate maintenance procedures for 6900 Volts Circuit Breaker inspection and overhaul. Specifically, the licensee failed to incorporate required relay armature gap checks identified in applicable operating experience into maintenance procedure steps resulting in the failure to start of the D-A Essential Raw Cooling Water (ERCW) pump on April 3, 2024.
Description:
On April 3, 2024, Operations attempted to start the D-A ERCW pump (WBN-0-MTR-067-0040-A) in preparations for maintenance on the C-A ERCW pump. The D-A ERCW pump breaker failed to close. Unit 1 and Unit 2 entered a TS LCO 3.7.8 for the failure of D-A ERCW Pump Start, C-A ERCW Pump was left in service and generated CR 1921724.
TVA found that the D-A ERCW pump motor breaker had failed to close. Troubleshooting identified contacts 4 and 8 on the 52Y anti-pump relay open. These contacts are part of the closing circuit required for breaker closure. The 52Y anti-pump relay was replaced under corrective maintenance (WO 124413061) using 0-MI-57.001, 6900 Volt Circuit Breaker Inspection, and 0-MI-57.006, 6900 Volt Circuit Breaker Overhaul. TVA discovered improper alignment of the armature tailpiece causing binding into one of the molded posts. This binding prevented full closure of the relay contacts required to complete the breaker closing circuit.
Information Notice 97-08 documented the susceptibility of Type HMA Control Relays to potential binding of the armature against the molded phenolic post, and provided reference to General Electric Service Advisory Letter (GE SAL) 721-PSM No. 171.1, "HMA Relay Armature Binding," which specified that: "Normally, when an HMA relay is assembled at the factory, the armature is centered between the two molded posts with a gap of 0.005 inch on each side."
On August 19, 1997, the licensee performed a review of IN 97-08 (WBPER970835). This determined that the HMA relay problem identified applied to the 6.9kV breakers at Watts Bar.
TVA created corrective actions to revise the maintenance procedures to incorporate the required armature gap checks. Further, NPG-SPP-01.2, Administration of Site Technical Procedures, Section 3.2.5 M requires that changes to technical procedures are reviewed to ensure inclusion of applicable significant Operating Experience. 0-MI-57.001 and 0-MI-57.006 identify IN 97-08 and GE SAL 721-PSM as applicable operating experience.
Analysis found that all successive revisions to 0-MI-57.001 and 0-MI-57.006, including revisions 17 and 20 issued on February 28, 2024, and February 22, 2024, respectively, did not incorporate the applicable significant operating experience from IN 97-08 and GE SAL 721-PSM 171.1. Had the applicable significant operating experience been procedurally incorporated, planned maintenance (WO 121906017) using 0-MI-57.001, completed in March 2024, would have ensured the proper 52Y relay armature gap and prevented the start failure of the D-A ERCW pump on April 3, 2024.
Corrective Actions: TVA performed corrective maintenance, incorporating the applicable operating experience, to restore the pump. On May 09, 2024, TVA revised 0-MI-57.001 and 0-MI-57.006 to incorporate the applicable significant operating experience.
Corrective Action References: CR 1921724, CR 1927890, CR 1927886
Performance Assessment:
Performance Deficiency: The failure to check the D-A ERCW pump-motor 52Y relay armature gap was a performance deficiency reasonably within the licensee's ability to foresee and prevent. Specifically, the licensee failed to incorporate required relay armature gap checks, identified in applicable operating experience, into maintenance procedure steps, resulting in the failure to start of the D-A ERCW pump.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Procedure Quality 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 subject breaker's 52Y relay armature gap was out of specification and adversely affected the mitigating equipment (ERCW Pump D-A) and resulted in a failure to start on April 3, 2024.
Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power. Using Inspection Manual Chapter 0609, Appendix A, The Significance Determination Process for Findings At-Power, Exhibit 2, Mitigating Systems Screening Questions, Section A, the screening questions, were all answered "NO", therefore, the inspectors determined the finding was of very low safety significance (Green).
Cross-Cutting Aspect: P.5 - Operating Experience: The organization systematically and effectively collects, evaluates, and implements relevant internal and external operating experience in a timely manner. Specifically, most recently in February 2024, the licensee failed to incorporate required relay armature gap checks, identified in applicable operating experience, into maintenance procedure steps, resulting in the failure to start of the D-A ERCW pump on April 3, 2024.
Enforcement:
Violation: Title 10 CFR 50 Appendix B Criterion V, Instructions, Procedures, and Drawings requires that: "Activities affecting quality shall be prescribed by documented instructions, procedures, or drawings, of a type appropriate to the circumstances and shall be accomplished in accordance with these instructions, procedures, or drawings. Instructions, procedures, or drawings shall include appropriate quantitative or qualitative acceptance criteria for determining that important activities have been satisfactorily accomplished."
Contrary to the above from August 19, 1997 to May 09, 2024, licensee procedures 0-MI-57.001, 6900 Volt Circuit Breaker Inspection and 0-MI-57.006, 6900 Volt Circuit Breaker Overhaul, were not appropriate to the circumstances in that they failed to have adequate procedural requirements to ensure that the armature gap check was performed. This directly resulted in the failure to check the armature gap on the D-A ERCW pump breaker 52Y relay which resulted in the failure of the pump to start.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Failure to assess and manage risk associated with A train essential air header work resulting in loss of shield building.
Cornerstone Significance Cross-Cutting Aspect Report Section Barrier Integrity Green NCV 05000390,05000391/2024002-02 Open/Closed
[H.11] -
Challenge the Unknown 71111.13 A self-revealed Green finding and associated NCV of 10 CFR 50.65(a)(4), for failure to assess and manage the increase in risk that resulted from the maintenance activities. Specifically, the licensee failed to assess the loss of shield building as a probable outcome of the maintenance activity and manage the increase in risk associated with the loss of shield buildings on Unit 1 and Unit 2.
Description:
On April 25, 2024, a critical evolutions meeting was held to approve the High Risk Management Plan for the split tee installation welding on A train essential air header.
This plan discussed potential loss of essential air resulting in meeting the entry conditions for 0-AOI-10, Loss of Control Air, and entry into multiple TS LCO action statements with 72-hour completion times. However, it did not address potential entry into TS LCO 3.6.15 Shield Building, a 24-hour completion time action statement, nor did the risk mitigation check list address methods to prevent a loss of the shield building.
UFSAR Section 6.2.3. Secondary Containment Functional Design 3. Design Evaluation 1.
Secondary Containment Enclosures 1. Shield Building states, in part, that: "The Shield Building provides the physical barrier for airborne primary containment leakage during a LOCA or a Fuel Handling Accident inside containment... The low leakage characteristics of this barrier help to reduce the rate at which purified air must be released to maintain the enclosed volume at a negative pressure. This factor contributes significantly to keeping the site boundary and the low population zone dosage within 10 CFR 100 guidelines."
On May 1, 2024, welding was performed under WO 121900145 to install a split tee. At 12:11 station logs document that during the performance of the welding the structural integrity of the piping was compromised resulting in Unit 1 and Unit 2 entering into numerous TS shutdown action statements as had been evaluated in the high risk management plan. However, the impact to annulus vacuum was not addressed in the plan and was not recognized by the shift operations staff.
At 00:06 on May 02, 2024, Authorized performance of WO 124471141, Jumper out EGTS train A FCV's. This WO installed N2 jumpers to 1-FCV-65-52 and 2-FCV-65-5 to allow maintaining these dampers open when the A train aux air header is depressurized.
At 00:52 operators utilized an emergent risk assessment process to re-evaluate previously approved activities based upon different plant conditions and assumptions than were presented in the original risk management plan. Jumpers were used to maintain annulus vacuum system in service during the contingency repairs required to replace aux air piping.
Corrective Actions: Licensee reassessed risk and created compensatory measures to ensure that the shield building vacuum was maintained throughout the essential air header repair.
The loss of shield building was documented in the station logs and in the corrective action program.
Corrective Action References: CR 1928443, CR 1928370
Performance Assessment:
Performance Deficiency: Failure to implement the requirements of 10 CFR 50.65(a)(4) was a performance deficiency reasonably within the licensee's ability to foresee and prevent.
Specifically, the licensee's critical evolutions meeting and high risk management plan failed to adequately assess and manage the risk associated with the A train essential air header work.
Furthermore, the high risk management plan determined that loss of A train essential air was a probable outcome. However, the plan did not discuss the potential challenges to shield building operability or develop Risk Management Activities (RMAs) to mitigate the impact to shield building operability.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Configuration Control attribute of the Barrier Integrity cornerstone and adversely affected the cornerstone objective to provide reasonable assurance that physical design barriers protect the public from radionuclide releases caused by accidents or events. Specifically, the configuration control attribute of the barrier integrity cornerstone objective was adversely affected because the risk assessment failed to correctly account for the loss of a key operating function, shield building annulus vacuum, and that function was not maintained due to the failure to identify or implement RMAs.
Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The questions in exhibit 3, Barrier Integrity Screening Questions, Section D, Control Room, Auxiliary, Reactor, or Spent Fuel Pool Building, were answered with "NO" which screens to Green.
Cross-Cutting Aspect: H.11 - Challenge the Unknown: Individuals stop when faced with uncertain conditions. Risks are evaluated and managed before proceeding. Specifically, licensee personnel failed to fully assess the impact of the depressurization of A train essential air, which resulted in the failure to identify the impact to shield building annulus vacuum this allowed the work to proceed without the risk being managed. This directly resulted in the loss of shield building experienced by Unit 1 and Unit 2.
Enforcement:
Violation: Title 10 CFR 50.65(a)(4) states, in part, that: "Before performing maintenance activities (including but not limited to surveillance, post-maintenance testing, and corrective and preventive maintenance), the licensee shall assess and manage the increase in risk that may result from the proposed maintenance activities."
Contrary to the above, from April 25, 2024, to May 2, 2024, the licensee failed to assess and manage the increase in risk that resulted from the maintenance activities, specifically, the licensee failed to assess the loss of shield building as a probable outcome of the maintenance activity, and manage the increase in risk associated with the loss of shield buildings on Unit 1 and Unit 2. The failure to develop risk management activities directly resulted in the inoperability of the shield building on Unit 1 and Unit 2.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Unit 2 Loss of RHR Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000391/2024002-03 Open/Closed
[H.3] - Change Management 71111.15 A self-revealed Green finding associated with NCV of TS 5.7.1.1.a for failure to follow the plant procedure. Specifically, an operator inadvertently closed the B Train Residual Heat Removal (RHR) Heat Exchanger outlet flow control valve during a planned A Train RHR outage resulted in loss of RHR safety function.
Description:
On May 13, 2024, at 01:00 the licensee declared the Unit 2 2A residual heat removal (RHR) pump inoperable and entered TS LCO 3.5.2 (ECCS Operating) Condition A and TS LCO 3.6.6 (Containment Spray) Condition B; with a required action to restore the 2A RHR 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 />. This condition was to support scheduled maintenance on the 2A RHR train.
An operator failed to follow Step 6.2.1 [5] of 2-SI-74-63-A and inadvertently closed the B Train RHR heat exchanger outlet flow control valve during a planned A Train RHR outage. This human error resulted in a loss of both RHR trains.
At 09:17, Unit 2 entered LCO 3.0.3 due to both trains of RHR being inoperable due to 2-FCV-74-28 (RHR HX B Outlet Isolation) being closed; therefore, a loss of safety function was determined to exist.
At 09:21, Unit 2 exited TS LCO 3.0.3 and remained in TS LCO 3.5.2 Condition A and TS LCO 3.6.6 Condition B due to restoration of 2-FCV-74-28 to full open.
Condition Report 1930872 was initiated to document the unplanned LCO entries and the loss of safety function. The prompt investigation performed under CR 1930872 determined that procedure use and adherence standards were not met in accordance with NPG-SPP-22.207 "Procedure Use and Adherence." Specifically, during the surveillance, the operator and instrumentation and controls technician swapped roles for various performance steps.
Additionally, the operator did not have the procedure in hand during the component manipulation. These actions resulted in the incorrect component being manipulated.
TS 5.7.1.1 a. requires that procedures shall be established, implemented, and maintained covering the applicable procedures recommended in Regulatory Guide 1.33, Revision 2, Appendix A, February 1978.
Regulatory Guide 1.33, Revision 2, Appendix A, Section 1. Administrative Procedures d.
specifies Procedure Adherence and Temporary Change Method procedures.
Step 6.2.1 [5] of 2-SI-74-63-A, 18 Month Channel Calibration of Remote Shutdown Control RHR Heat Exchanger A Outlet Flow Loop 2-LPF-74-16, requires step 6.2.1 [5] which states ENSURE 2-FCV-74-28 RHR HX B FLOW CONTROL is FULLY OPEN.
2-SI-74-63-A Rev 004 was issued on September 12, 2023, as a minor editorial change which states: "Performed critical step evaluation and deleted excessive use of critical step statement. Performed CV/IV evaluation and deleted excessive use of Concurrent Verification (CV)." This change removed a concurrent verification requirement from step 6.2.2 [1] which states LOCATE and IDENTIFY 2-HIC-74-16A, RHR HX A FLOW CONTROL. Additionally, this change removed the Critical Step marking from step 6.2.1 [5] which states ENSURE 2-FCV-74-28 RHR HX B FLOW CONTROL is FULLY OPEN.
Corrective Actions: Operators restored 2FCV-74-28 to the fully open position, then documented the issue in the Station Logs and Corrective Action Program.
Corrective Action References: CR 1930872
Performance Assessment:
Performance Deficiency: Failure to follow 2-SI-74-63-A was a performance deficiency reasonably within the licensee's ability to foresee and prevent. Specifically, the failure to adhere to 2-SI-74-63-A resulted in the closing of the B Train RHR HX Outlet valve which resulted in a loss of safety function.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Human 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 human performance error caused an improper valve manipulation to occur that resulted in a loss of safety function and entry into TS LCO 3.0.3.
Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power. Using Inspection Manual Chapter 0609, Appendix A, The Significance Determination Process for Findings At-Power, Exhibit 2, Mitigating Systems Screening Questions, Section A, the screening questions, were all answered "NO", therefore, the inspectors determined the finding was of very low safety significance (Green).
Cross-Cutting Aspect: H.3 - Change Management: Leaders use a systematic process for evaluating and implementing change so that nuclear safety remains the overriding priority.
Specifically, 2-SI-74-63-A Rev 004 was issued on September 12, 2023, as a minor editorial change however, these changes to the procedure do not appear to meet the intent of a minor/editorial change. This change removed a concurrent verification requirement from step 6.2.2 [1]. The removal of the concurrent verification from the step removed a barrier which guarded against human error. Additionally, the removal of the critical step marking from step 6.2.1 [5]. This change removed the heightened awareness to the implication of the consequences of a human performance error.
Enforcement:
Violation: TS 5.7.1.1 a. requires procedures shall be established, implemented, and maintained covering the applicable procedures recommended in Regulatory Guide 1.33, Revision 2, Appendix A, February 1978.
Regulatory Guide 1.33, Revision 2, Appendix A, Section 1. Administrative Procedures d.
specifies Procedure Adherence and Temporary Change Method procedures.
Step 6.2.1 [5] of 2-SI-74-63-A, 18 Month Channel Calibration of Remote Shutdown Control RHR Heat Exchanger A Outlet Flow Loop 2-LPF-74-16, requires step 6.2.1 [5] which states ENSURE 2-FCV-74-28 RHR HX B FLOW CONTROL is FULLY OPEN.
Contrary to the above, on May 13, 2024, the licensee failed to follow Step 6.2.1 [5] of 2-SI-74-63-A and inadvertently closed the B Train Residual Heat Removal (RHR) Heat Exchanger outlet flow control valve during a planned A Train RHR outage. This action resulted in a loss of RHR safety function for four minutes.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Minor Violation 71152S Failure to preform maintenance in accordance with written instructions Minor Violation: During the 2023 Bi-annual PI&R inspection a Minor Violation was documented for failure to maintain records of activities affecting quality. Specifically, there were 11 instances of maintenance being performed on the EDGs without documentation. The third quarter integrated inspection report documented a Green NCV of Title 10 CFR 50 Appendix B Criterion XVII Criterion XVII, Quality Assurance Records for failure to maintain QA records. Specifically, 354 safety related items were installed in the plant did not have the QA records establishing traceability. A review of the licensee's Corrective action documentation for the period of December 2023 through May of 2024 discovered one instance (CR 1915086) documenting the failure to retain records of activities affecting quality.
Specifically, the CR documented the failure of the licensee to create documentation of work performed on the 1B-B ERCW strainer motor.
Technical Specifications 5.7.1.1 a., requires, in part, that written procedures shall be established, implemented, and maintained for the applicable procedures recommended in Regulatory Guide 1.33 Revision 2, Appendix A February 1978. Section 9.a of Appendix A of RG 1.33 required in part, that maintenance which can affect the performance of safety-related equipment should be performed in accordance with written procedures. Contrary to this requirement, from February 2024 to March 2024, the licensee utilized toolpouch maintenance to perform maintenance on the 1B-B ERCW strainer motor without written instructions. This is documented in CR 1909369 and CR 1915086.
Screening: The inspectors determined the performance deficiency was minor. The inspectors determined the performance deficiency was minor. This performance deficiency is minor due to not adversely impacting a cornerstone objective. Specifically, the maintenance performed did not affect the Equipment Performance attribute of the Mitigating Systems cornerstone objective.
Enforcement:
This failure to comply with TS 5.7.1.1 constitutes a minor violation that is not subject to enforcement action in accordance with the NRCs Enforcement Policy.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On July 31, 2024, the inspectors presented the integrated inspection results to Christopher Reneau, Site Vice President and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Drawings
0-47W803-2
Flow Diagram Auxiliary Feedwater
R18
Procedures
0-MI-0.026
Heat Exchanger Cleaning and Inspection
0013
Procedures
NPG-SPP-09.14
Generic Letter 89-13 Implementation
006
Procedures
PM-M1256F
Inspection of Diesel Generator Jacket Water Cooler
Procedures
0-SOI-211.02
6.9KV Shutdown Board 1B-B
008
Work Orders
Work Orders
21506807, 123647077, 124483919, 123647526
Miscellaneous
24 WBN June
Training Drill
Package
24 WBN June Training Drill Package
06/12/2024