IR 05000382/2024003
| ML24311A182 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 11/08/2024 |
| From: | John Dixon NRC/RGN-IV/DORS/PBD |
| To: | Sullivan J Entergy Operations |
| References | |
| EA-24-081 IR 2024003 | |
| Download: ML24311A182 (1) | |
Text
November 08, 2024
SUBJECT:
WATERFORD STEAM ELECTRIC STATION, UNIT 3 - INTEGRATED INSPECTION REPORT 05000382/2024003
Dear Joseph Sullivan:
On September 30, 2024, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Waterford Steam Electric Station, Unit 3. On October 16, 2024, the NRC inspectors discussed the results of this inspection with you and other members of your staff.
The results of this inspection are documented in the enclosed report.
Two findings of very low safety significance (Green) are documented in this report. One of these findings 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.
A licensee-identified violation which was determined to be of very low safety significance is documented in this report. We are treating this violation as an NCV 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 IV; the Director, Office of Enforcement; and the NRC Resident Inspector at Waterford Steam Electric Station, Unit 3.
If you disagree with a cross-cutting aspect assignment or a finding not associated with a regulatory requirement 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 Waterford Steam Electric Station, Unit 3. 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, John L. Dixon, Jr., Chief Reactor Projects Branch D Division of Operating Reactor Safety Docket No. 05000382 License No. NPF-38
Enclosure:
As stated
Inspection Report
Docket No:
05000382
License No:
Report No:
Enterprise Identifier:
I-2024-003-0003
Licensee:
Entergy Operations, Inc.
Facility:
Waterford Steam Electric Station, Unit 3
Location:
Killona, LA 70057
Inspection Dates:
July 1, 2024 to September 30, 2024
Inspectors:
D. Childs, Senior Resident Inspector
K. Cook-Smith, Resident Inspector
R. Kopriva, Senior Project Engineer
E. Powell, Resident Inspector
A. Sanchez, Senior Project Engineer
Approved By:
John L. Dixon, Jr., Chief
Reactor Projects Branch D
Division of Operating Reactor Safety
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Waterford Steam Electric Station, Unit 3, 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. A licensee-identified non-cited violation is documented in report section: 7115
List of Findings and Violations
Load Bank Fire in Safety-Related Switchgear during Battery Performance Testing due to Inadequate Procedure Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000382/2024003-01 Open/Closed
[H.3] - Change Management 71152A The inspectors reviewed a self-revealed Green finding and associated non-cited violation of Technical Specification 6.8.1.a for the licensees failure to have an adequate maintenance procedure as required by Regulatory Guide 1.33, Quality Assurance Program Requirements, revision 2. Specifically, licensee procedure ME-004-257, 3014 AB Battery Performance Test, revision 16, to perform performance testing of the static uninterruptable power supply (SUPS)3014 AB batteries was unclear in how electrical connections were to be made, resulting in incorrect wiring of the test equipment and subsequent overheating and firing of the test equipment during testing.
Main Transformer Fire due to Inadequate Maintenance Procedure Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green FIN 05000382/2024003-02 Open/Closed EA-24-081
[H.12] - Avoid Complacency 71153 The inspectors reviewed a self-revealed Green finding for the licensees failure to establish and maintain adequate procedures for maintenance and testing associated with main transformer B. Specifically, licensee procedure ME-004-051, Main Transformer B is inadequate because it does not contain testing instructions to appropriately identify degraded conditions prior to failure.
Additional Tracking Items
Type Issue Number Title Report Section Status LER 05000382/2023-004-00 Non-Compliance with Technical Specifications due to Performing Startup Channel 1 Functional Testing during Fuel Movement 71153 Closed
LER 05000382/2023-003-00 LER 2023-003-00 for Waterford Steam Electric Station, Unit 3, Steam Generator Tube Degradation Indicated by Failed In-Situ Pressure Testing 71153 Closed LER 05000382/2024-002-00 LER 2024-002-00 for Waterford Steam Electric Station, Unit 3, Automatic Reactor Trip Due to Transformer Failure 71153 Closed
PLANT STATUS
Unit 3 began the inspection period at 94 percent power due the reduced capacity of main transformer B and remained at this 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 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 due to Hurricane Francine on September 11, 2024.
71111.04 - Equipment Alignment
Partial Walkdown Sample (IP Section 03.01) (5 Samples)
The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:
(1)permanent temporary emergency diesel generator while emergency diesel generator B was inoperable on July 5, 2024 (2)component cooling water train A while component cooling water train B was inoperable on July 15, 2024 (3)auxiliary component cooling water train A while auxiliary component cooling water train B was inoperable on August 6, 2024 (4)low pressure safety injection system train A while low pressure safety injection system train B was inoperable on September 9, 2024 (5)emergency diesel generator B while emergency generator A was inoperable on September 25, 2024
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)fire area RAB 1A, B, C, D, elevation +46.00 foot reactor auxiliary building control room on July 22, 2024 (2)fire area RAB 2-002, elevation +46.00 foot reactor auxiliary building main steam isolation valve passage on July 25, 2024 (3)fire area RAB 31-001, elevation -4.00 foot reactor auxiliary building general area on July 30, 2024
71111.11Q - Licensed Operator Requalification Program and Licensed Operator Performance
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed and evaluated licensed operator exam scenario in the simulator on September 16, 2024.
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (5 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)high risk due to planned maintenance outage of component cooling water system train B and light switchyard work on July 15, 2024 (2)high risk due to planned maintenance outage of containment spray system train B on July 17, 2024 (3)high risk due to emergent heavy work in switchyard after damage was discovered on the 230kV common line from the main transformers on August 1, 2024 (4)high risk due to emergent repairs of auxiliary component cooling water pump B for bearing damage on August 6, 2024 (5)high risk due to planned maintenance that removed train A boric acid makeup pumps from service during the swapping of essential service water chillers on August 28, 2024
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (2 Samples)
The inspectors evaluated the licensees justifications and actions associated with the following operability determinations and functionality assessments:
(1)refueling outage 25 containment integrity operability determination due to the failure of the containment equipment hatch on July 18, 2024 (2)steam driven emergency feedwater pump AB after inboard bearing oil level was found low out of specification on September 6, 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) (6 Samples)
(1)safety injection valve SI-106B, refueling water storage pool outlet isolation valve, following limit switch replacement, on July 17, 2024 (2)shield building ventilation system train B following planned maintenance, on July 24, 2024 (3)auxiliary component cooling water system train A wet cooling tower fans 1 through 4 following planned maintenance, on July 30, 2024 (4)high pressure safety injection pump AB following planned maintenance, on September 5, 2024 (5)emergency diesel generator B following planned maintenance, on September 16, 2024 (6)emergency diesel generator A following planned maintenance, on September 27, 2024
Surveillance Testing (IP Section 03.01) (1 Sample)
(1)emergency diesel generator B and subgroup relay operability test on July 22, 2024
71114.06 - Drill Evaluation
Required Emergency Preparedness Drill (1 Sample)
- (1) The inspectors evaluated an emergency preparedness drill involving a small break loss of coolant accident and drill team turnover on August 28,
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) Unit 3 (July 1, 2023, through June 30, 2024)
MS09: Residual Heat Removal Systems (IP Section 02.08) (1 Sample)
- (1) Unit 3 (July 1, 2023, through June 30, 2024)
MS10: Cooling Water Support Systems (IP Section 02.09) (1 Sample)
- (1) Unit 3 (July 1, 2023, through June 30, 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)fire in switchgear A during performance testing of static uninterruptable power supply SUPS 3014 AB backup battery, on September 18, 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 that might be indicative of a more significant safety issue. Specifically, the inspectors reviewed condition reports regarding erosion in the emergency feedwater system and other steam system piping; corrosion on component cooling water and auxiliary component cooling water. The inspectors did identify a long-standing trend associated with the licensees corrosion program. The inspectors moved further inspection of the trend to the biennial problem identification and resolution team inspection and is documented in inspection report 05000382/2024010.
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 05000382/2023-003-00, Steam Generator Tube Degradation Indicated by Fail In-Situ Pressure Testing (ADAMS Accession No. ML23364A001). The inspection conclusions associated with this LER are documented in Inspection Report 05000382/2024013-01. This LER is closed.
- (2) LER 05000382/2023-004-00, Non-Compliance with Technical Specifications due to Performing Startup Channel 1 Functional Testing during Fuel Movement (ADAMS Accession No. ML24045A179). The inspectors determined that the non-compliance with technical specifications was a violation of NRC requirements. The inspection conclusions associated with this LER are documented in this report under the Inspection Results section. This LER is closed.
- (3) LER 05000382/2023-002-00, Automatic Reactor Trip Due to Transformer Failure (ADAMS Accession No. ML24137A335). The inspectors determined that the failure of the licensee to provide adequate transformer testing and maintenance procedures was a performance deficiency. The inspection conclusions associated with this LER are documented in this report under the Inspection Results section. This LER is closed.
INSPECTION RESULTS
Load Bank Fire in Safety-Related Switchgear during Battery Performance Testing due to Inadequate Procedure Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000382/2024003-01 Open/Closed
[H.3] - Change Management 71152A The inspectors reviewed a self-revealed Green finding and associated non-cited violation of Technical Specification 6.8.1.a for the licensees failure to have an adequate maintenance procedure as required by Regulatory Guide 1.33, Quality Assurance Program Requirements, revision 2. Specifically, licensee procedure ME-004-257, 3014 AB Battery Performance Test, revision 16, to perform performance testing of the static uninterruptable power supply (SUPS) 3014 AB batteries was unclear in how electrical connections were to be made, resulting in incorrect wiring of the test equipment and subsequent overheating and firing of the test equipment during testing.
Description:
On January 17, 2024, a discharge capacity test of the SUPS 3014 AB backup battery within switchgear A was to be conducted in accordance with the station procedure ME-004-257, 3014 AB Battery Performance Test, revision 16. This testing ensures that this backup SUPS battery will perform as intended to provide continuous power to its loads in the event of a loss of AC power and the A or B SUPS battery. Previously, these batteries were 135-volts DC, therefore testing would normally be done using a 135-volt DC load bank. The 135-volt DC configuration remained in use until the completion of WO-00485495, EC-74128 Replace COMP/SUPS Batteries (Outage) RF22 on March 4, 2019. This work order replaced the existing 135-volt DC SUPS battery with a 270-volt DC SUPS battery to provide an available backup and supply full rated load for one hour under loss of AC conditions. This replacement necessitated use of a 270-volt testing load bank. Revision 13 of ME-004-257 was issued June 26, 2017, to account for the new 270-volt DC battery and load bank.
When testing was conducted on January 17, 2024, and this updated procedure was used with the new 270-volt DC configuration for the first time, sparks and smoke issued from the control panel of the load bank. Attending electricians immediately stopped the test and notified the control room of the fire and location. The continuous fire watch who was assigned expelled a carbon dioxide fire extinguisher. The fire brigade then arrived and expelled a second carbon dioxide fire extinguisher. The fire was extinguished in approximately 5 minutes.
During this event, there were no other plant effects or perturbations noted, and no safety systems were impacted.
The licensee initiated condition report CR-WF3-2024-00333 and performed an adverse condition analysis to determine the cause of the fire and develop a corrective action plan.
During this analysis it was found that the load bank configuration outlined in Attachment 12.2 of ME-004-257 was incorrect. Specifically, the diagram in the attachment instructed to install a jumper normally installed in the 135-volt DC configuration that should not be installed in the 270-volt DC configuration.
Corrective Actions: The licensee initiated a condition report to enter this issue into the corrective action program. The licensee performed a cause analysis and developed corrective action. Some of which included: revising ME-004-257 to specify differences between testing using 135-volt and 270-volt load banks and performed an extent of condition of all load bank procedures to validate procedure and diagrams.
Corrective Action References: CR-WF3-2024-00333.
Performance Assessment:
Performance Deficiency: The failure to provide adequate work instructions for performing maintenance on the static uninterruptable power supply 3014 AB backup battery in switchgear A was a performance deficiency. Specifically, the inadequate work instructions resulted in a fire in the load bank.
Screening: The inspectors determined the performance deficiency was more than minor because if left uncorrected, it would have the potential to lead to a more significant safety concern. Specifically, the incorrect load bank configuration within the procedure caused a fire which could have affected safety-related components in switchgear A.
Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The inspectors determined the finding impacted mitigating systems and used exhibit 2 to evaluate the condition. The finding was determined to be of very low safety significance (Green)because it
- (1) was not a deficiency affecting design or qualification of a mitigating system,
- (2) does not represent a loss of the probability risk analysis (PRA) function of a single train TS system for greater than allowed outage time,
- (3) does not represent a loss of PRA function of one train of a multi-train TS system for greater than its allowed outage time,
- (4) does not represent a loss of the PRA function of two separate TS systems for greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />,
- (5) does not represent a loss of PRA system and/or function as defined by the plant risk information e-book or the licensees PRA for greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, and
- (6) does not result in the loss of a high safety-significant, non-TS train for greater than 3 days.
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, the licensee did not adequately evaluate the changes made to the testing procedure to ensure that diagrams were correct prior to conducting testing.
Enforcement:
Violation: Technical Specification 6.8.1.a, Procedures and Programs, states in part, that written procedures shall be established, implemented, and maintained covering the applicable procedures listed in Regulatory Guide 1.33, Quality Assurance Program Requirements, revision 2, Appendix A, February 1978. Regulatory Guide 1.33, revision 2, Appendix A, section 9, Procedures for Performing Maintenance, requires, in part, that maintenance that can affect the performance of safety-related equipment should be properly pre-planned and performed in accordance with written procedures, documented instructions, or drawings appropriate to the circumstances. The licensee established work instruction, ME-004-257, 3014 AB Battery Performance Test, revision 16, in part, to meet this requirement for battery surveillance testing.
Contrary to the above, from June 26, 2017, to January 17, 2024, for maintenance that can affect the performance of safety-related equipment, the licensee failed to perform the maintenance in accordance with instructions appropriate to the circumstances. Specifically, instruction ME-004-257 failed to include adequate instructions to correctly configure the load bank during battery surveillance testing. As a result, on January 17, 2024, the implementation of the procedure resulted in a fire in safety-related switchgear A.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Main Transformer Fire due to Inadequate Maintenance Procedure Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green FIN 05000382/2024003-02 Open/Closed EA-24-081
[H.12] - Avoid Complacency 71153 The inspectors reviewed a self-revealed Green finding for the licensees failure to establish and maintain adequate procedures for maintenance and testing associated with main transformer B. Specifically, licensee procedure ME-004-051, Main Transformer B is inadequate because it does not contain testing instructions to appropriately identify degraded conditions prior to failure.
Description:
On March 21, 2024, a fire and catastrophic failure of main transformer B occurred causing an automatic reactor trip and partial loss of offsite power (B side). Due to the partial loss of offsite power, two reactor coolant pumps tripped, and train B safety-related loads were powered by emergency diesel generator B. In addition, the licensee had a steam generator overfeed condition which created an overcooling event that resulted in a Safety Injection and Containment Isolation Actuations. These feedwater system issues, and actuation signals caused an Emergency Feedwater Actuation. An Unusual Event was declared due to a fire in the protected area requiring offsite firefighting support; however, this declaration was later retracted after the onsite fire brigade was able to extinguish the fire in approximately 40 minutes without offsite assistance.
Waterford has two forced oil/forced air cooled 25KV / 230KV transformers located in the transformer yard. Each transformer is designed to carry approximately 50 percent of the power outputted by the main generator and transfer it to the grid. Adjacent to each main transformer is an associated startup transformer which provides offsite power during shutdowns. Behind the main transformers are both unit auxiliary transformers which receive power from the main generator during normal plant operations and provide it to the plant electrical distribution system. The licensees investigation identified that the catastrophic failure of main transformer B resulted from a fault that is suspected to have originated within the H1 bushing due to evidence that the transformer was over pressurized on the H1 bushing side. Startup transformer B was extensively damaged during the catastrophic failure of main transformer B and was unavailable to provide offsite power to train B equipment.
Maintenance and testing of main transformer B is governed by licensee procedure ME-004-051, Main Transformer B, revision 310. Similarly, maintenance and testing of main transformer A is governed by licensee procedure ME-004-052, Main Transformer A, revision 314. Maintenance and testing of both startup transformers are governed by licensee procedure ME-004-071, Startup Transformer, revision 326, and maintenance and testing of both unit auxiliary transformers are governed by licensee procedure ME-004-061, Unit Auxiliary Transformer, revision 310. These procedures lack the industry governance/best practices/guidance and do not incorporate related operational experience that gives one the ability to identify degraded conditions.
For example, criteria outlined in IEEE C57.19.100-2013 for monitoring rate of change which states that bushing capacitance should be measured with each power factor test and compared carefully with both nameplate and previous tests in assessing bushing condition.
These procedures do not contain certain steps with signatures to ensure results are appropriately evaluated prior to restoring a transformer to service with unacceptable test results. On October 20, 2023, doble testing was performed on main transformer B which provided an investigate warning for the H1 bushing. On October 26, 2023, the system engineer questioned the vendor concerning the doble test report warnings. The vendor responded that the evaluation of each result was an artifact of the software. The results were within the acceptance criteria of ME-004-051 and step 9.4.7 (system engineer has reviewed power factor testing prior to restoration of the transformer) of the procedure was signed off. Additionally, the procedures have not incorporated industry best practices when performing capacitance and power factor testing per IEEE C57.152.
Additionally, Entergy fleet procedure EN-EE-G-001, Large Power Transformer Inspection Guidelines, revision 3, references standard industry guidance including multiple IEEE/EPRI standards. This procedure is not referenced in licensee procedures ME-004-051, 052, 061 or 071. EN-EE-G-001 recommends additional specific testing, such as Dissolved Gas Analysis, that is not currently required by the site transformer maintenance and testing procedures.
Another example is Entergy internal operational experience, which includes transformer failures, that Waterford did not incorporate the lessons learned within transformer maintenance procedures. ANO Unit 2, Unit Auxiliary Transformer Failure (CR-ANO-2-2013-02242); ANO Unit 1, Startup Transformer Surge Arrestor Failure (CR-ANO-1-2011-01102);
Indian Point Unit 2, Main Transformer Failure of B Phase Bushing (CR-IP2-2010-06801); and Indian Point Unit 3, Main Transformer Bushing Failure (CR-IP3-2015-02913).
Corrective Actions: The licensee has replaced main transformer B and repaired startup transformer B and revised transformer maintenance and testing procedures to include specific procedure steps to perform Doble testing and to reference applicable industry standards.
Corrective Action References: CR-WF3-2024-01597
Performance Assessment:
Performance Deficiency: The inspectors determined that the licensees failure to establish and maintain adequate procedures for maintenance and testing associated with main transformer B was a performance deficiency. Specifically, licensee procedure ME-004-051, Main Transformer B is inadequate because it does not contain testing instructions to appropriately identify degraded conditions prior to failure.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Procedure Quality attribute of the Initiating Events cornerstone and adversely affected the cornerstone objective to limit the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. Specifically, the failure to provide adequate transformer maintenance and testing procedures resulted in a fire and catastrophic failure of main transformer B which resulted in a reactor trip and partial loss of offsite power.
Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power.
Specifically, using Exhibit 1, Initiating Events Screening Questions, the inspectors determined that a detailed risk evaluation (DRE) was required since the finding caused a reactor trip and involved a fire.
A Region IV senior reactor analyst performed the DRE and determined the incremental conditional core damage probability (CCDP) of the finding to be 9.0E-7, or to be of very low safety significance (Green). The analyst used a modified version of the Waterford SPAR model, revision 8.81, run on SAPHIRE, version 8.2.11, to run an initiating events analysis to estimate the CCDP of the transformer fire. The model was modified to:
- (1) correct a modeling error in the loss of seal cooling modeling which was erroneously flagging the occurrence of a reactor coolant pump seal loss of coolant accident if train A of the auxiliary component cooling water system was unavailable for reactor trips;
- (2) remove switchgear room cooling dependency for offsite power to the 4160V engineered safety features electrical buses after the licensee demonstrated that the temperature in the switchgear rooms would not exceed temperatures typically associated with electrical equipment failures;
- (3) adjust the human error probability for the failure to align the permanent temporary emergency diesel to reflect the newer diesel generator alignment adopted by the station several years ago;
- (4) group the switchyard transformers to reflect the possibility of common cause failures because the performance deficiency for the failure of main transformer B dealing with poor maintenance was typical of all transformers;
- (5) allow for continued operation of motor driven auxiliary feedwater pumps upon the loss of certain 480 volt motor control center and dc power panel failures for which the model had previously discounted use of that pump;
- (6) create a main transformer fire sequence which renders startup transformer B unavailable to add this previously unmodeled event; and
- (7) remove credit for restoring offsite power at one hour after the event start because the analyst considered that recovery unlikely.
The analyst then subtracted out the core damage probability, obtained from applying the nominal transformer fire initiating event frequency of 2.41E-4/year to nominal failure probabilities, which yielded an incremental conditional core damage probability of 9.0E-7.
Dominant sequences were transients which progressed to plant-centered losses of offsite power with emergency feedwater failures. The CCDP was mitigated because the main feedwater and condenser remained available. The analyst used Manual Chapter 0609, Appendix H, Containment Integrity Significance Determination Process, to determine that the performance deficiency when evaluated for incremental conditional large early release probability would be of very low safety significance. Because of the unlikely occurrence of a simultaneous external event, the increase in incremental conditional CCDP from external events was qualitatively considered to be negligible.
Cross-Cutting Aspect: H.12 - Avoid Complacency: Individuals recognize and plan for the possibility of mistakes, latent issues, and inherent risk, even while expecting successful outcomes. Individuals implement appropriate error reduction tools. Specifically, the licensee failed to ensure test results were not trending in manner that indicated an adverse condition requiring additional actions prior to restoration of main transformer B.
Enforcement:
Inspectors did not identify a violation of regulatory requirements associated with this finding.
Licensee-Identified Non-Cited Violation 71153 This violation of very low safety significance was identified by the licensee and has been entered into the licensee corrective action program and is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Violation: Technical specification 3.9.2 states As a minimum, two source range neutron flux monitors shall be OPERABLE and operating, each with continuous visual indication in the control room and one with audible indication in the containment and control room and is applicable while the plant is in MODE 6. Contrary to the above, on December 14, 2023, startup channel 1 was inoperable during the performance of OP-903-101 Startup Channel Functional Test Startup Channel 1 and 2, revision 10, while fuel movements were ongoing, and the licensee failed to enter the appropriate technical specification 3.9.2 actions.
Significance/Severity: Green. The inspectors determined that the failure to have an adequate procedure to perform startup channel functional testing was a performance deficiency.
Specifically, the licensee failed to provide precautions and limitations to work instructions in OP-903-101 Startup Channel Functional Test Startup Channel 1 and 2, revision 10, that appropriately indicated the technical specifications that could be impacted during the performance of this functional testing. The inspectors determined the performance deficiency was more than minor because if left uncorrected, the performance deficiency would have the potential to lead to a more significant safety concern. Specifically, the failure to update the test procedure could result in the failure to detect an unplanned change in the reactivity condition of the core during fuel movements. The inspectors assessed the significance of the finding using IMC 0609 Appendix G, Shutdown Operations Significance Determination Process. The inspectors determined the finding was of very low safety significance (Green)because no unplanned changes in the reactivity condition of the core occurred during the time the licensee was in violation of technical specification 3.9.2. This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Corrective Action References: CR-WF3-2023-18308
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On October 16, 2024, the inspectors presented the integrated inspection results to Joseph Sullivan, Site Vice President, and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Procedures
EN-FAP_EP-010
Severe Weather Response
Corrective Action
Documents
CR-WF3-YYYY-
NNNN
24-02909, 2023-17176, 2023-17121, 2023-16995, 2023-
16918, 2023-00634
Procedures
OP-002-001
Auxiliary Component Cooling Water
20
Procedures
OP-002-003
Component Cooling Water
2
Procedures
OP-006-010
TEDG Operations
Procedures
OP-009-002
360
Procedures
OP-009-008
Safety Injection System
048
Fire Plans
RAB 2-002
Main Steam Isolation Valve Passage
Fire Plans
RAB 31-001
-4 RAB General Area
Fire Plans
RAB1A-B-C-D-
001 0
Control Room Proper, H&V Room, Emergency Living
Quarters and Computer Room
014
Corrective Action
Documents
CR-WF3-YYYY-
NNNN
24-03910, 2024-03924, 2024-03930, 2024-03954
Miscellaneous
ECCS-B - 72hr SDLCO with 30day RICT
07/15/2024
Procedures
Protected Equipment Postings
Procedures
Protected Equipment Postings
Procedures
On Line Risk Assessment
Procedures
OP-903-094
ESFAS Subgroup Relay Test - Operating
Calculations
ECM95-008
Ultimate Heat Sink Design Basis
Corrective Action
Documents
CR-WF3-YYYY-
NNNN
23-16294, 2024-01476, 2024-01584
Engineering
Changes
Operability Input to EFW Pump AB Mission Time
Procedures
Shutdown Safety Management Program (SSMP)
Procedures
MM-008-001
Inside Maintenance Hatch and Outside Maintenance Access
Hatch Shield Door, Inspection, and Closing
Procedures
OP-010-006
Outage Operations
344
Work Orders
54065661
Corrective Action
Documents
CR-WF3-YYYY-
XXXX
24-04595
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Procedures
Post-Maintenance Testing
Procedures
Offline Motor Electrical Testing
Procedures
ME-007-006
480 VAC and Less Squirrel Cage Induction Motors
Procedures
OP-009-002
360
Procedures
OP-903-030
Safety Injection Pump Operability Verification
Procedures
OP-903-043
Shield Building Ventilation System Operability Check
317
Procedures
OP-903-068
Emergency Diesel Generator and Subgroup Relay
Operability Verification
27
Procedures
OP-903-068
Emergency Diesel Generator and Subgroup Relay
Operability Verification
27
Procedures
OP-903-118
Primary Auxiliaries Quarterly IST Valve Tests
Procedures
OP-903-121
Safety Systems Quarterly IST Valve Tests
036
Work Orders
253894, 54181469, 53013888
Work Orders
54180097, 54180022
Procedures
Recognition & Classification of Emergency Conditions
Procedures
OP-901-111
307
Procedures
OP-902-000
Standard Post Trip Actions
Corrective Action
Documents
CR-WF3-YYYY-
NNNNN
24-00333
Procedures
ME-004-257
3014 AB Battery Performance Test
016