ML25037A330
| ML25037A330 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 02/12/2025 |
| From: | James Baptist NRC/RGN-II/DORS |
| To: | Carr E Dominion Energy |
| References | |
| IR 2024004 | |
| Download: ML25037A330 (20) | |
Text
Eric S. Carr Chief Nuclear Officer and President of Nuclear Operations Dominion Energy Innsbrook Technical Center 5000 Dominion Blvd., Floor: 1N-3SE Glenn Allen, VA 23060-6711
SUBJECT:
VIRGIL C. SUMMER - INTEGRATED INSPECTION REPORT 05000395/2024004
Dear Eric S. Carr:
On December 31, 2024, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Virgil C. Summer. On January 28, 2025, the NRC inspectors discussed the results of this inspection with Beth Jenkins, 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.
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 II; the Director, Office of Enforcement; and the NRC Resident Inspector at Virgil C. Summer.
February 12, 2025
E. Carr 2
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 Virgil C. Summer.
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, James B. Baptist, Chief Projects Branch 4 Division of Operating Reactor Safety Docket No. 05000395 License No. NPF-12
Enclosure:
As stated cc w/ encl: Distribution via LISTSERV Signed by Baptist, James on 02/12/25
SUNSI Review X
Non-Sensitive
Sensitive X
Publicly Available
Non-Publicly Available OFFICE RII/DORS RII/DORS RII/DORS NAME C. Even C. Read J. Baptist DATE 2/6/25 2/7/25 2/12/25
Enclosure U.S. NUCLEAR REGULATORY COMMISSION Inspection Report Docket Number:
05000395 License Number:
NPF-12 Report Number:
05000395/2024004 Enterprise Identifier:
I-2024-004-0025 Licensee:
Dominion Energy Facility:
Virgil C. Summer Location:
Jenkinsville, SC Inspection Dates:
September 23, 2024, to December 31, 2024 Inspectors:
B. Bowker, Senior Reactor Inspector K. Dials, Resident Inspector J. Diaz-Velez, Senior Health Physicist S. Downey, Senior Reactor Inspector B. Kellner, Senior Health Physicist M. Read, Senior Resident Inspector J. Rivera, Health Physicist Approved By:
James B. Baptist, Chief Projects Branch 4 Division of Operating Reactor Safety
2
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Virgil C. Summer, 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: 71111.15.
List of Findings and Violations Inadequate Post-Maintenance Testing for a Safety-Related Chiller Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000395/2024004-01 Open/Closed
[H.3] - Change Management 71111.15 A self-revealed Green finding and associated Non-cited Violation (NCV) of 10 CFR 50, Appendix B, Criterion XI, "Test Control," was identified for the licensee's failure to identify during post-maintenance testing a design deficiency that would have prevented the C safety-related chiller from restarting from the emergency safeguards load sequencer following a loss of offsite power.
Additional Tracking Items None.
3 PLANT STATUS Unit 1 began the inspection period in a refueling outage. The unit was returned to rated thermal power on November 5, 2024. On November 20, 2024, Unit 1 was shut down to support main condenser maintenance. The unit remained in Mode 3 until November 25, 2024, when the unit was restarted. On November 30, 2024, the unit was returned to rated thermal power 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 71111.04 - Equipment Alignment Partial Walkdown Sample (IP Section 03.01) (1 Sample)
The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:
(1)
Spent fuel pool cooling on October 2, 2024 71111.05 - Fire Protection Fire Area Walkdown and Inspection Sample (IP Section 03.01) (2 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)
Reactor building elevation 463 on October 24, 2024 (2)
Service water pump house on October 15, 2024 Fire Brigade Drill Performance Sample (IP Section 03.02) (1 Sample)
(1)
The inspectors evaluated the onsite fire brigade training and performance during fire drills in the turbine building on November 6 and 13, 2024.
4 71111.08P - Inservice Inspection Activities (PWR)
The inspectors verified that the reactor coolant system boundary, reactor vessel internals, risk-significant piping system boundaries, and containment boundary are appropriately monitored for degradation and that repairs and replacements were appropriately fabricated, examined and accepted by reviewing the following activities during refueling outage RF28 from 9/30/2024 to 10/17/2024.
PWR Inservice Inspection Activities Sample - Nondestructive Examination and Welding Activities (IP Section 03.01) (1 Sample)
The inspectors verified that the following nondestructive examination and welding activities were performed appropriately:
(1)
Ultrasonic Examination
- 1-4200A-28, SG B hot leg nozzle to safe end DM weld, ASME Class 1
- 1-4300A-30, SG C cold leg nozzle to safe end DM weld, ASME Class 1
- 1-4501-4, PZR A safety line, elbow to pipe, ASME Class 1
- 1-4501-6, PZR A safety line, elbow to pipe, ASME Class 1
- CGE-1-4308-3, C loop RC drain line, elbow to pipe, ASME Class 1
- CGE-1-4308-4, C loop RC drain line, pipe to elbow, ASME Class 1 Dye Penetrant Examination XPP-0043A-WS, RHR pump suction line integral attachment, ASME Class 2 Visual # Examination IWE/IWL containment penetrations (XRP0001, XRP0007, XRP0014, XRP0016, XRP0034, XRP0052, XRP0505)
Welding Activities Gas Tungsten Arc Welding, o
WO88201690757, Welds 2C1 and MW-1C1, XVT-08055C-RC valve replacement, ASME Class 2 PWR Inservice Inspection Activities Sample - Boric Acid Corrosion Control Inspection Activities (IP Section 03.03) (1 Sample)
The inspectors verified the licensee is managing the boric acid corrosion control program through a review of the following evaluations:
(1)
Boric Acid Walkdown - September 30, 2024 Review of the following engineering evaluations:
o CR1269325 o
CR1269413 o
CR1269420 o
CR1269433 Review of the following corrective actions performed for evidence of boric acid leaks that were identified:
o CR1270442 o
CR1270446
5 o
CR1270447 o
CR1270449 PWR Inservice Inspection Activities Sample - Steam Generator Tube Inspection Activities (Section 03.04) (1 Sample)
The inspectors verified that the licensee is monitoring the steam generator tube integrity appropriately through a review of the following examinations:
(1)
Steam Generator A: Eddy Current Testing (ECT) for tube R96C55 Steam Generator B: ECT for tube R90C29 Steam Generator C: ECT for tubes R35C92, R105C55 71111.11A - Licensed Operator Requalification Program and Licensed Operator Performance Requalification Examination Results (IP Section 03.03) (1 Sample)
The licensee completed the annual requalification operating examinations required to be administered to all licensed operators in accordance with Title 10 of the Code of Federal Regulations 55.59(a)(2), "Requalification Requirements," of the NRC's "Operator's Licenses." The inspector performed an in-office review of the overall pass/fail results of the individual operating examinations, and the crew simulator operating examinations in accordance with Inspection Procedure (IP) 71111.11, "Licensed Operator Requalification Program and Licensed Operator Performance." These results were compared to the thresholds established in Section 3.03, "Requalification Examination Results," of IP 71111.11.
(1)
The inspectors reviewed and evaluated the licensed operator examination failure rates for the requalification annual operating exam completed on August 1, 2024 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 reactor startup and low power physics testing on October 30, 2024.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
(1)
The inspectors observed and evaluated licensed operator requalification simulator training exercise involving [scenario details controlled] on December 9, 2024 71111.12 - Maintenance Effectiveness
6 Maintenance Effectiveness (IP Section 03.01) (4 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)
Safety-related batteries and chargers, review completed on November 13, 2024 (2)
Replacement of magnesium rotor motor-operated valves in containment, review completed on October 31, 2024 (3)
MVG-8808A/B/C, accumulator isolation valves, review completed on December 9, 2024 (4)
Charging / safety injection pumps on December 19, 2024 Aging Management (IP Section 03.03) (1 Sample)
The inspectors evaluated the effectiveness of the aging management program for the following SSCs that did not meet their inspection or test acceptance criteria:
(1)
Inspectors reviewed aging management of the fire service water piping degradation and treatment of system repairs, replacement, and modifications in the corrective action program. The review was completed on December 17, 2024.
71111.13 - Maintenance Risk Assessments and Emergent Work Control Risk Assessment and Management Sample (IP Section 03.01) (3 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)
Elevated risk during emergency bus '1DA' and '1EA' bus outage on October 15, 2024 (2)
Elevated risk during security inverter swap on October 25, 2024 (3)
Unplanned orange risk when the 'A' residual heat removal pump failed to start during integrated safeguards testing on October 22, 2024 71111.15 - Operability Determinations and Functionality Assessments Operability Determination or Functionality Assessment (IP Section 03.01) (5 Samples)
The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:
(1)
CR1265396, safety injection header relief valve nozzle ring settings found incorrectly set, review completed on November 14, 2024 (2)
CR1277649, 'A' emergency diesel generator kilowatt oscillations during testing, review completed on December 17, 2024 (3)
CR1207743, service water pump testing calculation discrepancy, review completed on December 19, 2024 (4)
CR1273320, 'C' chiller failed to start, review completed on December 17, 2024 (5)
CR1266916, missed Technical Specification 3.0.3 entry, review completed on December 31, 2024
7 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)
ECR-50733, 'A' emergency diesel generator excitation system, review completed on October 28, 2024 71111.20 - Refueling and Other Outage Activities Refueling/Other Outage Sample (IP Section 03.01) (1 Sample)
(1)
The inspectors evaluated refueling outage #28 activities, which completed on November 1, 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) (8 Samples)
(1)
STP-125.013A, 'A' emergency diesel generator semiannual operability test, on October 7, 2024, following governor replacement (2)
MTP-E-50733 and STP-125.010, 'A' emergency diesel generator testing on October 21-24, 2024, following exciter replacement (3)
STP-130.003B, 'A' feedwater flow control valve testing, on October 24, 2024, following packing replacement (4)
'C' chiller, in August, September, and October 2024, following chiller replacement (5)
'A' feedwater venturi replacement on November 1, 2024 (6)
SOP-211, emergency feedwater system, to run the turbine-driven emergency feedwater pump on December 17, 2024, following minor pump maintenance (7)
SOP-507, fire suppression system, to test the diesel-driven fire pump on December 18, 2024, following oil switch and tachometer replacements (8)
'A' to 'C' charging pump cross-connect valve testing on October 10, 2024, as part of MOVAT program Inservice Testing (IST) (IP Section 03.01) (1 Sample)
(1)
STP-220.007, backup air supply check valve test for emergency feedwater valves, on December 20, 2024 Containment Isolation Valve (CIV) Testing (IP Section 03.01) (1 Sample)
(1)
STP 215.004, Containment isolation valve test, for valve XVG-8811B-SI, on October 8, 2024 71114.06 - Drill Evaluation
8 Additional Drill and/or Training Evolution (1 Sample)
The inspectors evaluated:
(1)
Inspectors observed an emergency response drill from the site on December 11, 2024. Although not performed or billed under this inspection procedure 71114.06, NRC Headquarters and Region II staff observed the drill at the Dominion Energy Corporate Emergency Response Center (CERC) located in Glen Allen, Virginia involving simulated, concurrent events at the Virgil C. Summer Nuclear Station and Surry Power Station. The State of Virginia also participated in the dual-site drill. The conduct of this dual-site drill successfully demonstrated the ability of the Dominion Energy CERC to continue to effectively function during simultaneous events at multiple nuclear power reactor sites with different technologies and to interface effectively with the State agencies.
RADIATION SAFETY 71124.01 - Radiological Hazard Assessment and Exposure Controls Radiological Hazard Assessment (IP Section 03.01) (1 Sample)
(1)
The inspectors evaluated how the licensee identifies the magnitude and extent of radiation levels and the concentrations and quantities of radioactive materials and how the licensee assesses radiological hazards.
Instructions to Workers (IP Section 03.02) (1 Sample)
(1)
The inspectors evaluated how the licensee instructs workers on plant-related radiological hazards and the radiation protection requirements intended to protect workers from those hazards.
Contamination and Radioactive Material Control (IP Section 03.03) (3 Samples)
The inspectors observed/evaluated the following licensee processes for monitoring and controlling contamination and radioactive material:
(1)
Licensee surveys of potentially contaminated material leaving the radiologically controlled area (RCA).
(2)
Workers exiting the RCA during the refueling outage.
(3)
Workers exiting containment during the refueling outage.
Radiological Hazards Control and Work Coverage (IP Section 03.04) (3 Samples)
The inspectors evaluated the licensee's control of radiological hazards for the following radiological work:
(1)
Refueling Outage (RF28) Mechanical Maintenance Activities (2)
RF28 Scaffolding Activities (3)
RF28 Steam Generator Eddy Current Activities
9 High Radiation Area and Very High Radiation Area Controls (IP Section 03.05) (4 Samples)
The inspectors evaluated licensee controls of the following high radiation areas (HRAs) and very high radiation areas (VHRAs):
(1)
East Penetration Room (2)
West Penetration Room (3)
Spent Fuel Pool Cooling Demineralizer Room (4)
Demin Valve Gallery Radiation Worker Performance and Radiation Protection Technician Proficiency (IP Section 03.06) (1 Sample)
(1)
The inspectors evaluated radiation worker and radiation protection technician performance as it pertains to radiation protection requirements.
71124.03 - In-Plant Airborne Radioactivity Control and Mitigation Permanent Ventilation Systems (IP Section 03.01) (1 Sample)
The inspectors evaluated the configuration of the following permanently installed ventilation systems:
(1)
Unit 1 Main Control Room Emergency Ventilation Temporary Ventilation Systems (IP Section 03.02) (2 Samples)
The inspectors evaluated the configuration of the following temporary ventilation systems:
(1)
HEPA-34, S/N 5299 Integrity DOP test 08/11/2022 and 08/08/2024 (unit in service for reactor head stud cleaning activities)
(2)
HEPA-17, S/N1653 Integrity DOP test 08/11/2022 and 08/08/2024 (unit not in service)
Use of Respiratory Protection Devices (IP Section 03.03) (1 Sample)
(1)
The inspectors evaluated the licensees use of respiratory protection devices.
Self-Contained Breathing Apparatus for Emergency Use (IP Section 03.04) (1 Sample)
(1)
The inspectors evaluated the licensees use and maintenance of self-contained breathing apparatuses.
Observed monthly checks and reviewed functional test records (calibration) of three SCBA units in service and available for use.
Unit ID # 000000100007145789, 3/7/2024 Unit ID # 000000100007130513, 3/7/2024 Unit ID # 000000100007145576, 3/7/2024 71124.04 - Occupational Dose Assessment
10 Source Term Characterization (IP Section 03.01) (1 Sample)
(1)
The inspectors evaluated licensee performance as it pertains to radioactive source term characterization.
External Dosimetry (IP Section 03.02) (1 Sample)
(1)
The inspectors evaluated how the licensee processes, stores, and uses external dosimetry.
Internal Dosimetry (IP Section 03.03) (3 Samples)
The inspectors evaluated the following internal dose assessments:
(1)
For Cause whole body counts for follow-up to Level 2 Facial contamination Individual
- 1 (no dose assigned) 5/3/2023 (2)
For Cause whole body counts for follow-up to Level 2 Facial contamination Individual
- 2 (no dose assigned) 5/3/2023 (3)
For Cause whole body counts for follow-up to Level 2 Facial contamination Individual
- 3 (no dose assigned) 10/7/2024 Special Dosimetric Situations (IP Section 03.04) (3 Samples)
The inspectors evaluated the following special dosimetric situations:
(1)
Declared pregnant worker #1 (April 2023)
(2)
Declared pregnant worker #2 (July 2024)
(3)
Declared pregnant worker #3 (August 2024) 71124.05 - Radiation Monitoring Instrumentation Walkdowns and Observations (IP Section 03.01) (10 Samples)
The inspectors evaluated the following radiation detection instrumentation during plant walkdowns:
(1)
RMG0001 Control Room Area Radiation Monitor (2)
RM-A1 Main Control Room Ventilation Radiation Monitor (3)
RML0005 Liquid Radwaste Radiation Monitor (4)
RM-A4 Reactor Building Purge Exhaust Monitor (5)
RM-A14 Purge Exhaust Effluent High Range Radiation Monitor (6)
RM-A3 Main Plant Vent Exhaust Monitor (7)
RM-A13 Main Plant Vent Exhaust High Range Gas Discharge Monitor (8)
Ludlum Model 177 Benchtop Counter with pancake GM detector (Sn: 334064)
(9)
Cronos-4 at RCA exit, Sn: 2011-277 (10)
Argos-5ABZ, Sn: 1608-116 Calibration and Testing Program (IP Section 03.02) (15 Samples)
The inspectors evaluated the calibration and testing of the following radiation detection instruments:
11 (1)
RMG0007 Reactor Building High Range Radiation Monitor, calibrated 10/11/2021, and 04/11/2023 (2)
RMG0001 Main Control Room Area Radiation Monitor, calibrated 07/12/2022, and 01/22/2024 (3)
Whole-Body Counters: ORTEC StandFast, calibrated 08/20/2024, and ND People Mover, calibrated 11/06/2023 (4)
Thermo-Eberline AMS-4, Continuous Air Monitor, Sn: 1752, calibrated 12/20/2023 (5)
Ludlum Model 177, Frisker w/GM probe Sn: 334064, calibrated 08/22/2024 (6)
Thermo-Eberline ASP-2E, Neutron Survey Instrument, Sn: 395, calibrated 12/20/2023 (7)
GEM-5, Sn:1809-259, calibrated 09/20/2022, and 09/19/2023 (8)
Mirion Technologies TELE-STTC-2, Telescopic Survey Instrument, Sn: 34101, calibrated: 09/10/2024 (9)
RADECO Low Volume Air Sampler, Sn: 6857, calibrated 11/02/2023 (10)
Mirion Technologies Model Telepole, Telescopic Survey Instrument, Sn: 6609-039, calibrated 06/03/2024 (11)
Mirion Technologies Model DMC3000 Personal Electronic Dosimeter, Sn(s): 929099, 918202, A24908, and 930433, calibrated 09/17/2024.
(12)
Ludlum Model 9-3, Ion Chamber Survey Meter, Sn: 330684, calibrated 07/31/2024 (13)
Mirion Technologies Model RDS-31, Telescopic Survey Instrument, Sn: 712847, calibrated 09/27/2023 (14)
High Purity Ge Gamma Spectroscopy Detectors #22, 23, and 25, calibrated for 1 Liter Marinelli geometry, calibrated 02/27/2023, (15)
Argos 5AB, Sn:1610-222, calibrated 05/01/2024 Effluent Monitoring Calibration and Testing Program Sample (IP Section 03.03) (3 Samples)
The inspectors evaluated the calibration and maintenance of the following radioactive effluent monitoring and measurement instrumentation:
(1)
Liquid Radwaste Radiation Monitors: RML0005, calibrated 11/10/2022, and 06/03/2024; RML00009, calibrated 10/03/2022, and 03/26/2024 (2)
Plant Vent Radiation Monitors: RMA0003, calibrated 11/29/2022, and 05/13/2024; RMA0013, calibrated 01/30/2023, and 07/16/2024.
(3)
Reactor Building Purge Radiation Monitors: RM0004, calibrated 8/6/2024, and 02/01/2023; RMA0014, calibrated 06/18/2024, and 12/19/2022 OTHER ACTIVITIES - BASELINE 71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:
MS05: Safety System Functional Failures (SSFFs) Sample (IP Section 02.04) (1 Sample)
(1)
MS05: Unit 1 (October 1, 2023, to September 30, 2024)
MS08: Heat Removal Systems (IP Section 02.07) (1 Sample)
(1)
MS08: Unit 1 (October 1, 2023, through September 30, 2024)
12 MS10: Cooling Water Support Systems (IP Section 02.09) (1 Sample)
(1)
MS10: Unit 1 (October 1, 2023, through September 30, 2024)
OR01: Occupational Exposure Control Effectiveness Sample (IP Section 02.15) (1 Sample)
(1)
April 1, 2023 - October 10, 2024 71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02) (1 Sample)
(1)
The inspectors reviewed the licensees corrective action program for potential adverse trends related to subcomponent failures on the safety-related chillers. The review was completed on December 19, 2024.
INSPECTION RESULTS Inadequate Post-Maintenance Testing for a Safety-Related Chiller Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000395/2024004-01 Open/Closed
[H.3] - Change Management 71111.15 A self-revealed Green finding and associated NCV of 10 CFR 50, Appendix B, Criterion XI, "Test Control," was identified for the licensee's failure to identify during post-maintenance testing a design deficiency that would have prevented the C safety-related chiller from restarting from the emergency safeguards load sequencer following a loss of offsite power.
==
Description:==
V.C. Summer has three safety-related chillers. The 'C' chiller is used as an installed spare that can be aligned mechanically and electrically to either of the two emergency busses. The 'C' chiller was replaced in 2024 with a "new, state-of-the-art" chiller with digital controls and improved functionality. The 'C' chiller post-maintenance testing included tests simulating a loss of offsite power to each of the emergency busses, including a test on the '1DA' emergency bus on August 17, 2024. On October 23, 2024, during the refueling outage integrated safeguards testing for the '1DA' emergency bus, the 'C' chiller failed to start when demanded by the load sequencer.
Engineering change request ECR-50585, "Chiller Replacement," was used to replace the 'C' chiller. The scope of the design change did not include the auxiliary relays for the loading sequencer, which due to the unique "swing" design of the 'C' chiller being able to electrically align to either emergency bus, would deenergize upon a loss of power to the bus. The chiller logic controller (PLC) detected the emergency safeguards load sequencer K3 relay "stop" signal immediately when power was removed from the emergency bus and initiated the K5 "loss of offsite power" relay flag. This 120V circuit was powered from the 1DA2 emergency bus which lost power when the bus voltage was lost. The loss of the 120V power resulted in the PLC K3/K5 input only being true momentarily before the ESFX1A relay coil deenergized.
One second after the K5 "loss of offsite power" signal went "true", the chiller status changed from "On" to "Off", indicating that the ESFX1A relay de-energized the chiller "start" relay, causing the chiller to be "Off". When the chiller status changed to "Off", the chiller circuit #1
13 soft starter registered in alarm and remained locked-in, as expected. During a loss of power event, the chiller PLC should have registered a LOOP Event, which would have reset any existing alarms and prevented new alarms from being registered until the chiller started. The logic was designed to detect the K3/K5 relays changing state for 4.5 seconds, the duration of the load sequencer Step #1, but because of the loss of power to the auxiliary relays, the K3/K5 input condition went "false" after only a momentary "true", which engaged the alarm and chiller lockout. The alarm condition prevented the restart of the chiller after the loss of offsite power condition.
The design issue related to the powering and sequencing of the auxiliary relays was a deficiency that existed for the life of the plant, but it did not have any impact on the functionality of the original C chiller due to its analog controls. With the introduction of the digital controls of the new C chiller, the legacy design issue began impacting the chillers functionality.
The licensees post-maintenance testing procedure, MTP-50585X.001, XHX0001C Chiller Replacement Functional Test, revision 0, step 7.15, tested a loss of power to the chiller but failed to adequately test a loss of control power to the auxiliary relays.
In the event of a true loss of offsite power, the chiller lockout could have been cleared using a local "reset" pushbutton on the chiller, by placing the chiller "on/off" switch in "pull-to-lock", or bypassed during a "LOOP Event" emergency start logic in the PLC.
This condition did not exist on the 'A' and 'B' chillers since they are connected to one emergency bus each. Their chiller "stop" and "start" relays are directly wired into the chiller relay controls and PLC digital inputs without any additional auxiliary relaying.
Corrective Actions: The licensee implemented an interim software change which ensured that a loss of power to the auxiliary relays for the 'C' chiller would not prevent an automatic start during a loss of offsite power event.
Corrective Action References: CR1273320 Performance Assessment:
Performance Deficiency: The licensee's failure to identify the design deficiency during post-maintenance testing was a performance deficiency that was within the licensee's ability to foresee and correct.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Design Control 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 'C' chiller would not have been able to restart during a loss of offsite power event when the emergency diesel generator load sequencer demanded a start.
Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power.
Inspectors determined that the finding screened to Green based on answering "No" to the screening question, "Does the degraded condition represent a loss of the PRA function of one or more non-TS trains of equipment designated as risk-significant in accordance with the licensees maintenance rule program for greater than 3 days?" since the chillers are not
14 explicit in the licensee's Technical Specifications and the equipment is designated low-risk in accordance with the licensee's risk analysis and maintenance rule program.
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 post-maintenance testing did not fully test the new chiller such that the legacy design issue was not identified.
Enforcement:
Violation: 10 CFR 50, Appendix B, Criterion XI requires, in part, "A test program shall be established to assure that all testing required to demonstrate that structures, systems, and components will perform satisfactorily in service is identified and performed in accordance with written test procedures which incorporate the requirements and acceptance limits contained in applicable design documents. The test program shall include, as appropriate, proof tests prior to installation, preoperational tests, and operational tests during nuclear power plant or fuel reprocessing plant operation, of structures, systems, and components."
Contrary to the above, the licensee replaced the 'C' chiller which would not have been able to restart following a loss of offsite power event, and post-maintenance testing failed to identify the legacy design issue.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Licensee-Identified Non-Cited Violation 71111.15 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: On August 20, 2024, during shift turnover and reviews of equipment issues from the shift, the licensee identified that they failed to identify a condition which required entry into Technical Specification (TS) 3.0.3. The 'B' train control room emergency filtration system (CREFS) was inoperable to due maintenance activities prior to the shift. During retesting of the 'B' train at 10:15AM, which required securing the 'A' train, the 'A' train inlet damper failed to close. Secondary attempts to close the 'A' train inlet damper were unsuccessful. Multiple senior reactor operators identified the potential impacts over the course of the shift, but various plant equipment issues, communications challenges, and interim shift management were factors which contributed to the lack of understanding of the impacts of the failed damper. The licensee realized during shift turnover that the damper was not in its fail-safe (emergency) position when discussing the day's issues. The licensee determined the 'A' train was inoperable and entered TS 3.0.3 at 8:01PM. The licensee restored compliance by placing the damper in the fail-safe (emergency) position at 9:07PM.
TS 3.0.3 requires, in part, "When a Limiting Condition for Operation is not met as provided in the associated action requirements, within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> action shall be initiated to place the unit in a mode in which the specification does not apply by placing it, as applicable, in: 1. At least hot standby within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />".
Contrary to the above, on August 20, 2024, the licensee failed to comply with TS 3.0.3 which required placing the plant in hot standby by 5:15PM.
15 Significance/Severity: Green. Specifically, the licensee failed to identify that both trains of the CREFS were inoperable in excess of the TS allowed outage time. The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power. Appendix A states, in part, "Findings that impact control room habitability require further evaluation. Findings related to the radiological barrier functions of the control room, auxiliary building, reactor building, and spent fuel pool building are not expected to impact CDF or LERF. If degradation of the radiological barrier could result in a substantial potential for overexposure, the finding should also be evaluated using IMC 0609 Appendix C." This example did not meet the definition of "substantial potential for overexposure" in Appendix C, and therefore screened to Green.
Corrective Action References: CR1266916 EXIT MEETINGS AND DEBRIEFS The inspectors verified no proprietary information was retained or documented in this report.
On January 28, 2025, the inspectors presented the integrated inspection results to Beth Jenkins, Site Vice President, and other members of the licensee staff.
On October 10, 2024, the inspectors presented the radiation safety inspection results to Robert Justice, Site Vice President and other members of the licensee staff.
On October 17, 2024, the inspectors presented the in-service inspection results to Robert Justice, site VP and other members of the licensee staff.
16 DOCUMENTS REVIEWED Inspection Procedure Type Designation Description or Title Revision or Date 71124.01 Corrective Action Documents CRs 1266783,
- 1225216, 1226969, and 1225207 8040234505 PortaCount Plus Model 8040 [Respirator Fit Test]
08/28/2024 Calibration Records 8040234507 PortaCount Plus Model 8040 [Respirator Fit Test]
11/10/2023 Corrective Action Documents CAP Documents reviewed during inspection: CR1215060 12/12/2022 230814130-00 Grade D Breathing Air sample analysis results for Bauer XAC-0013 SCBA compressor 08/15/2023 Miscellaneous 240809002-00 Grade D Breathing Air sample analysis results for Bauer XAC-0013 SCBA compressor 08/12/2024 RP-AA-110 Radiological Respiratory Protection Program Revision 4 RP-AA-162 Issue and Control of Respiratory Protection Equipment Revision 8 RP-AA-163 Inspection and Inventory of Respiratory Protection Equipment Revision 9 VCS-HPP-0633 Inspection, Maintenance and Storage of Respiratory Protective Devices Revision 0 Procedures VCS-HPP-0652 Respirator Decision Logic Revision 0 WO-88101048907 STP0454.001 -XAA0029B BRAVO TRAIN CONTROL ROOM EMERGENCY AIR CANISTER TEST [Laboratory Charcoal Analysis]
03/07/2023 WO-88101049390 STP0454.002-XAA0029B BRAVO TRAIN CONTROL ROOM EMERGENCY AIR CLEANUP SYSTEM PERFORMACE [In-situ testing and flow verification]
03/07/2023 WO-88201688807 STP0454.002-XAA0029B CONTROL ROOM EMERGENCY AIR CLEANUP SYSTEM PERFORMACE TEST [In-situ testing and flow verification]
08/23/2024 71124.03 Work Orders WO-88201688808 STP0454.001 -XAA0029B BRAVO TRAIN CONTROL ROOM EMERGENCY AIR CANISTER TEST [Laboratory Charcoal 08/24/2024
17 Inspection Procedure Type Designation Description or Title Revision or Date Analysis]
RW22-0398 2022 Dry Active Waste (DAW) 10 CFR Part 61 Characterization 04/14/2022 TRW: 2.2.1 003 Alpha Source Term Characterization Cycle 27 08/29/2022 TWR# 2.2.2 006 People Mover (Whole Body Counter) Screening Criteria 07/07/2016 Calculations TWR: 2.1.4 001 Neutron Correction Factor Update 04/23/2024 Corrective Action Documents CAP Documents reviewed during inspection: CR1203493, CR1208400, CR1213956, CR1218133, CR1219724, CR1221722, CR1224517, CR1226969, CR1240317, CR1256094, and CR1263870 Various NVLAP LAB CODE: 100512-0 Dosimetry Processor Accreditation [Radiation Detection Company] for the period 01/01/2024 thru 12/31/2024 Various 71124.04 Miscellaneous NVLAP LAB CODE: 100555-0 Dosimetry Processor Accreditation [Mirion Technologies (GDS), Inc] for the period 07/01/2022 thru 06/30/2023 Various 71124.05 Corrective Action Documents CRs # 1228373,
- 1234690, 1247829, and 1262318 Various