IR 05000395/2023002

Integrated Inspection Report - Integrated Inspection Report 05000395/2023002 and Apparent Violation

ML23223A006
Person / Time
Site:	Summer
Issue date:	08/14/2023
From:	David Dumbacher NRC/RGN-II
To:	Carr E Dominion Energy Co
References
EA-23-093 IR 2023002
Download: ML23223A006 (23)

Text

SUBJECT:

VIRGIL C. SUMMER NUCLEAR STATION - INTEGRATED INSPECTION REPORT 05000395/2023002 AND APPARENT VIOLATION

Dear Mr. Eric S. Carr:

On June 30, 2023, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Virgil C. Summer Nuclear Station. On August 10, 2023, the NRC inspectors discussed the results of this inspection with Mr. Robert Justice, Site Vice President, and other members of your staff. The results of this inspection are documented in the enclosed report.

Section 71111.12 of the enclosed report discusses a finding with an associated apparent violation (AV) for which the NRC has not yet reached a preliminary significance determination.

This finding involved a failure to identify and correct a condition adverse to quality for the emergency diesel generator (EDG) fuel oil system that left the system vulnerable to premature piping cracks and eventually resulted in the failure of the A EDG during testing.

We intend to issue our final safety significance determination and enforcement decision, in writing, within 90 days from the date of this letter. The NRCs significance determination process (SDP) is designed to encourage an open dialogue between your staff and the NRC; however, neither the dialogue nor the written information you provide should affect the timeliness of our final determination. We ask that you promptly provide any relevant information that you would like us to consider in making our determination. We are currently evaluating the significance of this finding and will notify you in a separate correspondence once we have completed our preliminary significance review. You will be given an additional opportunity to provide additional information prior to our final significance determination unless our review concludes that the finding has very low safety significance (i.e., Green).

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.

August 14, 2023 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 Nuclear Station.

If you disagree with a cross-cutting aspect assignment in this report, you should provide a response within 30 days of the date of this inspection report, with the basis for your disagreement, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region II; and the NRC Resident Inspector at Virgil C. Summer Nuclear Station.

This letter, its enclosure, and your response (if any) will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with Title 10 of the Code of Federal Regulations 2.390, Public Inspections, Exemptions, Requests for Withholding.

Sincerely, David E. Dumbacher, Chief Reactor Projects Branch 3 Division of Reactor Projects Docket No. 05000395 License No. NPF-12

Enclosure:

As stated

Inspection Report

Docket Number:

05000395

License Number:

NPF-12

Report Number:

05000395/2023002

Enterprise Identifier:

I-2023-002-0043

Licensee:

Dominion Energy

Facility:

Virgil C. Summer Nuclear Station

Location:

Jenkinsville, SC

Inspection Dates:

April 01, 2023, to June 30, 2023

Inspectors:

J. Bell, Senior Health Physicist

B. Bowker, Reactor Inspector

N. Childs, Senior Project Engineer

J. Copeland, Reactor Inspector

S. Downey, Senior Reactor Operations Engineer

J. Hickey, Senior Project Engineer

A. Hutto, Senior Project Engineer

B. Kellner, Senior Health Physicist

T. McGowan, Acting Senior Resident Inspector

M. Read, Senior Resident Inspector

A. Rosebrook, Senior Reactor Analyst

A. Wang, Resident Inspector

Approved By:

David E. Dumbacher, Chief

Reactor Projects Branch 3

Division of Reactor Projects

SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Virgil C. Summer Nuclear Station, in accordance with the Reactor Oversight Process. The Reactor Oversight Process is the NRCs program for overseeing the safe operation of commercial nuclear power reactors. Refer to https://www.nrc.gov/reactors/operating/oversight.html for more information.

List of Findings and Violations

Failure to Identify and Correct a Condition Adverse to Quality Associated with the EDG Fuel Oil System Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Pending AV 05000395/2023002-01 Open EA-23-093 None (NPP)71111.12 A self-revealed finding with significance to be determined (Pending) and associated AV of Title of the Code of Federal Regulations (10 CFR) Part 50, Appendix B, Criterion XVI,

"Corrective Action," was identified when the licensee failed to identify and correct a condition adverse to quality for the EDG fuel oil system that left the system vulnerable to premature piping cracks and eventually resulted in the failure of the A EDG during testing on November 2, 2022. Specifically, inspectors determined that, based on the failure history of the EDGs and the licensees documented conclusions that attributed pipe cracks to prior maintenance events, the licensee had sufficient information to identify the existence of a condition adverse to quality related to the design of the EDG fuel oil system. This condition caused threaded fuel oil piping connections to be vulnerable to maintenance activities that over torqued, strained, or impacted the piping. Despite the challenge to maintain leak-tight connections and repeat occurrences of cracked piping, no significant changes were made to maintenance practices, procedures or system design, and the licensee continued to reactively monitor for leakage even after vulnerabilities were identified.

Failure to Manage Risk During Scaffold Removal Activities Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000395/2023002-02 Open/Closed

[H.3] - Change Management 71111.20 An NRC-identified finding of very low safety significance (Green) and associated NCV of 10 CFR Part 50.65(a)(4), Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, was identified for the licensee's failure to manage the increase in risk during scaffold removal activities. Specifically, scaffold workers removed scaffolding from the

'A' residual heat removal (RHR) heat exchanger room while RHR was protected.

Additional Tracking Items

Type Issue Number Title Report Section Status LER 05000395/2022-001-01 LER 2022-001-01 for Virgil C. Summer Nuclear Station 71153 Closed (VCSN), Unit 1, Manual Reactor Trip Due to Main Transformer Fault LER 05000395/2022-002-01 LER 2022-002-01 for Virgil C. Summer, Unit 1,

Condition Prohibited by Technical Specifications:

Inoperable 'B' Emergency Diesel Generator 71153 Closed

PLANT STATUS

The site began the inspection period at rated thermal power. On April 5, 2023, the site began lowering power for a refueling outage. While at 85 percent power, the reactor was manually tripped due to the loss of a main feedwater pump. The site remained shut down for a planned refueling outage until startup on May 19, 2023, and returned to rated thermal power on May 28, 2023. The site 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 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.

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) RHR system, on April 8 - 9, April 21, and May 1, 2023

(2) Emergency feedwater system, on May 22, 2023

(3) Safety-related inverters, on June 23, 2023

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) Reactor building elevations 412, 436, and 463 feet, on April 8, 2023

(2) Turbine lube oil room, on May 9, 2023

(3) Intermediate building elevation 412 feet battery rooms, on May 22, 2023

(4) Fuel handling building, on June 6, 2023

(5) Auxiliary building elevation 412 feet, on June 23, 2023

71111.07A - Heat Exchanger/Sink Performance

Annual Review (IP Section 03.01) (1 Sample)

The inspectors evaluated readiness and performance of:

(1) RHR heat exchangers, on April 10, 2023

===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 from April 17 to April 21, 2023.

PWR Inservice Inspection Activities Sample - Nondestructive Examination and Welding Activities (IP Section 03.01)===

The inspectors verified that the following nondestructive examination and welding activities were performed appropriately:

(1) Magnetic Particle Examination

Weld FW-7C1, pipe to elbow weld, ASME Class 2

Weld FW-9C1, pipe to valve weld, ASME Class 2

Weld MW-8, pipe to elbow weld, ASME Class 2 Ultrasonic Examination

Weld 1-4107A-8, pipe to elbow weld, ASME Class 1

Weld 1-4107A-10, pipe to elbow weld, ASME Class 1

Weld 1-4107A-12, pipe to tee weld, ASME Class 1

Weld 1-4107A-14, tee to pipe weld, ASME Class 1

Weld 1-4202A-4, pipe to elbow weld, ASME Class 1

Weld 1-4202A-5, pipe to elbow weld, ASME Class 1

Weld 2-2522A-13, pipe to tee weld, ASME Class 1

Weld 2-2522A-14, tee to pipe weld, ASME Class 1 Visual Examination

1-4100A-28, steam generator B hot leg nozzle to safe end weld, ASME Class 1-4100A-29, steam generator C hot leg nozzle to safe end weld, ASME Class 1-4100A-31, steam generator A hot leg nozzle to safe end weld, ASME Class Welding Activities

Gas Tungsten Arc Welding o

Service Air Piping Replacement, Welds FW-7C1, ASME Class 2 o

Service Air Piping Replacement, Weld FW-9C1. ASME Class 2 o

Service Air Piping Replacement, Weld MW-8. 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, on April 18, 2023

Condition Report (CR) 1197380

CR 1197430

CR 1219096

CR 21-03721

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 coolant system (RCS) cooldown to Mode 5 on April 6, 2023, during filling lower end of reactor cavity, and filling of cavity to 23 feet on April 12, 2023, and during fuel offload on April 14, 2023.

Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)

(1) The inspectors observed a licensed operator requalification simulator training exercise involving a failed pressurizer pressure transmitter, reactor failure to trip, and a faulted steam generator on June 12, 2023.

71111.12 - Maintenance Effectiveness

Maintenance Effectiveness (IP Section 03.01) (2 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 ventilation fans and dampers in the air handling system, review completed on May 8, 2023

(2) EDG fuel oil systems, review completed on June 30, 2023

Quality Control (IP Section 03.02) (1 Sample)

The inspectors evaluated the effectiveness of maintenance and quality control activities to ensure the following SSC remains capable of performing its intended function:

(1) Overhaul of XVG-503B/C, 'B' and 'C' steam generator blowdown isolation valves, on May 15, 2023

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) No SSCs were identified that failed to meet inspection and test acceptance criteria, so inspectors reviewed issues with wall coatings inside containment on May 8, 2023, and condensate storage tank outlet piping corrosion on June 28, 2023.

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 reactor shutdown and nuclear instrumentation operational testing, on April 7, 2023

(2) Yellow risk during RCS drain down to lowered inventory conditions, on April 10, 2023

(3) Elevated risk during maintenance on the 'A' stator water cooling pump, on May 25, 2023

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) CR 1217936, 'A' EDG fuel oil piping support clamp not holding pipe, review completed on April 3, 2023

(2) CR 1223854, magnesium rotor degradation of motor operator for accumulator isolation valve 8808A, review completed on April 10, 2023

(3) CR 1217255 and CR 1217180, EDG fuel oil sample discrepancies, review completed on May 24, 2023

(4) CR 1205895, pressurizer spray header isolation valve stroke time, review completed on June 16, 2023

(5) CR 1214320, diesel-driven fire service pump low coolant level, review completed on June 22, 2023

71111.18 - Plant Modifications

Temporary Modifications and/or Permanent Modifications (IP Section 03.01 and/or 03.02) (2 Samples)

The inspectors evaluated the following modifications:

(1) VC-20-00006, emergency feedwater check valves modification, review completed on May 12, 2023

(2) ECR50883, vital bus inverter XIT5904 replacement, review completed on May 22, 2023

71111.20 - Refueling and Other Outage Activities

Refueling/Other Outage Sample (IP Section 03.01) (1 Sample)

(1) The inspectors evaluated refueling outage RF27 from April 5, 2023, to May 19, 2023.

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) EMP-295.004, post-accident hydrogen monitor alternate purge vent exhaust fan functional testing, following fan inspection, on March 20, 2023

(2) STP-215.002A, penetration XRP0310, XVC02913-SA, reactor building isolation check valve as-left leakage test following valve repairs, on April 24, 2023

(3) STP-121.002C, turbine driven emergency feedwater pump main steam supply valve operability test of IFV02030-MS (emergency feedwater pump turbine supply flow control valve - train A) after replacement of valve control components, on April 27, 2023

(4) STP-0502.005, reactor building sump isolation functional test of XMC1DB2Y-021M following breaker preventive maintenance on April 30, 2023

(5) MTP-50883.005, inverter XIT5904 functional testing, following controller card replacement, on May 9, 2023

(6) STP-136.001, steam generator blowdown isolation valve testing following overhauls of the 'B' and 'C' steam generator isolation valves, on May 17, 2023

(7) STP-205.003, 'A' charging pump testing, document review and observation of pump performance following pump outboard seal replacement on June 13, 2023

(8) Starting and running of the Parr blackstart diesel generator following annual preventive maintenance, on June 14, 2023

Surveillance Testing (IP Section 03.01) (3 Samples)

(1) STP-345.074, solid state protection system actuation logic and master relay test 'B,'

on April 4, 2023

(2) STP-125.004B, diesel generator 'B' load rejection testing, on May 3, 2023

(3) STP-503.003A, functional testing of train 'A' service water to emergency feedwater cross-connect circuits, on June 14, 2023

Inservice Testing (IST) (IP Section 03.01) (1 Sample)

(1) STP-130.004E, feedwater isolation valve stroke time testing for isolation valves 'A' and 'B,' on May 10, 2023

Containment Isolation Valve (CIV) Testing (IP Section 03.01) (1 Sample)

(1) Containment penetration 425 protective chamber XSM0005B, on April 27,

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 RCA

(2) Workers exiting the RCA at Unit 1 during a refueling outage.

(3) Workers exiting the Unit 1 reactor building during a refueling outage.

Radiological Hazards Control and Work Coverage (IP Section 03.04) (4 Samples)

The inspectors evaluated the licensee's control of radiological hazards for the following radiological work:

(1) Removal of the blind flange in the Unit 1 transfer canal

(2) Unit 1 incore seal table disconnect and rollback

(3) Unit 1 reactor head lift and placement on the head stand

(4) Concrete removal (chipping) in the Unit 1 reactor building 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) Unit 1 incore pit (under vessel access door, locked VHRA in the reactor building)

(2) Unit 1 Regenerative Heat Exchanger Room (locked high radiation area (LHRA) in the reactor building)

(3) Spent fuel demineralizer tank access in the 436' hallway in the auxiliary building (LHRA)

(4) Locked high rad storage area gate on the 436' elevation of the auxiliary building (LHRA)

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.

71124.08 - Radioactive Solid Waste Processing & Radioactive Material Handling, Storage, &

Transportation

Radioactive Material Storage (IP Section 03.01)

The inspectors evaluated the licensees performance in controlling, labeling and securing the following radioactive materials:

(1) Old steam generators at mausoleum

(2) Spent resins and filters in radwaste yard

Radioactive Waste System Walkdown (IP Section 03.02) (2 Samples)

The inspectors walked down the following accessible portions of the solid radioactive waste systems and evaluated system configuration and functionality:

(1) Unit 1 liquid radwaste processing system

(2) Unit 1 solid radwaste processing system

Waste Characterization and Classification (IP Section 03.03) (3 Samples)

The inspectors evaluated the following characterization and classification of radioactive waste:

(1)2022 dry active waste Part 61 analysis, sample #RW22-0398 (2)2022 primary resin Part 61 analysis, sample #RW22-0429 (3)2021 XFL-009 normal operations filter Part 61 analysis, sample #RW22-1573

Shipment Preparation (IP Section 03.04) (1 Sample)

(1) The inspectors observed the preparation of radioactive shipment #23-019, dry active waste.

Shipping Records (IP Section 03.05) (4 Samples)

The inspectors evaluated the following non-excepted radioactive material shipments through a record review:

(1) Shipment #21-039, LSA-II, primary resin

(2) Shipment #23-004, LSA-II, primary resin

(3) Shipment #23-019, LSA-1, dry active waste

(4) Shipment #22-039, LSA-II, charcoal and mixed bed resin

OTHER ACTIVITIES - BASELINE

===71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:

IE01: Unplanned Scrams per 7000 Critical Hours Sample (IP Section 02.01)===

(1) April 1, 2022, through March 31, 2023 IE03: Unplanned Power Changes per 7000 Critical Hours Sample (IP Section 02.02) (1 Sample)

(1) April 1, 2022, through March 31, 2023

IE04: Unplanned Scrams with Complications (USwC) Sample (IP Section 02.03) (1 Sample)

(1) April 1, 2022, through March 31, 2023 BI01: Reactor Coolant System (RCS) Specific Activity Sample (IP Section 02.10) (1 Sample)

(1) April 1, 2022, through March 31, 2023

BI02: RCS Leak Rate Sample (IP Section 02.11) (1 Sample)

(1) April 1, 2022, through March 31, 2023

OR01: Occupational Exposure Control Effectiveness Sample (IP Section 02.15) (1 Sample)

(1) March 24, 2022, through March 31, 2023 PR01: Radiological Effluent Technical Specifications/Offsite Dose Calculation Manual Radiological Effluent Occurrences (RETS/ODCM) Radiological Effluent Occurrences Sample (IP Section 02.16) (1 Sample)

(1) May 14, 2022, through April 19, 2023

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) CR 1195990, 'A' chiller trip, review completed on June 22, 2023

(2) CR 1211780, 'A' EDG failed 24-hour surveillance test, review completed on June 30, 2023

71153 - Follow-Up of Events and Notices of Enforcement Discretion Event Report (IP section 03.02)

The inspectors evaluated the following licensee event reports (LERs):

(1) LER 05000395/2022-001-01, Manual Reactor Trip Due to Main Transformer Fault (ADAMS Accession No. ML22349A700). The inspectors reviewed the updated LER submittal. The previous LER submittal was reviewed in inspection report 2022-001 (ML22132A192). The inspection conclusions associated with this LER are documented in this report under Inspection Results Section 71153 and the updated LER submittal does not change those conclusions. This LER is Closed.

(2) LER 05000395/2022-002-00 and 2022-002-01, Potential Condition Prohibited by Technical Specification 3.8.1.1 (ADAMS Accession Nos. ML22101A284 and ML22342B247). The LER and updated LER submittal were reviewed, and the conclusions were documented in inspection reports 2022-001 (ML22132A192), 2022-004 (ML22194A020), 2022-090 (ML22194A020), 2022-091 (ML22287A184), and 2023-040 (ML23114A094). This LER and the updated submittal are Closed.

Personnel Performance (IP section 03.03) (1 Sample)

(1) The inspectors evaluated the manual reactor trip in response to the 'C' main feedwater pump trip, and licensees performance on April 5,

INSPECTION RESULTS

Failure to Identify and Correct a Condition Adverse to Quality Associated with the EDG Fuel Oil System Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Pending AV 05000395/2023002-01 Open EA-23-093 None (NPP)71111.12 A self-revealed finding with significance to be determined (Pending) and associated AV of Title of the Code of Federal Regulations (10 CFR) Part 50, Appendix B, Criterion XVI, "Corrective Action," was identified when the licensee failed to identify and correct a condition adverse to quality for the EDG fuel oil system that left the system vulnerable to premature piping cracks and eventually resulted in the failure of the A EDG during testing on November 2, 2022. Specifically, inspectors determined that, based on the failure history of the EDGs and the licensees documented conclusions that attributed pipe cracks to prior maintenance events, the licensee had sufficient information to identify the existence of a condition adverse to quality related to the design of the EDG fuel oil system. This condition caused threaded fuel oil piping connections to be vulnerable to maintenance activities that over torqued, strained, or impacted the piping. Despite the challenge to maintain leak-tight connections and repeat occurrences of cracked piping, no significant changes were made to maintenance practices, procedures or system design, and the licensee continued to reactively monitor for leakage even after vulnerabilities were identified.

Description:

On November 2, 2022, during the performance of a 24-hour surveillance test, operations identified a small leak on the 3/4 fuel piping header supplying the A EDG right bank cylinders fuel injectors. The leakage was monitored and observed to increase over several hours until operations stopped the surveillance test, secured the engine, and prepared the EDG for repairs.

During the repairs, the licensee identified that a crack between the threads of the male end of the pipe had propagated 140-degrees around the circumference of the pipe. An engineering assessment determined that the EDG was unlikely to have been able to perform its 24-hour mission time.

The location of the crack was in a section of piping that experienced vibrations during operation. The original design of the fuel oil delivery piping included threaded connections for ease of maintenance. Inspectors reviewed historical CRs and maintenance records and noted that the A and B EDGs have experienced fuel oil piping cracking near the left and right fuel header connections where vibrations are present.

On October 21, 2003, while performing maintenance testing the A EDG, the right bank fuel supply line ruptured at the threaded connection. The licensee documented NCN-03-03500 and attributed the crack to manual manipulation of the pipe. The pipe nipple was replaced, and the 10-foot crossover pipe between the left and right fuel oil header banks was shortened to minimize piping spring.

On August 20, 2014, the A EDG left bank 3/4 x 2 nipple developed a 120 drops per minute leak. The licensee initiated CR 14-04564 to repair the connection. During repairs, mechanics identified a hairline crack in the threads. The nipple was replaced, and the licensee initiated CR 14-04592 to document the hairline crack. The CR actions included a quick cause evaluation and assignments for engineering to inspect other threaded connections for evidence of leakage during the next runs of the A and B EDGs. The quick cause evaluation noted the 2003 pipe crack on the opposite side of the A EDG and determined that the single impact event during a 2003 maintenance activity damaged the left bank nipple and over 11 subsequent years of operation, the crack developed due to fatigue.

On November 4, 2014, the B EDG right bank 3/4 x 15 nipple developed a small leak. The licensee initiated CR 14-05797 to repair the connection. During repairs, mechanics identified a hairline crack in the threads. The pipe nipple was replaced, and the D-OTH evaluation by engineering stated that the most likely cause was a single impact event followed by subsequent high stress low cycle fatigue. The licensee established a corrective action to monitor the system for early signs of leakage during EDG runs.

On March 2, 2020, during repairs to correct minor fuel oil leakage under WO1909952 step 2, the licensee identified a crack on the A EDG 1 x 1/2 reducer bushing on the left bank header. There was no condition report generated to document the cracked bushing. During the retest on March 5, 2020, fuel oil leakage was identified, and the licensee initiated CR 20-00712 as a non-condition adverse to quality (NCAQ) to document the leakage. After subsequent repairs on March 6, 2020, during the maintenance retest, the licensee identified a leak and a crack on the newly installed pipe nipple that was attached to a new bushing installed on March 5, 2020, which was documented in CR-20-00735 as an NCAQ. The nipple was replaced and no further evaluation was performed.

Licensee procedure SAP-0999, Corrective Action Program, Revision 19, step 1.2.3 required the determination of CR category and evaluation type using examples and guidance in s A and J. Although maintenance rework items were identified as NCAQs and did not require evaluations, the identification of cracked bushing and fittings should have been identified as a condition adverse to quality (CAQ) because both components were found degraded in a condition that had the potential to inhibit a safety-related SSC from satisfactory performance of a safety-related function. This may have driven an evaluation of previous conditions, cause of the issue, and extent of condition, but guidance in Enclosure A to determine the level of evaluation would have been subjective based on the perceived consequence. Since the component cracked, it should have received at least a D-OTH evaluation which would have identified the most probable cause of the cracks. Since the failure was treated as a broke/fix even though the components were cracked prior to the maintenance window, the licensee missed an opportunity to identify if a CAQ existed and determine if previous failures in 2003 and 2014 were indicative of a more significant problem with the A EDG fuel oil system.

Each of these instances of piping or bushing cracks were remediated by replacement of the components and monitoring for future leakage from similar components. The EDG fuel oil systems were designed to be robust to withstand the expected high vibrations for the life of the plant. Due to the standby nature of EDGs at nuclear power plants which only run during testing and events involving a loss of offsite power, it is rare that an EDG would operate more than 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> per year. Although the EDGs fuel oil system cracks were separated by many years between events, the total run time of the EDGs between failures was small compared to the expected life of the system. The licensee had evidence that maintenance activities including piping manipulation and impact events could not only damage multiple connections, but the damage may not reveal itself through an open crack for years. This vulnerability of the EDG system is exacerbated by using schedule-40 piping with tapered threads, which is more susceptible to cracking than thicker piping or different connection designs.

Inspectors determined that based on the failure history of the EDGs and the licensees documented conclusions that attributed pipe cracks to prior maintenance events, the licensee had sufficient information to identify that a CAQ adverse to quality existed with the design of the EDG fuel oil system that caused the threaded connections to be vulnerable to maintenance activities that over torqued, strained, or impacted the piping. This vulnerability in the system was most prevalent in the left and right bank fuel oil connections which were subject to high vibrations during EDG operation. Despite the challenge to maintain leak-tight connections and cracked pipes, no significant changes were made to maintenance practices or procedures, and the licensee continued to reactively monitor for leakage even after vulnerabilities were identified. The licensee also did not make any substantive changes to the design of the system to reduce the vulnerability to maintenance-induced challenges.

The licensee treated individual pipe failures as broke/fix rather than identifying the system vulnerability and implementing corrective actions. The licensee had evidence prior to the November 2022 failure of the A EDG supply header pipe that cracks could propagate rapidly during EDG operation as seen in the October 2003 rupture of the same A EDG supply header pipe. If the licensee had identified and corrected the system vulnerability or implemented mitigating actions beyond monitoring for leakage following evidence of cracked piping in 2003, twice in 2014, or in 2020, then the failure of the piping on the A EDG on November 2, 2022, could have been prevented.

Corrective Actions: The licensee replaced the cracked pipe nipple on the 'A' EDG and reperformed the 24-hour surveillance test. The licensee also replaced the same nipple on the

'B' EDG to extend the life of the piping.

Corrective Action References: CR 1211780

Performance Assessment:

Performance Deficiency: The licensee's failure to identify and correct a CAQ for the EDG fuel oil system that left the system vulnerable to premature piping cracks was a performance deficiency.

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 condition caused the threaded fuel oil piping connections to be vulnerable to maintenance activities which resulted in the premature failure of a pipe nipple and inoperability of the 'A' EDG on November 2, 2022.

Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The finding could not be screened to Green and is pending a significance determination.

Cross-Cutting Aspect: Not Present Performance. No cross-cutting aspect was assigned to this finding because the inspectors determined the finding did not reflect present licensee performance.

Enforcement:

Violation: 10 CFR Part 50 Appendix B, Criterion XVI Corrective Action, states, in part that, measures shall be established to assure that conditions adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective material and equipment, and nonconformances are promptly identified and corrected.

The V.C. Summer Quality Assurance Program Description (QAPD), Revision 2 (2014),described the methods and establishes quality assurance program and administrative control requirements that meet 10 CFR Part 50, Appendix B. Section 16, Corrective Action, of the QAPD described the methods to meet Criterion XVI. It stated, in part, when complex issues arise where it cannot be readily determined if a condition adverse to quality exist, [the licensee] documents establish the requirements for documentation and timely evaluation of the issue.

Licensee procedure SAP-0999, Corrective Action Program, Revision 12 (2014), step 6.3.1 stated, When an issue is recognized that it is not meeting performance expectations, the event should be documented via a CR. An example of a condition that required a CR is D.

The failure mechanism has implications that may affect multiple systems or components.

Contrary to the above, following discovery of cracked components in the EDG fuel oil systems in 2003, twice in 2014, and in 2020, the licensee fixed the cracked piping but failed to identify and correct the failure mechanism that affected the fuel oil system piping on both EDGs. If the licensee had identified and corrected the condition of the system which left the system vulnerable to premature piping cracks, the A EDG failure on November 2, 2022, may have been prevented.

Enforcement Action: This violation is being treated as an AV pending a final significance (enforcement) determination.

Failure to Manage Risk During Scaffold Removal Activities Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000395/2023002-02 Open/Closed

[H.3] - Change Management 71111.20 An NRC-identified finding of very low safety significance (Green) and associated NCV of 10 CFR Part 50.65(a)(4), Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, was identified for the licensee's failure to manage the increase in risk during scaffold removal activities. Specifically, scaffold workers removed scaffolding from the

'A' residual heat removal (RHR) heat exchanger room while RHR was protected.

Description:

On May 15, 2023. while Unit 1 was in Mode 5, "Cold Shutdown," inspectors observed scaffold builders removing scaffold from the 'A' RHR heat exchanger room. Upon review, inspectors identified that the on-duty operations crew was not aware of the work and therefore did not release the work activities to be performed. The scaffold had been erected in March 2023 for the refueling outage. Due to a 2023 change in the tracking system for scaffold orders, the erection and removal were both documented under the same order. The system listed the order as "authorized" because operations had authorized the erection in March 2023 when the 'A' RHR train was not protected.

Inspectors identified that the operations department was aware of the vulnerability to control scaffold activities if erections and disassembly were combined into the same order and had discussed their expectation with a scaffold planner to consult with operations work control before removing scaffolding. On the day of the event, the scaffold planner was not onsite, and the backup was not aware of the vulnerability or expectations.

Licensee procedure OP-VC-601, "Protected Equipment," revision 0, step 3.5.1, stated, "Refer to OP-AA-600 for restrictions on evolutions on protected equipment or work near protected equipment." Fleet procedure OP-AA-600, "Protected Equipment," revision 5, step 3.3.2 stated, in part, "Do not allow routine entry or work on protected equipment in a Protected Equipment Zone." It also provided limited exceptions and controls if operations determined work near protected equipment was necessary.

Corrective Actions: Nuclear site services supervision was coached on the expectation to coordinate scaffolding activities with the operations' work control center.

Corrective Action References: CR 1228652

Performance Assessment:

Performance Deficiency: The licensee's failure to manage the increase in risk that resulted from scaffold removal activities, as required by 10 CFR Part 50.65(a)(4), was a performance deficiency. Specifically, the licensee failed to limit work activities in the proximity of safety-related equipment which was identified to be protected under the licensee's "Protected Equipment" procedure. This performance deficiency was within the licensees ability to foresee and prevent.

Screening: The inspectors determined the performance deficiency was more-than-minor because it was associated with the Configuration 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 licensees failure to limit work activities in the proximity of safety-related equipment resulted in inappropriate work in the vicinity of protected 'A' RHR train equipment and could have affected the availability, reliability, or capability of the system.

This performance deficiency is similar to Example 8.f of Inspection Manual Chapter 0612, Appendix E, "Examples of Minor Issues," dated December 10, 2020, which lists a performance deficiency as more-than-minor if there were unauthorized individuals in a protected equipment area or work was ongoing in the vicinity of protected equipment.

Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix K, Maintenance Risk Assessment and Risk Management SDP. Inspection Manual Chapter (IMC) 0609, Attachment 4, Table 3 directs the inspector to go to IMC 0609 Appendix K, Maintenance Risk Assessment and Risk Management SDP. However, Section 0609K-03, "General Guidance," contains the following note, This guidance does not apply to the following situations:

(1) those licensees who only perform qualitative analyses of plant configuration risk due to maintenance activities, or

(2) performance deficiencies related to maintenance activities affecting SSCs needed for fire (unless quantitatively analyzed) or seismic mitigation. When performance deficiencies are identified with either 1 or 2 above, the significance of the deficiencies must be determined by an internal NRC management review using risk insights where possible in accordance with IMC 0612, Issue Screening. The licensees PRA model for shutdown risk is qualitative; plant risk for this risk management action (RMA) cannot be estimated using IMC 0609 Appendix G, Shutdown Operations Significance Determination Process, and the NRC does not have a low power/shutdown model for V.C. Summer, therefore this note applies to this case. The SRA chose to use IMC 0609 Appendix M, Significance Determination Process Using Qualitative Criteria, to document management review. The licensee qualitatively determined plant risk was Green at the time of the event and RMAs were established to protect the A ECCS Train. Access to the RHR heat exchanger room was administratively controlled; however, these actions were ineffective, and work was conducted in the vicinity of protected equipment. This equipment included safety-related flow indications and Motor Operated Valves (MOVs) in the RHR system. Taking into account, the equipment in the room would not have resulted in a pump trip, and significant time was available to identify and recover from an inadvertent operation of any of the MOVs, the SRA determined this issue was of very low safety significance (Green). Additionally, if Appendix K had been used, because the performance deficiency was related to inadequate RMAs, the inspectors would be directed to IMC 0609, Appendix K, Flowchart 2, "Assessment of RMAs." The inspectors would have determined the finding screened to very low safety significance (Green) if the incremental core damage probability for the activities was less than 1E-6. Given the licensees qualitative risk assessment of Green, it is reasonable to conclude this to be true.

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, when implementing a new tracking system for scaffold orders, the licensee recognized the vulnerability of work authorizations covering erection and removal activities, but failed to establish an adequate process to ensure that operations managed the risk of scaffolding activities.

Enforcement:

Violation: 10 CFR Part 50.65(a)(4), Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, requires, in part that, licensees manage the increase in risk that may result from maintenance activities.

Contrary to the above, on May 15, 2023, the licensee failed to manage the increase in risk during scaffold removal activities. Specifically, scaffold workers removed scaffolding from the

'A' RHR heat exchanger room while RHR was protected.

Enforcement Action: This violation is being treated as an NCV, consistent with Section 2.3.2 of the Enforcement Policy.

EXIT MEETINGS AND DEBRIEFS

The inspectors verified no proprietary information was retained or documented in this report.

On August 10, 2023, the inspectors presented the integrated inspection results to Mr.

Robert Justice, Site Vice President, and other members of the licensee staff.

On April 20, 2023, the inspectors presented the Baseline Radiation Safety Inspection results to Mr. Robert Justice, Site Vice President, and other members of the licensee staff.

DOCUMENTS REVIEWED

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

V1RF27UT-009

Ultrasonic Examination of Weld 2-2522A-14

04/13/2023

V1RF27UT-010

Ultrasonic Examination of Weld 2-2522A-13

04/13/2023

V1RF27UT-011

Ultrasonic Examination (Flaw Sizing) of Weld 2-2522A-13

04/14/2023

71111.08P

NDE Reports

V1RF27UT-012

Ultrasonic Examination (Flaw Sizing) of Weld 2-2522A-14

04/14/2023

23-04003-1

Scaffold Activities for RF-27

Revision 00

23-04200

Refueling Activities RF27

Revision 0

ALARA Plans

23-04201

High Risk Refueling Activities RF27

Revision 0

Corrective Action

Documents

CR1204105, CR1221722, CR1205011, CR1213124,

CR1221330, CR1225216, and CR1225267

Various

VC Summer Nuclear Station Refueling Outage RF26 ALARA

Report

Undated

VCS 2021 Radiation Protection Program Annual Review

Undated

RF27 Shiftly Dose Summary Reports 4/18 thru 4/20/2023

Various

List of RF-27 TEDE ALARA Evaluations

Undated

V.C. Summer Nuclear Station Exposure Reduction 5 Year

Plan 2021-2026

Undated

23-04004

TEDE ALARA Review, lncore System Eddy Current Testing

03/27/2023

23-04005

TEDE ALARA Review, lncore System Drive Box Work

03/27/2023

23-04200-1

Work In Progress ALARA Review (WIPR) for RWP 23-04200

ALARA Plan, Refuel Maintenance Activities for RF 27

04/19/2023

23-04201

TEDE ALARA Review, Remove RX head 0-Ring

03/17/2023

Technical Work

Record 2.2.1-22-

003

2-003 Alpha Characterization Cycle 27, Revision 1

09/06/2022

Miscellaneous

TSR 23-001

Temporary Shield Request, Shield Seismic Gap FHB436 in

support of Fuel Movement

01/11/2023

23-0776

Air sample obtained during preventative maintenance

activities in the transfer canal (PAPR worn)

04/05/2023

23-0854

Air sample obtained during transfer canal blind flange

removal (PAPR worn)

04/08/2023

71124.01

Radiation

Surveys

VCS1-M-

230407-1

Incore Sump Pit entry

04/06/2023

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

VCS1-M-

230407-11

Seal Table Disassembly

04/07/2023

VCS1-M-

230408-17

Transfer Canal Blind Flange Removal

04/08/2023

VCS1-M-

230412-17

Reactor Head Laydown Area After Head Move

04/12/2023

VCS1-M-

230412-22

Reactor Head Lift

04/12/2023

VCS1-M-

230418-17

Grout removal on 436' elevation

04/18/2023

VCS1-M-

230419-20

Intermediate Building Elevation 436 [workers bypassing RCA

boundary barricade CR1225216]

04/19/2023

Self-Assessments CR-21-02094

ALARA Program Self-Assessment

09/30/2021

Corrective Action

Documents

CR 1216244

Duratek poly injection PV-10 valve leaking

2/29/2022

71124.08

Procedures

VC-PROC-000-

HPP-733

Processing or transfer of liquid waste to the waste monitor

tanks

Rev. 3D

CR 1214086

RMA-3 OOS compensatory actions

11/29/2022

CR 1214318

RMA-3 continuous sample collection not maintained.

2/01/2022

Corrective Action

Documents

CR1212485

Worker receives SRD dose and dose rate alarm

11/09/2022

Corrective Action

Documents

Resulting from

Inspection

CR1225777

NRC Identified Minor Violation for RMA-3 OOS

04/24/2023

71151

Miscellaneous

Monthly Performance Indicator Data Collection Summaries

for the period April 2022 through February 2023

Various

71153

Procedures

OP-AP-105,

Reactor Shutdown and Trip Report (Reactor trip on April 5,

23)