IR 05000395/2024002

Integrated Inspection Report 05000395/2024002

ML24220A069
Person / Time
Site:	Summer
Issue date:	08/12/2024
From:	Renee Taylor Division Reactor Projects II
To:	Carr E Dominion Energy, Dominion Energy Virginia
References
IR 2024002
Download: ML24220A069 (11)

Text

SUBJECT:

VIRGIL C. SUMMER - INTEGRATED INSPECTION REPORT 05000395/2024002

Dear Eric S. Carr:

On June 30, 2024, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Virgil C. Summer. On July 18, 2024, the NRC inspectors discussed the results of this inspection with Mr. Will Kearney and other members of your staff. The results of this inspection are documented in the enclosed report.

No findings or violations of more than minor significance were identified during this inspection.

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, Ryan C. Taylor, 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: 05000395/2024002

Licensee: Dominion Energy

Facility: Virgil C. Summer

Location: Jenkinsville, SC

Inspection Dates: April 01, 2024 to June 30, 2024

Inspectors: K. Dials, Resident Inspector M. Read, Sr. Resident Inspector

Approved By: Ryan C. Taylor, Chief Reactor Projects Branch 3 Division of Reactor Projects

Enclosure

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.

List of Findings and Violations

No findings or violations of more than minor significance were identified.

Additional Tracking Items

Type Issue Number Title Report Section Status LER 05000395/2024-001-00 LER 2024-001-00 for Virgil 71153 Closed C. Summer Nuclear Station (VCSNS), Unit 1, Automatic Actuation of 'B' Emergency Diesel Generator

PLANT STATUS

Unit 1 began the inspection period at rated thermal power. On June 21, 2024, the unit was down powered to 92 percent to perform turbine valve testing, returned to rated thermal power on the same day, 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.

71111.04 - Equipment Alignment

Partial Walkdown Sample (IP Section 03.01) (2 Samples)

The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:

(1) 'B' emergency diesel generator on May 14, 2024, during testing of the 'A' emergency diesel generator

(2) Service water pump house ventilation system during the weeks of June 17 and 25, 2024

71111.05 - Fire Protection

Fire Area Walkdown and Inspection Sample (IP Section 03.01) (4 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) Control building elevation 448 feet on April 25, 2024

(2) Control room evacuation panel and component cooling pump speed switch rooms in the intermediate building elevation 436 feet on April 30, 2024

(3) 1A and 1B battery and charger rooms on June 13, 2024

(4) Emergency diesel generator building on June 17, 2024

71111.06 - Flood Protection Measures

Flooding Sample (IP Section 03.01) (1 Sample)

(1) The inspectors evaluated internal flooding mitigation protections in the control building elevation 448 feet. The review was completed on April 25, 2024

71111.07A - Heat Exchanger/Sink Performance

Annual Review (IP Section 03.01) (2 Samples)

The inspectors evaluated readiness and performance of:

(1) 'B' emergency diesel generator heat exchangers on May 28-30, 2024

(2) 'B' train component cooling water heat exchanger performance on June 13, 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 validation of available emergency communications following partial loss of telecommunications on April 19, 2024, and response to reactor power increase following failure of a temperature control valve controller in the letdown system on April 23, 2024

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

(1) Inspectors observed licensed operator requalification simulator training exercise involving a loss of one train of DC power, loss of balance of plant power resulting in reactor trip, and natural circulation cooldown on May 29, 2024

71111.12 - Maintenance Effectiveness

Maintenance Effectiveness (IP Section 03.01) (1 Sample)

The inspectors evaluated the effectiveness of maintenance to ensure the following structures, systems, and components (SSCs) remain capable of performing their intended function:

(1) Chilled water system, review completed on May 13, 2024

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) 'C' chiller replacement structural supports and grouting from June 18 to 20, 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) Elevated risk during freeze seal isolation and repairs to reactor building air compressor cooling piping on April 10, 2024

(2) Yellow risk during 'B' train solid state protection system testing on April 12, 2024

(3) Elevated risk during 'A' emergency diesel generator maintenance on April 15, 2024

(4) Elevated risk during overcurrent relay calibrations for normal incoming breaker to emergency bus '1DA' on June 19, 2024

(5) Elevated risk during power reduction and turbine valve testing on June 20, 2024

71111.15 - Operability Determinations and Functionality Assessments

Operability Determination or Functionality Assessment (IP Section 03.01) (6 Samples)

The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:

(1) CR1255111, breaker 'XSW1DB 10', backup closing control power breaker for the 'B' emergency diesel generator local control panel, found in the 'OFF' position, review completed on April 11, 2024

(2) CR1257292, turbine-driven emergency feedwater pump low lube oil trip linkage did not engage during testing, review completed on May 1, 2024

(3) CR1258150, resistive fusible links for relay room dampers XFD-19 and XFD-20 read "open circuit" during testing, review completed on May 1, 2024

(4) CR1231184, inverter XIT5904 trouble alarm, review completed on June 17, 2024

(5) CR1262702, turbine-driven emergency feedwater pump turbine and valve conduit junction box were not in compliance with NEMA-4 rating, review completed on June 26, 2024

(6) CR1260706, missing locking washers on rubber support blocks for 'B' emergency diesel generator rocker arm lubricating oil lines, review completed on June 13, 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) (2 Samples)

(1) STP-360.045, testing of radiation monitor RM-A13, main plant vent, following ratemeter replacement on April 19, 2024

(2) STP-125.002B, 'B' emergency diesel generator testing, on May 30, 2024, following replacement of turbocharger cooling piping and remediation of fuel and lubricating oil leaks

Surveillance Testing (IP Section 03.01) (4 Samples)

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

'B', on April 12, 2024

(2) STP-170.002, diesel-driven fire service pump test, on April 21, 2024

(3) STP-606.001, emergency diesel generator fuel oil analysis, on May 14, 2024, during addition of fuel oil into underground tanks from tanker

(4) STP-125.008, 'A' emergency diesel generator 24-hour test, on May 13 and 14, 2024

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

(1) STP 220.007A, 'A' emergency feedwater system backup air supply check valve test, on June 18, 2024

71114.06 - Drill Evaluation

Required Emergency Preparedness Drill (1 Sample)

(1) The inspectors evaluated a drill involving seismic events, large break loss of coolant accident, and loss of containment on June 12,

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) IE01: Unit 1 (April 1, 2023, to March 31, 2024)

IE03: Unplanned Power Changes per 7000 Critical Hours Sample (IP Section 02.02) (1 Sample)

(1) IE03: Unit 1 (April 1, 2023, to March 31, 2024)

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

(1) IE04: Unit 1 (April 1, 2023, to March 31, 2024)

BI01: Reactor Coolant System (RCS) Specific Activity Sample (IP Section 02.10) (1 Sample)

(1) BI01: Unit 1 (April 1, 2023, to March 31, 2024)

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

(1) BI02: Unit 1 (April 1, 2023, to March 31, 2024)

71152A - Annual Follow-up Problem Identification and Resolution Annual Follow-up of Selected Issues (Section 03.03)

The inspectors reviewed the licensees implementation of its corrective action program related to the following issues:

(1) CR1248440, CR-21-01157, and CR-21-00672, repetitive chiller soft starter power supply failures resulting in inoperable chillers. Inspectors completed the review on May 16, 2024. Inspectors reviewed the licensee's failure evaluation and vendor laboratory report following failures of two Eaton power supplies in March and May of 2021 which resulted in a lockout of the 'A' safety-related chiller in both instances. The licensee utilized a vendor laboratory to provide a failure analysis which identified premature degradation of the power supplies while in storage and during the first several years in service. The degraded electrolytic capacitors caused a voltage drop which prevented the power supplies from outputting the required 10A current to the soft starters for a long enough time. The soft starters had been stored onsite from 2009-2017 and installed from 2017-2021. Following the 2021 failures, the licensee replaced the power supplies with ones that were received more recently (2012 and 2021) and established a 3-year replacement interval based on the recommendations from the failure analysis. A subsequent failure in January 2024 was within the 3-year replacement frequency and was corrected by replacing the power supply with one received in 2021. Inspectors reviewed the corrective actions, failure evaluations, and treatment of the system per the NRC's Maintenance Rule and determined that the repetitive failures, especially the January 2024 failure, were not within the licensee's ability to foresee and correct. Inspectors noted that the licensee continued to run the

'A' chiller with obsolete power supplies following the January 2024 failure because the increased plant risk to remove the 'A' chiller from service for upgrades was higher than the risk of a subsequent failure and emergent upgrade, given the ongoing replacement of the 'C' chiller during this period.

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 05000395/2024-001-00, Automatic Actuation of the B Emergency Diesel Generator (ADAMS Accession No. ML24108A143) Following the loss of offsite power to the 1DB emergency bus on February 19, 2024, and the subsequent automatic starting and loading of the B EDG, the licensee identified a loose fuse block holder. The fuse provided control power to the 1DB emergency bus undervoltage and degraded voltage relays. Upon the loss of control power, the relays actuated to isolate the bus by opening the normal incoming breaker. Inspectors reviewed fuse control procedures, testing and maintenance procedures which required pulling the fuse, and industry operating experience. The only means of detecting poor engagement of the clips is by manually removing and inserting the fuse holder plug while checking for looseness. Since the fuse was only pulled every 9 years, it is not reasonable that the licensee would have identified the loosening clips prior to the inservice failure. Since the component was not subject to high temperatures, mechanical stress, and repeated insertion and removal of fuses, which could indicate a need to be included in a preventive maintenance program per NUREG-1760, Aging Assessment of Safety-Related Fuses used in Low-and Medium-Voltage Applications in Nuclear Power Plants, and since there were no historical onsite failures of this type in similar applications, inspectors determined that the cause of the condition described in the LER was not reasonably within the licensee's ability to foresee and correct, and therefore was not reasonably preventable. No performance deficiency nor violation of NRC requirements was identified. This LER is Closed.

INSPECTION RESULTS

No findings were identified.

EXIT MEETINGS AND DEBRIEFS

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

• On July 18, 2024, the inspectors presented the integrated inspection results to Mr. Will Kearney and other members of the licensee staff.

THIRD PARTY REVIEWS

Inspectors reviewed Institute on Nuclear Power Operations reports that were issued during the previous year.

DOCUMENTS REVIEWED

Inspection Type Designation Description or Title Revision or

Procedure Date

71153 Corrective Action CR1251189, CR-

Documents 18-03111, CR-15-

05393, CR13-

03600, CR-13-

03426

Miscellaneous General Electric Instructions for inspection of fuse holders, contact grease of 1978

Service Advisory proper fuse holder engagement, and potential corrections as

Letter 322.1 required

Procedures EMP-405.018 7.2KV Switchgear Preventative Maintenance 5A

STP-506.004 7.2KV Emergency Bus Undervoltage Unit Calibration 11D

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