IR 05000400/2025001

Integrated Inspection Report 05000400/2025001

ML25107A024
Person / Time
Site:	Harris
Issue date:	04/28/2025
From:	Matthew Fannon Division of Operating Reactors
To:	Haaf T Duke Energy Progress
References
IR 2025001
Download: ML25107A024 (13)

Text

SUBJECT:

SHEARON HARRIS NUCLEAR PLANT - INTEGRATED INSPECTION REPORT 05000400/2025001

Dear Thomas Haaf:

On March 31, 2025, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Shearon Harris Nuclear Plant. On April 16, 2025, the NRC inspectors discussed the results of this inspection with you and other members of your staff. The results of this inspection are documented in the enclosed report.

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.

If you contest the violation or the significance or severity of the violation 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 Shearon Harris Nuclear Plant.

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

April 28, 2025 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, Matthew S. Fannon, Chief Projects Branch 2 Division of Operating Reactor Safety Docket No. 05000400 License No. NPF-63

Enclosure:

As stated

Inspection Report

Docket Number:

05000400

License Number:

NPF-63

Report Number:

05000400/2025001

Enterprise Identifier:

I-2025-001-0021

Licensee:

Duke Energy Progress, LLC

Facility:

Shearon Harris Nuclear Plant

Location:

New Hill, North Carolina

Inspection Dates:

January 01, 2025, to March 31, 2025

Inspectors:

P. Boguszewski, Senior Resident Inspector

M. Kay, Resident Inspector

A. Rosebrook, Senior Reactor Analyst

A. Ruh, Senior Reactor Inspector

Approved By:

Matthew S. Fannon, Chief

Projects Branch 2

Division of Operating Reactor Safety

SUMMARY

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

List of Findings and Violations

'A' Containment Spray Pump Inoperability Due to Untimely Corrective Actions Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000400/2025001-01 Open/Closed

[P.2] -

Evaluation 71152A A self-revealed Green finding and associated non-cited violation (NCV) of Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix B, Criterion XVI, Corrective Action, was identified for the licensees failure to identify and correct a condition adverse to quality (CAQ).

Specifically, the licensee failed to recognize and correct a CAQ associated with the A containment spray (CS) pump breaker, resulting in the disconnection of an electrical spade connector associated with the A CS pump breaker rendering the pump inoperable.

Additional Tracking Items

None.

PLANT STATUS

Unit 1 operated at or near rated thermal power for the entire 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.

71111.01 - Adverse Weather Protection

Seasonal Extreme Weather Sample (IP Section 03.01) (1 Sample)

(1) The inspectors evaluated readiness for seasonal extreme weather conditions prior to the onset of seasonal cold temperatures on January 8, 2025, for the following systems:

• Emergency diesel generators

• Diverse and flexible coping strategies (FLEX) equipment

• Turbine building equipment

Impending Severe Weather Sample (IP Section 03.02) (1 Sample)

(1) The inspectors evaluated the adequacy of the overall preparations to protect risk-significant systems from impending severe weather including snow and ice on February 19, 2025.

71111.04 - Equipment Alignment

Partial Walkdown Sample (IP Section 03.01) (4 Samples)

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

(1)

'B' essential services chilled water during planned 'A' essential services chilled water maintenance on January 16, 2025 (2)

'B' control room emergency filtration system during 'A' control room emergency filtration system maintenance on February 12, 2025 (3)

'B' residual heat removal system during 'A' residual heat removal system maintenance on February 13, 2025 (4)

'A' essential services chilled water during planned 'B' essential services chilled water maintenance on February 27, 2025

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) Fuel handling building 261' elevation on January 30, 2025

(2) Reactor auxiliary building 305' elevation on January 30, 2025

(3) Diesel fuel oil storage building on March 4, 2025 (4)

'B' switchgear, battery room, cable vault, and auxiliary control panel on March 4, 2025

(5) Emergency diesel generator building on March 6, 2025

Fire Brigade Drill Performance Sample (IP Section 03.02) (1 Sample)

(1) The inspectors evaluated the onsite fire brigade training and performance during an announced fire drill on the turbine building 286' elevation on February 5, 2025.

71111.06 - Flood Protection Measures

Flooding Sample (IP Section 03.01) (1 Sample)

(1) The inspectors evaluated internal flooding mitigation protections in the reactor auxiliary building on February 17, 2025.

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 turbine driven auxiliary feedwater testing on March 3, 2025.

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

(1) The inspectors observed and evaluated a simulator training scenario involving a large break loss of coolant accident on March 11, 2025.

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) Moveable incore detector system reliability [nuclear condition report (NCR) 2537140]

on February 25, 2025 (2)

'B' emergency sequencer system relay exceeded time tolerance (NCR 02545589) on March 18, 2025

71111.13 - Maintenance Risk Assessments and Emergent Work Control

Risk Assessment and Management Sample (IP Section 03.01) (4 Samples)

The inspectors evaluated the accuracy and completeness of risk assessments for the following planned and emergent work activities to ensure configuration changes and appropriate work controls were addressed:

(1) Elevated risk due to 'A' containment spray pump failure to start on January 14, 2025

(2) Elevated risk due to a planned dedicated shutdown diesel generator outage on February 12, 2025

(3) Elevated risk due to emergent 'B' emergency sequencer relay failures on February 25, 2025

(4) Elevated risk due to emergent 'B' essential services chilled water maintenance on February 28, 2025

71111.15 - Operability Determinations and Functionality Assessments

Operability Determination or Functionality Assessment (IP Section 03.01) (4 Samples)

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

(1) Auxiliary control panel indication failed to illuminate on March 12, 2025 (NCR

===2545831)

(2) Emergency sequencer system load sequencing calculation error on March 24, 2025 (NCR 2546300)

(3) Safety injection pipe temperature exceeding criterion for thermal stratification on March 25, 2025 (NCR 02546819)

(4) Incorrect safety class boundary identified on safety injection system on March 26, 2025 (NCR 02542335)

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) Engineering change 425122 and work order 20702819, temporary air compressor installation on January 29, 2025

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)===

(1)

'A' containment spray pump after maintenance on January 15, 2025 (2)

'B' emergency sequencer after maintenance on February 25, 2025 (3)

'B' essential services chilled water circulation pump breaker after maintenance on February 27, 2025 (4)

'B' essential services chilled water after maintenance on March 7, 2025

(5) OST-1038, "Sampling, Chemical Addition, and Main Steam Drain Systems ISI Valve Quarterly," to test 1SP-227, 'C' steam generator to sampling panel containment isolation valve, on March 20, 2025

(6) OST-1040, "Essential Services Chilled Water Operability Quarterly," test after 1CH-115, chilled water to nonessential services chilled water fan coolers isolation valve, solenoid replacement on March 20, 2025

Surveillance Testing (IP Section 03.01) (3 Samples)

(1) OST-1118, "Containment Spray Operability Train A Quarterly," on January 31, 2025

(2) OST-1215, "Emergency Service Water System Operability Train B Quarterly," on February 4, 2025

(3) OST-1231, "Control Room Emergency Filtration System Operability 18 Month Interval," on February 7, 2025

71114.06 - Drill Evaluation

Additional Drill and/or Training Evolution (2 Samples)

The inspectors evaluated:

(1) Operations shift 'A' simulator training involving a loss of the reactor coolant system fission product barrier on March 11, 2025

(2) Operations shift 'B' simulator training involving a loss of the reactor coolant system fission product barrier on March 18,

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) January 1, 2024, through December 31, 2024 IE03: Unplanned Power Changes per 7000 Critical Hours Sample (IP Section 02.02) (1 Sample)

(1) January 1, 2024, through December 31, 2024

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

(1) January 1, 2024, through December 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)6.9 kV emergency bus 1A-SA undervoltage backup relays out of calibration (NCR 2515576) on January 29, 2025 (2)

'C' cold leg accumulator relief valve 1SI-227 potential over pressurization at pancake flange (NCR 02525809) on February 8, 2025 (3)

'A' containment spray pump breaker spade connection found disconnected (NCR 02543095) on March 31,

INSPECTION RESULTS

'A' Containment Spray Pump Inoperability Due to Untimely Corrective Actions Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000400/2025001-01 Open/Closed

[P.2] -

Evaluation 71152A A self-revealed Green finding and associated non-cited violation (NCV) of Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix B, Criterion XVI, Corrective Action, was identified for the licensees failure to identify and correct a condition adverse to quality (CAQ). Specifically, the licensee failed to recognize and correct a CAQ associated with the A containment spray (CS) pump breaker, resulting in the disconnection of an electrical spade connector associated with the A CS pump breaker rendering the pump inoperable.

Description:

The safety-related CS system is designed to remove heat from the containment atmosphere following a loss of coolant accident or a secondary system rupture inside containment. The CS pumps are powered by 480 VAC Siemens Type RLN Load Center Breakers that will automatically close to start the CS pumps upon a CS actuation signal. The pumps can also be manually started from the main control room.

During routine surveillance testing on January 13, 2025, the A CS pump breaker failed to close, preventing the A CS pump from starting. Operations declared the A CS pump inoperable and commenced troubleshooting. Troubleshooting identified a loose spade connector from an auxiliary switch spade terminal. It was determined that the wiring bundles and spade connectors for the breaker were not tie wrapped to prevent movement and loosening of connections as required by licensee procedure PM-E0044, 480 VAC Siemens Type RLN Load Center Breaker and Cubicle Preventative Maintenance.

A similar condition was previously identified on March 29, 2021, when the B residual heat removal (RHR) breaker charging springs failed to charge due to a loose spade connection on the motor cutoff switch. The B RHR pump breaker is the same 480 VAC Siemens Type RLN Load Center Breaker as the A CS pump breaker. Following the B RHR pump breaker failure, the licensee issued revision 25 to procedure PM-E0044 on June 14, 2021, to add a detailed note and specific steps to ensure spade connections are tight and secured with tie wraps to the breaker frame in response to action request (AR) 02376252.

A second similar condition occurred on August 12, 2022, when the safety-related essential services chilled water (ESCW) pump breaker failed to operate. This occurred after vendor performance of procedure PM-E0044, Revision 25, during a planned overhaul of fifteen (15)480 VAC Siemens Type RLN Load Center circuit breakers (overhauls took place over a one-year period). The extent of condition performed as a result of this failed breaker was to inspect the two RLN breakers associated with the RHR pumps. Breaker inspections of the other RLN breakers overhauled by the vendor were not performed or scheduled at that time.

The licensee also issued revision 27 to PM-E0044 on June 7, 2023, including a prerequisite step for a brief with a supervisor to discuss the sites operating experience with loose spade connections. Despite revisions 25 and 27 following breaker failures, the licensee identified in their flex cause evaluation for the A CS pump breaker that the guidance in procedure PM-E0044 remained inadequate.

Since the failure of the A CS pump on January 13, 2025, the licensee has performed additional extent of condition inspections, prioritizing safety related 480 VAC Siemens Type RLN Load Center Breakers. The licensee has inspected seven circuit breakers and identified loose connections on three breakers and five inspections found the tie wrapping to be deficient. None of the loose connections identified caused a safety-related component to become inoperable.

Corrective Actions: The licensee entered the condition into their corrective action program, performed corrective actions to restore operability of the 'A' CS pump, and completed a causal evaluation.

Corrective Action References: NCR 02540559

Performance Assessment:

Performance Deficiency: The licensee failed to identify and correct a CAQ in accordance with 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Action. Specifically, the licensee failed to identify and correct a CAQ associated with the A CS pump breaker, resulting in the disconnection of electrical spade connectors associated with the A CS pump breaker rendering the pump inoperable.

Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Procedure Quality attribute of the Mitigating Systems cornerstone and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the maintenance procedure failed to provide clear guidance to ensure tight spade connections and wire bundles. This affected the availability and reliability of the 'A' CS pump.

Significance: Using IMC 0609, Appendix A, Exhibit 2, Mitigating System Screening Questions, the inspectors determined the finding required a detailed risk evaluation because the degraded condition represents a loss of the PRA function of one train of a multi-train technical specification (TS) system for greater than its TS allowed outage time.

A regional senior reactor analyst (SRA) performed a detailed risk evaluation using the guidance in IMC 0609 Appendix A, "The Significance Determination Process for Findings At-Power," IMC 0609 Appendix H, "Containment Integrity Significance Determination Process,"

and the Risk Assessment of Operational Events Handbook (RASP Manual) Volume 1 - Internal Events. In this case a population of 15 RLN 480V AC circuit breakers needed to be evaluated due to multiple wiring deficiencies. The SRA used SAPHRIE 8 Version 8.2.11 and the Harris SPAR model revision 8.83 dated September 21, 2023. The most risk significant loads were identified to be the RHR pump 1A-SA and RHR pump 1B-SB for core damage frequency (CDF) and the CS pump 1A-SA and CS pump 1B-SB for large early release frequency (LERF). The SRA performed a Bayesian update using industry reliability data for 480 VAC breakers failing to open/close as a prior and the as-found data from Harris during the extent of condition in two cases. Four connectors were found loose. For case 1 all four loose connectors were considered failures. This resulted in an increase in failure rate by a factor of 19. The second case considered that only one of the loose connections would have definitively prevented breaker operation thus only one failure was considered. This resulted in a factor of 6 increase. These multiplication factors were applied to the Failure to Start terms for both RHR pumps and used a 3-month exposure time to account for quarterly RHR system testing. The dominant accident sequence was a small break loss of coolant accident with a failure of both RHR pumps, and failure of high pressure and low pressure recirculation functions. This gives a range of low E-7 to mid E-8 for delta CDF. Thus, this can be bounded as a very low safety significance issue (Green) for CDF. In accordance with Table 4.1 of IMC 0609 Appendix H, CS is a contributor to late containment failure but is not a significant LERF contributor. This item also screens to Green for LERF.

Cross-Cutting Aspect: P.2 - Evaluation: The organization thoroughly evaluates issues to ensure that resolutions address causes and extent of conditions commensurate with their safety significance. Specifically, the licensee failed to perform an adequate extent of condition to include the A CS pump breaker after two failures on similar breakers occurred. This lack of extent of condition resulted in the missed identification of this condition adverse to quality on the A CS pump breaker.

Enforcement:

Violation: 10 CFR 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.

Contrary to the above, through January 13, 2025, the licensee did not establish measures to assure conditions adverse to quality were promptly identified and corrected on the A CS pump breaker. Specifically, the licensee failed to identify and correct a deficient spade connection and loose wire bundles on the 'A' CS pump breaker, which resulted in the system being declared inoperable.

Enforcement Action: This violation is being treated as a non-cited violation, 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 April 16, 2025, the inspectors presented the integrated inspection results to Thomas Haaf and other members of the licensee staff.

DOCUMENTS REVIEWED

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

71111.01

Procedures

AP-301

Seasonal Weather Preparations and Monitoring

Corrective Action

Documents

2515576

1364-14965

6.9 KV Emergency Bus 1A-SA Feed to Transf. Breaker

Schematic

CAR 2166-B-401

Sheet 1125

Shearon Harris Nuclear Power Plant Unit No. 1 Control

Wiring Diagram Emergency Load Sequencer ESS Cabinet

1A-SA

CAR 2166-B-401

Sheet 1729

Shearon Harris Nuclear Power Plant Unit No. 1 Control

Wiring Diagram 6.9 KV Emergency Bus 1A-SA Relays and

Instrumentation Potential

Drawings

CAR 2166-B-401

Sheet 1731

Shearon Harris Nuclear Power Plant Unit No. 1 Control

Wiring Diagram 6.9 KV Emergency Bus 1A-SA Undervoltage

Trip

71152A

Procedures

OST-1122

Train A 6.9 KV Emergency Bus Undervoltage Trip Actuating

Device Operational Test and Contact Check Modes 1-6

25