IR 05000413/2025001
| ML25128A338 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 05/09/2025 |
| From: | Robert Williams NRC/RGN-II/DORS/PB1 |
| To: | Flippin N Duke Energy Carolinas |
| References | |
| IR 2025001 | |
| Download: ML25128A338 (1) | |
Text
SUBJECT:
CATAWBA NUCLEAR STATION - INTEGRATED INSPECTION REPORT 05000413/2025001, 05000414/2025001 AND 07200045/2025001
Dear Nicole Flippin:
On March 31, 2025, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Catawba Nuclear Station. On May 1, 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.
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, Robert E. Williams, Jr., Chief Projects Branch 1 Division of Operating Reactor Safety Docket Nos. 05000413, 05000414 and 07200045 License Nos. NPF-35 and NPF-52
Enclosure:
As stated
Inspection Report
Docket Numbers:
05000413, 05000414 and 07200045
License Numbers:
Report Numbers:
05000413/2025001, 05000414/2025001 AND 07200045/2025001
Enterprise Identifier:
I-2025-001-0023 and I-2025-002-0068
Licensee:
Duke Energy Carolinas, LLC
Facility:
Catawba Nuclear Station
Location:
York, South Carolina
Inspection Dates:
January 01, 2025, to March 31, 2025
Inspectors:
D. Rivard, Senior Resident Inspector
A. Wang, Resident Inspector
D. Neal, Health Physicist
A. Ponko, Senior Construction Project Inspector
J. Vasquez, Construction Project Inspector
Approved By:
Robert E. Williams, Jr., Chief
Projects Branch 1
Division of Operating Reactor Safety
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Catawba 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
No findings or violations of more than minor significance were identified.
Additional Tracking Items
None.
PLANT STATUS
Unit 1 began the inspection period operating at or near 100 percent rated thermal power (RTP).
On January 28, 2025, Unit 1 was shut down due to an unidentified reactor coolant system leak greater than licensed limits. Unit 1 was restarted on January 31, 2025, and reached RTP on February 1, 2025. Unit 1 remained at or near RTP for the remainder of the inspection period.
Unit 2 operated at or near 100 percent RTP 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.
REACTOR SAFETY
71111.01 - Adverse Weather Protection
Impending Severe Weather Sample (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated the adequacy of the overall preparations to protect risk-significant systems from impending extreme cold temperatures from January 16 to 24, 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)2A emergency diesel generator (EDG) during 2B EDG maintenance window on January 14, 2025 (2)1A and 1B motor driven auxiliary feedwater pumps on February 10, 2025 (3)
"B" train EDG service water alignment while the "A" train EDGs were declared inoperable for service water pit diving inspections on February 12, 2025 (4)
"B" train of control room ventilation alignment while the "A" train was declared inoperable for maintenance on March 12, 2025
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (6 Samples)
The inspectors evaluated the implementation of the fire protection program by conducting a walkdown and performing a review to verify program compliance, equipment functionality, material condition, and operational readiness of the following fire areas:
- (1) Fire Area 27 and 43: 2A EDG and associated sequencer hallway on January 14, 2025
- (2) Fire Area 3: Unit 1 auxiliary feedwater (CA) pump room, room 250, 1A motor driven pump pit, room 255, and 1B motor driven pump pit, room 256, on February 10 and 11, 2025
- (3) Fire Area 29 and 30: nuclear service water pump structure, building 778, on February 24, 2025
- (4) Fire Area 39: Unit 2 turbine driven auxiliary feedpump pit, room 264, on February 26, 2025
- (5) Fire Area 26 and 42: 1B EDG and associated sequencer hallway on March 5, 2025
- (6) Fire Area 4: 1A/1B safety injection pump rooms and general area on March 31, 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 unannounced fire drill in the Unit 1 main turbine lube oil tank room on March 11, 2025.
71111.07A - Heat Exchanger/Sink Performance
Annual Review (IP Section 03.01) (1 Sample)
The inspectors evaluated readiness and performance of:
- (1) PT/2/A/4400/006A, "NS Heat Exchanger 2A Heat Capacity Test," for 2A containment spray heat exchanger performed on January 9, 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) (2 Samples)
- (1) The inspectors observed entry to AP 1/A/5500/009, "Rapid Downpower," for Unit 1 to enter Mode 3 due to unidentified reactor coolant leakage greater than technical specification limits, on January 28, 2025.
- (2) The inspectors observed and evaluated licensed operator performance in the control room during reactor startup from a forced outage, on January 31, 2025.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed and evaluated licensed operator annual requalification exams conducted in the plant reference simulator, on February 5, 2025.
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) Buried exterior fire protection (RY) components following an underground RY leak on February 17, 2025 (nuclear condition report [NCR] 02544292)
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) Unit 2 elevated risk due to 2B EDG maintenance window during the week of January 13, 2025
- (2) Elevated risk due to A train VC/YC (control room area ventilation/control area chilled water) system maintenance, on February 3, 2025
- (3) Licensee evaluated the risk associated with NCR 02542746 2A, generator breaker air actuating system leak, and deferred the maintenance on 1A EDG, on February 3, 2025
- (4) Maintenance risk evaluation for Unit 1 and Unit 2 turbine driven auxiliary feedwater pumps - steam supply isolation, during safe shutdown facility outage work window on February 11, 2025
- (5) Elevated risk due to 1B EDG extended maintenance window and extraction steam line leak extending into A train work, the week of March 3, 2025
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) NCR 02539809 and work request (WR) 20281292, Unit 1 leading edge flow meter non-functional
- (2) NCR 02539612, 1CA-188, 1D main feed tempering flow to auxiliary feed nozzle isolation, failed surveillance stroke time test
- (3) Operability of intermediate range nuclear instruments prior to Mode 2 entry and reactor startup on January 31, 2025
- (4) NCR 02473418, oil leak at LD-17, 1A EDG lube oil strainer 1A1 check valve
- (5) NCR 02545452, 2SV-19 2A steam generator power operated relief valve
- (6) NCR 02546105, 1B emergency diesel generator, cylinder 5R air start valve failed operability test
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:
71111.24 - Testing and Maintenance of Equipment Important to Risk
The inspectors evaluated the following testing and maintenance activities to verify system operability and/or functionality:
Post-Maintenance Testing (PMT) (IP Section 03.01) (6 Samples)
- (1) PT/1/A/4350/002A, "Diesel Generator 1A Operability Test," following completion of 1A EDG maintenance window, on February 11, 2025
- (2) PT/0/A/4200/017A, "Standby Shutdown Facility (SSF) Diesel Test," following completion of SSF diesel maintenance window, on February 14, 2025
- (3) PT/2/A/4200/069, "Nitrogen Leakage Test" for valve 2SV-19 (2S steam generator power operated relief valve) following gauge leak repair, on February 27, 2025
- (4) WO 20695515, relay 'R3' and WO 20695744, relay 'R6' post maintenance test for EDG control system relay replacements, on February 28, 2025
- (5) WO 20681579, 1B EDG relay fuel assembly (FA)2 replacement
- (6) WO 20715669, 1KD-21 diesel engine cooling water system check valve repair
Surveillance Testing (IP Section 03.01) (4 Samples)
- (1) PT/2/A/4200/001F, "Lower Containment Personnel Air Lock Leak Rate Test," on February 16, 2025
- (2) PT/1/A/4200/010A, "Residual Heat Removal Pump 1A Performance Test," performed under WO 20705229, on March 6, 2025
- (3) PT/1/A/4350/015B, "Diesel Generator 1B Periodic Test," for the conduct of 18-month periodic surveillances, on March 29, 2025
- (4) PT/1/A/4200/005A, "Safety Injection Pump 1A Performance Test," on March 31, 2025
Inservice Testing (IST) (IP Section 03.01) (2 Samples)
- (1) PT/1/A/4200/007A, "Centrifugal Charging Pump 1A Test," on March 12 through 13, 2025
- (2) WO 20687801 and PT/0/A/4200/013, "RN (nuclear service water) Shared Valves Inservice Test (QU)," for testing valve 1RN-04B
OTHER ACTIVITIES - BASELINE
===71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:
IE04: Unplanned Scrams with Complications (USwC) Sample (IP Section 02.03)===
- (1) Unit 1 (January 1 through December 31, 2024)
- (2) Unit 2 (January 1 through December 31, 2024)
MS10: Cooling Water Support Systems (IP Section 02.09) (2 Samples)
- (1) Unit 1 (January 1 through December 31, 2024)
- (2) Unit 2 (January 1 through December 31, 2024)
BI02: RCS Leak Rate Sample (IP Section 02.11) (2 Samples)
- (1) Unit 1 (January 1 through December 31, 2024)
- (2) Unit 2 (January 1 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) NCR 02477709, Valcor valves end of service life replacements
71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02)
- (1) The inspectors reviewed the licensees corrective action program to identify potential trends with the EDG control system timer end of service life replacements that might be indicative of a more significant safety issue.
71153 - Follow Up of Events and Notices of Enforcement Discretion Event Follow up (IP Section 03.01)
- (1) The inspectors evaluated a Unit 1 rapid plant shutdown due to unidentified reactor coolant system leakage in excess of technical specification limits and licensee's response to identify and correct the leakage on January 28,
OTHER ACTIVITIES
- TEMPORARY INSTRUCTIONS, INFREQUENT AND ABNORMAL
===60853 - Onsite Fabrication of Components and Construction of an Independent Spent Fuel Storage Installation 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) 2690, Inspection Program for Storage of Spent Reactor Fuel and Reactor-Related Greater-than-Class C Waste at Independent Spent Fuel Storage Installations (ISFSI) and for 10 CFR Part 71 Transportation Packagings." 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.
Onsite Fabrication of Components and Construction of an Independent Spent Fuel Storage Installation===
- (1) On January 29, 2025 to April 2, 2025, the inspectors conducted a review of licensee and vendor activities in preparation for the construction of a concrete storage pad.
The inspectors verified that activities related to the ISFSI have been properly incorporated into the existing licensee programs by reviewing the following activities:
1. ISFSI pad design: The inspectors verified that the licensee completed
evaluations which established that the ISFSI storage pads and areas have been designed to adequately support the static and dynamic loads of the stored dry storage systems (DSS), considering potential amplification of earthquakes through soil-structure interaction, and soil liquefaction potential or other soil instability due to vibratory ground motion.
2. ISFSI pad construction: The inspectors verified the ISFSI storage pad was
constructed in accordance with the DSS Certificate of Compliance (CoC) and reviewed licensee controls that ensured no adverse impact on site operations or technical specifications, by performing the following activities:
a.
The inspectors walked down the construction area of the ISFSI pad to verify the formwork and rebar placement complied with licensee-approved drawings and specifications.
b.
The inspectors observed the placement of the ISFSI slab, and observed tests for concrete slump, air content, temperature measurements, and the collection/preparation of cylinder samples for compression tests, to verify that the work was implemented in accordance with the approved specifications and procedures.
c.
The inspectors verified that the pad was being finished according to approved specifications and code requirements.
d.
Following completion of the 7-day and 28-day compression tests by the independent laboratory, the inspectors reviewed the results to verify that the acceptance criteria were met.
INSPECTION RESULTS
Observation: Valcor Solenoid Valve End of Service Life Replacement 71152A The inspectors reviewed the licensees corrective action program to evaluate the progress of end of service life replacements associated with Valcor solenoid valves, which has been outstanding since 2019. The inspectors noted that the licensee had addressed the initial aging concerns through performing replacements on valve o-rings, which were identified to be the most susceptible component to aging. However, a subsequent evaluation in 2023, while implementing corrective actions, determined that the overall valve assemblies had an associated service life and would also require replacements. In 2024, work associated with a number of solenoid valves associated with the main steam isolation valve bypasses, at the end of their qualified service life, was deferred on the justification of lacking qualified replacements. The inspectors noted that impacted valves did not have any safety functions that would be challenged prior to the current projected dates for replacement during the next outage, since the valves were normally shut during operations and only opened during plant startup operations. The inspectors plan to continue to monitor the progress of the licensees corrective action program in facilitating end of service life valve replacements.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified that no proprietary information was retained or documented in this report.
- On March 26, 2025, the inspectors presented the ISFSI construction inspection results to Nicole Flippin and other members of the licensee staff.
- On May 1, 2025, the inspectors presented the integrated inspection results to Nicole Flippin and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
60853
Drawings
ISFSI Pad Plans
60853
Drawings
No. 50060.002
Rebar Shop Drawings
60853
Engineering
Evaluations
CNC -1140.04-00-
0006
Tip-Over Analysis for MAGNASTOR Cask System at
Catawba Nuclear Power Station
60853
Miscellaneous
CNS-1109.00-00-
0007
Concrete Procurement Specification
60853
Miscellaneous
CNS-1109.00-00-
0008
Concrete Receiving and Placing Specification
60853
Miscellaneous
Compressive
Strength of
Concrete
Seven and twenty-eight day concrete compressive strength
test results
Procedures
MP/0/A/7450/086A
Control Room Ventilation (VC) Ductwork and AHU Access
Procedures
AP/1/A/5500/009
Rapid Downpower
Procedures
PT/0/A/4150/019
1/M
Approach to Criticality
041
Drawings
CN-15991.0
Miscellaneous
NEI 09-14 Guideline for the Management of Underground
Piping and Tank Integrity
Work Orders
20493321
Procedures
AD-OP-ALL-0102
Operational Decision Making
Procedures
AD-OP-ALL-1000
Conduct of Operations
26
Procedures
AD-WC-ALL-0410
Work Activity Integrated Risk Management
016
Procedures
PT/1/A/4600/019
B
Premode 2 Periodic Items
055
Work Orders
WRs 20275538, 20275532
Corrective Action
Documents
PIP C-12-1063
Procedures
IP/2/A/3680/008B
DG-2A EQC System Time Delay and Undervoltage Relays
Calibration