ML25223A117
| ML25223A117 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 08/11/2025 |
| From: | Matt Young Division of Operating Reactors |
| To: | Rhoades D Constellation Energy Generation, Constellation Nuclear |
| References | |
| IR 2025002 | |
| Download: ML25223A117 (1) | |
Text
August 11, 2025 David P. Rhoades Senior Vice President Constellation Energy Generation, LLC President and Chief Nuclear Officer (CNO)
Constellation Nuclear 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
CALVERT CLIFFS NUCLEAR POWER PLANT, UNITS 1 AND 2 -
INTEGRATED INSPECTION REPORT 05000317/2025002 AND 05000318/2025002
Dear David Rhoades:
On June 30, 2025, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Calvert Cliffs Nuclear Power Plant, Units 1 and 2. On July 21, 2025, the NRC inspectors discussed the results of this inspection with Christopher Smith, Plant Manager, 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 (10 CFR) 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely, Matt R. Young, Chief Projects Branch 2 Division of Operating Reactor Safety Docket Nos. 05000317 and 05000318 License Nos. DPR-53 and DPR-69
Enclosure:
As stated cc w/ encl: Distribution via LISTSERV MATTHEW YOUNG Digitally signed by MATTHEW YOUNG Date: 2025.08.11 11:42:18 -04'00'
ML25223A117 SUNSI Review Non-Sensitive Sensitive Publicly Available Non-Publicly Available OFFICE RI/DORS RI/DORS NAME GDipaolo MYoung DATE 8/11/2025 8/11/2025
Enclosure U.S. NUCLEAR REGULATORY COMMISSION Inspection Report Docket Numbers:
05000317 and 05000318 License Numbers:
DPR-53 and DPR-69 Report Numbers:
05000317/2025002 and 05000318/2025002 Enterprise Identifier: I-2025-002-0035 Licensee:
Constellation Energy Generation, LLC Facility:
Calvert Cliffs Nuclear Power Plant, Units 1 and 2 Location:
Lusby, MD Inspection Dates:
April 01, 2025 to June 30, 2025 Inspectors:
G. Dipaolo, Senior Resident Inspector A. Tran, Resident Inspector R. Clagg, Senior Project Engineer J. Cunningham, Reactor Inspector Approved By:
Matt R. Young, Chief Projects Branch 2 Division of Operating Reactor Safety
2
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Calvert Cliffs Nuclear Power Plant, Units 1 and 2, 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.
3 PLANT STATUS Unit 1 began the inspection period at rated thermal power and operated at or near full power until May 18, 2025, when operators shut down the unit for a planned maintenance outage to repair main generator hydrogen-to-stator liquid water system leakage. Following repairs, operators commenced a unit startup on May 29, 2025, and returned the unit to 100 percent power on May 31, 2025. Operators commenced a unit down power to less than 5 percent power on June 2, 2025, as directed by abnormal operating procedure (AOP) for abnormal chemistry conditions in the steam generators. Following restoration of steam generator chemistry parameters and the completion of evaluations, operators commenced power ascension from approximately 2 percent power on June 3, 2025, and returned the unit to 100 percent power on June 4, 2025. The unit remained at or near rated thermal power for the remainder of the inspection period.
Unit 2 began the inspection period at rated thermal power and operated at or near full power for the remainder of the inspection period.
INSPECTION SCOPES Inspections were conducted using the appropriate portions of the inspection procedures (IPs) in effect at the beginning of the inspection unless otherwise noted. Currently approved IPs with their attached revision histories are located on the public website at http://www.nrc.gov/reading-rm/doc-collections/insp-manual/inspection-procedure/index.html. Samples were declared complete when the IP requirements most appropriate to the inspection activity were met consistent with Inspection Manual Chapter (IMC) 2515, Light-Water Reactor Inspection Program - Operations Phase. The inspectors performed activities described in IMC 2515, Appendix D, Plant Status, observed risk significant activities, and completed on-site portions of IPs. The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel to assess licensee performance and compliance with Commission rules and regulations, license conditions, site procedures, and standards.
REACTOR SAFETY 71111.01 - 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 high temperature for the Units 1 and 2 emergency diesel generators (EDG) and the steam driven auxiliary feedwater pumps on June 17, 2025.
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)
Unit 1, auxiliary feedwater from steam and motor driven pumps to the steam generator block valves, May 16, 2025
4 (2)
Unit 1, shutdown cooling during Mode 5, low pressure safety injection pumps, shutdown cooling heat exchangers, and electrical supply breakers, May 20, 2025 (3)
Unit 1, 11, 12, and 13 coolant charging pumps following 13 coolant charging pump return-to-service following maintenance, June 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)
Unit 1, service water pump room, fire area 39, April 24, 2025 (2)
Units 1 and 2, charging pump rooms, fire areas 5, 6, 7, 8, 9, and 10, April 24, 2025 (3)
Units 1 and 2, west penetration rooms and horizontal cable chases, fire areas 35, 36, 37, and 38, May 7, 2025 (4)
Unit 1, switchgear rooms and purge air room, fire areas 19, 19A, and 34, May 12, 2025 (5)
Units 1 and 2, cable chases and control room complex, fire areas 20, 21, 22, 23, and 24, June 11, 2025 71111.07A - Heat Exchanger/Sink Performance Annual Review (IP Section 03.01) (1 Sample)
The inspectors evaluated readiness and performance of:
(1)
Unit 1, 12 component cooling water heat exchanger, May 8, 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 main control room during Unit 1 shutdown for the maintenance outage on May 18, 2025.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (2 Samples)
(1)
The inspectors observed and evaluated a licensed operator simulator training scenario involving a reactor coolant system overcooling transient, a rapid unit down power due to an electrical grid issue, a steam generator tube rupture event, and a faulted steam generator event resulting in the declaration of a Site Area Emergency on April 29, 2025.
(2)
The inspectors observed and evaluated a licensed operator training and simulator scenario involving an extended loss of alternating current (AC) power resulting in the declaration of a Site Area Emergency on June 11, 2025.
5 71111.12 - Maintenance Effectiveness Maintenance Effectiveness (IP Section 03.01) (1 Sample 1 Partial)
The inspectors evaluated the effectiveness of maintenance to ensure the following structures, systems, and components remain capable of performing their intended function:
(1)
Unit 2, auxiliary feedwater actuation system steam generator level transmitter calibration adverse as-found conditions, May 7, 2025 (2)
(Partial)
Units 1 and 2, maintenance effectiveness review of infrequently operated equipment necessary to support safe shutdown due to a fire in the control room and cable spreading room, June 15, 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)
Units 1 and 2, elevated risk condition and fire risk management actions due to 1B EDG planned maintenance, April 17, 2025 (2)
Unit 1, Technical Requirements Manual 15.0.3 evaluation and compensatory measures due to data acquisition room fire detection and halon suppression system being out-of-service greater than 30 days, May 2, 2025 (3)
Unit 1, Technical Evaluation, ECP-25-000198, following Chemistry Action Level 3 event from elevated chloride levels in steam generators, June 5, 2025 (4)
Unit 2, Action Request (AR) 4867136, temporary power cable not removed from 480-volt load centers in 27' and 45' switchgear rooms post refueling outage, June 13, 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)
Units 1 and 2, AR 4851050, control room envelope operability determination following discovery of boundary degradation in Unit 1 data acquisition room, April 4, 2025 (2)
Unit 2, AR 4857314, 22A safety injection tank check valve leakage control valve, 2-SI-648-CV, failed to fully shut following surveillance testing, April 16, 2025 (3)
Unit 1, AR 4869158, control element assembly motion inhibit bypass alarm received during startup, May 20, 2025 (4)
Unit 2, AR 4866808, boric acid deposits on 12B safety injection header check valve, SI-148-CV, due to swing arm packing leak, June 9, 2025
6 71111.20 - Refueling and Other Outage Activities Refueling/Other Outage Sample (IP Section 03.01) (1 Sample)
(1)
The inspectors evaluated Unit 1 maintenance outage, CC1M2501, from May 19, 2025 to May 30, 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) (6 Samples)
(1)
Unit 2, Work Order (WO) C93945308, 12B safety injection header check valve, 2-SI-148-CV, post-maintenance testing following overhaul and packing adjustment, April 1, 2025 (2)
Units 1 and 2, WO C93974716, diverse and flexible coping strategies (FLEX) auxiliary feedwater pump, 0AFWPUMPBDB0, post-maintenance testing following repairs due to failing to start, April 18, 2025 (3)
Unit 1, WO C93934876, 1B EDG post-maintenance testing following maintenance overhaul, April 21, 2025 (4)
Units 1 and 2, WO C94015266, FLEX 500-kilowatt generator set, 2GEN500DWBDB1, post-maintenance testing following repairs due to failed engine coolant hose, April 29, 2025 (5)
Unit 1, WOs C93976809 and C93970173, reactor protection system Tcold resistance temperature detectors, 1TE112CB and 1TE122CC, post-maintenance testing following repairs due to erratic indications, May 28, 2025 (6)
Unit 1, WO C94020055, 12B safety injection header check valve, 1-SI-148-CV, post-maintenance testing following packing replacement and weighted swing arm replacement, June 20, 2025 Surveillance Testing (IP Section 03.01) (2 Samples)
(1)
Unit 2, STP-O-8A-2, "2A Emergency Diesel Generator and 4kV Bus 21 UV," Revision 038, April 24, 2025 (2)
Unit 1, STP-O-0731B-1, "B-Train High Pressure Safety Injection Pump and Check Valve Operability Test," Revision 1, May 7, 2025 Inservice Testing (IST) (IP Section 03.01) (1 Sample)
(1)
Unit 2, STP-O-5A22-2, "22 Auxiliary Feedwater Pump Quarterly Surveillance Test,"
Revision 11, May 6, 2025 Diverse and Flexible Coping Strategies (FLEX) Testing (IP Section 03.02) (1 Sample)
(1)
Units 1 and 2, WO C93963472, semi-annual maintenance and testing of FLEX equipment, April 28, 2025
7 71114.06 - Drill Evaluation Required Emergency Preparedness Drill (1 Sample)
(1)
The inspectors observed and evaluated the conduct of an emergency preparedness drill in the main control room simulator and technical support center involving failures that resulted in the declaration of a General Emergency on May 13, 2025.
OTHER ACTIVITIES - BASELINE 71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:
MS05: Safety System Functional Failures (SSFFs) Sample (IP Section 02.04) (2 Samples)
(1)
Unit 1, April 1, 2024 through March 31, 2025 (2)
Unit 2, April 1, 2024 through March 31, 2025 MS06: Emergency AC Power Systems (IP Section 02.05) (2 Samples)
(1)
Unit 1, April 1, 2024 through March 31, 2025 (2)
Unit 2, April 1, 2024 through March 31, 2025 MS08: Heat Removal Systems (IP Section 02.07) (2 Samples)
(1)
Unit 1, April 1, 2024 through March 31, 2025 (2)
Unit 2, April 1, 2024 through March 31, 2025 71152A - Annual Follow-up Problem Identification and Resolution Annual Follow-up of Selected Issues (Section 03.03) (1 Partial)
The inspectors reviewed the licensees implementation of its corrective action program related to the following issues:
(1)
(Partial)
ARs 4801524 and 4842240 associated with deficiencies in testing fire safe shutdown equipment, June 27, 2025 71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02) (1 Sample)
(1)
The inspectors reviewed the licensees corrective action program for potential trends that may be indicative of a more significant safety issue.
8 71153 - Follow Up of Events and Notices of Enforcement Discretion Event Follow up (IP Section 03.01) (1 Sample)
(1)
The inspectors reviewed and evaluated AR 4870317, Unit 1 entered AOP-10, "Abnormal Secondary Chemistry Conditions," due to meeting Action Level 3 steam generator conditions on June 2, 2025.
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 21, 2025, the inspectors presented the integrated inspection results to Christopher Smith, Plant Manager, and other members of the licensee staff.
THIRD PARTY REVIEWS Inspectors reviewed the World Association of Nuclear Operators report that was issued for an evaluation that was completed in November 2024.
9 DOCUMENTS REVIEWED Inspection Procedure Type Designation Description or Title Revision or Date 71111.01 Miscellaneous Calvert Cliffs Site Certification Letter for Summer Readiness 06/2025 71111.04 Corrective Action Documents AR 4872896 Through Wall Leak on 13 Charging Pump Suction Welded Connection 06/13/2025 Drawings Drawing Number 60730, Sheet 2 Chemical and Volume Control System 79 Procedures OI-2A Chemical and Volume Control System 06601 71111.07A Corrective Action Documents AR 4854745 Rust Indications and Blisters in 12 Component Cooling Water Exchanger 04/08/2025 Procedures ER-AA-340 GL 89-13 Program Implementing Procedure 11 FTI-14B-1 Single Tube Thermal Performance Testing for 12 Component Cooling Heat Exchanger 0000 71111.13 Corrective Action Documents Resulting from Inspection AR 4867136 NRC ID: Temporary Power Cable Not Removed Post 2025 Unit 2 Refueling Outage 71111.15 Corrective Action Documents AR 4847456 22A Safety Injection Tank Safety Injection Check Valve Leakage Control Valve, 2-SI-648-CV, Failed to Open Drawings 62731SH0002 Safety Injection and Containment Spray Systems 50 Miscellaneous IST-CCNP-BDOC-V-015 Calvert Cliffs - Inservice Testing Valve Basis Document 08/15/2022 71111.24 Corrective Action Documents AR 4854502 FLEX Auxiliary Feedwater Pump 0AFWPUMPBDB0 Failed to Start 04/08/2025 AR 4854664 FLEX Fuel Tanker Truck #2 Brake Malfunction 04/08/2025 AR 4855029 FLEX Batteries Trend 04/09/2025 AR 4855044 FLEX 500 KW Generator Set 2GEN500KWBDB1 Engine Coolant Hose Failure During Testing 04/09/2025 Procedures CC-AA-118 Diverse and Flexible Coping Strategies (FLEX), Spent Fuel Pool Instrumentation (SFPI), and Hardened Containment Cent System (HCVS) Program Document 10 CC-CA-118 Calvert Cliffs Implementation of Diverse and Flexible Coping Strategies (FLEX) and Spent Fuel Pool Instrumentation Program 8
10 Inspection Procedure Type Designation Description or Title Revision or Date 71151 Corrective Action Documents Resulting from Inspection AR 4876541 NRC ID: Incorrect method used for MSPI EAC Run Hours 06/26/2024