ML25206A041
| ML25206A041 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 07/25/2025 |
| From: | Nicole Warnek Division of Operating Reactors |
| To: | Rhoades D Constellation Energy Generation, Constellation Nuclear |
| References | |
| IR 2025002 | |
| Download: ML25206A041 (1) | |
Text
July 25, 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:
PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3 -
INTEGRATED INSPECTION REPORT 05000277/2025002 AND 05000278/2025002
Dear David Rhoades:
On June 30, 2025, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Peach Bottom Atomic Power Station, Units 2 and 3. On July 3, 2025, the NRC inspectors discussed the results of this inspection with Martin Bonifanti, Site Vice President, 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, Nicole S. Warnek, Chief Projects Branch 3 Division of Operating Reactor Safety Docket Nos. 05000277 and 05000278 License Nos. DPR-44 and DPR-56
Enclosure:
As stated cc w/ encl: Distribution via LISTSERV NICOLE WARNEK Digitally signed by NICOLE WARNEK Date: 2025.07.25 08:48:38 -04'00'
ML25206A041 SUNSI Review Non-Sensitive Sensitive Publicly Available Non-Publicly Available OFFICE RI/DORS RI/DORS RI/DORS NAME LCline RClagg NWarnek DATE 7/24/2025 7/24/2025 7/25/2025
Enclosure U.S. NUCLEAR REGULATORY COMMISSION Inspection Report Docket Numbers:
05000277 and 05000278 License Numbers:
DPR-44 and DPR-56 Report Numbers:
05000277/2025002 and 05000278/2025002 Enterprise Identifier: I-2025-002-0040 Licensee:
Constellation Energy Generation, LLC Facility:
Peach Bottom Atomic Power Station, Units 2 and 3 Location:
Delta, PA 17314 Inspection Dates:
April 1, 2025 to June 30, 2025 Inspectors:
L. Cline, Senior Resident Inspector C. Dukehart, Resident Inspector B. Edwards, Health Physicist D. McHugh, Reactor Inspector N. Mentzer, Senior Project Engineer Approved By:
Nicole S. Warnek, Chief Projects Branch 3 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 Peach Bottom Atomic Power Station, Units 2 and 3, 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 2 began the inspection period at rated thermal power (RTP). On May 16, 2025, the unit was down powered to 56 percent for a control rod pattern adjustment, main turbine valve testing, and condenser waterbox cleaning, and returned to RTP on May 18, 2025. On May 19, 2025, the unit was down powered to 86 percent for a control rod pattern adjustment and returned to RTP that day. The unit remained at or near RTP for the remainder of the inspection period.
Unit 3 began the inspection period at RTP. On April 22, 2025, the 3B recirculating pump tripped, and the unit was down powered to 30 percent. The recirculating pump was restored, and the unit was returned to RTP on April 25, 2025. Later on, April 25, 2025, the unit was down powered to 72 percent for a rod pattern adjustment and returned to RTP the next day. On May 30, 2025, the unit was down powered to 55 percent for control rod scram time testing, turbine testing, and condenser waterbox cleaning, and returned to RTP the next day. On June 2, 2025, the 3C condensate pump tripped which initiated a recirculation pump runback, and the unit was down powered to 51 percent. The condensate pump was restored, and the unit was returned to RTP on June 4, 2025. On June 23, 2025, the 3B reactor feed pump malfunctioned and initiated a recirculation pump runback, and the unit was down powered to 37 percent. The reactor feed pump was restored and the unit returned to RTP on June 25, 2025. On June 27, 2025, the unit was down powered to 68 percent for a rod pattern adjustment and returned to RTP the next day. The unit remained at or near RTP 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 71111.04 - 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)
Units 2 and 3, 'E-3 emergency diesel generator (EDG) following completion of slow start and full load surveillance testing on May 12, 2025 (2)
Unit 2, high-pressure coolant injection (HPCI) following completion of HPCI system surveillance testing on May 23, 2025
4 Complete Walkdown Sample (IP Section 03.02) (1 Sample)
(1)
The inspectors evaluated system configurations during a complete walkdown of the Units 2 and 3 standby liquid control system on June 17-18, 2025.
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)
Unit 2, reactor building elevation 195'-0", fire area/zone 6S-5K, on April 4, 2025 (2)
Units 2 and 3, EDG building, fire area/zone PF-132, on April 8, 2025 (3)
Units 2 and 3, radwaste building fan room elevation 165'-0," fire area/zone PF-108A, on April 15, 2025 (4)
Unit 3, reactor building closed loop cooling water elevation 116,' fire area/zone PF-12B, on June 13, 2025 71111.06 - Flood Protection Measures Flooding Sample (IP Section 03.01) (1 Sample)
(1)
The inspectors evaluated the internal flood protection measures for the Unit 3 reactor building closed loop cooling water, HPCI, 'A/C' residual heat removal (RHR), and recirculation pump motor generator set rooms. Specifically, the design, condition, and maintenance of the mitigation barriers were assessed on June 13, 2025.
71111.07A - Heat Exchanger/Sink Performance Annual Review (IP Section 03.01) (1 Sample)
The inspectors evaluated readiness and performance of:
(1)
'E-4' EDG air coolant heat exchanger on May 20, 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 trip of the '3B' recirculation pump on April 22, 2025.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
(1)
The inspectors observed and evaluated licensed operator requalification training on April 14, 2025.
5 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 remain capable of performing their intended function:
(1)
Units 2 and 3, standby liquid control system Quality Control (IP Section 03.02) (1 Sample)
The inspectors evaluated the effectiveness of maintenance and quality control activities to ensure the following structure, system, and component remains capable of performing its intended function:
(1)
Unit 3, 'A' RHR room cooler repairs (work order (WO) 05640264-01) on April 3, 2025, due to an emergency service water leak identified on March 31, 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)
Unit 3, emergent troubleshooting and maintenance on '3A' RHR pump on April 1, 2025 (2)
Unit 3, emergent failure of the 'D' main steam line flow instrument, DPIS-3-02-119D, that required risk informed completion time assessment and risk management action evaluation on May 2, 2025 (3)
Unit 2, emergent failure of instrument N2 primary containment isolation valve, AO 16-2969B, requiring risk informed completion time assessment and risk management action evaluation on May 5, 2025 (4)
Unit 3, emergent troubleshooting and maintenance following trip of the '3C' condensate pump on June 3, 2025 71111.15 - Operability Determinations and Functionality Assessments Operability Determination or Functionality Assessment (IP Section 03.01) (7 Samples)
The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:
(1)
Unit 3, '3A' RHR room cooler leak on March 31, 2025 (2)
Units 2 and 3, 'E-2' EDG fuel leak on April 4, 2025 (3)
Unit 2, '2D' RHR heat exchanger leakage on April 22, 2025 (4)
Unit 3, '3B' recirculation pump adjustable speed drive trip due to power cell C4 failure on April 22, 2025 (5)
Unit 3, reactor protection system/primary containment isolation system gross fail alarm for the 'D' main steam line flow instrument, DPIS-3-02-119D on May 2, 2025
6 (6)
Unit 3, 'B' drywell instrument N2 header isolation valve to 'A' header, AO-2-16-2969B, inoperable due to failed stroke time on May 5, 2025 (7)
Units 2 and 3, 'E-4' EDG room CO2 system circuit trouble on May 13, 2025 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)
Units 2 and 3, 'B' control room ventilation flow controller, FC-00484, replacement on May 16, 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) (4 Samples)
(1)
Unit 3, power cell 'C4' replacement (WO 04802025) for the '3B' adjustable speed drive, on April 24, 2025 (2)
Unit 2, partial performance of SI3A-2-MSL-D1F1, functional test main steam line high flow instruments reactor protection system 'D' card file, after emergent repairs to 'D' main steam line flow instrument, DPIS-3-02-119D, on May 5, 2025 (3)
Unit 2, ST-O-07G-480-2, primary containment isolation system normally open valves functional test, after repairs to 'B' containment instrument N2 primary containment isolation valve, AO-2-16-2969B, on May 9, 2025 (4)
Units 2 and 3, ST-O-40D-325-2, 'B' control room emergency ventilation train operational test following planned replacement of 'B' train control room ventilation flow controller, FC-00484, (WO 005195934-01), on May 28, 2025 Surveillance Testing (IP Section 03.01) (3 Samples)
(1)
Unit 2, ST-O-010-616-2, RHR loop 'B' pressure inspection, on April 22, 2025 (2)
Unit 3, ST-O-032-635-3, high-pressure service water (HPSW) system pressure test examination, on April 28, 2025 (3)
Unit 3, ST-I-014-100-3, core spray loop logic system functional test, on May 29, 2025 Inservice Testing (IST) (IP Section 03.01) (1 Sample)
(1)
Unit 3, ST-O-011-301-3, standby liquid control pump 'A' functional test for inservice testing, on May 16, 2025 Diverse and Flexible Coping Strategies (FLEX) Testing (IP Section 03.02) (1 Sample)
(1)
Units 2 and 3, RT-O-100-511-2, flex tow vehicle functional test, on May 30, 2025
7 RADIATION SAFETY 71124.05 - Radiation Monitoring Instrumentation Walkdowns and Observations (IP Section 03.01) (8 Samples)
The inspectors evaluated the following radiation detection instrumentation during plant walkdowns:
(1)
Radioactive waste vent exhaust radiation monitor RY-07061 (2)
Unit 3, area radiation monitor (ARM) 7-8 #202112 (3)
Unit 2, area radiation monitor (ARM) 3-6 #202068 (4)
Unit 2, area radiation monitor (ARM) 4-11 #202083 (5)
Unit 3, vent stack radiation monitor RY-3979A (6)
Unit 2, HPSW radiation monitor 2AS331 (7)
Unit 3, refuel floor Eberline AMS4 # 334635 (8)
Unit 3, outside drywell Ludlum model 177 #0017427 Calibration and Testing Program (IP Section 03.02) (13 Samples)
The inspectors evaluated the calibration and testing of the following radiation detection instruments:
(1)
ARGOS-5AB S/N 1312328 (2)
SAM-12 S/N 12228 (3)
PM-12 S/N 13041271 (4)
Ludlum Model 3 S/N 261800 (5)
Eberline RO-20 S/N 0022847 (6)
Canberra FastScan Whole Body Counter (7)
Canberra AccuScan II Whole Body Counter (8)
ARGOS-5PAB S/N 1504045 (9)
Ludlum Model 177 S/N 0026424 (10)
Ludlum Model 3 S/N 0021746 (11)
Ludlum Model 26 S/N 22571 (12)
Eberline RO-20 S/N 12771 (13)
MGP Telepole S/N 6618-058 Effluent Monitoring Calibration and Testing Program Sample (IP Section 03.03) (2 Samples)
The inspectors evaluated the calibration and maintenance of the following radioactive effluent monitoring and measurement instrumentation:
(1)
Unit 3, vent stack radiation monitor RY-3979A (2)
Unit 3, HPSW radiation monitor 3AS331
8 OTHER ACTIVITIES - BASELINE 71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:
BI01: Reactor Coolant System (RCS) Specific Activity Sample (IP Section 02.10) (2 Samples)
(1)
Unit 2, April 1, 2024 to March 31, 2025 (2)
Unit 3, April 1, 2024 to March 31, 2025 BI02: RCS Leak Rate Sample (IP Section 02.11) (2 Samples)
(1)
Unit 2, April 1, 2024 to March 31, 2025 (2)
Unit 3, April 1, 2024 to March 31, 2025 71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02) (1 Sample)
(1)
The inspectors conducted a semiannual trend review by evaluating the causes of equipment failures that occurred in the first and second quarters of 2025.
INSPECTION RESULTS Observation: Semiannual Trend Review 71152S The inspectors conducted a semiannual review to identify trends that might indicate the existence of significant safety issues, including those documented outside the normal corrective action program. The review focused on Constellation's ability to identify, evaluate, and resolve adverse trends.
The inspectors observed that Constellation was generally effective in identifying, evaluating, and resolving adverse trends. However, Constellation documented an adverse trend involving insufficient mitigation of equipment vulnerabilities. This issue led to two automatic reactor scrams, three automatic recirculation pump runbacks, a recirculation pump trip, and spurious equipment actuations over the past 24 months.
In response to the identified trend, Constellation conducted an Organizational Effectiveness Review and a stream analysis to identify commonalities among equipment issues from January 1, 2023, to October 2, 2024. The findings were used to develop a Performance Improvement Action Plan (PIAP AP-2024-2236). Key actions included:
- 1. Cross-functional system reviews
- 2. Quality reviews of system and risk issues
- 3. Life cycle management entry reviews
- 4. Identification of potential equipment reliability issues during the corrective action screening process
- 5. Maintenance prioritization reviews
- 6. Parts quality reviews
- 7. Training on improving equipment reliability
9 The inspectors reviewed the corrective action products and evaluations, performed walkdowns in the plant, and discussed system performance with Constellation staff from operations, maintenance, and engineering. The inspectors determined that Constellation was taking reasonable actions to correct the adverse trend. No findings or violations of more than minor significance were identified.
EXIT MEETINGS AND DEBRIEFS The inspectors verified that no proprietary information was retained or documented in this report.
On July 3, 2025, the inspectors presented the integrated inspection results to Martin Bonifanti, Site Vice President, and other members of the licensee staff.
On May 9, 2025, the inspectors presented the IP 71124.05 Radiation Monitoring Instrumentation inspection results to Ryan Stiltner, Plant Manager, and other members of the licensee staff.
10 DOCUMENTS REVIEWED Inspection Procedure Type Designation Description or Title Revision or Date 71111.04 Drawings M-358 Sheet 1 and 2 Standby Liquid Control System Revision 39 Procedures SO 11.1.A-2(3)
Standby Liquid Control System Setup for Operation Revision 9 71111.12 Corrective Action Documents 04844195 04866461 71152S Corrective Action Documents 04750732 2024 ER Excellence Plan Streaming Analysis 04819362 2024 ER Stream Analysis Procedures ER-AA-20 Equipment Reliability Program Description Revision 5 PI-AA-125-1006 Investigation Techniques Manual Revision 8 Self-Assessments PIAP AP-2004-2236 Peach Bottom Fleet Assessment T6 GTE: ER.2 (Gap to Excellence)