IR 05000277/2025004
| ML26036A069 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 02/05/2026 |
| From: | Nicole Warnek Division of Operating Reactors |
| To: | Mudrick C Constellation Energy Generation, Constellation Nuclear |
| References | |
| EAF-NMSS-2025-0221 IR 2025004 | |
| Download: ML26036A069 (0) | |
Text
February 5, 2026
SUBJECT:
PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3 -
INTEGRATED INSPECTION REPORT 05000277/2025004 AND 05000278/2025004 AND INDEPENDENT SPENT FUEL STORAGE INSTALLATION INSPECTION REPORT 07200029/2024001 AND EXERCISE OF ENFORCEMENT DISCRETION
Dear Christopher Mudrick:
On December 31, 2025, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Peach Bottom Atomic Power Station, Units 2 and 3. On January 26, 2026, 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.
One finding of very low safety significance (Green) is documented in this report. This finding did not involve a violation of NRC requirements.
The NRC identified a violation of Title 10 of the Code of Federal Regulations (10 CFR) 72.48, paragraphs (c)(1), (c)(2), and (d)(1), and provisions of 10 CFR 72.212 that resulted from a Certificate of Compliance (CoC) holders failure to comply with 10 CFR 72.48 for a CoC holder-generated change for the Holtec continuous basket shim multi-purpose canister variant design.
However, an Interim Enforcement Policy issued in August 2025 is applicable to this violation.
Specifically, Enforcement Policy Section 9.4, Enforcement Discretion for General Licensee Adoption of Certificate of Compliance (CoC) Holder-Generated Modifications under 10 CFR 72.48, provides enforcement discretion to not issue an enforcement action for this violation. The licensee will be expected to comply with 10 CFR 72.212 provisions after the NRC dispositions the noncompliance for a CoC holder-generated change that affects the general licensee. 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 205550001; with copies to the Regional Administrator, Region I; the Director, Office of Enforcement; and the NRC Resident Inspector at Peach Bottom Atomic Power Station, Units 2 and 3.
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 10 CFR 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely, Nicole S. Warnek, Chief Projects Branch 3 Division of Operating Reactor Safety
Docket Nos. 05000277, 05000278, and
07200029 License Nos. DPR-44 and DPR-56
Enclosure:
As stated
Inspection Report
Docket Numbers:
05000277, 05000278, and 07200029
License Numbers:
Report Numbers:
05000277/2025004, 05000278/2025004, and 07200029/2024001
Enterprise Identifier: I-2025-004-0040 and I-2024-001-0109
Licensee:
Constellation Energy Generation, LLC
Facility:
Peach Bottom Atomic Power Station, Units 2 and 3
Location:
Delta, PA 17314
Inspection Dates:
October 1, 2025 to December 31, 2025
Inspectors:
L. Cline, Senior Resident Inspector
C. Dukehart, Resident Inspector
H. Anagnostopoulos, Senior Health Physicist
N. Eckhoff, Health Physicist
B. Edwards, Health Physicist
A. Kostick, Health Physicist
D. McHugh, Reactor Inspector
K. Smetana, Project Engineer
A. Turilin, Reactor Inspector
Approved By:
Nicole S. Warnek, Chief
Projects Branch 3
Division of Operating Reactor Safety
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
PI&R Sample for 3B Reactor Feed Pump Signal Conditioning Card Wetting Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green FIN 05000278/2025004-01 Open/Closed None (NPP)71152A A self-revealed Green finding was identified because Constellation did not properly install air-conditioning (AC) unit condensate drain lines. The improperly installed drain lines caused water to drip onto components in the digital feedwater control cabinet, which resulted in the loss of one of the reactor feed pumps (RFPs), a recirculation pump runback, and rapid down-power.
Additional Tracking Items
Type Issue Number Title Report Section Status EDG EAF-NMSS-2025-0221 Noncompliance Related to a General Licensees Use of Non-Qualified Spent Fuel Casks (IEP 9.4)
60855 Closed
PLANT STATUS
Unit 2 began the inspection period at rated thermal power (RTP). On November 21, the unit was down powered to 65 percent for a control rod pattern adjustment, turbine valve testing, and water box cleaning and was returned to RTP the following day. The unit remained at or near RTP for the remainder of the inspection period.
Unit 3 began the inspection period in end-of-cycle coastdown. On October 12 and 13, the unit was down powered and then shutdown for a planned refueling outage (RFO). After completing the refueling, the unit was restarted and synchronized to the grid on November 3, and returned to RTP on November 5. On November 5, the unit was down powered to 70 percent for a control rod pattern adjustment and returned to RTP the following day. On November 7, the unit was down powered to 70 percent for a control rod pattern adjustment and returned to RTP the following day. On November 24, the unit was down powered to 65 percent for a water box leak repair and returned to RTP the following 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
71111.01 - 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 severe cold weather during the week of December 1, 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) Unit 3, 'B' residual heat removal system (RHR) in shutdown cooling mode on October 27, 2025
- (2) Units 2 and 3, FLEX equipment on November 6, 2025
- (3) Unit 2, 'D' RHR on December 11, 2025
- (4) Unit 2, 'D' core spray on December 11, 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 3, turbine building, RFP turbine and drywell chiller area, elevation 165'-0", fire area/zone 50-78A, on October 15, 2025
- (2) Units 2 and 3, FLEX equipment storage building, fire area/zone PF-199, on November 6, 2025
- (3) Units 2 and 3, high-pressure service water pump room, fire areas/zones 47/143 and 48/144 of PF-144, on November 6, 2025
- (4) Unit 2, reactor building, 2B and 2D core spray room, elevation 91'-6", fire area/zone PF-5D, on December 11, 2025
71111.08G - Inservice Inspection Activities (BWR)
BWR Inservice Inspection Activities Sample - Nondestructive Examination and Welding
Activities (IP Section 03.01) (1 Sample)
The following non-destructive testing were evaluated by inspectors through remote document review from November 18 - December 30, 2025:
(1)
1. Ultrasonic Examination of N1A Main Recirculation Outlet Shell to Nozzle Weld
2. Ultrasonic Examination of N1A0-IRS Main Recirculation Outlet Nozzle Inner
Radius (P3R25-VEN-009)
3. Ultrasonic Examination of N2F Main Recirculation Inlet Nozzle to Shell Weld
4. Ultrasonic Examination of N2F Main Recirculation Inlet Nozzle Inner Radius
5. Visual Examination of Drywell Interior Moisture Barrier (3R25-IWE-VT-045,
==3R25 -IWE-VT-134, 3R25-IWE-VT-008)
==
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 a normal plant shutdown on October 12, 2025.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed and evaluated licensed operator requalification training that included a loss of uninterruptible alternating current power and an anticipated transient without scram on November 18, 2025.
71111.12 - Maintenance Effectiveness
Maintenance Effectiveness (IP Section 03.01) (3 Samples)
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, compressed air system (36B/D) (Work Order (WO) 05396606-02)
- (2) Units 2 and 3, emergency diesel generators (EDGs) (Issue Reports (IRs) 04902654, 04908311)
- (3) Units 2 and 3, emergency core cooling pump room coolers (IRs 04900940, 04908605)
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (1 Sample)
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 2 and 3, risk-informed completion time package review for the E-1 EDG trip on high crankcase vacuum on October 3, 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 2 and 3, E-1 EDG high crank case trip, on September 28, 2025
- (3) Unit 3, Engineering Change (EC) 645571 past functionality assessment for main steam line snubber 3-1-GG-S-23, on October 30, 2025
- (4) Unit 3, EC 645922, unsatisfactory main steam isolation valve (MSIV) stroke times during performance of ST-O-07G-475-3, MSIV Closure Timing at Shutdown, on October 30, 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) Unit 3, reactor core isolation cooling (RCIC) remote shutdown panel flow controller permanent replacement (ECR 470433 and EE-01341)
71111.20 - Refueling and Other Outage Activities
Refueling/Other Outage Sample (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated P3R25 activities from October 12 to November 3, 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) (5 Samples)
- (1) Units 2 and 3, ST-O-052-71-2, E-1 EDG 24-hr Endurance Test, after completion of repairs following E-1 EDG trip on high crankcase pressure (WO 05729157), on October 9, 2025
- (2) Unit 3, RT-O-013-240-3, RCIC Overspeed Trip Test Using Auxiliary Steam, after major inspection (WO 04300077), on October 27, 2025
- (3) Unit 3, ST-O-013-200-3, RCIC Flow Rate at Less Than or Equal to 175 psig Steam Pressure, after major inspection (WO 04300077), on October 28, 2025
- (4) Unit 3, ST-O-080-675-3, Reactor Pressure Vessel (ASME Class I) Leakage Pressure Test, after reassembling the reactor pressure vessel (WO 05435137), on October 30, 2025
- (5) Unit 3, ST-O-023-200-3, High Pressure Coolant Injection Flow Rate at Less than or Equal to 175 psig Steam Pressure, after steam supply valve MO-3-23-014 replacement (WO 05330179), on November 1, 2025
Surveillance Testing (IP Section 03.01) (2 Samples)
- (1) Units 2 and 3, ST-O-052-202-2, E-2 Diesel Generator Slow Start and Full Load Test, on October 10, 2025
- (2) Unit 3, ST-O-054-753-3, E-33 4 kilovolt Bus Undervoltage Relays and Loss of Coolant Accident Loss of Offsite Power Functional Test, on October 24, 2025
Containment Isolation Valve (CIV) Testing (IP Section 03.01) (1 Sample)
- (1) Unit 3, Local Leak Rate Testing of the Main Steam Line Isolation Valves, on October 15, 2025
71114.06 - Drill Evaluation
Additional Drill and/or Training Evolution (1 Sample)
- (1) The inspectors observed and evaluated the conduct of an emergency preparedness drill in the technical support center which included, but was not limited to, an earthquake, an anticipated transient without scram, and declaration of a General Emergency on December 9, 2025.
RADIATION SAFETY
71124.01 - Radiological Hazard Assessment and Exposure Controls
Radiological Hazard Assessment (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated how the licensee identifies the magnitude and extent of radiation levels, identifies the concentrations and quantities of radioactive materials, and assesses radiological hazards.
Instructions to Workers (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated how the licensee instructs workers on plant-related radiological hazards and the radiation protection requirements intended to protect workers from those hazards.
Contamination and Radioactive Material Control (IP Section 03.03) (2 Samples)
The inspectors observed/evaluated the following licensee processes for monitoring and controlling contamination and radioactive material:
- (1) Workers exiting the radiologically controlled area during online operations
- (2) Radiological set-up and work performed in the Hot Shop
Radiological Hazards Control and Work Coverage (IP Section 03.04) (3 Samples)
The inspectors evaluated the licensee's control of radiological hazards for the following radiological work:
- (1) Unit 3 turbine building sand blasting package (radiation work permit (RWP) PB-3-25-00805)
- (2) Unit 3 dry well control rod drive exchange package (RWP PB-3-25-00513)
- (3) Unit 3 radiography package (RWP PB-3-25-00401)
High Radiation Area and Very High Radiation Area Controls (IP Section 03.05) (2 Samples)
The inspectors evaluated licensee controls of the following high radiation areas and very high radiation areas:
- (1) Unit 3 recombiner pipe tunnel
- (2) Radwaste pump room Radiation Worker Performance and Radiation Protection Technician Proficiency (IP Section 03.06) (1 Sample)
- (1) The inspectors evaluated radiation worker and radiation protection technician performance as it pertains to radiation protection requirements.
71124.08 - Radioactive Solid Waste Processing & Radioactive Material Handling, Storage, &
Transportation
Radioactive Material Storage (IP Section 03.01) (1 Sample)
The inspectors evaluated the licensees performance in controlling, labeling, and securing the following radioactive materials:
- (1) Boxes and intermodal container located in the "southeast quadrant" outdoor radioactive material storage area
Radioactive Waste System Walkdown (IP Section 03.02) (1 Sample)
The inspectors walked down the following accessible portions of the solid radioactive waste systems and evaluated system configuration and functionality:
- (1) Resins transfer and dewatering in the resin dewatering building 135' elevation
Waste Characterization and Classification (IP Section 03.03) (2 Samples)
The inspectors evaluated the following characterization and classification of radioactive waste:
- (1) Shipment PM-25-0032, UN2910 Limited Quantity, Spent Fuel Pool Coupon
- (2) Shipment PW-24-0028, UN2916 Type B(U), Reactor Water Cleanup Resins
Shipment Preparation (IP Section 03.04) (1 Sample)
- (1) Shipment PM-25-0113, UN2910 LQ, Equipment sent to Limerick Clean Energy Center
Shipping Records (IP Section 03.05) (3 Samples)
The inspectors evaluated the following non-excepted radioactive material shipments through a record review:
- (1) Shipment PM-25-0013, UN2915 Type A, RT-11 Source
- (2) Shipment PW-25-0028, UN2912 LSA-I, Waste Oil for Processing
- (3) Shipment PW-24-0004, UN3321 LSA-II, Condensate Filter Demin Elements
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 2, October 1, 2024 through September 30, 2025
- (2) Unit 3, October 1, 2024 through September 30, 2025
MS06: Emergency AC Power Systems (IP Section 02.05) (2 Samples)
- (1) Unit 2, October 1, 2024 through September 30, 2025
- (2) Unit 3, October 1, 2024 through September 30, 2025
OR01: Occupational Exposure Control Effectiveness Sample (IP Section 02.15) (1 Sample)
- (1) October 1, 2024 through September 30 2025
PR01: Radiological Effluent Technical Specifications/Offsite Dose Calculation Manual Radiological Effluent Occurrences (RETS/ODCM) Radiological Effluent Occurrences Sample (IP Section 02.16) (1 Sample)
- (1) October 1, 2024 through September 30 2025
71152A - Annual Follow-up Problem Identification and Resolution
Annual Follow-up of Selected Issues (Section 03.03) (3 Samples)
The inspectors reviewed the licensees implementation of its corrective action program (CAP) related to the following issues:
- (1) IR 4812989, IR 4813700, IR 4812992, IR 4812993, and IR 4812983, Air Operator Diaphragm Excessive Leakage
- (2) IR 04875613, IR 04875884, and IR 04880328, 3B RFP speed demand to zero due to signal conditioner wetting
- (3) IR 4813873, IR 4813263, IR 04906597, IR 04907063, IR 04907165/04907063, and IR 04907548, P2R25 Snubber failures and snubber scope modification
71152S - Semiannual Trend Problem Identification and Resolution
Semiannual Trend Review (Section 03.02) (1 Sample)
- (1) The inspectors reviewed the licensees corrective action program (CAP) to identify and assess potential trends in measuring and test equipment performance and tracking, fire brigade performance, emergency cooling pump room cooler fouling, and overall equipment reliability that might be indicative of a more significant safety issue.
OTHER ACTIVITIES
- TEMPORARY INSTRUCTIONS, INFREQUENT AND ABNORMAL
60855 - Operation of an Independent Spent Fuel Storage Installation
Inspections were conducted using the appropriate portions of the 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 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 Title 10 of the Code of Federal Regulations (10 CFR) Part 71 Transportation Packagings."
Operation of an Independent Spent Fuel Storage Installation (1 Sample)
- (1) The inspectors conducted a periodic in-office follow-up that focused on the review of the general licensees (GLs) implementation of the 10 CFR 72.48 process and associated corrective actions related to ISFSI activities. The review included:
- 10 CFR 72.48 Evaluations and Screenings: Reviewed the GLs 10 CFR 72.48 process and associated evaluation associated with the adoption of the continuous basket shim (CBS) variant
- CAP: Reviewed condition reports related to the design change of the CBS variant
INSPECTION RESULTS
Enforcement Discretion Enforcement Action EAF-NMSS-2025-0221: Noncompliance Related to a General Licensees Use of Non-Qualified Spent Fuel Casks (IEP 9.4)60855
Description:
Holtec International (also referred to as the CoC (Certificate of Compliance)holder) implemented a design change to its multi-purpose canister fuel basket, known as the CBS variant, which altered the structural configuration from welded to bolted shims. This change resulted in a departure from the method of evaluation (MOE) described in the final safety analysis report (FSAR) used to establish the design basis for tip-over events. Holtec did not fully evaluate the cumulative impact of the MOE changes or apply them consistently with the licensing basis. As a result, the NRC issued three Severity Level IV violations to Holtec for noncompliance with 10 CFR 72.48 requirements (see U.S. NRC Inspection Report 07201014/2022-201, Holtec International, Agencywide Documents Access and Management System (ADAMS) Accession No. ML23145A175, and Holtec International, Inc. - Notice of Violation; The U.S. NRC Inspection Report No. 07201014/2022-201, ML24016A190).
When the GL chooses to adopt a change the CoC holder made pursuant to a CoC holder's change authority under 10 CFR 72.48 (referred to herein as a CoC holder-generated change), the GL must perform a separate review using the requirements of 10 CFR 72.48(c).
Accordingly, when the GL chooses to adopt a CoC holder-generated change, and that change results in a non-conforming cask, there is a violation of 10 CFR 72.48 and certain provisions of 10 CFR 72.212 by the GL, in addition to a CoC holder violation of 10 CFR 72.48. As it relates to the adoption of the CBS variant casks, the GL failed to recognize the noncompliance with 10 CFR 72.48 requirements made by the CoC holders design change and subsequently loaded the CBS variant casks.
Corrective Actions:
The GL entered this into its CAP with actions to restore compliance with the 10 CFR 72.212 provisions that require each cask to conform to the terms, conditions, and specifications of a CoC or an amended CoC listed in 10 CFR 72.214.
Corrective Action References: ECO-5018-105 / ECO-101-39, IR 4744308
Enforcement:
Significance/Severity: This violation was dispositioned in accordance with Section 9.4, Enforcement Discretion for GL Adoption of CoC Holder-Generated Changes Under 10 CFR 72.48, of the NRCs Enforcement Policy.
Specifically, as stated in the Policy, the NRC will exercise enforcement discretion and not issue an enforcement action to a GL, for a noncompliance with the requirements of paragraphs (c)(1) and
- (2) and (d)(1) of 10 CFR 72.48 and with provisions of 10 CFR 72.212 that require GLs to ensure use of casks that conform to the terms, conditions, and specifications of a CoC listed in 10 CFR 72.214, when the noncompliance results from a CoC holders failure to comply with 10 CFR 72.48 for a CoC holder-generated change.
Violation:
10 CFR 72.48 (c)(1) requires, in part, that a licensee or certificate holder may make changes in the facility or spent fuel storage cask design as described in the FSAR (as updated), without obtaining:
- (ii) CoC amendment submitted by the certificate holder pursuant to § 72.244 if:
- (c) The change, test, or experiment does not meet any of the criteria in paragraph (c)(2) of this section.
10 CFR 72.48(c)(2) requires, in part, that a GL shall request that the certificate holder obtain a CoC amendment, prior to implementing a proposed change, if the change would: (viii) Result in a departure from an MOE described in the FSAR used in establishing the design bases or in the safety analyses.
10 CFR 72.48(d)(1) requires, in part, that the licensee shall have a written evaluation which provides the bases for the determination that the change does not require a CoC amendment pursuant to 10 CFR 72.48(c)(2).
10 CFR 72.212(b)(3) requires, in part, a GL must ensure that each cask used by the GL conforms to the terms, conditions, and specifications of a CoC or an amended CoC listed in 10 CFR 72.214.
Contrary to the above, in June 2022, the GL loaded the first CBS design variant and failed to maintain records of changes in the spent fuel storage cask design made pursuant to 10 CFR 72.48(c) that include a written evaluation which provided the bases for the determination that the change did not require a CoC amendment. The GL failed to request that the certificate holder obtain a CoC amendment, prior to implementing a proposed change, if the change would: (viii) result in a departure from an MOE described in the FSAR used in establishing the design bases or in the safety analyses. Further, the GL failed to ensure each cask conformed to the terms, conditions, and specifications of a CoC or amended CoC listed in 10 CFR 72.214.
Basis for Discretion: When a GL chooses to adopt a CoC holder-generated change, and that change results in a non-conforming cask, there is a violation of 10 CFR 72.48 and certain provisions of 10 CFR 72.212 by the GL, in addition to a CoC holder violation of 10 CFR 72.48.
And, when a GL chooses to adopt a CoC holder-generated change without performing a separate 10 CFR 72.48 analysis, the GL is in violation of 10 CFR 72.48. These requirements could lead to enforcement actions being issued against both the GL's 10 CFR 72.48 program (as well as certain 10 CFR 72.212 violations) and the CoC holder's 10 CFR 72.48 program for changes that originated with the CoC holder. The NRC has concluded that this enforcement approach would be inconsistent with efficiency, which is one of the NRC's Principles of Good Regulation, and NRC's mission of efficient and reliable oversight.
Since this violation meets the conditions of the NRC's Enforcement Policy Section 9.4, "Enforcement Discretion for GL Adoption of Certificate of Compliance Holder-Generated Changes under 10 CFR 72.48" (ML25224A097), and the GL has entered the noncompliance into the CAP, the NRC is exercising enforcement discretion by not issuing an enforcement action for this violation.
PI&R Sample for 3B Reactor Feed Pump Signal Conditioning Card Wetting Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events
Green FIN 05000278/2025004-01 Open/Closed
None (NPP)71152A A self-revealed Green finding was identified because Constellation did not properly install AC unit condensate drain lines. The improperly installed drain lines caused water to drip onto components in the digital feedwater control cabinet, which resulted in the loss of one of the RFPs, a recirculation pump runback, and rapid down-power.
Description:
On June 23, 2025, at 2005, the demand on the 3B RFP unexpectedly went to zero and operators entered OT-100, "Reactor Low Level - Procedure," due to reactor low level. A recirculation system runback was successful, with 45 percent runback on the 3A and 3B recirculation pumps. Inspection of the RFP system revealed a water leak originating from the top-mounted AC unit which dripped directly onto the signal conditioner for the 3B RFP. The water caused the speed demand for 3B RFP to go to zero.
The AC unit has a condensate drain connection where flexible tubing was connected to allow the draining of any built-up water into a catch basin. The vendor manual for the AC unit indicates that this drain line must be kept at a suitable and constant gradient to facilitate draining. The AC unit was installed in 2018 using EC 0000645414. The EC did not contain the vendor manual requirement for the drain lines to be "laid with a suitable and constant gradient." The installed drain line was not sloped and allowed water to accumulate and ultimately resulted in the AC unit condensate tray overflowing, which dripped water inside the electrical cabinet.
Corrective Actions:
Constellation developed and installed an EC package to raise the AC unit and replace the condensate drain lines with the appropriate slope. An IR was issued to perform a similar repair on Unit 2.
Corrective Action References: EC 0000645414, Riser Frame Installation for '3B' Reactor Feed Pump Turbine HVAC Unit Replacement; IR 04914082, Unit 2 2AV373 and 2BV373 Drain Line Routing
Performance Assessment:
Performance Deficiency: Procedure CC-AA-103, "Configuration Change Control for Permanent Physical Plant," step 4.5 indicates that the 90 percent review should validate that the installation instructions and acceptance testing requirements are complete. The EC did not contain the installation instructions from the vendor manual for installing the drain lines with a suitable and constant gradient. Therefore, the installation instructions were not complete. This was reasonably within Constellation's ability to foresee and correct.
Screening:
The inspectors determined the performance deficiency was more than minor because it was associated with the Design Control attribute of the Initiating Events cornerstone and adversely affected the cornerstone objective to limit the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. Specifically, the performance deficiency resulted in the RFP speed demand going to zero when it was needed to remain functional with the reactor at 100 percent power. The incorrect installation of the AC unit condensate drain lines caused a feedwater transient resulting in a rapid downpower.
Significance:
The inspectors assessed the significance of the finding using IMC 0609, Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The inspectors determined that the finding screened as very low safety significance (Green)because the transient did not result in a reactor trip and the loss of mitigating equipment relied upon to transition the plant from the onset of the trip to a stable shutdown condition (e.g., loss of condenser, loss of feedwater). Specifically, the finding caused a recirculation system runback due to the loss of one of the RFPs and not a total loss of feedwater.
Cross-Cutting Aspect:
Not Present Performance. No cross-cutting aspect was assigned to this finding because the inspectors determined the finding did not reflect present licensee performance.
Enforcement:
Inspectors did not identify a violation of regulatory requirements associated with this finding.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified that no proprietary information was retained or documented in this report.
- On January 26, 2026, the inspectors presented the integrated inspection results to Martin Bonifanti, Site Vice President, and other members of the licensee staff.
- On December 15, 2025, the inspectors presented the IP 71124.08
Exit Meeting
inspection results to Martin Bonifanti, Site Vice President, and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Procedures
FLEX Equipment Battery and Tire Checks
Revision 4
Corrective Action
Documents
Resulting from
Inspection
Corrective Action
Documents
Resulting from
Inspection
Procedures
M-C-750-001
RCIC Turbine Major Inspection
Revision 26
Corrective Action
Documents
04853138
04906597
Corrective Action
Documents
Resulting from
Inspection
04920272
Procedures
ER-PB-330-1007
Snubber Inservice Testing Program
Revision 2