ML25225A027
| ML25225A027 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 08/13/2025 |
| From: | Sherlyn Haney Division of Operating Reactors |
| To: | Rhoades D Constellation Energy Generation, Constellation Nuclear |
| References | |
| IR 2025002 | |
| Download: ML25225A027 (1) | |
Text
August 13, 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:
NINE MILE POINT NUCLEAR STATION, UNITS 1 AND 2 - INTEGRATED INSPECTION REPORT 05000220/2025002 AND 05000410/2025002 AND INDEPENDENT SPENT FUEL STORAGE INSTALLATION (ISFSI) REPORT 07201036/2025001
Dear David Rhoades:
On June 30, 2025, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Nine Mile Point Nuclear Station, Units 1 and 2. On August 7, 2025, the NRC inspectors discussed the results of this inspection with Tim Peter, Site Vice President, and other members of your staff. The results of this inspection are documented in the enclosed report.
Two findings of very low safety significance (Green) are documented in this report. One of these findings 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 I; the Director, Office of Enforcement; and the NRC Resident Inspector at Nine Mile Point Nuclear Station.
If you disagree with a cross-cutting aspect assignment or a finding not associated with a regulatory requirement 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 I; and the NRC Resident Inspector at Nine Mile Point Nuclear Station.
D. Rhoades 2
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, Sherlyn I. Haney, Acting Chief Projects Branch 1 Division of Operating Reactor Safety Docket Nos. 05000220, 05000410 and 07201036 License Nos. DPR-63 and NPF-69
Enclosure:
As stated cc w/ encl: Distribution via LISTSERV SHERLYN HANEY Digitally signed by SHERLYN HANEY Date: 2025.08.13 07:51:16 -04'00'
ML25225A027 SUNSI Review Non-Sensitive Sensitive Publicly Available Non-Publicly Available OFFICE RI/DORS RI/DORS RI/DORS NAME CKline DBeacon SHaney DATE 8/11/2025 8/11/2025 8/12/2025
Enclosure U.S. NUCLEAR REGULATORY COMMISSION Inspection Report Docket Numbers:
05000220, 05000410 and 07201036 License Numbers:
DPR-63 and NPF-69 Report Numbers:
05000220/2025002, 05000410/2025002 and 07201036/2025001 Enterprise Identifier: I-2025-002-0046 I-2025-001-0105 Licensee:
Constellation Nuclear Facility:
Nine Mile Point Nuclear Station, Units 1 and 2 Location:
Oswego, NY Inspection Dates:
April 1, 2025 to June 30, 2025 Inspectors:
C. Kline, Senior Resident Inspector E. Adams, Resident Inspector B. Sienel, Resident Inspector D. Beacon, Senior Project Engineer C. Borman, Health Physicist A. Kostick, Health Physicist K. Mangan, Senior Reactor Inspector D. McHugh, Reactor Inspector K. Smetana, Reactor Engineer Approved By:
Sherlyn I. Haney, Acting Chief Projects Branch 1 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 Nine Mile Point 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 Failure to Perform American Society of Mechanical Engineers (ASME) Inservice Test (IST)
Code Requirements Following Containment Spray Pump and Check Valve Testing Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000220/2025002-02 Open/Closed
[H.14] -
Conservative Bias 71152A A Green NRC-identified finding and associated non-cited violation (NCV) of Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(f), Preservice and Inservice Testing Requirements, Subsection (4), Inservice Testing Standards Requirement for Operating Plants, was identified when Constellation did not follow ASME Code requirements for an IST failure. Specifically, following an IST comprehensive pump and check valve flow test of the containment spray system loop 112 pump and discharge check valve (80-26) in accordance with the 2012 ASME Operation and Maintenance (OM) Code requirements, Constellation failed to take required actions when flow acceptance values were not met.
Failure to Control System Boundaries Results in Loss of Reactor Pressure Vessel (RPV)
Inventory During Unit 1 Shutdown Operations Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green FIN 05000220/2025002-03 Open/Closed
[H.3] - Change Management 71153 A self-revealed Green finding was identified when the licensee failed to control the Unit 1 RPV boundary when establishing conditions for an RPV pressure test. Specifically, Constellation failed to ensure that electromatic relief valves (ERVs), which served as a pressure boundary for the RPV pressure test, were in a position that would not adversely impact the unit, contrary to procedure OP-AA-109-101, "Operations Tagout," Section 8.5.3, "Executing a Temp Lift." As a result, static head pressure lifted unisolated ERVs, resulting in the loss of 3 feet of RPV water level to the suppression pool.
Additional Tracking Items Type Issue Number Title Report Section Status URI 05000410/2025002-01 Calibration of Containment High Range Radiation Monitor System (CHRRMs) 71124.05 Open
3 PLANT STATUS Unit 1 began the inspection period shut down for planned refueling outage N1R28. Reactor startup was commenced on April 4, 2025. Rated thermal power was reached on April 8, 2025. A subsequent planned power reduction to 80 percent was performed on April 9, 2025, to perform a rod pattern adjustment. Rated thermal power was restored the following day. On May 2, 2025, the unit was downpowered to approximately 72 percent for a planned control rod pattern adjustment and friction testing. Rated thermal power was restored on May 3, 2025. Unit 1 remained at or near rated thermal power for the rest of the inspection period.
Unit 2 began the inspection period at rated thermal power. On May 17, 2025, the unit was downpowered to approximately 83 percent for a planned rod sequence exchange. Rated thermal power was restored on May 18, 2025. Unit 2 remained at rated thermal power for the rest 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 hot temperatures for the flex building and Unit 2 service water system on June 27, 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 2 Division III emergency diesel generator on April 2, 2025 (2)
Unit 2 high pressure core spray on May 5, 2025 (3)
Unit 1 containment spray on May 20, 2025
4 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 2 diesel generator building 261', Division III diesel generator room, fire area 30, on April 1, 2025 (2)
Unit 2 diesel generator building 261', Division I diesel generator room, fire area 28, on April 2, 2025 (3)
Unit 2 diesel generator building 261', Division II diesel generator room, fire area 29, on April 2, 2025 (4)
Unit 2 reactor building 175', fire area 34, on June 2, 2025 (5)
Unit 2 reactor building 175', fire area 35, on June 2, 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 on May 30, 2025.
71111.06 - Flood Protection Measures Flooding Sample (IP Section 03.01) (1 Sample)
(1)
The inspectors evaluated external flooding mitigation protections of the 10,000 year berm and revetment ditch on April 28, 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 and evaluated Unit 1 licensed operator performance in the control room during reactor startup from refueling outage N1R28 on April 4, 2025.
(2)
The inspectors observed and evaluated Unit 2 licensed operator performance in the control room during a reduction in power to 83 percent for rod pattern adjustment on May 17, 2025.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (2 Samples)
(1)
The inspectors observed a Unit 1 simulator evaluation that included a control rod drift, fuel failure, a seismic event, and a steam leak in the turbine building on April 29, 2025.
(2)
The inspectors observed a Unit 2 simulator evaluation that included a 4160 volt bus electrical fault, a main generator load rejection, and a small break loss of coolant in the primary containment on May 13, 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 (SSCs) remain capable of performing their intended function:
(1)
Unit 1 containment spray 122 suction valve failure to open during surveillance on April 16, 2025 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 replacement of the Division II emergency diesel generator air start valve on April 9, 2025 (2)
Unit 2 elevated risk during removal of main turbine bypass valve 1 from service on April 18, 2025 (3)
Unit 1 elevated risk during reactor building emergency ventilation 12 system outage window on April 29, 2025 (4)
Unit 2 elevated risk during planned maintenance on reactor and control building ventilation and drywell spray systems on April 30, 2025 (5)
Unit 2 elevated risk due to reactor core isolation cooling system outage window on May 5, 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)
Unit 1 source range monitors reading downscale during refueling outage N1R28 on April 2, 2025 (2)
Unit 1 electromatic relief valve 121 for failure of as found testing on April 8, 2025 (3)
Unit 1 turbine bypass valve 3 linkage bolt shear on April 16, 2025 (4)
Unit 1 containment spray 122 suction valve failure to open during surveillance on April 17, 2025 (5)
Unit 2 extended operation with turbine bypass valve 1 removed from service on April 21, 2025 (6)
Unit 1 containment spray 112 when required flow could not be established during surveillance testing on April 22, 2025
6 71111.18 - Plant Modifications Temporary Modifications and/or Permanent Modifications (IP Section 03.01 and/or 03.02)
(4 Samples)
The inspectors evaluated the following temporary or permanent modifications:
(1)
Permanent Modification: ECP-23-000151, Unit 1 Replace Level Detector Assembly for High Level Scram Discharge Volume RPS [Reactor Protection System] Channels 11 and 12 (2)
Permanent Modification: ECP-23-000314, Replace Unit 1 Emergency Condenser Initiation Time Delay Dropout Relay (3)
Permanent Modification: ECP-24-000148, Unit 1 Feedwater Regulating Valve Positioner Upgrade (4)
Temporary Modification: ECP-25-000153, Installation of Modification for 13 Feedwater Pump Clutch Oil Reservoir 71111.20 - Refueling and Other Outage Activities Refueling/Other Outage Sample (IP Section 03.01) (1 Sample)
(1)
The inspectors evaluated Unit 1 refueling outage N1R28 activities from April 1 to April 5, 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) (9 Samples)
(1)
N1-ST-Q5, Primary Containment Isolation Valves Operability Test, on March 3, 2025 (2)
Unit 1 main steam isolation valve 01-03 following maintenance during N1R28, on April 7, 2025 (3)
N1-ISP-036-104, Low Low Reactor Water Level Instrument Trip Channel Calibration, following time delay relay replacement during N1R28, on April 7, 2025 (4)
N2-OSP-EGS-M@001, Diesel Generator and Diesel Air Start Valve Operability Test, following Divisions I and II air start valve replacement, on April 9, 2025 (5)
Unit 2 reactor core isolation cooling relay timing following inspection on April 14, 2025 (6)
N1-ST-Q1D, Core Spray 122 Pump and Valve Operability Test, following maintenance, on May 5, 2025 (7)
N1-ST-Q6C, Containment Spray System Loop 112 Quarterly Operability Test, following flow control valve adjustment and pump lift adjustment, on May 19, 2025 (8)
Unit 1 scram discharge volume instrumentation following replacement during N1R28, on May 20, 20205 (9)
Unit 1 battery 12 testing following battery replacement during N1R28, on June 30, 2025
7 Surveillance Testing (IP Section 03.01) (3 Samples)
(1)
N1-ISP-066-003, Auto Depressurization System Operability Test, on April 2, 2025 (2)
N1-ST-R2B, LOCA [Loss of Coolant Accident] and EDG [Emergency Diesel Generator] 103 Simulated Auto Initiation Test, performed during N1R28, on April 15, 2025 (3)
N2-OSP-ICS-Q@002, RCIC [Reactor Core Isolation Cooling] Pump and Valve Operability Test, and System Integrity Test and ASME XI Functional Test and Analysis, on May 8, 2025 71114.06 - Drill Evaluation Additional Drill and/or Training Evolution (1 Sample)
(1)
The inspectors evaluated a Unit 2 simulator evaluation that included the declaration of an Alert on May 13, 2025.
RADIATION SAFETY 71124.04 - Occupational Dose Assessment Source Term Characterization (IP Section 03.01) (1 Sample)
(1)
The inspectors evaluated licensee performance as it pertains to radioactive source term characterization.
External Dosimetry (IP Section 03.02) (1 Sample)
(1)
The inspectors evaluated how the licensee processes, stores, and uses external dosimetry.
Internal Dosimetry (IP Section 03.03) (2 Samples)
(1)
Reviewed whole body count and internal dose assessment of individual X8314 (2)
Observed whole body count of individual X2852 Special Dosimetric Situations (IP Section 03.04) (2 Samples)
The inspectors evaluated the following special dosimetric situations:
(1)
Neutron dosimetry program and assessment (2)
Declared pregnant workers program and assessment 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:
8 (1)
Ludlum 177 S/N 0016974 used at the exit to the Unit 2 radiologically controlled area (2)
Gamma remote detector S/N 1231 in the Unit 1 reactor waste building (3)
Merion data radiation monitoring system 2 (DRM-2) S/N 12711-324 in the Unit 2 reactor building 261' (4)
Area radiation monitor identification number 26 in the Unit 1 chemistry lab (5)
Telepole S/N 0025701 in the Unit 2 calibration room (6)
Ludlum 3030P S/N 0018426 in the Unit 2 calibration room (7)
Particulate iodine noble gas monitor S/N 225 in the Unit 1 radwaste building (8) 2RMS-RE116 S/N 95-2180-003 in the Unit 2 turbine building 250' Calibration and Testing Program (IP Section 03.02) (13 Samples)
The inspectors evaluated the calibration and testing of the following radiation detection instruments:
(1)
Ludlum Model 3 S/N 0017856 (2)
Eberline Ro-2A S/N 6443-05 (3)
Ludlum 177 S/N 0016974 (4)
Telepole S/N 079460 (5)
Ludlum 177 S/N 0025422 (6)
Ludlum Model 26 S/N 0027394 (7)
AMS-4 S/N 1748/1745 (8)
SAM-12 S/N 12252 (9)
Eberline Scintillation Alpha Counter S/N 1245 (10)
Eberline Beta Counter S/N 698 (11)
Canberra Argos 5-AB Zeus S/N 1012-316 (12)
Eberline AMS-4 S/N 1742/146-26 (13)
Canberra Argos 5-AB Zeus S/N 1012/323 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 1 service water effluent discharge monitor RAM-72-406 (2)
Unit 2 stack wide range gas monitor 2RMS-PN2170A 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 1 for the period April 1, 2024 through March 31, 2025 (2)
Unit 2 for the period April 1, 2024 through March 31, 2025 BI02: RCS Leak Rate Sample (IP Section 02.11) (2 Samples)
(1)
Unit 1 for the period April 1, 2024 through March 31, 2025
9 (2)
Unit 2 for the period April 1, 2024 through March 31, 2025 71152A - Annual Follow-Up Problem Identification and Resolution Annual Follow-Up of Selected Issues (Section 03.03) (2 Samples)
The inspectors reviewed the licensees implementation of its corrective action program related to the following issues:
(1)
Issue Report (IR) 04836433 - Multiple Trips of Unit 1 Liquid Poison Pump 12 (2)
IR 04859274 - Unit 1 Failed Containment Spray Pump 112 71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02) (1 Sample)
(1)
The inspectors reviewed Constellation's corrective action program to identify potential trends 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 Sample)
(1)
The inspectors evaluated the unplanned loss of RPV inventory during Unit 1 refueling outage N1R28 and the licensees response.
Per IMC 0309, Reactive Inspection Decision Basis for Power Reactors, the NRC considered whether this inspection sample should be the subject of a reactive inspection and determined that a reactive inspection was not necessary, as documented in ML25097A075.
OTHER ACTIVITIES - TEMPORARY INSTRUCTIONS, INFREQUENT AND ABNORMAL 60855 - Operation of an Independent Spent Fuel Storage Installation (ISFSI)
The inspectors evaluated the licensee's ISFSI dry storage cask loadings June 9-13, 2025.
Specifically, the inspectors observed and/or reviewed the following activities for Cask #3 of the ISFSI campaign:
Operation of an ISFSI (1 Sample)
(1)
Heavy load movements of spent fuel storage canisters and transfer casks, in accordance with Final Safety Analysis Report (FSAR) and Technical Specifications (TS)
Fuel selection and verification of compliance with TS and 10 CFR 72.48 evaluation criteria Welding, closure, and non-destructive examination of cask welds, as required by the Certificate of Compliance (CoC) and applicable quality assurance programs
10 Vacuum drying, helium backfilling, and associated monitoring activities in compliance with FSAR requirements Radiation surveys of the ISFSI pad, haul path, and surrounding areas to ensure compliance with 10 CFR 72.104 dose limits Evaluation of occupational and public radiation exposures per NRC regulations and licensee radiation protection programs Inspection of ISFSI structural conditions, including cask integrity and pad assessments, to verify compliance with CoC and FSAR commitments Compliance with CoC requirements and FSAR commitments Review of procedural adherence, operational performance, and training effectiveness per NRC-approved procedures Examination of selected corrective action program reports and licensee-identified issues in accordance with 10 CFR 72.48 screening requirements Assessment of changes made under the 10 CFR 72.48 screening process for compliance with NRC regulations INSPECTION RESULTS Unresolved Item (Open)
Calibration of Containment High Range Radiation Monitor Systems (CHRRMs)
URI 05000410/2025002-01 71124.05
==
Description:==
The NRC inspectors identified an unresolved item (URI) associated with Constellations program for the calibration of the CHRRMs at Unit 1. The instruments are used, in part, for assessing radiation levels and determining if, and when, to declare emergency action levels (EALs) during emergency events. The inspectors noted that, in 2025, Constellation switched from a Co-60 source to a Cs-137 source for calibration of its drywell radiation monitors. Constellation could not provide an adequate technical basis for the change in calibration source. Additionally, multiple other associated technical concerns related to calibration accuracy created uncertainty in the validity of the calibrations including the calibration geometry and associated uncertainty analysis.
The inspectors require more information to determine whether the calibration methods used resulted in accurate, repeatable calibrations that ensured that the CHRRMs would have adequately supported correct EAL declarations during emergency events. The inspectors noted that Unit 1 TS 3.6.11, "Accident Monitoring Instrumentation," requires, in part, that CHRRMs remain operable or the actions in TS Table 3.6.11-2, Action - 3, be taken.
This URI is being opened because more information is required to determine if the issue of concern constitutes a performance deficiency and/or violation.
Planned Closure Actions: The inspectors will review justification, to be provided by Constellation, that address whether the CHRRM calibrations performed were accurate and repeatable such that the instruments would have adequately supported EAL declarations during emergency events. This information will be used to assess whether a performance deficiency and/or violation of TS 3.6.11 exists.
Licensee Actions: Constellation is evaluating the CHRRM calibration.
Corrective Action References: IRs 04768249 and 04870745
11 Failure to Perform American Society of Mechanical Engineers (ASME) Inservice Test (IST)
Code Requirements Following Containment Spray Pump and Check Valve Testing Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000220/2025002-02 Open/Closed
[H.14] -
Conservative Bias 71152A A Green NRC-identified finding and associated NCV of the 10 CFR 50.55a, Codes and Standards, paragraph (f), Preservice and Inservice Testing Requirements, subparagraph (4), Inservice Testing Standards Requirement for Operating Plants, was identified when Constellation did not comply with ASME Code requirements following an IST. Specifically, following an IST comprehensive pump and check valve flow test of the containment spray system loop 112 pump (80-24) and discharge check valve (80-26) in accordance with the 2012 Edition of the ASME, Operation and Maintenance of Nuclear Power Plants, Division 1, OM Code: Section IST (OM Code) requirements, Constellation failed to take required actions when flow acceptance values were not met.
==
Description:==
On April 22, 2025, Constellation performed the quarterly TS surveillance test in accordance with the 2012 ASME OM Code (Code) ISTB-5322 Comprehensive Test Procedure, and OM Code Mandatory Appendix II Check Valve Condition-Monitoring Program II-4000 Condition-Monitoring Activities on the Unit 1 containment spray loop (112) pump (80-
- 24) and discharge check valve (80-26), per N1-ST-Q6C, Containment Spray System Loop 112 Quarterly Operability Test, Revision 025.
During the April 22, 2025 test, the required flow could not be established by operators. Flow reached a maximum of 2765 gallons per minute (gpm) (on April 23, the flow rate was recalculated to 2792 gpm), outside the required test acceptance criteria. Additionally, the required flow (2800 gpm) to demonstrate adequate obturator movement for the pump discharge check valve (80-26) operability was not achieved. As a result, Constellation staff marked procedure Steps 6.5.46, 6.5.47, 6.8.3, 6.8.6 and 6.8.11 unsatisfactory (UNSAT).
NRC inspectors reviewed Constellations actions to resolve the test discrepancies. Inspectors reviewed the test procedure, test results, operability determination, and the OM Code to determine testing requirements, required actions, and basis for operability for the containment spray pump, check valve, and containment spray system train.
Specifically, the inspectors reviewed Constellation test procedure N1-ST-Q6C, used to perform the pump and valve testing. N1-ST-Q6C, Section 2.11, "Acceptance Criteria," Step 2.11.2, states:
The letters IST in brackets [IST] will denote steps required for compliance with ASME OM Code as delineated in the NMP Pump and Valve Inservice Testing (IST) Program.
If specific Acceptance Criteria is required, the acceptable value will be given in parenthesis Further, Step 2.11.2 of N1-ST-Q6C states, in part:
Acceptance Criteria for Steps required for compliance with the Pump and Valve lnservice Testing Program (IST) are shown in parentheses Values shown as
12
( ) are the IST Acceptable range (or Acceptance Criteria), valves outside the IST Acceptable range shall be immediately retested (only one time) or declared INOPERABLE.
Likewise, Step 2.11.3 delineates that TS acceptance criteria required for Technical Specification compliance are denoted in brackets [ ].
Inspectors noted that Steps 6.5.46 and 6.5.47 contained IST acceptance criteria established by the licensee to comply with the ASME OM Code, and were both marked UNSAT, along with subsequent acceptance criteria verification Steps 6.8.3, 6.8.6 and 6.8.11. Specifically, Step 6.5.46 specified containment spray pump 112 flow rate IST acceptance criteria of 2850 to 2908 gpm, denoted in parentheses ( ), and TS acceptance criteria of 2800 gpm, denoted in brackets [ ], in alignment with Steps 2.11.2 and 2.11.3. Inspectors further noted that Step 6.5.47 directed that containment spray pump 112 discharge check valve partial forward flow IST acceptance criteria of 2800 GPM, be indicated. Both steps were marked UNSAT because the required flow was not established during the test.
The inspectors concluded that the criteria contained in N1-ST-Q6C, Step 6.5.46, were IST acceptance criteria (2850 to 2908 gpm) and TS acceptance criteria [ 2800 gpm].
Additionally, inspectors noted that Step 6.5.47 specified an IST acceptance criterion of 2800 gpm for the discharge check valve. The inspectors concluded that the Step 2.11.2 requirement, valves outside the IST Acceptable range shall be immediately retested (only one time) or declared INOPERABLE, remained applicable to the discharge check valve.
Subsequent to the test, Constellation concluded that the test was a no test because the pump reference point flow could not be achieved. However, the inspectors determined that when performing an OM Code test, actions must be taken based on the data collected, as required by the OM Code when acceptance criteria are not met. A no test is not an option allowed by the OM Code. The inspectors determined that the stations entry into test procedure N1-ST-Q6C with the intention to satisfy IST testing requirements, performance of the specified procedure steps, and measurement of IST data per the test procedure constituted an IST test and, therefore, the requirements of the OM Code applied to the test.
Nine Mile Point, Unit 1, is required to comply with the 2012 Edition of the ASME OM Code as incorporated by reference in 10 CFR 50.55a as its current IST Code of Record. The inspectors reviewed the OM Code to determine the requirements following a pump test failure due to deviations from the reference values. The inspectors noted that the ASME OM Code, Subsection ISTB, for pump testing provides two options (ISTB-6200 or ISTB-6300) if a test cannot be satisfactorily completed. The inspectors found the OM Code requires that when the pump test results fall outside of the acceptable range established by the licensee to comply with the ASME OM Code, either paragraph ISTB-6200 or ISTB-6300 must be satisfied.
ISTB-6200, "Corrective Actions," states the pump shall be declared inoperable until either the cause of the deviation has been determined and the condition is corrected or an analysis of the pump is performed in accordance with subparagraph ISTB-6200(c).
ISTB-6300, "Systematic Error," states that if the test shows measured parameter values have resulted from an identified systematic error, such as improper system lineup or inaccurate instrumentation, the test shall be rerun after correcting the error.
13 The inspectors determined Constellation performed an OM Code test that produced measured results that required performance of ISTB-6200 or ISTB-6300. Constellation did not declare the pump inoperable, determine the cause of the deviation, or perform an analysis of the pump in accordance with ISTB-6200. Constellation also did not identify a systematic error, correct the error, and retest the pump in accordance with ISTB-6300.
Therefore, the inspectors concluded that Constellation violated OM Code requirements when the system was declared operable and returned to service following the failed IST test without completing either action.
Additionally, the inspectors reviewed the OM Code to determine the requirements following a check valve test failure. The inspectors noted Subsection IST, Inservice Testing of Valves in Light-Water Reactor Nuclear Power Plants, paragraph ISTC-5224:
ISTC-5224, "Corrective Actions," states, in part, if a check valve fails to exhibit the required change of obturator position, it shall be declared inoperable and a retest showing acceptable performance shall be run following any required corrective action before the valve is returned to service.
Inspectors noted that the N1-ST-Q6C IST test relies on the satisfaction of the Step 6.5.47 IST acceptance criterion (system flow rate of 2800 gpm) to demonstrate adequate change in obturator position for the discharge check valve. Because the criterion was not met during the test on April 22, 2025, the discharge check valve was required to be declared inoperable in accordance with paragraph ISTC-5224, and a subsequent retest conducted to demonstrate acceptable performance following required corrective action, before returning the valve to service. The inspectors determined that Constellations failure to perform these actions violated OM Code requirements.
In response to inspector questions related to meeting the requirements of ISTC-5224, Constellation staff asserted that ISTC-5224 did not apply because Nine Mile Point was implementing ASME OM Code, Mandatory Appendix II, "Check Valve Monitoring Program."
However, ISTC-5222, Condition-Monitoring Program, states that a condition-monitoring program may be established as an alternative to the testing or examination requirements of ISTC-3510, ISTC-3520, ISTC-3530, and ISTC-5221. Paragraph ISTC-5224 is not listed among these ASME OM Code provisions, so it remains applicable when implementing Appendix II. Further, Footnote 1 in Appendix II states that this Mandatory Appendix contains requirements to augment the rules of Subsection ISTC. Historical experience also indicates that the NRC staff and the ASME OM Code have considered ISTC-5224 to apply if a licensee elects to implement a Check Valve Condition-Monitoring Program using Appendix II.
Therefore, the inspectors concluded that ISTC-5224 continues to apply to the licensee when implementing Appendix II to the ASME OM Code.
Following performance of N1-ST-Q6C, in response to the UNSAT steps and acceptance criteria, Constellation performed an operability determination (ENGDOC-25-000007),
concluded the containment spray system was operable, and returned the loop to service. The operability evaluation stated that Constellation engineering determined that failure to reach the required flow reference point was a no test, which resulted in Constellation not considering the test an IST failure.
The licensees operability determination report concluded that the check valve and containment spray pump were operable because the recorded pump flow during the test,
14 combined with ultimate heat sink temperature at the time, would be sufficient to meet the long term decay heat removal requirements for the system following an event. Constellation stated that performance issues were possible with both the check valve and pump in the operability determination. Upon questioning by inspectors, Constellation stated the most likely cause of the unsatisfactory flow was a degraded discharge check valve. The operability evaluation assigned an action to disassemble and inspect the check valve (80-26) with a due date of June 3, 2025. The inspectors found the operability determination did not identify the cause of the check valve degradation, and did not address why the check valve would not further degrade (reducing flow) during the system mission time following an event. Additionally, the operability evaluation did not address component operability readiness requirements associated with OM Code requirements for a failed test because it incorrectly dispositioned the test as a no test. Finally, the evaluation did not address the flow requirements for the containment spray function of the system. Therefore, the inspectors concluded that the associated operability evaluation did not establish a comprehensive basis for operability, given the unknown degradation mechanism of the check valve or pump.
Finally, the inspectors noted that Constellation declared the containment spray system inoperable on April 22, 2025, and entered the containment spray system TS limiting condition of operation (LCO) to perform the OM Code testing. Following review of the test results, the inspectors concluded Constellation should have remained in the LCO because the test results indicated the check valve and/or pump were inoperable. Therefore, absent an operability determination that established reasonable assurance of containment spray system operability, the LCO should not have been exited until corrective actions were completed and a satisfactory retest was performed. However, Constellation exited the LCO based on an incomplete operability determination on April 25, 2025.
Following interactions with NRC staff, Constellation investigated the cause of the containment spray systems inability to establish adequate flow to meet IST requirements and identified excessive movement on the discharge check valve obturator shaft as well as pump degradation.
Corrective Actions: Constellation performed repairs on the discharge check valve and adjusted the pump alignment to partially restore pump performance. Additionally, Constellation performed an analysis to revise the pump reference values and retested the system as required by ISTB-6200 to establish new reference values for the pump. The containment spray loop was satisfactorily retested on May 19, 2025. Finally, Constellation staff performed an additional evaluation of the impact of the as-found degraded condition of the check valve and pump based on NRC questions. Constellation concluded that the condition would not result in loss of function sufficient to cause the containment spray system train to be inoperable. The inspectors reviewed the evaluation and concluded there was reasonable assurance that the system would operate as required.
Corrective Action References: IRs 04859274 and 04865142 Performance Assessment:
Performance Deficiency: The inspectors determined that Constellation failed to perform required actions as specified in the ASME OM Code following the identification of test results that did not meet OM Code IST requirements for the containment spray loop 112 pump and discharge check valve was a performance deficiency and was within the licensees ability to identify and correct.
15 Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Equipment Performance 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. Additionally, the performance deficiency was similar to IMC 0612, Appendix E, Example, 2.b., because required actions were not taken after failing to meet OM Code IST acceptance criteria for applicable pump and check valve. Specifically, corrective actions as described in the OM Code for the pump and check valve were not performed, as required, following IST results that failed to provide the required pump flow and did not demonstrate that the check valve achieved the required change of obturator position.
Significance: Green. The inspectors assessed the significance of the finding using IMC 0609, Appendix A, The Significance Determination Process (SDP) for Findings At-Power. Using Exhibit 2, Section A, the inspectors determined the degraded condition represented a design or qualification condition that resulted in inoperability but maintained probabilistic risk assessment functionality of the containment spray system.
Cross-Cutting Aspect: H.14 - Conservative Bias: Individuals use decision-making practices that emphasize prudent choices over those that are simply allowable. A proposed action is determined to be safe in order to proceed, rather than unsafe in order to stop. Specifically, Constellation did not take timely action to address degraded conditions commensurate with their safety significance. The licensee considered the applicable pump test a no test without following the requirements as outlined in the OM Code that when performing an IST test, actions must be taken based on the data collected.
Enforcement:
Violation: 10 CFR 50.55a(f)(4), "Inservice Testing Standards Requirement for Operating Plants," states, in part, throughout service life of a boiling or pressurized water-cooled nuclear power facility, pumps and valves that are within the scope of the ASME OM Code must meet the IST requirements set forth in the ASME OM Code as incorporated by refence in 10 CFR 50.55a.
ASME OM Code (2012 Edition), Subsection ISTB, paragraph ISTB-6200(b), "Corrective Actions," states, in part, "if the measured test parameter values fall within the required action range of Table ISTB-5221-1, the pump shall be declared inoperable until either the cause of the deviation has been determined and the condition is corrected, or an analysis of the pump is performed in accordance with subpart ISTB-6200(c)."
ASME OM Code, Subsection ISTB, paragraph ISTB-6300, "Systematic Error," states, in part, "when a test shows measured parameter values that fall outside of the acceptable range of Table ISTB-5221-1 that have resulted from an identified systematic error, such as improper system lineup or inaccurate instrumentation, the test shall be rerun after correcting the error."
ASME OM Code, Subsection ISTC, paragraph ISTC-5224, "Corrective Action," states, in part, "if a check valve fails to exhibit the required change of obturator position, it shall be declared inoperable. A retest showing acceptable performance shall be run following any required corrective action before the valve is returned to service."
Contrary to the above, on April 22, 2025, Constellation did not comply with the requirements of the 2012 Edition of the ASME OM Code, as incorporated by reference, in 10 CFR 50.55a for the current IST program at Nine Mile Point, Unit 1, for Subsections ISTB-6200, ISTB-6300
16 and ISTC-5224.
Specifically, after test results for the containment spray system loop 112 pump (80-24) did not fall within the acceptable range specified by Constellation to comply with the ASME OM Code during IST testing. Constellation did not declare the pump inoperable until either the cause of the deviation had been determined and the condition was corrected, or perform an analysis to determine the cause of the deviation in accordance with ISTB-6200(c) or identify a systematic error, correct the error, and retest the pump in accordance with ISTB-6300. Lastly, Constellation did not declare the discharge check valve (80-26) inoperable when it failed to exhibit the required change in obturator position in accordance with ISTC-5224. Instead, Constellation declared the affected components and system operable and returned them to service without completing the actions required by ASME OM Code as incorporated by reference in 10 CFR 50.55a.
Enforcement Action: This violation is being treated as an NCV, consistent with Section 2.3.2 of the Enforcement Policy.
Observation: Multiple Trips of Unit 1 Liquid Poison Pump 12 71152A The inspectors reviewed actions taken to address the failed surveillance tests on the Unit 1 liquid poison pump 12. The sample was selected due to multiple failures. The initial failure occurred on April 29, 2024, and was documented in IR 04770428. There were three subsequent failures which were documented in Constellation's corrective action program.
After the second trip, a 4.0 critique was performed and placed in the corrective action program. Constellation raised the instantaneous setpoint on the circuit breaker based on feedback from corporate. There remains an action to replace the liquid poison pump 12 motor under IR 04819724. On February 11, 2025, troubleshooting was completed satisfactorily under IR 04836433.
In some cases the level of detail in the documentation could be improved. For example, an action was created to replace the control switch on liquid poison pump 11, however the work order measured the resistance and determined that the switch did not need to be replaced.
This information was not documented in the action to replace the switch.
Failure to Control System Boundaries Results in Loss of Reactor Pressure Vessel (RPV)
Inventory During Unit 1 Shutdown Operations Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green FIN 05000220/2025002-03 Open/Closed
[H.3] - Change Management 71153 A self-revealed Green finding was identified when the licensee failed to control the Unit 1 RPV boundary when establishing conditions for an RPV pressure test. Specifically, Constellation failed to ensure that electromatic relief valves (ERVs), which served as a pressure boundary for the RPV pressure test, were in a position that would not adversely impact the unit, contrary to procedure OP-AA-109-101, "Operations Tagout," Section 8.5.3, "Executing a Temp Lift." As a result, static head pressure lifted unisolated ERVs, resulting in the loss of 3 feet of RPV water level to the suppression pool.
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Description:==
The Unit 1 refueling outage N1R28 schedule included ERV preventive maintenance, which would then be followed by commencement of an RPV pressure test. On March 27, 2025, ERV preventive maintenance required gags to be placed on all six ERV pilot
17 valves. The gags placed the ERV pilot valve actuator in the depressed position, which allows the ERV to pass flow under static head pressure. On March 28, 2025, the work site was turned over to the final work group and authorization to start work was accompanied by a control room log note which stated, ERV blocking valves are closed per tagout UY-01-0098.
ERV pilots verified closed as of 3/27@1600 (EMD). However, inspectors noted that the log entry was misleading, in that the ERV pilots were not closed at the time. Subsequently, the maintenance actions became delayed due to an unrelated issue and the licensee placed a hold on ERV maintenance to establish conditions for the RPV pressure test to be performed while waiting on the delayed maintenance. In the process of managing the schedule change, licensee personnel determined that a temporary tag lift would be required to restore three of the six ERVs to meet minimum RPV pressure test criteria.
The temporary tag lift was developed, reviewed, and sent to the system coordination team (SCT) lead for approval. The SCT lead verified the condition of the ERVs through the erroneous control room log note recorded on March 28, 2025. By relying on this previous log note, the SCT lead carried forward the original error and inappropriately approved the temporary lift, leaving four ERVs as a vulnerable leak path during establishment of the tests prerequisites.
Step 8.5.3.1 of OP-AA-109-101, "Operations Tagout," states, in part, that an on-shift SRO, or equivalent as determined by the Senior License Holder, should complete the Temp Lift SRO Removal Authorization once they have verified that the unit is in a condition that will not adversely be impacted by the Temp Lift.
On March 30, 2025, operations personnel implemented the temporary tag lift to establish the necessary configuration for the RPV pressure test. This included opening the ERV blocking valves, which had previously isolated the ERVs from the reactor vessel. Upon opening the valves, water filled the ERV piping and flowed through two of the gagged ERVs, diverting reactor vessel water to the torus. Operations personnel briefed that unblocking the relief valves would cause a small change in level, as inventory filled the space between the blocking valves and the ERVs. Operations personnel recognized that the level was lowering more significantly and faster than anticipated and directed in-field operators to close the blocking valves, terminating the event. The event resulted in 3 feet of reactor water inventory flowing to the suppression pool.
Per IMC 0309, Reactive Inspection Decision Basis for Power Reactors, the NRC considered whether this inspection sample should be the subject of a reactive inspection and determined that a reactive inspection was not necessary, as documented in ML25097A075.
Corrective Actions: Operators recognized the inadvertently created flow paths and took action to isolate them. The licensee entered this issue into its corrective action program as IR 04850676. The licensee completed a corrective action program evaluation in accordance with procedure PI-AA-125-1003, "Corrective Actions Program Evaluation Manual," Revision
- 7.
Corrective Action Reference: IR 04850676 Performance Assessment:
Performance Deficiency: The licensee failed to adequately control the status of RPV boundary valves, and did not effectively verify that plant conditions would not lead to an undesirable system response in accordance with procedure OP-AA-109-101.
18 Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Configuration 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, it resulted in the unplanned loss of 3 feet of RPV level during shut down conditions.
Significance: The inspectors assessed the significance of the finding using IMC 0609, Appendix G, Shutdown Operations Significance Determination Process. Attachment 1, Exhibit 2, questions 2 and 3, related to loss of inventory initiators, were answered NO and YES, respectively, and the finding therefore screened to Green, because the configuration of the flow path established inherently limited the potential for draining the RPV. Specifically, if the flow path went unrecognized or unmitigated, the RPV could only have drained to the level of the main steam lines, which is much higher than lines required for the decay heat removal system and, therefore, could not have significantly impacted decay heat removal capability.
Cross-Cutting Aspect: H.3 - Change Management: Leaders use a systematic process for evaluating and implementing change so that nuclear safety remains the overriding priority.
Enforcement: Inspectors did not identify a violation of regulatory requirements associated with this finding.
EXIT MEETINGS AND DEBRIEFS The inspectors verified no proprietary information was retained or documented in this report.
On August 7, 2025, the inspectors presented the integrated inspection results to Tim Peter, Site Vice President, and other members of the licensee staff.
On July 18, 2025, the inspectors presented the dose assessment inspection results to Carl Crawford, Plant Manager, and other members of the licensee staff.
19 DOCUMENTS REVIEWED Inspection Procedure Type Designation Description or Title Revision or Date 71111.01 Procedures N2-OP-102 Meteorological Monitoring 028 WC-AA-107 Seasonal Readiness 031 71111.04 Procedures N1-OP-14 Containment Spray System 048 N2-OP-33 High Pressure Core Spray System 020 71111.05 Fire Plans N2-FPI-PFP-0201 Unit 2 Pre-Fire Plans 007 71111.12 Corrective Action Documents 04850103 04857999 71111.13 Engineering Evaluations ECP-25-000162 Bypass Valve #1 Ovation Isolation 0
Procedures N2-OP-23A Hydraulic Isolation and Restoration of Turbine Stop or Turbine Control or Combined Intercept Valves or Bypass Valves 002T2 71111.15 Corrective Action Documents 02086957 04850226 04853562 04855847 04857784 04857999 04859274 04868710 Miscellaneous Core Operating Limits Report Nine Mile Point 2 8
Procedures N1-OP-31 Tandem Compound Reheat Turbine 055 N1-ST-C6 Source Range Monitor Operability Test completed 3/29/25 N2-RESP-001 Power Distribution Limits Verification completed 4/21/25 71111.18 Engineering Changes ECP-23-000151 Replace Level Detector Assembly for High Level Scram Discharge Volume RPS Channels 11 and 12 0
ECP-25-000153 Installation of Modification for 13 Feedwater Pump Clutch Oil Reservoir 000 Procedures IP-ENG-001 Nuclear Industry Standard Process - Engineering 3
20 Inspection Procedure Type Designation Description or Title Revision or Date N1-MFT-104 Mod Functional Test for FCV-29-134 QuickTrak Upgrade 00300 Work Orders C93895357 71111.24 Procedures N1-ISP-036-104 Low Low Reactor Water Level Instrument Trip Channel Calibration 016 N1-ISP-044-005 High Water Level Scram Discharge Volume Instrument Channel Functional Calibration 010 N1-ISP-066-003 Auto Depressurization System Operability Test 00400 N1-ST-Q1D Core Spray 122 Pump and Valve Operability Test 027 N1-ST-Q5 Primary Containment Isolation Valves Operability Test 041 N1-ST-Q6C Containment Spray System Loop 112 Quarterly Operability Test 025 N1-ST-R2B LOCA [Loss of Coolant Accident] and EDG [Emergency Diesel Generator] 103 Simulated Auto Initiation Test 006 N1-ST-V8 Main Steam Feedwater Shutdown Cooling Emergency Cooling Head Vent Valve Cold Shutdown Operability Test 014 N2-OSP-EGS-M@001 Diesel Generator and Diesel Air Start Valve Operability Test, Division I and II 026 N2-OSP-FOF-M001 Engine Driven Fire Pump Operability and Storage Tank Level Test 006 N2-OSP-ICS-Q@002 RCIC Pump and Valve Operability Test and System Integrity Test and ASME XI Functional Test and Analysis 020 N2-RCPM-GEN-V070 Protective/Auxiliary Relays and Timers 00800 Work Orders C93252557 C93895383 C93895530 C93911654 C93942693 C93962755 C93962757 C93971241 C94008457 71151 Miscellaneous NEI 99-02 Regulatory Assessment Performance Indicator Guideline 7
21 Inspection Procedure Type Designation Description or Title Revision or Date 71152S Corrective Action Documents 04468081 04475865 04478622 04494680 04538824 04541784 04552235 04553907 04675172 04721028 04721926 04817277 04824719 04826720 04827068 04829978 04833168