IR 05000461/2023004
| ML24031A638 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 02/02/2024 |
| From: | Robert Ruiz NRC/RGN-III/DORS/RPB1 |
| To: | Rhoades D Constellation Energy Generation |
| References | |
| IR 20232004 | |
| Download: ML24031A638 (1) | |
Text
SUBJECT:
CLINTON POWER STATION - INTEGRATED INSPECTION REPORT 05000461/2023004
Dear David Rhoades:
On December 31, 2023, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Clinton Power Station. On January 23, 2024, the NRC inspectors discussed the results of this inspection with Norha Plumey, 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 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 III; the Director, Office of Enforcement; and the NRC Resident Inspector at Clinton Power Station.
If you disagree with a cross-cutting aspect assignment 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 III; and the NRC Resident Inspector at Clinton Power Station.
February 2, 2024 This letter, its enclosure, and your response (if any) will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with Title 10 of the Code of Federal Regulations 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely, Robert Ruiz, Chief Reactor Projects Branch 1 Division of Operating Reactor Safety Docket No. 05000461 License No. NPF-62
Enclosure:
As stated
Inspection Report
Docket Number:
05000461
License Number:
Report Number:
Enterprise Identifier:
I-2023-004-0047
Licensee:
Constellation Nuclear
Facility:
Clinton Power Station
Location:
Clinton, IL
Inspection Dates:
October 01, 2023, to December 31, 2023
Inspectors:
T. Henning, Senior Operations Engineer
B. Jose, Senior Reactor Inspector
J. Kutlesa, Emergency Preparedness Inspector
A. Muneeruddin, Resident Inspector
J. Murphy, Illinois Emergency Management Agency
J. Nance, Operations Engineer
J. Steward, Senior Resident Inspector
Approved By:
Robert Ruiz, Chief
Reactor Projects Branch 1
Division of Operating Reactor Safety
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Clinton Power 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 Provide Switchyard Maintenance Oversight Led to Reactor Scram Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green NCV 05000461/2023004-01 Open/Closed
[H.4] -
Teamwork 71152A A self-revealed Green finding and associated non-cited violation (NCV) of Technical Specification (TS) 5.4.1.a, Procedures, was identified for the licensees failure to implement the requirements of procedure ER-AA-200, Preventative Maintenance Program, revision 7, to ensure an effective maintenance strategy via oversight of switchyard maintenance activities. Specifically, the licensee failed to ensure the manufacturers 12-year breaker maintenance was performed, resulting in a degraded condition on Gas Circuit Breaker (GCB) 4510, which prevented it from successfully tripping open and caused an actuation of breaker failure protective relaying. The protective relay tripped GCB-4506 (the other generator output breaker) and ultimately led to a main turbine trip and reactor scram.
Additional Tracking Items
Type Issue Number Title Report Section Status LER 05000461/2023-001-00 LER 05000461/2023-001-00 for Clinton Power Station,
Unit 1, Grid Fault Results in Switchyard Breaker Trips and Reactor Scram 71153 Closed
PLANT STATUS
Unit 1 began the inspection period in Mode 4, cold shutdown, for completion of a planned refueling outage (C1R21). On October 8, 2023, the unit was placed in Mode 2 and commenced reactor startup, heat-up, and pressurization to rated pressure. Following required testing at rated pressure, reactor power was raised, and the unit was placed in Mode 1. On October 10, 2023, the main generator was synchronized to the grid, ending C1R21. Following power ascension, the unit reached rated thermal power (RTP) on October 13, 2023. On December 30, 2023, Unit 1 lowered reactor power to 75 percent to perform a planned control rod sequence exchange and main turbine valve testing. On December 31, 2023, the unit returned to RTP and continued to operate at or near RTP for the remainder of the 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 cold temperatures for the following systems: fire protection, shutdown service water, and FLEX on December 21, 2023.
71111.04 - Equipment Alignment
Partial Walkdown Sample (IP Section 03.01) (1 Sample)
The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:
- (1) Division 1 battery and direct current distribution on October 24, 2023
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) Fire Area C-1, drywell elevations 723', 737', and 778' on October 7, 2023
- (2) Fire Area M-1 and M-2c, division 1 shutdown service water pump room and elevation 699' screen house general area on October 25, 2023
- (3) Fire Area N/A, makeup water pump house on October 25, 2023
- (4) Fire Area N/A, FLEX equipment storage building on October 25, 2023
71111.07A - Heat Exchanger/Sink Performance
Annual Review (IP Section 03.01) (1 Sample)
The inspectors evaluated readiness and performance of:
- (1) Division 2 diesel generator 12, and 16-cylinder cooling water heat exchanger inspection per Work Order (WO) 4771919
71111.11A - Licensed Operator Requalification Program and Licensed Operator Performance
Requalification Examination Results (IP Section 03.03) (1 Sample)
- (1) The inspectors reviewed and evaluated the licensed operator examination failure rates for the requalification annual operating exam administered between October 18, 2023, and November 17, 2023.
71111.11B - Licensed Operator Requalification Program and Licensed Operator Performance
Licensed Operator Requalification Program (IP Section 03.04) (1 Sample)
- (1) Biennial Requalification Written Examinations The inspectors evaluated the quality of the licensed operator biennial requalification written examination administered on November 3, 2023.
Annual Requalification Operating Tests The inspectors evaluated the adequacy of the facility licensees annual requalification operating test.
Administration of an Annual Requalification Operating Test The inspectors evaluated the effectiveness of the facility licensee in administering requalification operating tests required by 10 CFR 55.59(a)(2) and that the facility licensee is effectively evaluating their licensed operators for mastery of training objectives.
Requalification Examination Security The inspectors evaluated the ability of the facility licensee to safeguard examination material, such that the examination is not compromised.
Remedial Training and Re-examinations The inspectors evaluated the effectiveness of remedial training conducted by the licensee, and reviewed the adequacy of re-examinations for licensed operators who did not pass a required requalification examination.
Operator License Conditions The inspectors evaluated the licensees program for ensuring that licensed operators meet the conditions of their licenses.
Control Room Simulator The inspectors evaluated the adequacy of the facility licensees control room simulator in modeling the actual plant, and for meeting the requirements contained in 10 CFR 55.46.
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 on October 8, 2023, during reactor startup, during generator sync on October 10, 2023, and on November 18, 2023, during night shift routines.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed and evaluated the control room simulator annual exam on October 25 and November 8, 2023.
71111.12 - Maintenance Effectiveness
Maintenance Effectiveness (IP Section 03.01) (2 Samples)
The inspectors evaluated the effectiveness of maintenance to ensure the following structures, systems, and components (SSCs) remain capable of performing their intended function:
- (1) Action Request (AR) 4708369, Significant Leak-by Past 1B33F070A & 1B33F071A, Reactor Recirculation Pump A Drain Lines in Drywell
- (2) AR 4713073, Missed Technical Specification Channel Calibration Surveillance on APRM A
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (2 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) Elevated shutdown risk (Yellow) due to lowered vessel inventory below the flange during reactor vessel reassembly sequence on October 1, 2023
- (2) Elevated online risk (action Green) during scheduled division 2 diesel generator system outage window from October 23-28, 2023 on October 25, 2023
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (4 Samples)
The inspectors evaluated the licensees justifications and actions associated with the following operability determinations and functionality assessments:
- (1) AR 4706844, Control Rod Drive Mechanism (CRDM) 36-05 Leakage During Reactor Pressure Test
- (2) AR 4711563, LPRM [local power range monitor] 46-39A Upscale AR 4711563 Results in Half Scram on RPS B
- (3) AR 4713999, 4.16kV Bus 1B1 Momentary Voltage Dip
- (4) AR 4714921, Reserve Auxiliary Transformer Mechanically Switched Capacitor Bank Trip Results in Overvoltage Condition on 4.16kV Bus 1A1
71111.20 - Refueling and Other Outage Activities
Refueling/Other Outage Sample (IP Section 03.01) (1 Sample)
- (1) The inspectors continued to evaluate C1R21 refueling activities from October 1, 2023, through October 10, 2023.
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) (8 Samples)
- (1) Clinton Power Station (CPS) 9031.13, Source Range Monitor (SRM), D channel functional after replacement of motor module per WO 5400544 on October 12, 2023
- (2) CPS 9067.01, Standby Gas Treatment A Train Flow/Heater Operability, after replacement of hydramotor per WO 5402454-08 on October 18, 2023
- (3) PMT ATWS (anticipated transient without scram) system pressure and level test after incorporation of Engineering Change (EC) 629111 per WO 5016973-07 and -08 on October 27, 2023
- (4) CPS 9054.01C002, RCIC [reactor core isolation cooling] (1E51-C001) High Pressure Operability Checks, per WO 5407784 on October 27, 2023
- (5) CPS 9861.02D045, Local Leak Rate Test for 1FP092, after maintenance performed on valve per WO 5223875 on October 29, 2023
- (6) Division 2 diesel generator heat exchanger and starting air system PMTs per WOs 4771919-05 and 5212024-02 on November 3, 2023
- (7) Reserve auxiliary transformer B functional test of the mechanically switched capacitor banks per WO 4989193 on November 3, 2023
- (8) PMT of division 2 diesel generator 16-cylinder fuel priming pump following replacement of commutator brushes and motor end bell removal of excess oil and internal cleaning per WOs 54220844-01 and -02 on December 1, 2023
Surveillance Testing (IP Section 03.01) (3 Samples)
- (1) Core verification per the cycle 22 reload plan on October 2, 2023
Integrated Test, on October 12, 2023
- (3) High pressure core spray (HPCS) valve operability test per WOs 5254093 and
===5199618 on October 16, 2023
71114.04 - Emergency Action Level and Emergency Plan Changes
Inspection Review (IP Section 02.01-02.03)===
- (1) The inspectors evaluated the following submitted Emergency Action Level and Emergency Plan changes.
- Evaluation No. 22-59; 50.54(q) Program Evaluation/Assessment Review:
Emergency Action Levels for Clinton Station of January 9, 2023
- (q) Evaluator Training Report of June 30, 2023
- EP-AA-1003: Exelon Nuclear Radiological Emergency Plan Annex for Clinton Station, Revision 8
- EP-AA-1003, Addendum 3: Emergency Action Levels for Clinton Station, Revision 8
- EP-AA-1003, Addendum 3: Emergency Action Levels for Clinton Station, Revision 7 This evaluation does not constitute NRC approval.
OTHER ACTIVITIES - BASELINE
===71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:
BI02: RCS Leak Rate Sample (IP Section 02.11)===
- (1) Unit 1 (October 1, 2022, through September 30, 2023)
71152A - Annual Follow-up Problem Identification and Resolution Annual Follow-up of Selected Issues (Section 03.03)
The inspectors reviewed the licensees implementation of its corrective action program related to the following issues:
- (1) AR 4681106, Plant Shutdown Due to Increased Drywell Leakage Trend
- (2) AR 4717578, Escalating Concerns Regarding SCWE at Clinton Power Station
- (3) AR 4696290, NRC Green NCV 2023002-01 Integrated Inspection Report
- (4) AR 4551751, Trip of 4506 and 4510 Results in Reactor Scram
71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02)
- (1) The inspectors reviewed the licensees corrective action program for potential adverse trends in configuration control events on December 19, 2023, that might be indicative of a more significant safety issue. Inspectors documented conclusions of the review as an observation in the Inspection Results Section of the report.
71153 - Follow Up of Events and Notices of Enforcement Discretion Event Report (IP Section 03.02)
The inspectors evaluated the following licensee event reports (LERs):
- (1) LER 05000461/2023-001-00, Grid Fault Results in Switchyard Breaker Trips and Reactor Scram (ADAMS Accession No. ML23094A112). The inspection conclusions associated with this LER are documented in this report under the Inspection Results section. This LER is closed.
INSPECTION RESULTS
Failure to Provide Switchyard Maintenance Oversight Led to Reactor Scram Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green NCV 05000461/2023004-01 Open/Closed
[H.4] -
Teamwork 71152A A self-revealed Green finding and associated non-cited violation (NCV) of Technical Specification (TS) 5.4.1.a, Procedures, was identified for the licensees failure to implement the requirements of procedure ER-AA-200, Preventative Maintenance Program, revision 7, to ensure an effective maintenance strategy via oversight of switchyard maintenance activities. Specifically, the licensee failed to ensure the manufacturers 12-year breaker maintenance was performed, resulting in a degraded condition on Gas Circuit Breaker (GCB) 4510, which prevented it from successfully tripping open and caused an actuation of breaker failure protective relaying. The protective relay tripped GCB-4506 (the other generator output breaker) and ultimately led to a main turbine trip and reactor scram.
Description:
On January 31, 2023, approximately 16 miles from Clinton Power Station (CPS), a phase-to-phase fault occurred on the 345kV transmission line, 4571. Consequently, gas circuit breakers (GCBs) 4510 and 4514 were sent a trip signal to isolate 4571 from CPS. However, generator output breaker, GCB 4510, was unable to successfully trip open, resulting in tripping the other generator output breaker, GCB 4506. The trip of both generator output breakers, GCB 4506 and GCB 4510, effectively disconnected the main generator from the grid. This resulted in a main generator load reject and an actuation of the generator power load unbalance logic. In response to these conditions, the turbine tripped, and the reactor scrammed. The licensee documented the event under LER 05000461/2023-001-00, Grid Fault Results in Switchyard Breaker Trips and Reactor Scram.
The licensee performed a root cause investigation under Action Request (AR) 4551751 and determined the cause of the event was due to the manufacturers 12-year breaker maintenance not being performed. The direct failure mechanism of the unsuccessful trip of GCB 4510 was concluded to be a result of corrosion from expected moisture on the air system charging valve. The breakers in the licensees electrical switchyard are owned and maintained by the transmission distribution service provider, Ameren; however, CPS scopes the switchyard equipment under the maintenance rule program and Constellation equipment reliability program. Several functions are monitored under maintenance rule: supplying offsite power to the 4.16kV safety busses, distributing generated power to the offsite network, and providing offsite power to the balance of plant busses when the unit auxiliary transformers are not in service. Therefore, CPS is responsible to review breakers maintenance strategy and completion documents, and to work with Ameren to implement any changes required to maintain an effective strategy.
Consequently, Ameren and CPS have an interconnection agreement (IA) which requires Ameren to perform routine inspection and testing of the transmission and distribution system as well as to provide data. However, the IA does not require any specific breaker maintenance. Additionally, CPS has a standalone contract in place to perform further maintenance on these breakers. Nevertheless, there is no evidence that the vendor manual was thoroughly reviewed and compared to the performance centered maintenance (PCM)template and Amerens preventative maintenance plan. There is also no evidence that preventative maintenance was ever proposed on the charging valve or for a GCB 4510 overhaul during previous self-assessments and gap analyses. Step 4.3.4 of station procedure ER-AA-200, states PCM templates may not provide the complete maintenance strategy for all Critical or Non-Critical Components. As such, it is the responsibility of the Site Subject Matter Expert or Strategic Engineer to ensure that there is an effective maintenance strategy for all Critical or Non-Critical Components based on failure history, vendor recommendations, industry OPEX and engineering judgement.
TS 5.4.1. Procedures, states in part that, written procedures shall be established, implemented, and maintained covering the following activities: TS 5.4.1.a states in part that, the applicable procedures recommended in Regulatory Guide 1.33, Revision 2, Appendix A, February 1978; Regulatory Guide 1.33, Quality Assurance Program Requirements, revision 2, dated February 1978, contains requirements for performing maintenance at nuclear power plants and is committed to by the site through the licensees Technical Specifications. Section 9.b of Regulatory Guide 1.33 states in part that, preventative maintenance schedules should be developed to specify [] inspections of equipment, and section 9.c states in part that, procedures for the repair or replacement of equipment should be prepared prior to the beginning of work. Such procedures for major equipment that is expected to be repaired during the life of the plant should be written early in plant life.
Corrective Actions: Following the reactor scram, immediate actions by Ameren included troubleshooting and repair of GCB 4510, performing trip testing of GCB 4506 to ensure proper operation, performing line repairs to 4571, and performing drone flight inspections on the lines. Some long-term CPS corrective actions consist of developing and implementing preventative maintenance strategies for switchyard breakers in accordance with station procedure ER-AA-200. CPS will also work with Ameren to perform breaker overhaul or replacement of GCBs 4506 and 4510 as specified in the breaker manual. The breaker overhaul or replacement will later extend to all the other same type of breakers located in the 345kV switchyard.
Corrective Action References: AR 4551751, Trip of 4506 and 4510 Results in Reactor Scram
Performance Assessment:
Performance Deficiency: The licensees failure to implement requirements in procedure ER-AA-200, Preventative Maintenance Program, revision 7, to ensure that there is an effective maintenance strategy for switchyard components was a performance deficiency. Specifically, the licensee failed to ensure the manufacturers 12-year breaker maintenance was performed, resulting in a degraded condition on GCB 4510, which prevented it from successfully tripping open and caused an actuation of breaker failure protective relaying. The protective relay tripped GCB-4506 (the other generator output breaker) and ultimately led to a main turbine trip and reactor scram.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Equipment Performance 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 licensee failed to oversee the preventative maintenance strategies of switchyard components which caused a reactor scram.
Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power.
Specifically, in exhibit 1, Initiating Events Screening Questions, the inspectors determined that this finding is of very low safety significance (Green), because the finding did not cause both a reactor trip and the loss of mitigation equipment relied upon to transition the plant from the onset of the trip to a stable shutdown condition.
Cross-Cutting Aspect: H.4 - Teamwork: Individuals and work groups communicate and coordinate their activities within and across organizational boundaries to ensure nuclear safety is maintained. Specifically, the licensee failed to ensure Ameren was performing the required level of preventative maintenance in the switchyard. Moreover, communication between Ameren and CPS has not been consistent on work performed on breakers in the switchyard.
Enforcement:
Violation: Technical Specification 5.4.1.a, Procedures, states that written procedures shall be established, implemented, and maintained covering the applicable procedures recommended in Regulatory Guide 1.33, Revision 2, Appendix A, dated February 1978.
Regulatory Guide 1.33, Quality Assurance Program Requirements (Operation), Appendix A, Section 9, Procedures for Performing Maintenance, states, in part, that preventive maintenance schedules should be developed to specify lubrication schedules, inspections of equipment and replacement of such items as filters and strainers, furthermore, procedures for the repair or replacement of equipment should be prepared prior to the beginning of work. Such procedures for major equipment that is expected to be repaired during the life of the plant should be written early in plant life.
Licensee procedure ER-AA-200, Preventive Maintenance Program, is a procedure covered by Regulatory Guide 1.33. Procedure ER-AA-200 outlines the method through which the site develops the preventive maintenance strategy for plant structures, systems, and components in order to maintain them at an appropriate state of reliability based on their relative importance to safety, production, and cost. Further, step 4.3.4 of procedure ER-AA-200, states PCM templates may not provide the complete maintenance strategy for all Critical or Non-Critical Components. As such, it is the responsibility of the Site Subject Matter Expert or Strategic Engineer to ensure that there is an effective maintenance strategy for all Critical or Non-Critical Components based on failure history, vendor recommendations, industry OPEX and engineering judgement.
Contrary to the above, on January 31, 2023, the licensee failed to ensure that there was an effective maintenance strategy for all Critical or Non-Critical Components based on failure history, vendor recommendations, industry OPEX and engineering judgement, in accordance with the requirements in procedure ER-AA-200, Preventative Maintenance Program, revision 7. Specifically, the licensee failed to ensure switchyard preventive maintenance on breaker GCB 4510, to include the vendor recommended 12-year breaker maintenance, resulting in a degraded condition on GCB 4510 which prevented it from successfully tripping open, and caused an actuation of breaker failure protective relaying. The protective relay tripped GCB-4506 (the other generator output breaker) and ultimately led to a main turbine trip and reactor scram.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Observation: Adverse Trend in Configuration Control Events 71152S The inspectors performed a review of site issues, particularly those entered into the licensees corrective action program (CAP) over several months following the forced outage, C1F64, which ended in May 2023. During their review, the inspectors noted an adverse trend involving configuration control events. Specific CAP entries reviewed by the inspectors included, but were not limited to:
- On June 14, 2023, mechanical maintenance technicians began work on the incorrect section of discharge piping of the chemical waste area floor drain sump. Upon identification of water leakage from loosened pipe flange, a radiation protection technician notified the technicians that they were on the wrong piping section and notified the main control room. Work was stopped and equipment was placed in a safe condition. [AR 4684846]
- On August 4, 2023, an equipment operator left a component cooling water vent valve open following a venting evolution as required by a daily compensatory action. The oncoming crew recognized the lowering trend in component cooling water tank level and investigated to discover the vent valve was left open. The crew closed the valve and restored level. [AR 4694776]
- On August 21, 2023, Tagout 01-AP-F42D002-001 was hung on nightshift by operations to install alternate power to refuel components. During a worker tagout walk down on dayshift, the workers reported the isolation boundary was correct, but two tags were hung on opposite components. [AR 4697620]
- On October 19, 2023, while performing procedure CPS 8501.79, 4.16kV Bus 1A Reserve Feed Breaker Protective Relay Functional Testing, an electrical technician opened the incorrect test switch. This action resulted in an inadvertent trip of a non-safety breaker and subsequent loss of plant ventilation heating. [AR 4711009]
- On November 5, 2023, while placing condensate polisher D in rinse to return to service, the polisher vent valve to atmosphere (LCLC tank), was inadvertently left open by operations. The main control room was monitoring condensate and feedwater flows and identified an anomaly with diverging condensate pump flows and a lowering cycled condensate tank level. After identification, the valve was then shut and condensate flow returned to normal, thereby arresting the lowering cycled condensate tank level. [AR 4715397]
The licensee first identified an adverse trend in configuration control events on August 23, 2023, documented under AR 4698185, Trend in Operations: Configuration Control. The events listed in that AR were specifically recognizing the trend in operations.
As more configuration control events started to occur, the site rolled these events into a multidisciplinary-wide trend on October 20, 2023, under AR 4711360, Trend IR for Station Events Requiring a Prompt Investigation. The causal evaluations performed by the licensee determined the primary occurrence for these events was due to an absence of technical human performance (THU) behaviors and management involvement. The main corrective action coming from this AR was the implementation of an observation rotation plan for senior managers. They will be tasked to conduct cross-functional paired observations on jobs/tasks from pre-job brief to post-job critique. Senior managers will report out the learnings to the site leadership team on a weekly basis.
In general, the inspectors found that corrective actions coming out of the above ARs, specifically, individual coaching, human performance briefings, and training alone were not effective in mitigating the adverse trend based on a continuation of configuration control events throughout the latter half of calendar year 2023. Furthermore, the inspectors will observe how the formal addition of senior manager engagement via the observation rotation plan helps in arresting the adverse trend in configuration control events. The inspectors did not identify any violations of regulatory requirements or performance deficiencies of more than minor significance based on the circumstances above.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On January 23, 2024, the inspectors presented the integrated inspection results to Norha Plumey, Site Vice President, and other members of the licensee staff.
- On November 3, 2023, the inspectors presented the licensed operator biennial requalification program inspection results to Bryan Currier, Acting Site Vice President, and other members of the licensee staff.
- On December 20, 2023, the inspectors presented the emergency action level and emergency plan changes inspection results to Christopher Davenport, Emergency Preparedness Coordinator, and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Corrective Action
Documents
Items not Completed for Winter Readiness
2/04/2023
Miscellaneous
Correspondence
Certification of 2023/2024 Winter Readiness
10/20/2023
1860.01C001
Operations Department Cold Weather Preparations
Checklist
9d
CPS 1860.01
Cold Weather Operation
10a
1860.01C003
Cold Weather Heater and Heat Trace Operability Checklist
2c
Procedures
1860.01E001
Cold Weather Heat Tracing System Electrical Lineup
CPS 3503.01
Battery and DC Distribution (DC)
19c
Procedures
3503.01E001
Battery and DC Distribution Electrical Lineup
14b
1893.04M800
Div 1 SX Pump Room Prefire Plan
5a
1893.04M804
699 Screen House: General Area Prefire Plan
4a
1893.04M820
Makeup Water Pump House Ground Floor Prefire Plan
1a
1893.04M821
Makeup Water Pump House Upper-Level Floor Prefire Plan
Fire Plans
1893.04M838
FLEX Equipment Storage Building
Miscellaneous
Report No.
NUC2300059-L-
CAR-001
Coating Assessment Report, Clinton Station, 1DG11AB and
1DG12AB
10/21/2023
CPS 8130.01
Heat Exchanger Maintenance/Repairs
Procedures
Service Water Heat Exchanger Inspection Guide
Work Orders
and -02
1DG11AB and 1DG12AB Inspect HX, Borescope, Eddy
Current 100%, 12 Cylinder and 16 Cylinder Cooling Water
Heat Exchangers
11/17/2023
Procedures
TQ-AA-150-F25
23 Clinton LORT Annual Exam Status Report
11/17/2023
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Level 4 C&T Event - Wrong EIN Selected
MC Flush Valve Inadvertently Left Open
07/06/2022
Clinton Operations Elevation
08/31/2022
Trend: 1 Near Miss & 2 Ops CC Events in Less Than 3
Months
09/22/2023
TT Failed to Collect Data on 12-37 9813.01
01/02/2023
Hourly Fire Watch Missed for Fire Impairments
01/24/2023
NRC ID: Divisional DGs not Posted Protected During ERAT
03/21/2023
CC Vent Valve Inadvertently Left Open
08/04/2023
Unplanned RCIC INOP Time
08/16/2023
Corrective Action
Documents
IFTS Clearance Order Issue
08/21/2023
Corrective Action
Documents
Resulting from
Inspection
NRCID: DG Housekeeping
11/02/2023
22-2023 LOR Training Cycle Schedule
10/30/2023
Job Performance
Measure (JPM)
JPM-043
Job Performance
Measure (JPM)
JPM-271
Job Performance
Measure (JPM)
JPM-415
Job Performance
Measure (JPM)
JPM-523
Job Performance
Measure (JPM)
JPM-311
Job Performance
Measure (JPM)
JPM-222
Job Performance
Measure (JPM)
JPM-248
Job Performance
Measure (JPM)
JPM-419
Miscellaneous
Job Performance
JPM-535
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Measure (JPM)
2: Reactivation of License Log
1: Active License Tracking Log
PA-230904-001
Performance Analysis (RCIC INOP)
09/04/2023
Simulator
Exercise Guide
(SEG)
ESG-LOR-15
Simulator
Exercise Guide
(SEG)
ESG-LOR-95
Simulator
Exercise Guide
(SEG)
ESG-LOR-01
Simulator
Exercise Guide
(SEG)
ESG-LOR-28
SWR List
Simulator Work Request List (2021-2023)
TQ-AA-225-F020
Training Effectiveness Evaluation Worksheet
TQ-AA-306-F-02
Simulator Review Board Minutes
2/15/2021
TQ-AA-306-F-02
Simulator Review Board Minutes
09/28/2022
TQ-AA-306-F-02
Simulator Review Board Minutes
08/07/2023
TQ-AA-306-F-02
Simulator Review Board Minutes
2/16/2022
TQ-AA-306-F-03
Simulator Test Coversheet (Post-Event Testing)
05/30/2023
Written Exam
10/24/2023
Written Exam
10/24/2023
OP-AA-101-113-
1001
Station Event Free Clock (EFC) Program
OP-AA-103-102-
1001
Strategies for Successful Transient Mitigation
Administrative Process for NRC License and Medical
Requirements
NRC Active License Maintenance
Post Transient Review
Procedures
Protected Equipment Program
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Operator Training Programs
Examination Security and Administration
Simulator Management
Self-Assessments PI-AA-126-1001-
F-01
LOR Training Program Focused Self-Assessment
05/01/2023
Miscellaneous
ESG-LOR-01
Loss of Coolant Accident
Corrective Action
Documents
Drywell Leakage Identified
10/10/2023
Drawing M05-
1047, Sheet 008
P&ID Drywell Floor Drain System (RF) - Critical Control
Room Drawing
P
Drawing M05-
1072, Sheet 001
P&ID Reactor Recirculation (RR) - Critical Control Room
Drawing
AH
Drawings
Drawing RR-759
Containment Building Reactor Recirculation Piping
Engineering
Changes
Temporary Leak Seal Repair for 1B33F071A & 1B33F070A
10/10/2023
155549-07
Preventive Maintenance Requirement (PMRQ)
10/27/2023
Miscellaneous
CL-SURV-014
Risk Assessment Missed Surveillance - APRM Channel A
Calibration IR 04713073
APRM A Channel Calibration
10/27/2023
Work Orders
1B33F066A Leakby-Install Lockring
10/11/2023
Corrective Action
Documents
NRC-Identified PCRA Needed for CPS 9831.01C001
11/29/2023
Engineering
Changes
RAT MSC Trip 1A1 Bus Overvoltage Transient
19-AK-13
Analysis of Load Flow, Short Circuit, and Motor Starting
Using ETAP PowerStation
19-AN-19
Calculation for Functional Requirements for 1st and 2nd
Level Undervoltage Relays at 4 KV Buses, 1A1, 1B1 and
1C1 EC 631277
Miscellaneous
639890
EC Evaluation
10/03/2023
Engineering Technical Evaluations
9831.01C001
Whole Core LPRM Calibration Checklist
Procedures
Operability Determinations (CM-1)
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
OP-AA-108-115-
1002
Supplemental Consideration for On-Shift Immediate
Operability Determinations (CM-1)
Procedures
OU-CL-104
Shutdown Safety Management Program Clinton Power
Station
Corrective Action
Documents
ARs 4719873,
4719928,
20110,
20127
Various ARs Associated with the Division 2 DG 16 Cylinder
Fuel Oil Priming Pump Motor
11/30/2023
Engineering
Changes
ATWS Surveillance Test Switches
Clinton Unit 1 Cycle 22 Core Loading Plan
Miscellaneous
Core Verification
Videos
North and South Core Serial Number Verification Videos
10/02/2023
CPS 1014.11
6900/4160/480V Switchgear/Circuit Breaker Operability
Program
5e
9054.01C002
RCIC (1E51-C002) High Pressure Operability Checks
Procedures
CPS 9080.22
Diesel Generator 1B - ECCS Integrated
ATWS Surveillance Test Switch - EC 629111
09/29/2023
Work Orders
ATWS Surveillance Test Switch - EC 629111
09/29/2023
CFR 50.54 Q Evaluator Training Report
06/30/2023
Miscellaneous
Addendum 3,
Revision 8,
Evaluation No.
2-59
§50.54(q) Program Evaluation/Assessment Review:
Emergency Action Levels for Clinton Station
01/09/2023
Exelon Nuclear Radiological Emergency Plan Annex for
Clinton Station
Addendum 3
Emergency Action Levels for Clinton Station
Procedures
Addendum 3
Emergency Action Levels for Clinton Station
NRR Performance Indicators (PIs) SharePoint Site
10/24/2023
71151
Miscellaneous
Clinton PI Data
BI02 PI Data
10/24/2023
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Regulatory Assessment Performance Indicator Guideline
Trip of Gas Circuit Breakers (GCB) 4506 and 4510 Results
in Reactor Scram
2/29/2023
Drywell Floor Drain in Leakage High After Startup from
C1M26
05/25/2023
Plant Shutdown Due to Increased Drywell Leakage Trend
05/28/2023
C1F64
05/27/2023
NRC Green NCV 2023002-01 Integrated Inspection Report
2/28/2023
Corrective Action
Documents
ARs 4717578,
24893,
4477332,
4518197
Various ARs Associated with the Existence of a Safety
Conscious Work Environment at Clinton Nuclear Power
Station
2/29/2023
Engineering
Changes
Cut and Cap RR Drain Lines 1RE100AA/ AB for Both RR
Loop A and B
Adverse Condition Monitoring and Contingency Plan;
AC-RF-2306-0001 - Elevated Drywell Floor Drain Leakage
Procedures
Safety Culture Monitoring
4