IR 05000269/2024001

Integrated Inspection Report 05000269/2024001, 05000270/2024001 and 05000287/2024001

ML24121A187
Person / Time
Site:	Oconee
Issue date:	05/03/2024
From:	Eric Stamm Division Reactor Projects II
To:	Snider S Duke Energy Carolinas
References
IR 2024001
Download: ML24121A187 (23)

Text

SUBJECT:

OCONEE NUCLEAR STATION - INTEGRATED INSPECTION REPORT 05000269/2024001 AND 05000270/2024001 AND 05000287/2024001

Dear Steven Snider:

On March 31, 2024, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Oconee Nuclear Station. On May 1, 2024, the NRC inspectors discussed the results of this inspection with you 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. One Severity Level IV violation without an associated finding is documented in this report. We are treating these violations as non-cited violations (NCVs) consistent with Section 2.3.2 of the Enforcement Policy.

If you contest the violations or the significance or severity of the violations 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 II; the Director, Office of Enforcement; and the NRC Resident Inspector at Oconee Nuclear Station.May 3, 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, Eric J. Stamm, Chief Reactor Projects Branch 1 Division of Reactor Projects Docket Nos. 05000269 and 05000270 and 05000287 and 07200004 and 07200040 License Nos. DPR-38 and DPR-47 and DPR-55

Enclosure:

As stated

Inspection Report

Docket Numbers: 05000269, 05000270, 05000287, 07200004 and 07200040

License Numbers: DPR-38, DPR-47 and DPR-55

Report Numbers: 05000269/2024001, 05000270/2024001 and 05000287/2024001

Licensee: Duke Energy Carolinas, LLC

Facility: Oconee Nuclear Station

Location: Seneca, South Carolina

Inspection Dates: January 1, 2024, to March 31, 2024

Inspectors: N. Smalley, Senior Resident Inspector J. Nadel, Senior Resident Inspector E. Robinson, Resident Inspector

Approved By: Eric J. Stamm, Chief Reactor Projects Branch 1 Division of Reactor Projects

Enclosure

SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Oconee 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 Adequately Control Transient Combustible Material Near the Independent Spent Fuel Storage Installation (ISFSI)

Cornerstone Severity Cross-Cutting Report Aspect Section Not Applicable Severity Level IV Not Applicable 71111.05 NCV 05000269,05000270,05000287/

2024001-01 Open/Closed The inspectors identified a Severity Level IV non-cited violation (NCV) of 10 CFR 72.212,

Conditions of general license issued under 10 CFR 72.210, for the licensees failure to adequately control transient combustible material in accordance with procedure AD-FP-ALL-1520, "Transient Combustible Control," at the independent spent fuel storage installation (ISFSI).

Failure to Maintain Procedure for Axial Power Shaping Rod and Control Rod Drive Coupling Cornerstone Significance Cross-Cutting Report Aspect Section Barrier Integrity Green None (NPP) 71153 NCV 05000269,05000270,05000287/

2024001-02 Open/Closed A self-revealed finding and associated non-cited violation (NCV) of 10 CFR Part 50,

Appendix B, Criterion V, Instructions, Procedures, and Drawings, was identified when the licensee failed to ensure procedure MP/0/A/1140/009, [Control Rod Drive] CRD - [Axial Power Shaping Rods] APSR - Coupling, included appropriate acceptance criteria to ensure APSRs were coupled to the CRDs. This finding resulted in a violation of technical specification (TS) 3.1.6, Axial Power Shaping Rod (APSR) Alignment Limits, and TS 3.0.3 and TS 3.0.4,

Limiting Condition of Operation (LCO) Applicability.

Additional Tracking Items

Type Issue Number Title Report Section Status LER 05000270/2021-004-00 LER 2021-004-00 for Oconee 71153 Closed Nuclear Station, Unit 2, More Than One Axial Power Shaping Rod Not Aligned within Technical Specification Limits

PLANT STATUS

Unit 1 operated at or near 100 percent rated thermal power (RTP) for the entire inspection period.

Unit 2 operated at or near 100 percent RTP for the entire inspection period.

Unit 3 operated at or near 100 percent RTP for the entire 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.

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: low pressure injection (LPI), essential siphon vacuum, and auxiliary building ventilation on January 19, 2024.

Impending Severe Weather Sample (IP Section 03.02) (1 Sample)

(1) The inspectors evaluated the adequacy of the overall preparations to protect risk significant systems from an impending winter storm expected on January 9, 2024, to include heavy rain, gusty winds up to 55 miles per hour and widespread power outages.

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) 1B LPI train while 1A LPI train was out of service (OOS) for planned maintenance on February 5, 2024

(2) 2A reactor building spray (RBS) system while 2B RBS was OOS for planned maintenance on February 14, 2023

(3) Trains B and C of low pressure service water (LPSW) for Units 1 and 2 while A LPSW pump was OOS for packing seal test on March 20, 2024

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) Fire zone 92: Unit 2 equipment room on February 1, 2024

(2) Fire zone 90: Unit 2 auxiliary building 300 level hallway on February 6, 2024

(3) Fire zone 34: Unit 1 4160V switchgear on February 7, 2024

(4) Fire area WPL-002: independent spent fuel storage installation (ISFSI) facility on February 7, 2024

(5) Fire zone 101: Unit 3 cable room on February 21, 2024

Fire Brigade Drill Performance Sample (IP Section 03.02) (2 Samples)

(1) The inspectors evaluated the onsite fire brigade training and performance during an unannounced fire drill on February 13, 2024.

(2) The inspectors evaluated the onsite fire brigade training and performance during an unannounced fire drill on February 28, 2024.

71111.06 - Flood Protection Measures

Flooding Sample (IP Section 03.01) (1 Sample)

(1) The inspectors evaluated external flooding mitigation protections in the:

Protected service water (PSW) underground cable bank

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 LPI pump testing on the Unit 2 B and C pump trains from the main control room on March 4, 2024.

Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)

(1) The inspectors observed and evaluated a simulator exam for an operating crew in accordance with SEG 2323 (ASE1) on February 20, 2024.

71111.13 - Maintenance Risk Assessments and Emergent Work Control

Risk Assessment and Management Sample (IP Section 03.01) (4 Samples)

The inspectors evaluated the accuracy and completeness of risk assessments for the following planned and emergent work activities to ensure configuration changes and appropriate work controls were addressed:

(1) Unit 3 green risk due to planned maintenance on unit transformer fire protection system, on January 24, 2024

(2) Unit 1, 2, and 3 green risk due to various maintenance with increased risk of plant trip the week of January 29, 2024, including CRD breaker testing on Unit 1, and maintenance on the Unit 2 A motor driven emergency feedwater pump and the Unit 3 turbine driven emergency feedwater (TDEFW) pump

(3) Unit 2 green risk due to 2B RBS pump maintenance, on February 14, 2024

(4) Unit 3 green risk due to 3B RBS pump maintenance, on March 15, 2024

71111.15 - Operability Determinations and Functionality Assessments

Operability Determination or Functionality Assessment (IP Section 03.01) (8 Samples)

The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:

(1) Nuclear condition report (NCR) 2408835, operability determination of 2NI-5 detector on 2A reactor protection system (RPS) channel prior to unplanned scram

(2) NCR 2504330, watered PSW cable duct banks found during periodic inspection

(3) NCR 2505469, high pressure injection valve, 1HP-31, erratic air sounds

(4) NCRs 2501851, 2503151, air circuit breaker, ACB-1, failed to open on Keowee Hydro Unit 1 (KHU-1) shutdown

(5) NCR 2505744, 230kV switchyard external grid protection circuit undervoltage relay, 27BRX2, out of tolerance

(6) NCR 2508418, Unit 2 TDEFW pump following leakage found on valve, 2FDW-89, during visual examination

(7) NCR 2501532, ultrasonic examination results upstream of valve, 3HPSW-14, below acceptance criteria

(8) NCR 2510402, spare switchyard battery charger AC power failure

71111.18 - Plant Modifications

Temporary Modifications and/or Permanent Modifications (IP Section 03.01 and/or 03.02) (1 Sample)

The inspectors evaluated the following temporary or permanent modifications:

(1) Engineering change (EC) 419291, Keowee hydro linear variable differential transformer (LVDT) replacement

71111.24 - Testing and Maintenance of Equipment Important to Risk

The inspectors evaluated the following testing and maintenance activities to verify system operability and/or functionality:

Post-Maintenance Testing (PMT) (IP Section 03.01) (5 Samples)

(1) PT/0/A/0620/009, KHU-1 operability check following replacement of the Teleperm XS (TXS) governor control system card due to air circuit breaker, ACB-1 failure, on January 31, 2024

(2) PT/3/A/0204/007, "Reactor Building Spray Pump Test," on the 3A train following breaker maintenance, on February 29, 2024

(3) IP/1/A/0315/014 A, "TXS RPS Interposing Relay Test and Control Rod Drive Breaker Trip Timing Test," following CRD breaker replacement, on March 25, 2024

(4) PT/0/A/0620/009, KHU-1 operation following replacement of the LVDT on March 25, 2024

(5) TE-MN-ALL-0202, "Transformer and Apparatus Testing," following spare stand-by transformer, CT-4, inspection and maintenance, on March 27, 2024

Surveillance Testing (IP Section 03.01) (4 Samples)

(1) PT/1/A/0600/15, "Control Rod Movement," on Unit 1, on February 27, 2024

(2) PT/1/A/0600/12, "Turbine Driven Emergency Feedwater (TDEFDW) Pump Test," on February 29, 2024

(3) PT/2/A/0203/006 A, "Low Pressure Injection Pump Test," for both trains B and C, on March 4, 2024

(4) PT/0/A/0600/021, Standby Shutdown Facility Diesel-Generator Operation, on March 6, 2024

Inservice Testing (IST) (IP Section 03.01) (1 Sample)

(1) PT/2/A/0203/006 A, "Low Pressure Injection Pump Test," for train A, on February 20, 2024

Diverse and Flexible Coping Strategies (FLEX) Testing (IP Section 03.02) (1 Sample)

(1) FLEX testing, on the week of January 8, 2024

71114.06 - Drill Evaluation

Required Emergency Preparedness Drill (1 Sample)

(1) Training Drill 2024-01, with emergency response organization team 2 and participation from the emergency operations facility, on March 26,

OTHER ACTIVITIES - BASELINE

===71151 - Performance Indicator Verification

The inspectors verified licensee performance indicators submittals listed below:

IE01: Unplanned Scrams per 7000 Critical Hours Sample (IP Section 02.01)===

(1) Unit 1 (January 1, 2023, through December 31, 2023)

(2) Unit 2 (January 1, 2023, through December 31, 2023)

(3) Unit 3 (January 1, 2023, through December 31, 2023)

IE03: Unplanned Power Changes per 7000 Critical Hours Sample (IP Section 02.02) (3 Samples)

(1) Unit 1 (January 1, 2023, through December 31, 2023)

(2) Unit 2 (January 1, 2023, through December 31, 2023)

(3) Unit 3 (January 1, 2023, through December 31, 2023)

IE04: Unplanned Scrams with Complications (USwC) Sample (IP Section 02.03) (3 Samples)

(1) Unit 1 (January 1, 2023, through December 31, 2023)

(2) Unit 2 (January 1, 2023, through December 31, 2023)

(3) Unit 3 (January 1, 2023, through December 31, 2023)

MS07: High Pressure Injection Systems (IP Section 02.06) (3 Samples)

(1) Unit 1 (January 1, 2023, through December 31, 2023)

(2) Unit 2 (January 1, 2023, through December 31, 2023)

(3) Unit 3 (January 1, 2023, through December 31, 2023)

71153 - Follow Up of Events and Notices of Enforcement Discretion Event Report (IP Section 03.02)

The inspectors evaluated the following licensee event report (LER):

(1) LER 05000270/2021-004-00, More Than One Axial Power Shaping Rod Not Aligned within Technical Specification Limits (ADAMS Accession No. ML22038A970). The inspection conclusions associated with this LER are documented in this report under Inspection Results section 71153. This LER is Closed.

INSPECTION RESULTS

Failure to Adequately Control Transient Combustible Material Near the Independent Spent Fuel Storage Installation (ISFSI)

Cornerstone Severity Cross-Cutting Report Aspect Section Not Severity Level IV Not 71111.05 Applicable NCV Applicable 05000269,05000270,05000287/2024001-01 Open/Closed The inspectors identified a Severity Level IV non-cited violation (NCV) of 10 CFR 72.212, Conditions of general license issued under 10 CFR 72.210, for the licensees failure to adequately control transient combustible material in accordance with procedure AD-FP-ALL-1520, "Transient Combustible Control," at the independent spent fuel storage installation (ISFSI).

Description:

On February 7, 2024, while performing a fire protection walkdown of the ISFSI area, the inspectors observed two cranes and combustible material stored within the ISFSI yard area in close proximity to loaded horizontal storage modules (HSMs). A small 100-ton crane fitted with rubber tires was parked unattended approximately 10 feet from loaded HSMs in preparation for an upcoming loading campaign. A large 300-ton crane fitted with metal crawler tracks was parked unattended approximately 120 feet away from loaded HSMs.

Wooden boards, cribbing, and other support material was staged near the large crane in preparation for new ISFSI construction activities. The inspectors questioned the licensee on whether the storage of these vehicles and material was in compliance with procedures that control transient combustible materials in the area.

Licensee procedure AD-FP-ALL-1520, Rev 1, "Transient Combustible Control," establishes control of transient combustibles in the ISFSI. This procedure applies to personnel performing ISFSI-related activities per the transient combustible control requirements described in 9, Independent Spent Fuel Storage Installations (ISFSIs) Transient Combustible Controls. AD-FP-ALL-1520, Attachment 9, Section 5.0, ONS ISFSI Storage Controls, states that storage of combustible materials is prohibited at the loaded ISFSI modules and within the immediate vicinity, including the concrete pad area. Combustible material must be attended at all times within these areas. It also states to ensure vehicles are prevented from permanently parking (i.e., left unattended) within 100 feet of loaded ISFSI storage casks.

Additionally, it states that total liquid flammable materials and transient combustibles within the ISFSI storage yard areas shall not exceed the equivalent of 300 gallons of diesel fuel.

Upon notification of the inspectors concerns, the licensee removed the 100-ton crane from the ISFSI area. The inspectors confirmed the small crane had only been in the ISFSI yard area since February 7, 2024, and was being used for preparation of a HSM for an upcoming loading campaign scheduled for that week. The licensee conducted a walkdown of the ISFSI area on February 8, 2024, and the remaining transient combustible material was removed.

The large 300-ton crane was being used for construction of a new phase of the ISFSI and it was permanently parked greater than 100 feet from loaded HSMs. A licensee fire protection engineer reviewed the combustible loading of the materials that were identified, which included wood, hydraulic fluid in the small crane, rubber tires on the small crane, and diesel fuel in the small crane. The combined heat content of the identified material equated to approximately 527 gallons of diesel fuel. Following review of the administrative controls for storage of transient combustibles contained in AD-FP-ALL-1520, the inspectors determined that the licensee had stored combustible materials in excess of and contrary to the amount allowed in Attachment 9, Section 5.0, ONS ISFSI Storage Controls.

Corrective Actions: The small 100-ton crane was removed from the ISFSI yard. The licensee removed the remaining transient combustible material. The licensee also completed an analysis of the material identified stored in the immediate vicinity of loaded HSMs.

Corrective Action References: NCR 2504166

Performance Assessment:

None. The Reactor Oversight Process (ROP) was not used for this issue because inspections of ISFSI activities that do not involve the operating plant are not addressed by the reactor safety cornerstones in the ROPs Significance Determination Process.

Enforcement:

The ROPs significance determination process does not address 10 CFR Part 72 issues in its assessment of licensee performance. Therefore, it is necessary to address this violation using traditional enforcement.

Severity: Consistent with guidance in the NRC Enforcement Manual, Part I, section 1.2.6.D, if a violation does not fit an example in the Enforcement Policy violation examples, it should be assigned a severity level:

(1) commensurate with its safety significance; and

(2) informed by similar violation addressed in the violation examples. This issue was more than minor because if left uncorrected, it could become a more significant safety concern since the prolonged presence of combustible material in excess of the amounts allowed in the immediate vicinity of the stored fuel increased the vulnerability of the casks to a fire and therefore, increased the likelihood of fuel damage and/or release during a fire event. Because all stored fuel was located in dry shielded canisters (DSCs) within HSMs during the event, and because of the short duration of time that the combustible materials were stored in the immediate vicinity of the HSMs, the violation was not considered as a substantial threat for potential exposure to or release of radiation and was determined to be of very low safety significance, similar to the example in Section 6.2.d.2 of the NRC Enforcement Policy.

Violation: 10 CFR 72.212, "Conditions of general license issued under 10 CFR 72.210,"

Section (b)(13) states, in part, that the licensee shall, Conduct activities related to storage of spent fuel under this general license only in accordance with written procedures. This requirement is implemented in part by procedure AD-FP-ALL-1520, "Transient Combustible Control," where Attachment 9, Section 5.0, requires controls for transient combustibles at the Oconee Nuclear Station ISFSI. Specifically, Section 5.0 prohibits the storage of unattended combustible materials at the loaded ISFSI modules, prohibits vehicles from permanently parking within 100 feet of loaded storage casks, and limits the total liquid flammable materials and transient combustibles within the ISFSI storage yard to less than the equivalent of 300 gallons of diesel fuel.

Contrary to the above, from February 7 to February 8, 2024, transient combustible materials were stored unattended within the immediate vicinity of loaded ISFSI modules, a vehicle was permanently parked within 100 feet of loaded storage casks, and total liquid flammable materials and transient combustibles stored within the ISFSI yard exceeded 300 gallons of diesel fuel. Specifically, combustible materials were stored unattended within the immediate vicinity of loaded ISFSI modules, a 100-ton portable crane was permanently parked within approximately 10 feet of loaded ISFSI storage casks, and the total liquid flammable materials and transient combustibles within the ISFSI storage yard had an equivalent heat content of approximately 527 gallons of diesel fuel.

Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.

Failure to Maintain Procedure for Axial Power Shaping Rod and Control Rod Drive Coupling Cornerstone Significance Cross-Cutting Report Aspect Section Barrier Integrity Green None (NPP) 71153 NCV 05000269,05000270,05000287/

2024001-02 Open/Closed A self-revealed finding and associated non-cited violation (NCV) of 10 CFR Part 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, was identified when the licensee failed to ensure procedure MP/0/A/1140/009, [Control Rod Drive] CRD - [Axial Power Shaping Rods] APSR - Coupling, included appropriate acceptance criteria to ensure APSRs were coupled to the CRDs. This finding resulted in a violation of technical specification (TS) 3.1.6, Axial Power Shaping Rod (APSR) Alignment Limits, and TS 3.0.3 and TS 3.0.4, Limiting Condition of Operation (LCO) Applicability.

Description:

Axial power shaping rods (APSRs) are designed to contribute to the reactivity balance of the reactor while critical. APSRs are evenly distributed throughout the core to provide negative reactivity throughout to counterbalance surplus positive reactivity of the fuel.

In order to avoid flux tilting or power peaking in portions of the reactor core caused by asymmetric reactivity distribution, the APSRs typically move in or out of the core as one rod group (in Group 8). TS 3.1.6, Axial Power Shaping Rod (APSR) Alignment Limits, requires, in part, that each APSR is operable and aligned within 6.5% of its group average height. This LCO is applicable in Modes 1 and 2 when the APSRs are not fully withdrawn. Condition A states that when one APSR is inoperable, not aligned within its limits, or both, then perform surveillance requirement (SR) 3.2.2.1 within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> after each APSR movement. Condition B requires the unit to be in Mode 3 if Required Action and associated Completion Time of Condition A is not met. Failure to do so could cause quadrant power tilt and result in exceeding the limits on axial power imbalance. During the course of refueling outages, it is necessary to uncouple control rods, including APSRs, from the control rod drive (CRD). Prior to the startup of the refueled reactor, APSRs are recoupled to their respective CRD as directed by licensee procedure MP/0/A/1140/009, CRD - APSR - Coupling. TS 3.0.3, LCO Applicability, requires, in part, when an LCO is not met and the associated actions are not met, an associated action is not provided, or if directed by the associated actions, the unit shall be placed in a Mode or other specified condition in which the LCO is not applicable.

Action shall be initiated within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> to place the unit, as applicable, in Mode 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, Mode 4 within 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br />, and Mode 5 within 37 hours4.282407e-4 days <br />0.0103 hours <br />6.117725e-5 weeks <br />1.40785e-5 months <br />. TS 3.0.4, LCO Applicability, requires, in part, when an LCO is not met, entry into a Mode or other specified condition in the Applicability shall only be made when the associated Actions to be entered permit continued operation in the Mode or other specified condition in the Applicability for an unlimited period of time.

Upon startup from the Unit 2 fall 2021 refueling outage, testing revealed that two of the APSRs were not coupled as directed. Specifically, on December 7, 2021, at 0921, Unit 2 entered mode 2 and, therefore, LCO 3.1.6 was applicable, though the condition of the two APSRs being uncoupled was not known at this time. At 1131, Unit 2 entered mode 1, and on December 8, 2021, power was held at 73 percent for testing during the startup. This included power imbalance detector correlation (PIDC) testing to calibrate the reactor axial power imbalance as measured by the out-of-core nuclear instruments to the incore detectors. At 1654, Reactor Engineering reported that PIDC test acceptance criteria were not met, ultimately as a result of the two misaligned uncoupled APSRs, though this was not yet known at the time. On December 8, 2021, at approximately 1800, following troubleshooting of the PIDC testing failure, the recommendation was made to fully insert all APSRs. Insertion of all APSRs was completed at 1943 on December 9, 2021. Subsequent licensee investigation of nuclear instrument data concluded that APSRs F-12 and L-12 were fully inserted throughout the startup and had not moved with the rest of the Group 8 rods, as they were uncoupled from their respective CRD. At the time of discovery of this condition, all APSRs were fully inserted, and LCO 3.1.6 was no longer applicable. The licensee submitted Licensee Event Report 2021-004-00 to the NRC following discovery of this condition, for a condition prohibited by technical specifications, exceeding the allowed action time of placing the reactor in mode 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> as required by LCO 3.0.3, as they had greater than one rod misaligned, which exceeded the conditions required in LCO 3.1.6. Additionally, when Unit 2 entered Mode 2 and Mode 1 on December 7, 2021, Unit 2 entered a different mode or applicability condition in which the mode change did not comply with TS LCO 3.0.4.

The licensee completed an operability evaluation to support operation with all APSRs fully inserted through the two-year fuel cycle and determined there would be no adverse impact.

As such, following the Unit 2 2021 refueling outage, all APSRs were left fully inserted in the Unit 2 core, and the cause of the uncoupled APSRs was left to be determined following the subsequent Unit 2 refueling outage in the fall of 2023. Following the 2023 refueling outage, the licensee determined that there was no mechanical or electrical failure at fault for the APSRs being uncoupled and it was the result of inadequate procedural guidance.

Specifically, licensee procedure MP/0/A/1140/009, did not require operators to record air pressure or reference tang position to validate the coupling hubs were in the coupled position.

Additionally, the licensees cause evaluation, as documented in NCR 2408618, noted that three previous instances of similar events (from 2013-2015) of APSR uncoupling had occurred in the nuclear industry as a result of inadequate procedural guidance to verify coupling. This operating experience was not captured in Oconees reactor maintenance briefs or procedures prior to this event in 2021. The licensee updated AD-PI-ALL-0400, Operating Experience Program, to ensure relevant significant consequential events would be considered and evaluated appropriately. This revision was made following the evaluation of the operating experience event in 2015 but prior to the uncoupling event at Oconee in 2021.

Corrective Actions: The licensee revised MP/0/A/1140/009, "CRD - APSR - Coupling,"

(April 26, 2022, revision 45) to include guidance to verify adequate coupling has occurred.

Corrective Action References: PRR 02415204, NCR 02408618

Performance Assessment:

Performance Deficiency: The inspectors determined that the licensees failure to include appropriate acceptance criteria to verify coupling of APSRs in licensee procedure MP/0/A/1140/009, "CRD - APSR - Coupling," was a performance deficiency.

Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Configuration Control attribute of the Barrier Integrity cornerstone and adversely affected the cornerstone objective to provide reasonable assurance that physical design barriers protect the public from radionuclide releases caused by accidents or events. Specifically, it created a reactivity control issue that placed the plant in a condition unbounded by previous safety analyses. This previously unanalyzed condition posed a potential challenge to the barrier design criteria that meant a reasonable assurance could not be provided.

Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power. Using Exhibit 3 - Barrier Integrity Screening Questions, inspectors determined the finding was of very low safety significance (Green) because all questions were answered no. Specifically, upon further review, it was determined that the reactivity mismanagement in this event did not challenge fuel cladding integrity.

Cross-Cutting Aspect: Not Present Performance. No cross-cutting aspect was assigned to this finding because the inspectors determined the finding did not reflect present licensee performance.

Enforcement:

Violation: 10 CFR Part 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, requires in part, that procedures shall include appropriate quantitative or qualitative acceptance criteria for determining that important activities have been satisfactorily accomplished. Contrary to the above, from at least August 9, 1997, to April 26, 2022, the licensee failed to include appropriate acceptance criteria in procedure MP/0/A/1140/009, "CRD - APSR - Coupling," to ensure the coupling activity was satisfactorily accomplished.

As a result, on December 7, 2021, TS 3.1.6 requirements for APSR alignment and maximum number of misaligned APSRs in Modes 1 and 2 were exceeded when two APSRs did not withdraw on startup. Additionally, TS LCO 3.0.3 actions were not completed within the required time based on the time from Unit 2 entering Mode 2 with APSRs misaligned at 0921 on December 7, 2021, until the time APSRs were fully inserted at 1943 on December 9, 2021. Furthermore, when Unit 2 entered Mode 2 and Mode 1 on December 7, 2021, Unit 2 entered a different mode or applicability condition in which the mode change did not comply with TS LCO 3.0.4.

Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.

EXIT MEETINGS AND DEBRIEFS

The inspectors verified no proprietary information was retained or documented in this report.

• On May 1, 2024, the inspectors presented the integrated inspection results to Steven Snider and other members of the licensee staff.

DOCUMENTS REVIEWED

Inspection Type Designation Description or Title Revision or

Procedure Date

71111.01 Corrective Action 2497614, 2491962

Documents

Miscellaneous OHT-102A-1.1 Flow Diagram of Low Pressure Injection System (Borated 1

Water Supply & LPI Pump Suction) Heat Trace

OHT-130A-1.1 Flow Diagram of Essential Siphon Vacuum (ESV) System, 0

Heat Trace

OSS-0254.00-00- (Mech) Design Basis Spec for the Auxiliary Building HVAC 035

1019 System

OSS-0254.00-00- (Mech) Design Basis Spec for the Low Pressure Injection 070

28 and Core Flood System (LPI)

OSS-0254.00-00- (Mech) Design Basis Spec for the Essential Siphon Vacuum 015

1049 System

Procedures AD-OP-ALL-0120 Severe Weather Preparations and Considerations 0

AD-OP-ONS-Severe Weather Preparations 001

20

OP/0/A/1104/041 Auxiliary Building Ventilation 046

OP/0/A/1106/041 Turbine Building Ventilation 012

OP/0/B/1104/050 Weather Related Activities 007

OP/1/A/1104/051 ESV System 028

PT/0/A/0110/017 Cold Weather Protection 017

PT/1/A/0600/001 Periodic Instrument Surveillance 348

Work Orders 20628154

71111.04 Corrective Action 2493286, 2481037, 2410321, 2498560, 2510523, 2510534,

Documents 2510550

Drawings OFD-102A-1.1 Flow Diagram of Low Pressure Injection System (Borated 72

Water Supply & LPI Pump Suction)

OFD-103A-02-01 Flow Diagram Of Reactor Building Spray System (BS) 026

OFD-124A-1.1 Flow Diagram of Low Pressure Service Water System 056

Turbine Building LPSW Pumps

Miscellaneous Clearance OPS-1-23-LP-1LP-21 DIAG-0967

Clearance PRT-1-23-1A LPI OOS-0203

Inspection Type Designation Description or Title Revision or

Procedure Date

Procedures OP/1/A/1102/008 On-Line Valve Lineup for MOV Maintenance 042

OP/1/A/1104/010 Low Pressure Service Water 159

OP/2/A/1104/005 Reactor Building Spray System 039

PT/1-LPSW Pump Packing Seal Water Regulator Pressure Setup 014

2/A/0251/030

PT/1/A/0152/012 Low Pressure Injection System Valve Stroke Test 045

Work Orders 20550600, 20633989, 20555119

71111.05 Calculations OSC-10816 ONS TCCA A and B Area Basis for AD-EG-ALL-1520 005

OSC-9293 NFPA 805 Transition Radioactive Release G-1 Table 004

OSC-9314 NFPA 805 Transition Risk-Informed Performance-Based 006

Fire Risk Evaluation

Corrective Action 2275773, 2049530, 2276444, 2504166, 2501120, 2481802

Documents

Engineering EC 422486

Changes DUKE-QAPD-001 Duke Energy Corporation Topical Report Quality Assurance 50

Program Description Operating Fleet

Fire Plans CSD-ONS-PFP-Pre-Fire Plan for U1 Auxiliary Building Elevation 809 000

1AB-0809

CSD-ONS-PFP-Pre-Fire Plan for U2 Auxiliary Building Elevation 796 002

2AB-0796

CSD-ONS-PFP-Pref-Fire Plan for U3 Auxiliary Building[sic] Elevation 809000

3AB-0809

CSD-ONS-PFP-Pre-Fire Plan for Protected Area Southwest 000

PA-0003

Miscellaneous AD-OP-ALL-0207 Fire Brigade Administrative Controls 6

O-0310-K-008 Fire Protect Aux Bldg Unit 2 EL 796+6 026

OFD-124C-2.2 Flow Diagram of High Pressure Service Water System 43

Turbine Building

Procedures AD-FP-ALL-1520 Transient Combustible Control 1

AD-LS-ALL-0009 10 CFR 72.48 Review Process 4

AD-NF-ALL-0602 Spent Fuel Management and ISFSI 6

CSD-ONS-PFP-Pre-Fire Plan for U1 Turbine Building Elevation 796 000

1TB-0796

Inspection Type Designation Description or Title Revision or

Procedure Date

Work Orders 20218819

71111.06 Corrective Action 00451693, 00437391, PIP 06-1076, 02504330

Documents

Procedures MP/0/B/2002/002 Protected Service Water (PSW) Underground Cable Duct 002

Bank - Drainage System - Inspection

Work Orders 20579745

71111.11Q Corrective Action 2479354, 2487761

Documents

Procedures AD-OP-ALL-1000 Conduct of Operations 023

71111.12 Corrective Action 2473173, 2476626

Documents

Miscellaneous Equipment Reliability Suite (ERS) System information for

LPSW

71111.13 Drawings OFD-124C-3.2 Flow Diagram of High Pressure Service Water System 40

Turbine Building

OFD-124C-3.7 Flow Diagram of High Pressure Service Water System 1

Sprinkler Valve Sub-Components

Miscellaneous Unit 3 Operator Logs for January 24, 2024

Phoenix ONS Risk Profile for the week of January 29th,

24 for all three Units

Phoenix ONS Unit 3 Risk Profile for the week of March 11th,

24

Unit 3 Operator Logs for March 15th, 2024

Phoenix ONS Unit 3 Risk Profile for January 24, 2024

Procedures AD-NF-ALL-0501 Electronic Risk Assessment Tool (ERAT) 5

AD-WC-ALL-0240 On-Line Risk Management Process 4

AD-WC-ALL-0240 On-Line Risk Management Process 3

IP/1/A/0315/014 A TXS RPS Interposing Relay Test And Control Rod Drive 017

Breaker Trip Timing Test

OP/0/A/1104/011 High Pressure Service Water 110

PT/3/A.0600/012 Turbine Driven Emergency Feedwater Pump Test 096

PT/3/A/0152/002 Building Spray System Valve Stroke Test 034

PT/3/A/0204/007 Reactor Building Spray Pump Test 099

Inspection Type Designation Description or Title Revision or

Procedure Date

Work Orders 20580562, 20644146, 20559917, 20558612

71111.15 Calculations OSC-4300 (ELEC) Protective Relay Settings 041

Corrective Action 02492929, 02473883, 02477813, 02453927, 02503151,

Documents 02501851, 0419291

2408618, 2408835, 2504330, 2508418, 2393137, 2510402

Drawings O FD-102A-02-01 FLOW DIAGRAM OF LOW PRESSURE INJECTION 056F

SYSTEM (BORATED WATER SUPPLY AND LPI PUMP

SUCTION)

O FD-102A-02-01 FLOW DIAGRAM OF LOW PRESSURE INJECTION

O SYSTEM (BORATED WATER SUPPLY AND LPI PUMP

SUCTION)

O FD-102A-02-02 FLOW DIAGRAM OF LOW PRESSURE INJECTION 054A

SYSTEM (LPI PUMP DISCHARGE)

O-0800 One Line Diagram - Relays & Meters - 230kV Switchyard - 034

PCBs #1 Thru #12

O-0801 One Line Diagram 230kV Switchyard 480/240/120/VAC 048

O-0802 One Line Diagram 230kV Switchyard 125 VDC 035

O-398-A-001 PSW Ductbank And Manhole Location Plan & General 001A

Notes

O-398-A1-106G Protected Service Water Project - PSW Commercial Feeder 000

Relocation - Pullbox F-2 Concrete & Reinforcing - Plan,

Sections, & Details

O-398-A1-203 PSW Ductbank Ductbank Manhole No. 3 Sections & Details 000

OEE-76 External Grid Trouble Protective System One Line 11

OFD-101A-1.4 Flow Diagram of High Pressure Injection System (Charging 51

Section)

OFD-121D-2.1 Flow Diagram of Emergency Feedwater System 039

Miscellaneous NDE-NE-ALL-Request for Miscellaneous Inspection/NDE 000

0002

OSS-0254.00-00- (MECH) Design Basis Specification for the Emergency 059

1000 Feedwater System

OSS-0254.00-00- (Mech) High Pressure Injection and Purification & 065

1001 Deborating Demineralizer Systems

OSS-0254.00-00- (Mech) Design Basis Specification for Reactor Coolant 055

Inspection Type Designation Description or Title Revision or

Procedure Date

133 System

OSS-0254.00-00- (ELECT) 230kV Switchyard System 027

2004

OSS-0254.00-00- (ELECT) Design Basis Spec for Oconee 230kV Switchyard 010

2009 125 VDC Power System

Procedures AD-EG-ALL-1375 Instrument and Electrical Device Calibration Out of 1

Tolerance (OOT)

AD-EG-ALL-1615 Cable Aging Management Program Implementation 005

AD-OP-ALL-0105 Operability Determinations 7

AP/1/A/1700/014 Loss of Normal HPI Makeup and/or RCP Seal Injection 023

IP/0/A/2000/00 Power And Control Cable Inspection And Testing 016

IP/0/A/3000/011 230kV Switchyard Battery SY-1 Quarterly Surveillance 4

IP/0/A/4980/027B CV-22 Relay Test 011

OP/1/A/1107/010 Operation of Batteries and Battery Chargers 65

OP/2/A/1104/004 Low Pressure Injection System 174-177

OP/2/A/1104/004 LPI SYSTEM FILL AND STARTUP 037

B

PT/0/A/1720/002 Periodic Pressure Testing of ASME Section XI Components 000

PT/2/A/0203/006 Low Pressure Injection Pump Test - Recirculation 089

A

PT/2/A/0203/012 HPI/LPI/RBS Piping Vent 016

Work Orders 20594448, 20584211, 20643793, 20262241

20311170, 20311173, 20296203, 20296221, 20263581,

263583, 20579745, 20263771, 20545433, 20560755,

265055, 20266033

71111.18 Corrective Action 02453927, 02503151, 02501851

Documents

Engineering 419291

Changes

Procedures IP/0/A/0101/001 Low Risk Maintenance Configuration Control 019

IP/0/A/0401/001 B KHU-1 and 2 TXS Governor Control System Cabinet 010

Maintenance and Calibration

71111.24 Calculations OSC-2515 Verification of Emergency Feedwater System Flow Utilizing 025

MFW System Bypass

Inspection Type Designation Description or Title Revision or

Procedure Date

Corrective Action 2454667, 2455357, 2456329, 2461056, 2500872, 2500765,

Documents 2505803, 2467330, 2496568, 2495192, 2428148, 2505998,

2507352, 2496162, 2198433, 2304822, 2418167, 02497631

Drawings O-0709-02 Connection Diagram, 13,860 Volts/4160 Volts Spare Stand-2

By Transformer No. CT4

OFD-121A-1.7 Flow Diagram of Condensate System (Upper Surge Tank 047

Dome & Condensate Storage Tank)

OFD-121A-1.8 Flow Diagram of Condensate System (Condensate Make-up 027

& Emergency FDW Pump Suction)

OFD-121D-1.1 Flow Diagram of Emergency Feedwater System 039

OFD-122A-1.4 Flow Diagram of Main Steam System (Emergency FDW 025

Pump Turbine Steam Supply & Exhaust)

OFD-124C-1.2 Flow Diagram of High Pressure Service Water System 042

(Turbine Building)

OFD-133A-1.2 Flow Diagram of Condenser Circulating Water System 027

(Normal Intake & Discharge)

OFD-135B-1.2 Flow Diagram of Lube Oil System (Emergency Feedwater 007

Pump Turbine)

ONTC-1-121D-Oconee Nuclear Station Unit 1 Test Acceptance Criteria for 4

0002-001 Turbine Driven EFW Pump

Miscellaneous OSS-0254.00-00- (Mech) Design Basis Specification for the Emergency 059

1000 Feedwater System

Procedures CSD-EG-ONS-Diverse and Flexible Coping Strategies (FLEX) Program 005

1610.1000 Document-Oconee Nuclear Station

IP/0/A/0401/003 KHU-1 And 2 TXS Governor Control System Wicket Gate 11

Position Input String Test

IP/0/A/2001/003 A Inspection and Maintenance of 4.16 KV and 6.9 KV ACB 059

IP/0/A/2001/003 Removal and Installation of Metal Clad Air Circuit Breakers016

D

IP/0/A/2001/010 DSII-516 Power Circuit Breaker Inspection and Maintenance024

IP/0/A/2007/001 Transformer Inspection and Maintenance 42

IP/0/B/0350/004 CRD System Checkout Prior to Maintenance/Testing 027

IP/1/A/0315/014 A TXS RPS Interposing Relay Test and Control Rod Drive 017

Breaker Trip Timing Test

Inspection Type Designation Description or Title Revision or

Procedure Date

OP/0/A/1107/019 Keowee Hydro at Oconee 114

OP/0/A/1600/010 Operation of the SSF Diesel-Generator 101

OP/1/A/1105/019 Control Rod Drive System 036

OP/1/A/1106/006 Emergency FDW System 134

PT/0/A/0400/011 SSF Diesel Generator Test 015

PT/0/A/0600/021 Standby Shutdown Facility Diesel-Generator Operation 017

PT/0/A/0620/009 Keowee Hydro Operation 56

PT/1/A/0600/012 Turbine Driven Emergency Feedwater Pump Test 108

PT/1/A/0600/015 Control Rod Movement 031

PT/2/A/0203/006 Low Pressure Injection Pump Test - Recirculation 089

A

PT/2/A/0203/006 Low Pressure Injection Pump Test - Recirculation 088, 091

A

PT/2/A/0203/006 Low Pressure Injection Pump Test - Decay Heat 032

B

PT/3/A/0204/007 Reactor Building Spray Pump Test 099

TE-MN-ALL-0202 Transformer and Apparatus Testing 4

Work Orders 20638155, 20558232, 20636467, 20633990, 20633991,

20636016, 20650583, 20648274, 20644146, 20636162,

20636355, 20566807, 20447425

71114.06 Miscellaneous ONS 24-01 Drill Guide

CSD-EP-ONS-EAL Technical Basis Document 5

0101-01

CSD-EP-ONS-Classification of Emergency 3

0101-02

EP-ALL-EPLAN Duke Energy Common Emergency Plan 5

EP-ONS-EPLAN-Duke Energy Oconee Emergency Plan Annex 1

ANNEX

71151 Miscellaneous Unit 1 Operator Logs, November 2023

Unit 2 Operator Logs, October - November 2023

Unit 3 Operator Logs, June 2023

MSPI Derivation Reports for the High Pressure Injection

System for Units 1, 2 and 3 for all months of 2023

Inspection Type Designation Description or Title Revision or

Procedure Date

MSPI Margin Reports for the High Pressure Injection System

for Units 1, 2 and 3 for all months of 2023

AD-PI-ALL-0700 Performance Indicators 6

71153 Corrective Action 2408618, 2409112, 2415204, 1579134, 2040588, 2461378,

Documents 2196352, 2383415

Miscellaneous ONEI-0400-587 Figure 1. Oconee 2 Cycle 32 Final Core Load Map 0

Procedures AD/PI/ALL/0400 Operating Experience Program 11

MP/0/A/1140/001 CRD - Shim Drive - Leadscrew Couple 013

A

MP/0/A/1140/009 CRD - APSR - Coupling 045

PT/0/A/0750/002 Core Inspections Procedure 31

Work Orders 20522549, 20522553

20