IR 05000313/2024002
| ML24219A019 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 08/06/2024 |
| From: | John Dixon NRC/RGN-IV/DORS/PBD |
| To: | Pehrson D Entergy Operations |
| References | |
| IR 2024002 | |
| Download: ML24219A019 (1) | |
Text
August 6, 2024
SUBJECT:
ARKANSAS NUCLEAR ONE - INTEGRATED INSPECTION REPORT 05000313/2024002 AND 05000368/2024002
Dear Doug Pehrson:
On June 30, 2024, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Arkansas Nuclear One. On July 12, 2024, the NRC inspectors discussed the results of this inspection with Mark Skartvedt, General Manager of Plant Operations, 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. Two of these findings involved violations of NRC requirements. 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 IV; the Director, Office of Enforcement; and the NRC Resident Inspector at Arkansas Nuclear One.
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 IV; and the NRC Resident Inspector at Arkansas Nuclear One.
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, John L. Dixon, Jr., Chief Reactor Projects Branch D Division of Operating Reactor Safety Docket Nos. 05000313 and 05000368 License Nos. DPR-51 and NPF-6
Enclosure:
As stated
Inspection Report
Docket Nos:
05000313 and 05000368
License Nos:
Report Nos:
05000313/2024002 and 05000368/2024002
Enterprise Identifier:
I-2024-002-0005
Licensee:
Entergy Operations, Inc.
Facility:
Arkansas Nuclear One
Location:
Russellville, AR
Inspection Dates:
April 1, 2024, to June 30, 2024
Inspectors:
T. DeBey, Resident Inspector
J. Drake, Senior Reactor Inspector
J. Melfi, Project Engineer
B. Nytko, Nuclear Systems Engineer
A. Sanchez, Senior Project Engineer
B. Tindell, Senior Resident Inspector
Approved By:
John L. Dixon, Jr., Chief
Reactor Projects Branch D
Division of Operating Reactor Safety
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Arkansas Nuclear One, 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 Identify Inoperable Source Range Leads to Core Alterations with Less Than Required Reactivity Monitoring Cornerstone Significance Cross-Cutting Aspect Report Section Barrier Integrity Green NCV 05000313/2024002-01 Open/Closed
[H.7] -
Documentation 71111.15 The inspectors identified a Green finding and associated non-cited violation of Arkansas Nuclear One, Unit 1, Technical Specification 3.9.2 for the failure to immediately suspend core alterations with one source range neutron flux monitor inoperable. Specifically, the licensee failed to identify an inoperable neutron flux monitor in a timely manner so that core alterations could be immediately suspended, as required by technical specifications.
Failure to Properly Evaluate Operability of the Unit 2 Emergency Diesel Generator with a Failed Voltage Regulator Current Potential Transformer Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000368/2024002-02 Open/Closed
[H.1] -
Resources 71111.15 The inspectors identified a Green finding and associated non-cited violation of 10 CFR Part 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, for the licensees failure to appropriately assess the immediate operability of the Unit 2 emergency diesel generator 2K-4B in accordance with Procedure EN-OP-104, Operability Determination Process, revision 19. Specifically, the licensee failed to determine if the emergency diesel generator was capable of regulating voltage during isochronous operation from December 16, 2023, to January 23, 2024, due to a failed current potential transformer.
Additional Tracking Items
None.
PLANT STATUS
Unit 1 began the inspection period at full power. On April 27, 2024, the unit was shutdown to begin refueling outage 1R31. Following the refueling outage, Unit 1 was restarted on May 19, 2024, and returned to full power on May 24, 2024. Unit 1 remained at or near full power for the remainder of the inspection period.
Unit 2 began the inspection period at full power and remained there for the duration of the inspection period.
INSPECTION SCOPES
Inspections were conducted using the appropriate portions of the inspection procedures (IPs) in effect at the beginning of the inspection unless otherwise noted. Currently approved IPs with their attached revision histories are located on the public website at http://www.nrc.gov/reading-rm/doc-collections/insp-manual/inspection-procedure/index.html. Samples were declared complete when the IP requirements most appropriate to the inspection activity were met consistent with Inspection Manual Chapter (IMC) 2515, Light-Water Reactor Inspection Program - Operations Phase. The inspectors performed activities described in IMC 2515, Appendix D, Plant Status, observed risk-significant activities, and completed on-site portions of IPs. The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel to assess licensee performance and compliance with Commission rules and regulations, license conditions, site procedures, and standards.
REACTOR SAFETY
71111.04 - Equipment Alignment
Partial Walkdown Sample (IP Section 03.01) (2 Samples)
The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:
- (1) Unit 1 spent fuel pool cooling while installing temporary power modification on spent fuel pool cooling pump P-40A using Work Order 53023702 on April 10, 2024
- (2) Unit 1 decay heat removal train B, while train A was in an outage work window and unavailable on May 2, 2024
Complete Walkdown Sample (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated system configurations during a complete walkdown of the Unit 1 emergency diesel generator K-4B fuel oil storage and transfer system during extended outage of the emergency diesel generator K-4A on April 22-25, 2024.
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (4 Samples)
The inspectors evaluated the implementation of the fire protection program by conducting a walkdown and performing a review to verify program compliance, equipment functionality, material condition, and operational readiness of the following fire areas:
- (1) Unit 1 lower south electrical penetration room, fire zone FZ-1044, on April 22, 2024
- (2) Unit 1 reactor building zones 32K and 33K, all elevations, on April 28, 2024
- (3) Unit 1 emergency diesel generator B, fire zone 86G, on April 29, 2024
- (4) Unit 1 auxiliary building, 335-foot elevation general area, fire zone 20-Y, on May 6, 2024
Fire Brigade Drill Performance Sample (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated the onsite fire brigade training and performance during a Unit 1 announced fire drill for a fire in the T-28 fuel oil tank room, fire zone FZ-75-AA, on April 2, 2024.
71111.07A - Heat Exchanger/Sink Performance
Annual Review (IP Section 03.01) (1 Sample)
The inspectors evaluated readiness and performance of:
- (1) Unit 1 heat exchanger E-176 emergency switchgear room cooler VCH-4B on May 2, 2024
===71111.08P - Inservice Inspection Activities (PWR) The inspectors verified that the reactor coolant system boundary, reactor vessel internals, risk-significant piping system boundaries, and containment boundary are appropriately monitored for degradation and that repairs and replacements were appropriately fabricated, examined and accepted by reviewing the following activities in Unit 1 during refueling outage 1R31 from April 29, 2024, to May 10, 2024.
PWR Inservice Inspection Activities Sample - Nondestructive Examination and Welding Activities (IP Section 03.01)===
The inspectors observed or reviewed reports for the following nondestructive examination and welding activities:
- (1) Ultrasonic Examination
- Steam generator E24A, 03-110-24A, upper head to upper ring head weld
- Reactor coolant system, closure stud, H-B-6956
- Make up water, MU-45C CCA-5-21/2, fretting on pipe analyzed as acceptable Dye Penetrant Examination
- Reactor coolant system, TE-1013 and 1014 connection seal weld
- Makeup water system, MU-45C line CCA-5-21/2 Visual Examination
- Reactor coolant system, VT-1, nut H C0824
- Reactor coolant system, VT-1, washer set S 1006106-001-03
- Pressurizer, VT-1, heater bundle bolts 2,3,6,10, and 12. Identified relevant indication of sheared and damaged threads, analyzed as acceptable
- Emergency feed water, VT-3, Support 58-001 EFW-1 variable spring
- Make up water, VT-3,24-080 MU-135 variable spring
- Service water, VT-3, support 49-054 HBD-21-H20
- Service water, VT-3, support 50-018 HBD-20-H72
- Service water, VT-3, support 50-018W HBD-20-H72-Anchor Welding Activities
Electrohydraulic control, FW-1, "T" connection o
Electrohydraulic control, FW-2, "T" connection o
Electrohydraulic control, FW-3, "T" connection PWR Inservice Inspection Activities Sample - Vessel Upper Head Penetration Inspection
Activities (IP Section 03.02) (1 Sample)
No Code required bare metal visual inspection of the reactor vessel upper head penetrations was required this outage, however white residue was observed, so the licensee performed a visual inspection and cleaning of the head.
(1)reactor vessel head penetration number: 2, 15, 56, 58, 63, 64 PWR Inservice Inspection Activities Sample - Boric Acid Corrosion Control Inspection Activities (IP Section 03.03) (1 Sample)
The inspectors verified the licensee is managing the boric acid corrosion control program through a review of the following evaluations:
- (1) Boric acid evaluations and screenings:
- Boric acid evaluation, BW-2 CR CR-ANO-1-2023-01277
- Boric acid evaluation, CV-1400 CR-ANO-1-2023-01279
- Boric acid evaluation, DH-21B CR-ANO-1-2023-01270
- Boric acid evaluation, DH-23A CR-1-2022-30397
- Boric acid evaluation, SS-57, CR-ANO-1-2023-01568
- Boric acid evaluation, SS-1818B CR-ANO-1-2023-0972
- CR-ANO-1-2022-00202, MU-21A
- CR-ANO-1-2022-01991, P-35B (RB SPRAY PUMP)
- CR-ANO-1-2023-00098, (DHR Cooler E-35A outlet)
- CR-ANO-1-2023-00279, discharge piping of P-34A Decay Heat Pump
- CR-ANO-1-2023-00358, PSV-1226 (MU RCP SEAL RTN LINE RELIEF)
- CR-ANO-1-2023-00379, SS-18 pipe cap leak PWR Inservice Inspection Activities Sample - Steam Generator Tube Inspection Activities (Section 03.04)
No steam generator tube integrity inspections required this outage.
71111.11Q - Licensed Operator Requalification Program and Licensed Operator Performance
Licensed Operator Performance in the Actual Plant/Main Control Room (IP Section 03.01) (3 Samples)
- (1) The inspectors observed and evaluated licensed operator performance in the control room during Unit 1 end-of-cycle withdrawal of axial power shaping rods on April 5, 2024.
- (2) The inspectors observed and evaluated licensed operator performance in the control room during Unit 1 startup after refueling outage 1R31 on May 18, 2024.
- (3) The inspectors observed and evaluated licensed operator performance in the control room during Unit 2 surveillance run of the emergency diesel generator 2K-4A on June 2, 2024.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (2 Samples)
- (1) The inspectors observed and evaluated the Unit 1 crew-based simulator scenario for the annual requalification operating test on June 26, 2024.
- (2) The inspectors observed and evaluated the Unit 2 crew-based simulator scenario for the annual requalification operating test on June 26, 2024.
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (3 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 1 elevated risk due to major maintenance on emergency diesel generator K-4A on April 23, 2024
- (2) Unit 1 emergent work on main feedwater pump B during post-outage power escalation on May 2, 2024 (3)emergent leakage of sluice gate CV-1471-1 from the emergency cooling pond to the Unit 2 service water pump 2P-4A intake bay on June 21, 2024
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (5 Samples)
The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:
(1)operability determination of the emergency cooling pond volume on April 17, 2024
- (2) Unit 1 operability determination of the source range nuclear instruments on May 7, 2024
- (3) Unit 1 operability determination of the engineered safeguards actuation system on May 13, 2024
- (4) Unit 1 functionality of the control rod drive system on May 20, 2024
- (5) Unit 1 operability determination for control rod drop times on May 22, 2024
71111.20 - Refueling and Other Outage Activities
Refueling/Other Outage Sample (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated Unit 1 1R31 conduct of plant shutdown activities from April 27, 2024, to May 24, 2024.
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) (2 Samples)
- (1) Unit 1 post-maintenance test of high-pressure injection pump P-36B after shaft seal replacement on April 12, 2024
- (2) Unit 1 post-maintenance test of high-pressure injection pump P-36C after relief valve replacement and seal venting on April 18, 2024
Containment Isolation Valve (CIV) Testing (IP Section 03.01) (1 Sample)
(1)local leak rate test of Unit 1 quench tank outlet isolation outside containment isolation valve CV-1052 and quench tank containment penetration over-pressure relief valve PSV-1004 on May 2, 2024
Reactor Coolant System Leakage Detection Testing (IP Section 03.01) (1 Sample)
- (1) Unit 1 pressurizer safety relief valve leakage into quench tank on June 28,
OTHER ACTIVITIES - BASELINE
===71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:
MS05: Safety System Functional Failures (SSFFs) Sample (IP Section 02.04)===
- (1) Unit 1 (April 1, 2023, through March 31, 2024)
- (2) Unit 2 (April 1, 2023, through March 31, 2024)
BI01: Reactor Coolant System (RCS) Specific Activity Sample (IP Section 02.10) (2 Samples)
- (1) Unit 1 (April 1, 2023, through March 31, 2024)
- (2) Unit 2 (April 1, 2023, through March 31, 2024)
BI02: RCS Leak Rate Sample (IP Section 02.11) (2 Samples)
- (1) Unit 1 (April 1, 2023, through March 31, 2024)
- (2) Unit 2 (April 1, 2023, through March 31, 2024)
71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02)
- (1) The inspectors reviewed the licensees corrective action program to identify potential trends in spare part availability problems that might be indicative of a more significant safety issue. No more than minor violations were identified.
INSPECTION RESULTS
Failure to Identify Inoperable Source Range Leads to Core Alterations with Less Than Required Reactivity Monitoring Cornerstone Significance Cross-Cutting Aspect Report Section Barrier Integrity Green NCV 05000313/2024002-01 Open/Closed
[H.7] -
Documentation 71111.15 The inspectors identified a Green finding and associated non-cited violation of Arkansas Nuclear One, Unit 1, Technical Specification 3.9.2 for the failure to immediately suspend core alterations with one source range neutron flux monitor inoperable. Specifically, the licensee failed to identify an inoperable neutron flux monitor in a timely manner so that core alterations could be immediately suspended, as required by technical specifications.
Description:
Fuel reloading into the reactor pressure vessel began in the Unit 1 reactor on May 6, 2024, at approximately 8:37 p.m. Prior to that, the NI-1 and NI-2 source range nuclear instruments had been checked for operability by testing the response of the instrument amplifiers. However, the instruments high voltage power supplies were not checked, and the proper functioning of the instrument amplifiers does not depend on proper functioning of the high voltage power supply. Procedure OP-1502.004, Control of Unit 1 Refueling, revision 68, was used for the core reload process. That procedure contains Precautions and Limitations that state: Two source range neutron flux monitors operable during core alterations. (TS 3.9.2). Continuous action step 5.2.5 of OP-1502.004 states: Periodically MONITOR Source Range/Dunker (if installed) count rate to confirm response is as expected for the core load. At 6:46 p.m. on May 7, 2024, after 64 fuel assemblies had already been loaded, the licensee identified that source range detector NI-1 was not responding as expected. The control room operators made a log entry stating, Entered LCO 3.9.2 Nuclear Instrumentation Condition A due to NI-1 Source Range Detector Inoperable. Core alterations have been suspended to satisfy action A.1. Troubleshooting found the NI-1 instrument to have a failed high voltage power supply. Subsequently, the power supply was replaced, and NI-1 was declared operable at 4:40 a.m. on May 8, 2024. Core loading was then continued.
The inspectors review of the NI-1 source range indication for the period from 8:37 p.m. on May 6 to 6:46 p.m. on May 7 found that the NI-1 source range instrument did not respond as expected during that time as determined by comparison with the NI-1 response during the October 2022 fuel reloading. The inspectors concluded that the NI-1 response was not as expected during the core reloading, that the licensee should have identified the failed source range earlier than 6:46 p.m. on May 7, and that the licensee had not immediately suspended core alterations when the source range became inoperable per technical specifications.
A review of source range responses during other recent fuel reloading activities was done by the ANO reactor engineering staff and the fuel reloading activities of both April 2021 and October 2022 showed that both NI source range instruments were clearly on scale as soon as several fuel assemblies had been loaded into the reactor vessel. Other than several noise spikes, the NI-1 source range instrument during the May 6-7, 2024, loading of the first 64 fuel assemblies showed no response and the instrument was not on scale. There was a very clear difference in the May 2024 response of NI-1 when compared to the April 2021 and October 2022 instrument responses. In contrast, the NI-2 source range instrument response was essentially the same for the last three core reloads (May 2024, October 2022, and April 2021).
The inspectors noted that the reactor coolant system boron concentration was high enough to prevent any concerns about accidental criticality during the core reloading, and source range instrument NI-2 was operable during the core alterations.
Corrective Actions: The licensee replaced the failed high voltage power supply. The instrument was then calibrated and restored to operability. The licensee planned to change the core reloading procedure, operator training program, and instrument operability check procedure to help prompt identification of an inoperable neutron flux monitor.
Corrective Action References: Condition Reports CR-ANO-1-2024-00923, 00925, 00966, and 01364
Performance Assessment:
Performance Deficiency: The licensees failure to identify an inoperable neutron flux monitor in a timely manner so that core alterations could be immediately suspended, as required by Technical Specification 3.9.2, 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, the licensee did not identify an inoperable source range during core alterations, which adversely affected reactivity monitoring.
Significance: The inspectors assessed the significance of the finding using Inspection Manual Chapter 0609, Appendix G, Shutdown Safety SDP. The finding was determined to be of very low safety significance (Green) because it:
- (1) did not involve protection of the reactor pressure vessel against fracture;
- (2) did not involve fuel bundle misplacement or misorientation;
- (3) did not involve low temperature over pressurization;
- (4) did not involve a freeze seal;
- (5) did not involve steam generator nozzle dams;
- (6) did not involve the potential for, or an actual, reactor coolant system boron dilution event;
- (7) did not involve a drain down or leakage path;
- (8) did not involve the ability to close or isolate the containment;
- (9) did not involve degradation of the physical integrity of reactor containment, and
- (10) did not involve a BWR Mk III containment, PWR ice condenser containment, or an AP1000 containment.
Therefore, the finding screened as very low safety significance (Green).
Cross-Cutting Aspect: H.7 - Documentation: The organization creates and maintains complete, accurate and up-to-date documentation. Specifically, the work package to perform the operability checks of the source range instruments failed to include checks of the power supplies. Additionally, the procedure for Unit 1 fuel reloading did not provide clear guidance on how to know if source range instrument response is as expected for the core load.
Enforcement:
Violation: Arkansas Nuclear One, Unit 1, Technical Specification 3.9.2, requires that one source range neutron flux monitor shall be operable in Mode 6 and that one additional source range neutron flux monitor shall be operable during core alterations. Condition A requires, in part, that with one required source range neutron flux monitor inoperable during core alterations, to suspend core alterations immediately.
Contrary to above, on May 6 and May 7, 2024, during core alterations, the licensee failed to immediately suspend core alterations with one source range neutron flux monitor inoperable.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with section 2.3.2 of the Enforcement Policy.
Failure to Properly Evaluate Operability of the Unit 2 Emergency Diesel Generator with a Failed Voltage Regulator Current Potential Transformer Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000368/2024002-02 Open/Closed
[H.1] -
Resources 71111.15 The inspectors identified a Green finding and associated non-cited violation of 10 CFR Part 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, for the licensees failure to appropriately assess the immediate operability of the Unit 2 emergency diesel generator 2K-4B in accordance with Procedure EN-OP-104, Operability Determination Process, revision 19. Specifically, the licensee failed to determine if the emergency diesel generator was capable of regulating voltage during isochronous operation from December 16, 2023, to January 23, 2024, due to a failed current potential transformer.
Description:
On December 16, 2023, the licensee performed a surveillance run of the Unit 2 emergency diesel generator (EDG) 2K-4B per Procedure OP-2104.036, Emergency Diesel Generator Operations, revision 104. During the surveillance run, the licensee noted fluctuating kilovolt-amp reactive (KVAR) readings while the generator was connected to the grid and carrying an electrical load. Numerous attempts were made to stabilize the KVAR readings and eventual stabilization was achieved with the KVAR level at 900 KVAR out, although the EDG KVAR reading was normally maintained between 0 and 100 KVAR out.
The licensee initiated Condition Report CR-ANO-2-2023-02996 to document this issue in the corrective action program and assess operability. That condition report identified a failed voltage regulator transformer as a likely cause of the KVAR fluctuations and it identified that site engineering was contacted for input. The licensee declared the EDG operable without evaluating the voltage regulation effects of a failed transformer during isochronous (emergency condition) operation. This condition existed until January 23, 2024, when the failed transformer was replaced.
The inspectors reviewed Condition Report CR-ANO-2-2023-02996, the licensing and design basis for the EDG output voltage, the history of the Unit 2 EDG voltage regulators, and the licensees operability evaluation Procedure EN-OP-104, Operability Determination Process, revision 19. The inspectors noted the following:
- Condition Reports CR-ANO-2-2002-02036 and CR-ANO-2-2004-00229 documented similar problems with EDG KVAR fluctuations that resulted in identification of failed current potential transformers (CPTs) in the 2K-4A and 2K-4B EDG voltage regulator circuits, respectively. Further evaluation of those events by site engineers determined that the Unit 2 EDG voltage regulators should be upgraded to an improved design.
Plans were made to perform the voltage regulator upgrades over the next several refueling outages, but that work was repeatedly postponed and had not occurred as of March 2024. The specified safety functions of the EDGs include the requirement to achieve and maintain a specified output voltage, including voltage recovery criteria for step load transients. The site did not evaluate the ability of the EDG to meet the specified output voltage criteria with a failed CPT during isochronous operation but declared the EDG as operable based on its ability to carry a specified KW load at the proper voltage during synchronous operation.
- The KVAR fluctuations in the December 2023 surveillance run were not recognized during the operability determination as something that would cause output voltage fluctuations during isochronous EDG operation. The magnitude and time response of potential voltage fluctuations were not evaluated, so the effect of the deficiency on isochronous operation was not considered by the on-shift senior reactor operator when determining the operability of the EDG.
From the information above, the inspectors questioned the operability of the 2K-4B EDG to perform its specified safety function of output voltage control when it was used in isochronous mode. In response to the inspectors question, the licensee entered this issue into their corrective action program on February 8, 2024, as Condition Report CR-ANO-2-2024-00207 and reassessed operability of the EDG.
Upon further discussion with the inspectors, the licensee evaluated that the failed CPT would be expected to produce voltage regulation effects similarly to a 2014 event (CR-ANO-2-2014-01403) where capacitors had failed or were significantly degraded in the diesel voltage regulation system. That event measured EDG performance during isochronous operation and observed that the design basis criteria were met when the EDG performed its design basis functions of powering emergency loads.
The licensee performed a past operability evaluation and it concluded that the EDG was operable after the December 16, 2023, EDG surveillance. The inspectors noted that the conclusion relied heavily on the assumption that the 2014 failed capacitors in the voltage regulator circuit would have essentially the same effect as the 2023 failed CPT in the voltage regulator circuit. The initial version of the past operability evaluation also stated: Thus, the CPTs, by design, provide bulk voltage regulation, and The voltage regulator provides the fine adjustment for voltage regulation. Following additional questions from the inspectors, a second version of the past operability was performed with additional information and adequately concluded that the EDG was operable with the failed CPT.
Corrective Actions: The licensee replaced the failed CPT on January 23, 2024, and performed satisfactory post-maintenance testing of the EDG. The licensee also performed a past operability evaluation to evaluate the effect of the failed CPT on the EDG.
Corrective Action References: Condition Reports CR-ANO-2-2023-02996, CR-ANO-2-2024-00207, and WO 54094397
Performance Assessment:
Performance Deficiency: The licensees failure to appropriately assess the immediate operability of the 2K-4B EDG was a performance deficiency. Specifically, the licensee failed to determine if the EDG was capable of regulating voltage during isochronous operation from December 16, 2023, to January 23, 2024, due to a failed current potential transformer.
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. Specifically, the licensee failed to adequately establish reasonable assurance for operability, which left reasonable doubt that the EDG could perform its safety function with the failed CPT.
Significance: The inspectors assessed the significance of the finding using Inspection Manual Chapter 0609, Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The finding was determined to be of very low safety significance (Green) because it:
- (1) did not represent a deficiency affecting the design or qualification of a mitigating SSC;
- (2) did not represent a loss of the PRA function of a single train TS system;
- (3) did not represent an actual loss of the PRA function of one train of a multi-train TS system for more than its TS allowed outage time OR;
- (4) two separate safety systems for more than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />;
- (5) did not represent a loss of a PRA system and/or function as defined in the PRIB or the licensees PRA for greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />; and
- (6) did not represent a loss of a PRA function of one or more non-TS trains of equipment designated as risk-significant in accordance with the licensees maintenance rule program for greater than 3 days.
Cross-Cutting Aspect: H.1 - Resources: Leaders ensure that personnel, equipment, procedures, and other resources are available and adequate to support nuclear safety.
Specifically, the inspectors determined that current licensing basis document requirements for EDG transient voltage requirements were not readily available to the senior reactor operator performing the operability determination. The Unit 2 UFSAR description of the EDG and its design basis functions did not include the Regulatory Guide 1.9 (Selection of Diesel Generator Set Capacity For Standby Power Supplies) requirements for transient voltage response to the starting of ESF loads. The UFSAR contains a reference to the Regulatory Guide requirements, but the senior reactor operator would need to access that document to find the design basis specifications.
Enforcement:
Violation: Title 10 CFR Part 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, requires, in part, that activities affecting quality shall be prescribed by documented instructions, procedures, or drawings, of a type appropriate to the circumstances and shall be accomplished in accordance with these instructions, procedures, or drawings. Procedure EN-OP-104, Operability Determination Process, revision 19, a quality-related procedure, prescribes how to accomplish operability determinations.
Procedure EN-OP-104 states:
- 7.2.5 d. DETERMINE the impact of the Deficient Condition on the TS SSC or the specified safety function Contrary to above, from December 16, 2023, to January 23, 2024, the licensee failed to accomplish the Procedure EN-OP-104 requirements to determine the specified safety function for the SSC and determine the impact of the deficient condition on the SSC.
Specifically, the licensee failed to determine if the EDG was capable of regulating voltage during isochronous operation due to a failed current potential transformer.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with section 2.3.2 of the Enforcement Policy.
Observation: Review of Spare Part Availability Problems 71152S The inspectors performed a review of potential adverse trends in the licensees corrective action program with emphasis on the availability of spare parts that are ready for use in the plant when needed. Records in the sites corrective action program, in addition to other administrative records, showed there has been a negative trend with numerous occurrences of spare parts being shown as available in the warehouse stock and ready for installation when that was actually not true. There were also cases found where bad parts were sent to the warehouse to be repaired/refurbished and then those parts lingered in the warehouse for long periods of time (up to years) without being sent out for repair/refurbishment. Often, documentation of the parts does not clearly show that they need to be repaired. In some cases, this has resulted in the site not having replacement parts available for emergent events and that threatens to place the site in an increased risk condition. Many of the parts affected by the conditions noted above are obsolete, so purchasing a new replacement part from the vendor is not possible. The most notable example of the increased risk potential was that the Unit 2 plant protection system (PPS - a safety-related, TS-required system) had multiple reactor trip points placed in bypass from May 16, 2024, until July 2, 2024, due, in part, to the unavailability of several repair parts. This caused rescheduling of required PPS maintenance and the threat of needing to put one or more points in a TRIP condition that would cause an unplanned single point vulnerability to the unit.
The licensee was aware of issues with the availability of parts, and they are examining opportunities to improve the situation. The current status presents a threat to the availability and reliability of safety systems at the facility.
Some other examples of the spare part availability problem are:
1. Unit 1 EFIC spare parts were identified as being in short supply in condition report (CR)
CR-ANO-1-2022-02333, written on October 26, 2022. That CR stated, The site needs to take timely actions to assure that uninstalled spares are sent off for repair/refurb, or new spares are procured where possible and returned at the earliest opportunity to replenish stock to support possible emergent issues. Subsequent to the above CR, a new CR (CR-ANO-1-2022-02734) was written on November 13, 2022, to document that purchase orders for EFIC spare parts were on hold pending Engineering Review and Approval. The EFIC card repair plan was submitted on July 29, 2022. The Engineering Change Review was routed to engineering for approval on August 19, 2022, with need date documentation of August 23, 2022, and September 13, 2022. Although it was requested before the refueling outage, the repair plan was approved by engineering on November 19, 2022, which was after the Unit 1 outage that depleted many EFIC spare parts.
2. In May 2024, a Low Steam Generator Pressure trip signal was received, and it was
evaluated to be a failed Unit 2 Plant Protection System Steam Generator Variable Setpoint (S/G VSP) card. When the technicians went to acquire a replacement card, they found that the ANO warehouse had two of these cards, but they were both bad and were waiting to be sent to a contractor for repair. One of those cards had been sent to the warehouse a year earlier (in April 2023) for repair and no action had been taken as of April 2024.The cause of this delay appeared to be related to the practice of not repairing obsolete cards until a need was known to exist.
3. A Unit 2 automatic control element drive mechanism timing module card replacement was
planned on February 12, 2024, to assist with troubleshooting of a ground condition on the control rod drive power supply. When the technicians went to acquire a replacement card, they found that all 10 of the cards shown in the warehouse inventory as available were not usable because they did not have the correct revision of firmware in their EEPROM modules.
A CR was written in 2019 (CR-ANO-2-2019-01084) to have those 10 cards upgraded to the correct firmware version and that CR was closed to a work order that only replaced a card in use but did not fix the remaining 10 cards. As a result, there was no action being taken or tracked to ensure that the 10 cards would be made usable in a timely manner.
No more than minor violations were identified.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On May 7, 2024, the inspectors presented the ANO Unit 1 inservice inspection results to Doug Pehrson, Site Vice President, and other members of your staff.
- On July 12, 2024, the inspectors presented the integrated inspection results to Mark Skartvedt, General Manager of Plant Operations, and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Corrective Action
Documents
CR-ANO-
1-2024-00486
Drawings
E-108, Sheet 4
Schematic Diagram Diesel Generator #1 Auxiliary Control
Drawings
E-108, Sheet 4A
Schematic Diagram Diesel Generator #2 Fuel Transfer
Pump P16B and Fuel Prime Pump P104B
Drawings
E-451, Sheet 4
Schematic Diagram Annunciator K-01
Drawings
M-235, Sheet 1
Spent Fuel Cooling System
Engineering
Changes
T-MOD Power to P-40A
11/13/2014
Miscellaneous
ANSI/ANS-59.51-
1997Property "ANSI code" (as page type) with input value "ANSI/ANS-59.51-</br></br>1997" contains invalid characters or is incomplete and therefore can cause unexpected results during a query or annotation process.
Fuel Oil Systems for Safety-related Emergency Diesel
Generators
1997
Miscellaneous
Regulatory
Guide 1.137
Fuel Oil Systems for Emergency Power Supplies
Miscellaneous
ULD-0-SYS-03
ANO New and Spent Fuel Storage, Spent Fuel Cooling,
New and Spent Fuel Handling Systems
Miscellaneous
ULD-1-SYS-01
ANO-1 Emergency Diesel Generator (EDG) System
Procedures
OP-1000.113
Diesel Fuel Monitoring Program
Procedures
OP-1104.004
Decay Heat Removal Operating Procedure
140
Procedures
OP-1104.006
Spent Fuel Cooling System
Procedures
OP-1104.036
Emergency Diesel Generator Operation
Procedures
OP-1203.012A
Annunciator K01 Corrective Action
Work Orders
Corrective Action
Documents
CR-ANO-
1-2024-00540, 1-2024-00867
Drawings
FP-101, Sheet 1
Fire Zones, Fuel Handling Floor Plan, El 404'-0" ad 422'-0"
Drawings
FP-102, Sheet 1
Fire Zone, Operating Floor Plan, El 386'-0"
Drawings
FP-103 1 - (032)
Fire Zones Intermediate Floor Plan EL 368-0 and 372-0
Drawings
FP-103, Sheet 1
Fire Zones, Intermediate Floor Plan, El 368'-0" and 372'-0"
Drawings
FP-104, Sheet 1
Fire Zone, Ground Floor Plan, El 354'-0"
Drawings
FP-105, Sheet 1
Fire Zone, Plan Below Grade, El 335'-0"
Engineering
Changes
T-Mod Power to P-40B
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Miscellaneous
PFP-U1_R022
Unit 1 Prefire Plans
Procedures
Control of Combustibles
Work Orders
Corrective Action
Documents
CR-ANO-
1-2019-03944
Procedures
SEP-HX-ANO-
001
Arkansas Nuclear One Heat Exchanger Program
Work Orders
Corrective Action
Documents
CR-ANO-
1-2019-04771, 1-2019-04774, 1-2020-01128, 1-2021-01244,
1-2021-01948, 1-2022-00202, 1-2022-01284, 1-2022-01748,
1-2022-01818, 1-2022-01991, 1-2022-02007, 1-2022-02029,
1-2022-02101, 1-2022-02317, 1-2022-02478, 1-2022-02659,
1-2022-02773, 1-2022-02907, 1-2022-02973, 1-2022-03039,
1-2022-03101, 1-2022-03198, 1-2023-00093, 1-2023-00098,
1-2023-00279, 1-2023-00358, 1-2023-00379, 1-2023-00658,
1-2023-00719, 1-2023-00736, 1-2023-00830, 1-2023-00831,
1-2023-00866, 1-2023-00972, 1-2023-01096, 1-2023-01187,
1-2023-01190, 1-2023-01221, 1-2023-01255, 1-2023-01269,
1-2023-01270, 1-2023-01271, 1-2023-01272, 1-2023-01273,
1-2023-01274, 1-2023-01275, 1-2023-01276, 1-2023-01277,
1-2023-01279, 1-2023-01288, 1-2023-01364, 1-2023-01568,
1-2023-01642, C-2022-01449, C-2022-02817, C-2022-
03059, C-2022-03231
Engineering
Changes
Engineering
Evaluations
CALC-24-E-0002-
1R31 Fretting Evaluation for CCA-5, MU-45C Piping
Miscellaneous
lnservice Inspection Summary Report for the Arkansas
Nuclear One, Unit 1 Thirtieth Refueling Outage (1 R30)
03/20/2023
NDE Reports
1-BOP-UT-24-021 Replacement RPV Stud UT
NDE Reports
1-BOP-VT-24-005 Replacement RPV Nut and Washer VT-1
NDE Reports
1-ISI-LN-24-005
21477709 Linearity Inspection
NDE Reports
1-ISI-UT-24-006
WO-590267 03-
E-24A Upper Head to Upper Ring Head Weld
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
110
NDE Reports
1-ISI-VT-22-015
EC 94473 Pressurizer Heater Bundle Bolting
NDE Reports
1-ISI-VT-22-015
Heater Bundle Studs
NDE Reports
1-ISI-VT-22-020
EFW-1 Variable Spring
NDE Reports
1-ISI-VT-24-014
MU-135 Variable Spring
NDE Reports
1-ISI-VT-24-025
HDB-21-H20
NDE Reports
1-ISI-VT-24-028
HBD-20-H72
NDE Reports
1-ISI-VT-24-029
HBD-20-H72-Anchor
Procedures
1402.130
Snubber Removal and Installation
Procedures
CEP-BAC-001
Boric Acid Corrosion Control (BACC) Program Plan
Procedures
CEP-NDE-0423
Manual UT Austenitic Pipe ASME XI
Procedures
CEP-NDE-0497
Manual UT Weld in Vessels Non-App. VIII
Procedures
CEP-NDE-0641
Liquid Penetrant Exam for ASME XI
Procedures
CEP-NDE-0731
Magnetic Particle Exam for ASME XI
Procedures
CEP-NDE-0901
VT-1 Examination
Procedures
CEP-NDE-0903
VT-3 Examination
Procedures
CEP-NDE-0955
Visual Examination (VE) of Bare-Metal Surfaces
308
Procedures
CEP-RR-002
Control And Documentation of Repair/Replacement
Activities
Procedures
CEP-WP-002
WPS NO. WPS-CS-1/1-B Welding Procedure Specification
Procedures
CEP-WP-002
WPS NO. WPS-LA-5A/1-A Welding Procedure Specification
Procedures
System Walkdowns
Procedures
Boric Acid Corrosion Control Program (BACCP)
Procedures
EN-LI-104-
ATTACHMENT-1
Final Self-assessments for the Inservice Inspection,
Welding, and Alloy 600 Programs
Procedures
Fluid Leak Prevention and Management Program
Procedures
Decontamination Program
Procedures
SEP-BAC-ANO-
001
Arkansas Nuclear One (ANO) Boric Acid Corrosion Control
Program Inspection and Identification of Boric Acid Leaks for
ANO-1 And ANO-2
Procedures
SEP-BAC-ANO-
001
Appendix A Checklist for Boric Acid Inspections During
Outages
Procedures
SEP-ISI-ANO1-
Program Section for ASME Section Xi, Division 1 ANO 1
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
101
Inservice Inspection Program
Work Orders
WO 28330, 536783, 564092, 574129, 587351, 588541,
590142, 591333, 595370, 52566854, 52865060
Miscellaneous
9.1
PWR Reactivity Maneuver - 451 EFPD APSR Pull
03/28/2024
Procedures
EN-OP-115-14
Reactivity Management
Procedures
OP-1102.002
Plant Startup
21
Procedures
OP-1102.008
Approach to Criticality
Procedures
OP-1105.009
CRD Operating Procedure
Procedures
OP-1105.009
CRD System Operating Procedure
Procedures
OP-2104.036
Emergency Diesel Generator Operations
104
Calculations
91-E-0099-14
ECP Peak Temperature and Inventory Analysis
Calculations
91-E-0107-13
Unit 1 Fuel Oil Transfer Pumps Net Positive Suction Head
03/09/1994
Corrective Action
Documents
CR-ANO-
1-2021-03046, 1-2024-01157, 2-2024-00541, C-2024-00962
Drawings
M-204, Sheet 2
Condensate Feedwater
Miscellaneous
ODM K-2B
K-2B Maintenance Decision
Miscellaneous
SEP-ANO-2-IST-
ANO Unit 2 Inservice Testing Bases Document
Miscellaneous
ULD-0-TOP-27
Ultimate Heat Sink Analysis
Miscellaneous
ULD-1-SYS-01
ANO-1 Emergency Diesel Generator (EDG) System
Procedures
Protected Equipment Postings
Procedures
OP-1102.002
Plant Startup
21
Procedures
OP-1102.004
Power Operation
Procedures
OP-1104.026
Emergency Diesel Generator Operation
Procedures
OP-1105.004
Integrated Control System
Procedures
OP-1106.016
Condensate, Feedwater, and Steam System Operation
Procedures
OP-2104.029
Service Water System Operations
27
Work Orders
WO 553535, 590526, 52979143, 53030724, 54054074,
54149261
Corrective Action
Documents
CR-ANO-
1-2024-00923, 1-2024-00925, 1-2024-01023, C-2024-00497
Drawings
C-65
Emergency Cooling Reservoir
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Engineering
Changes
Temporary Neutron Monitoring System
Miscellaneous
February 2024 Hydrographic Survey Report of the
Emergency Cooling Pond, Russellville, Arkansas
03/27/2024
Miscellaneous
ER-ANO-2002-
0107
Testing of Gamma Metrics HV Power Supply
01/23/2002
Miscellaneous
U1 TS 3.9.2
Nuclear Instrumentation
Amendment
215
Miscellaneous
ULD-1-SYS-25
ANO-1 Nuclear Instrumentation System
Miscellaneous
ULD-1-SYS-36
ANO-1 Control Rod Drive (CRD) System
Procedures
OP-1103.015
Reactivity Balance Calculation
Procedures
OP-1304.035
Unit 1 Position Indicator Panel Alignment and Rod Drop Test
Procedures
OP-1304.047
Unit 1 Control Rod Drive System Calibration and Functional
Test
Procedures
OP-1304.057
Unit 1 Source Range Channels Calibration
Procedures
OP-1305.006
Integrated ES System Test
Procedures
OP-1306.019
Annual Emergency Cooling Pond Sounding
Procedures
OP-1502.004
Control of Unit 1 Refueling
Work Orders
WO 53030672, 53031475, 53033214, 54066803, 54081564,
54143771
Corrective Action
Documents
CR-CNS-
1-2024-01092, 1-2024-01102, 1-2024-01111, 1-2024-01117,
1-2024-01118, 1-2024-01119, 1-2024-01127, 1-2024-01134
Miscellaneous
Cycle 32 Core Operating Limits Report
Miscellaneous
Outage Risk Assessment Team Report
Procedures
EN-OP-115.02
Control Room Conduct and Access Control
Procedures
EN-OP-115.14
Reactivity Management
Procedures
OP 1102.010
Plant Shutdown and Cooldown
Procedures
OP 1102.016
Power Reduction and Plant Shutdown
Procedures
OP 1104.004
Decay Heat Removal Operating Instruction
140
Procedures
OP-1015.002
Decay Heat Removal and LTOP System Control
Procedures
OP-1102.008
Approach to Criticality
Procedures
OP-1102.010
Plant Shutdown and Cooldown
Procedures
OP-1103.018
Maintenance of RCS Water Level
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Work Orders
WO 53030672, 53031300, 53033214, 55303147
Corrective Action
Documents
CR-ANO-
1-2023-01221, 1-2024-00400, 1-2024-00415, 1-2024-01430,
1-2024-01452
Miscellaneous
CALC-ANO1-ME-
13-00008
Review of the Leakage Detection in Reactor Building Aging
Management Program for License Renewal Implementation
Miscellaneous
ULD-1-SYS-02
Makeup & Purification High-Pressure Injection System
Procedures
OP-1103.013
RCS Leak Detection
Procedures
OP-1305.018
Local Leak Rate Testing - Type C
Procedures
OP-1402.010
Unit 1 Primary Makeup Pumps (P-36 A, B, C)
Procedures
OP-5210.402
Unit 1 Primary Containment Leak Rate Running Total
Work Orders
WO 53019345, 53024244-03, 53029874-01, 54103265,
54127779
71151
Corrective Action
Documents
CR-ANO-
1-2023-00743, 2-2023-00026, 2-2023-01929, 2-2023-01938
Corrective Action
Documents
CR-ANO-
1-2022-02333, 1-2022-02734, 2-2019-01084
Miscellaneous
ECR-26433
Engineering to Review FTI Reverse Engineering and Repair
Plan
11/19/2022
Work Orders
WO 53011706, 53013699