IR 05000528/2024003
| ML24306A080 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 11/04/2024 |
| From: | John Dixon NRC/RGN-IV/DORS/PBD |
| To: | Heflin A Arizona Public Service Co |
| References | |
| IR 20242003 | |
| Download: ML24306A080 (1) | |
Text
November 4, 2024
SUBJECT:
PALO VERDE NUCLEAR GENERATING STATION - INTEGRATED INSPECTION REPORT 05000528/2024003 AND 05000529/2024003 AND 05000530/2024003
Dear Adam Heflin:
On September 30, 2024, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Palo Verde Nuclear Generating Station. On October 22, 2024, the NRC inspectors discussed the results of this inspection with Cary Harbor, Senior Vice President, Site 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. One of these findings involved a violation of NRC requirements. We are treating this violation as a non-cited violation (NCV) consistent with Section 2.3.2 of the Enforcement Policy.
A licensee-identified violation which was determined to be of very low safety significance is documented in this report. We are treating this violation as a non-cited violation (NCV)
consistent with Section 2.3.2 of the Enforcement Policy.
If you contest the 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 Palo Verde Nuclear Generating Station.
If you disagree with a cross-cutting aspect assignment or a finding not associated with a regulatory requirement in this report, you should provide a response within 30 days of the date of this inspection report, with the basis for your disagreement, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region IV; and the NRC Resident Inspector at Palo Verde Nuclear Generating Station. 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. 05000528, 05000529, 05000530 License Nos. NPF-41, NPF-51, NPF-74
Enclosure:
As stated
Inspection Report
Docket Numbers:
05000528, 05000529 and 05000530
License Numbers:
Report Numbers:
05000528/2024003, 05000529/2024003 and 05000530/2024003
Enterprise Identifier:
I-2024-003-0002
Licensee:
Arizona Public Service
Facility:
Palo Verde Nuclear Generating Station
Location:
Tonopah, AZ
Inspection Dates:
July 1, 2024 to September 30, 2024
Inspectors:
L. Merker, Senior Resident Inspector
N. Cuevas, Resident Inspector
D. Dodson, Senior Reactor Inspector
N. Hernandez, Senior Operations Engineer
R. Kopriva, Senior Project Engineer
C. Harrington, Operations Engineer
P. Nwafor, Project Engineer
C. Peabody, Nuclear Engineer
A. Sanchez, Senior Project Engineer
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 Palo Verde Nuclear Generating 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. A licensee-identified non-cited violation is documented in report section: 7115
List of Findings and Violations
Failure to Properly Evaluate Operability of the Unit 3 Excore Startup Range Monitor 2 During Fuel Movement Cornerstone Significance Cross-Cutting Aspect Report Section Barrier Integrity Green NCV 05000530/2024003-01 Open/Closed
[H.14] -
Conservative Bias 71111.15 The inspectors identified a Green, non-cited violation of Title 10 CFR Part 50, Appendix B,
Criterion V, Instructions, Procedures, and Drawings, for the licensees failure to follow procedure 40DP-9OP26, Operations Operability Determination Process, revision 48.
Specifically, the licensee failed to adequately determine the operability of the Unit 3 excore startup range monitor 2 after it failed on April 13, 2024, challenging whether there was reasonable assurance that the channel could perform its specified safety function.
Failure to Evaluate a Damaged Bushing Results in Partial Loss of Offsite Power in Unit 2 Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green FIN 05000529/2024003-02 Open/Closed None (NPP)71153 The inspectors reviewed a self-revealed, Green, finding for the failure to adequately assess and repair a damaged bushing mount for Unit 2, 13.8 kV switchgear bus, 2E-NAN-S04.
Specifically, the licensees failure to adequately assess and repair a crack through the B phase bushing mount on 2E-NAN-S04 resulted in water intrusion and a fault causing a partial loss of offsite power to Unit 2. The partial loss of offsite power to Unit 2 resulted in the valid actuation and loading of the Unit 2 emergency diesel generator B.
Additional Tracking Items
Type Issue Number Title Report Section Status LER 05000528/2023-002-00 LER 2023-002-00 for Palo Verde Nuclear Generating Station (PVNGS), Unit 1,
Reactor Coolant System Degraded Pressure Boundary 71153 Closed
LER 05000530/2024-001-00 LER 2024-001-00 for Palo Verde Nuclear Generating Station, Unit 3, Inoperable Boron Dilution Alarm System (BDAS) with Technical Specification Violation 71153 Closed LER 05000530/2024-001-01 LER 2024-001-01 for Palo Verde Nuclear Generating Station (PVNGS), Unit 3,
Inoperable Boron Dilution Alarm System (BDAS) with Technical Specification Violation 71153 Closed LER 05000530/2024-002-00 LER 2024-002-00 for Palo Verde, Unit 3, Invalid Specified System Actuation of Train B Emergency Diesel Generator 71153 Closed LER 05000529/2024-001-00 LER 2024-001-00 for Palo Verde Nuclear Generating Station Unit 2, Valid Specified System Actuations of Unit 2 Train B Emergency Diesel Generator and Train B Auxiliary Feedwater 71153 Closed
PLANT STATUS
Units 1, 2, and 3 operated at or near full power 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) (1 Sample)
The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:
- (1) Unit 2, 480V class 1E power system train A, on July 30, 2024
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (2 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, main steam support structure, 100-foot and 120-foot levels, fire zones 74A and 74B, on July 10, 2024
- (2) Unit 2, containment spray trains A and B pump rooms, fire zones 30A and 30B, on August 16, 2024
71111.11A - Licensed Operator Requalification Program and Licensed Operator Performance
Requalification Examination Results (IP Section 03.03) (1 Sample)
- (1) The inspectors reviewed and evaluated the licensed operator examination failure rates for the requalification annual operating exam administered from August 19 to September 27, 2024.
71111.11B - Licensed Operator Requalification Program and Licensed Operator Performance
Licensed Operator Requalification Program (IP Section 03.04) (1 Sample)
- (1) Biennial Requalification Written Examinations The inspectors evaluated the quality of the licensed operator biennial requalification written examination administered on August 30, 2024.
Annual Requalification Operating Tests The inspectors evaluated the adequacy of the facility licensees annual requalification operating test.
Administration of an Annual Requalification Operating Test The inspectors evaluated the effectiveness of the facility licensee in administering requalification operating tests required by 10 CFR 55.59(a)(2) and that the facility licensee is effectively evaluating their licensed operators for mastery of training objectives.
Requalification Examination Security The inspectors evaluated the ability of the facility licensee to safeguard examination material, such that the examination is not compromised.
Remedial Training and Re-examinations The inspectors evaluated the effectiveness of remedial training conducted by the licensee, and reviewed the adequacy of re-examinations for licensed operators who did not pass a required requalification examination.
Operator License Conditions The inspectors evaluated the licensees program for ensuring that licensed operators meet the conditions of their licenses.
Control Room Simulator The inspectors evaluated the adequacy of the facility licensees control room simulator in modeling the actual plant, and for meeting the requirements contained in 10 CFR 55.46.
71111.11Q - Licensed Operator Requalification Program and Licensed Operator Performance
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed licensed operator continued training simulator activities, on September 24, 2024.
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (1 Sample)
The inspectors evaluated the accuracy and completeness of risk assessments for the following planned and emergent work activities to ensure configuration changes and appropriate work controls were addressed:
- (1) Unit 1, planned maintenance on balance of plant engineered safety features actuation system train A, on September 3, 2024
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (9 Samples)
The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:
- (1) Unit 1, emergency diesel generator train A operability determination due to droop setting discrepancy during testing of the auto voltage regulator 2, on July 1, 2024
- (2) Unit 3, essential chiller A operability determination due to tripping during integrated safeguards testing, on July 30, 2024
- (3) Unit 3, essential chilled water air cooling unit for DC equipment room train A operability determination due to excessive condensation build up in front drip pan, on August 5, 2024
- (4) Unit 1, turbine-driven auxiliary feedwater pump operability determination due to high room temperature alarm caused by supply steam isolation valve seat leakage, on August 9, 2024
- (5) Unit 2, containment spray pump A operability determination due to the discovery of a missing flow orifice in the seal water cooling system, on August 16, 2024
- (6) Unit 2, control room envelope train B operability determination due to pressurization acceptance criteria exceeded during surveillance testing, on August 20, 2024
- (7) Unit 3, containment spray pump A operability determination due to clearance between lower impeller wear surface and casing wear ring found outside allowable band, on August 21, 2024
- (8) Unit 3, excore startup range monitor 2 operability determination due to intermittent failure during core fuel movements, on September 10, 2024
- (9) Unit 1, emergency diesel generator train A operability determination due to turbocharger interior indications, on September 30, 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) (3 Samples)
- (1) Unit 2, emergency diesel generator train B post-maintenance testing following replacement of overspeed governor, on July 31, 2024
- (2) Unit 1, balance of plant engineered safety features actuation system train A post-maintenance testing following power supply replacement, on August 29, 2024
- (3) Unit 3, excore startup range monitor 2 post-maintenance testing following high voltage power supply, on September 12, 2024
Surveillance Testing (IP Section 03.01) (1 Sample)
- (1) Unit 2, control room essential filtration system train B air filtration unit airflow capacity and pressurization testing, on August 20, 2024
Inservice Testing (IST) (IP Section 03.01) (1 Sample)
- (1) Unit 2, essential chilled water pump A inservice testing, on July 10, 2024
Diverse and Flexible Coping Strategies (FLEX) Testing (IP Section 03.02) (1 Sample)
- (1) Units 1, 2, and 3, FLEX refueling water tank transfer pumps testing, on September 30, 2024
71114.06 - Drill Evaluation
Additional Drill and/or Training Evolution (1 Sample)
- (1) The inspectors evaluated an emergency preparedness drill, on August 13,
OTHER ACTIVITIES - BASELINE
===71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:
MS06: Emergency AC Power Systems (IP Section 02.05)===
- (1) Unit 1 (July 1, 2023, through June 30, 2024)
- (2) Unit 2 (July 1, 2023, through June 30, 2024)
- (3) Unit 3 (July 1, 2023, through June 30, 2024)
MS07: High Pressure Injection Systems (IP Section 02.06) (3 Samples)
- (1) Unit 1 (July 1, 2023, through June 30, 2024)
- (2) Unit 2 (July 1, 2023, through June 30, 2024)
- (3) Unit 3 (July 1, 2023, through June 30, 2024)
MS08: Heat Removal Systems (IP Section 02.07) (3 Samples)
- (1) Unit 1 (July 1, 2023, through June 30, 2024)
- (2) Unit 2 (July 1, 2023, through June 30, 2024)
- (3) Unit 3 (July 1, 2023, through June 30, 2024)
MS09: Residual Heat Removal Systems (IP Section 02.08) (3 Samples)
- (1) Unit 1 (July 1, 2023, through June 30, 2024)
- (2) Unit 2 (July 1, 2023, through June 30, 2024)
- (3) Unit 3 (July 1, 2023, through June 30, 2024)
MS10: Cooling Water Support Systems (IP Section 02.09) (3 Samples)
- (1) Unit 1 (July 1, 2023, through June 30, 2024)
- (2) Unit 2 (July 1, 2023, through June 30, 2024)
- (3) Unit 3 (July 1, 2023, through June 30, 2024)
71153 - Follow Up of Events and Notices of Enforcement Discretion Event Report (IP Section 03.02)
The inspectors evaluated the following licensees event reporting determinations to ensure it complied with reporting requirements.
- (1) The inspectors reviewed Licensee Event Report 05000528/2023-002-00, Reactor Coolant System Degraded Pressure Boundary (ADAMS accession No.
ML23342A068). The inspectors determined that the cause of the condition described in the LER was not reasonably within the licensees ability to foresee and correct and, therefore, was not reasonably preventable. No performance deficiency nor violation of NRC requirements was identified. This LER is closed.
- (2) Licensee Event Report 05000529/2024-001-00, Valid Specified System Actuations of Unit 2 Train B Emergency Diesel Generator and Train B Auxiliary Feedwater (ADAMS Accession No. ML24144A277). The inspection conclusions associated with this LER are documented in this report under Inspection Results section 71153. This LER is closed.
- (3) Licensee Event Report 05000530/2024-001-00 and LER 05000530/2024-001-01, Unit 3 Inoperable Boron Dilution Alarm System (BDAS) with Technical Specification Violation (ADAMS Accession Nos. ML24157A339 and ML24234A332). The inspection conclusions associated with this LER are documented in this report under Inspection Results section 71153. This LER is closed.
- (4) Licensee Event Report 05000529/2024-002-00, Invalid Specified System Actuation of Unit 3 B Emergency Diesel Generator (ADAMS Accession No. ML24177A322). 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 Properly Evaluate Operability of the Unit 3 Excore Startup Range Monitor 2 During Fuel Movement Cornerstone Significance Cross-Cutting Aspect Report Section Barrier Integrity Green NCV 05000530/2024003-01 Open/Closed
[H.14] -
Conservative Bias 71111.15 The inspectors identified a Green, non-cited violation of Title 10 CFR Part 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, for the licensees failure to follow procedure 40DP-9OP26, Operations Operability Determination Process, revision 48.
Specifically, the licensee failed to adequately determine the operability of the Unit 3 excore startup range monitor 2 after it failed on April 13, 2024, challenging whether there was reasonable assurance that the channel could perform its specified safety function.
Description:
Two startup channel neutron flux monitors or excore startup range monitors are part of the nuclear instrumentation system and are used to monitor the reactivity during core alterations. The detectors are external to the reactor vessel and detect neutrons leaking from the core. Each channel provides continuous visual indication in the main control room, audible indication in the main control room and containment, and a signal to the boron dilution alarm system (BDAS) to alert operators in the main control room of a possible boron dilution event.
On April13, 2024, Unit 3 was performing a core offload, in mode 6, when excore startup range monitor 2 instantaneously went from 8 to 0 counts per second. Operations personnel declared the startup channel inoperable and entered technical specification limiting conditions of operability (LCOs) 3.9.2.A and 3.3.12.A for the associated BDAS channel. Core alterations and positive reactivity additions were suspended, and boron concentration was sampled per the LCO required actions. Approximately three hours later, the excore startup range monitor 2 signal instantaneously reappeared providing similar indication as before, 8 counts per second. Prior to and after the lost signal, excore startup range monitor 2 displayed more noise when compared to excore startup range monitor 1. During the approximate three hours of lost signal, only discussions and preparations for troubleshooting were performed. After the channel signal instantaneously returned, the main control room completed a partial functional test and channel check per procedures 40ST-9ZZM6, Operations MODE 6 Surveillance Logs, revision 26, and 36ST-9SE05, BDAS Functional Test, revision 27, satisfactorily.
Operations personnel declared the excore startup range monitor operable, exited the LCO, and recommenced core alterations. However, the procedures performed did not include testing all the parameters in excore startup range monitor 2, such as taking high voltage power supply measurements, before the main control room incorrectly declared the excore startup range monitor operable based on the statement that it is no longer failed and is providing accurate count rate based on satisfactory channel check with startup channel 1. As a result, the licensee failed to meet technical specification LCOs 3.9.2 and 3.3.12, when operations personnel exited the LCOs and recommenced core alterations.
After the core was offloaded, the excore startup range monitor 2 high voltage power supply, PS4, was replaced, resulting in less signal noise, following similar counts per seconds as excore startup range monitor 1, and without the periodic spikes observed when it was degraded. The site performed an evaluation to determine the most probable cause of the failed excore startup range monitor 2 PS4. The licensee found that PS4s electrolytic capacitors dated back to 1987, which are commonly replaced every 10 to 15 years, as well as a deficient high voltage potted component, concluding the cause of the failure cannot be determined with certainty as the issue described in Condition Report 24-03849 only lasted for about 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> and no troubleshooting was performed while the condition was present.
However, the Electronic Restoration Teams findings provide strong evidence to support the degraded high voltage power supply (PS4) as apparent cause of the failure and because the condition was only present for a few hours, the high voltage power supply (PS4) for the startup detector was thought as a potential cause of the failure. Furthermore, per Condition Report 22-06446, the site had previously identified the need to inspect and replace these specific power supplies across all units due to old capacitors and per the evaluation the implementation of the preventive maintenance was too slow and PS4 in Unit 3 source range monitor 2 failed before the inspection was completed.
The sites procedure 40DP-9OP26, Operations Operability Determination Process, revision 48, provides guidance for the site to determine if a safety system should be considered operable. In step 3.24, it states, When system capability is degraded to a point where the system cannot perform with reasonable expectation or reliability, the system should be judged inoperable even if at this instantaneous point in time the system could provide the specified safety function. Given that no troubleshooting of the excore startup range monitor was performed during or immediately after the 3-hour failure, and was subsequently found to have degraded components, it should not have been reasonably expected to reliably perform its specified safety function.
Corrective Actions: The licensee wrote Condition Report 24-03849 to document the excore startup range monitor 2 failure. After the core offload was completed, the excore startup range monitor 2 high voltage power supply was replaced, and the channel was calibrated.
Condition report 24-04484 was written to document the evaluation of the status of all the excore startup range monitors high voltage power supplies at the site.
Corrective Action References: Condition reports 22-06446, 24-03849, and 24-04484
Performance Assessment:
Performance Deficiency: The licensees failure to follow procedure was a performance deficiency. Specifically, the licensee failed to properly evaluate the operability of the Unit 3 excore startup range monitor 2 per procedure 40DP-9OP26, Operations Operability Determination Process, revision 48.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Procedure Quality 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, during post-removal testing of the excore startup range monitor 2, its performance was found to be degraded by failed high voltage power supply components such that reasonable assurance of operability was called into question. Although the instrument was providing counts, it was degraded and should not have been evaluated to have the reliability or reasonable expectation of operability.
Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The inspectors used Appendix A because it was related to fuel handling issues (handling fuel with inadequate instrumentation). Using Exhibit 3, Barrier Integrity Screening Questions, of Appendix A, the inspectors screened the issue as Green because the finding did not challenge fuel integrity or result in a release of radionuclides.
Cross-Cutting Aspect: H.14 - Conservative Bias: Individuals use decision-making practices that emphasize prudent choices over those that are simply allowable. A proposed action is determined to be safe in order to proceed, rather than unsafe in order to stop. Specifically, the licensee relied upon the successful, partial functional test and channel check and did not take any high voltage power supply measurements or perform any troubleshooting.
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. The licensees procedure 40DP-9OP26, Operations Operability Determination Process, revision 48, step 3.24, requires, in part, that when system capability is degraded to a point where the system cannot perform with reasonable expectation or reliability, the system should be judged inoperable even if at this instantaneous point in time the system could provide the specified safety function.
Contrary to the above, on April 13, 2024, the licensee failed to accomplish an activity affecting quality in accordance with procedure 40DP-9OP26 when operability had been established when a systems capability was degraded to a point where the system cannot perform with reasonable expectation or reliability, the system was not judged inoperable even if at the instantaneous point in time the system could provide the specified safety function.
Specifically, the licensee failed to correctly determine operability of the Unit 3 excore startup range monitor 2, in accordance with procedure 40DP-9OP26, Operations Operability Determination Process, revision 48, step 3.24, when the capability of the excore startup range monitor 2 was degraded to a point it could not perform with reasonable expectation or reliability.
Additionally, this resulted in a violation of technical specifications when the licensee failed to meet technical specification LCOs 3.9.2 and 3.3.12 and operations personnel exited the LCOs and recommenced core alterations.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Failure to Evaluate a Damaged Bushing Results in Partial Loss of Offsite Power in Unit 2 Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green FIN 05000529/2024003-02 Open/Closed None (NPP)71153 The inspectors reviewed a self-revealed, Green, finding for the failure to adequately assess and repair a damaged bushing mount for Unit 2, 13.8 kV switchgear bus, 2E-NAN-S04.
Specifically, the licensees failure to adequately assess and repair a crack through the B phase bushing mount on 2E-NAN-S04 resulted in water intrusion and a fault causing a partial loss of offsite power to Unit 2. The partial loss of offsite power to Unit 2 resulted in the valid actuation and loading of the Unit 2 emergency diesel generator B.
Description:
Offsite 525 kV AC power is supplied to each units 13.8 kV intermediate buses via a preferred and alternate secondary winding from two of the three startup transformers.
Each 13.8 kV intermediate bus provides power to one class 1E 4.16 kV bus via the engineered safety features transformer which provides power to one train of safety-related equipment. On a loss of offsite power, the associated trains safety-related emergency diesel generator provides power to the class 1E 4.16 kV safety bus.
On March 24, 2024, the Unit 2 control room received indications of a loss of power to one of the two class 1E 4.16 kV buses. As designed, the Unit 2 emergency diesel generator B automatically started upon the undervoltage conditions and restored power to the class 1E 4.16 kV safety bus. After the event, licensee personnel walked down the 2E-NAN-S04 switchgear and discovered damage to the B phase bushing, a fault track path, and water stain residue along the fault path and fault path initiation. Per the licensees cause analysis evaluation, water intrusion into the 2E-NAN-S04 B phase bushing collar, after the station experienced rain in the area, resulted in a fault between the lower bushing and the switchgear housing which caused a trip of the engineered safety features transformer and a partial loss of offsite power to the respective class 1E 4.16 kV safety bus.
The inspectors reviewed the licensees cause analysis evaluation of the event and determined the licensees failure to perform an adequate assessment on a crack through the B phase bushing mounting flange on 2E-NAN-S04 switchgear during a previous outage on October 31, 2021, directly contributed to the fault. The crack was identified during the performance of work order 5253921 to clean and inspect the 2E-NAN-S04 switchgear. Per the licensees evaluation, an engineering work order was requested to troubleshoot and evaluate the condition, in response to the condition report on the crack.
Engineering work reply 21-13031-002 was completed, but it did not formally evaluate the issue and incorrectly determined that the crack was limited to the switchgear roof weather proofing material with the allowance to apply room temperature vulcanizing sealant. The licensees procedure 81DP-0CC15, Engineering Work Orders and Evaluations, revision 15, which provides directions for preparing an engineering work reply and formally documenting technical evaluations, step 4.2.1 states, engineering work replies provide information obtained from a reference document or clarifies approved design documents, standard engineering practices or other technical issues and responses include assessments based on existing design documentation. The engineering section leader who performed the engineering work reply did not troubleshoot or evaluate the condition and instead referenced procedure 32MT-9ZZ91, Inspection/Cleaning of 13.8kV and 4.16kV Switchgear, revision 20, that allowed to apply room temperature vulcanizing sealant to the crack on the weather proofing material, after incorrectly determining that no degradation or cracking was found on the bushings. The engineering work reply did not provide other reference documentation, clarification of approved design documents, standard engineering practices, and did not make the correct assessment based on existing design documentation.
Corrective Actions: The licensee replaced the bushing and bushing mounting flange and restored offsite power to the class 1E 4.16 kV bus. The licensee entered the issue into the corrective action program and performed a cause analysis evaluation.
Corrective Action References: Condition Reports 21-13031and 24-02828
Performance Assessment:
Performance Deficiency: The licensees failure to follow procedure was a performance deficiency. Specifically, after a crack was identified on the B phase bushing mounting flange on 2E-NAN-S04 switchgear, the licensee failed to include an assessment based on existing design documentation, provide information obtained from a reference document, or clarify approved design documents per procedure 81DP-0CC15, Engineering Work Orders and Evaluations, revision 15, and incorrectly determined that there was no degradation on the bushings.
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 licensees failure to adequately assess and repair a damaged bushing mount for 2E-NAN-S04, resulted in water intrusion and a fault causing a partial loss of offsite power to Unit 2. The partial loss of offsite power to Unit 2 resulted in the valid actuation and loading of the Unit 2 emergency diesel generator B.
Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The inspectors determined that the Initiating Events and Mitigating Systems cornerstones were affected. Using Exhibit 2, Mitigating Systems Screening Questions, the inspectors considered that the finding involved the loss or degradation of equipment or function specifically designed to mitigate a seismic, flooding, or severe weather initiating event (e.g.,
seismic snubbers, flooding barriers, tornado doors) for greater than 14 days and required further screening under Exhibit 4, External Events Screening Questions. Using Exhibit 4, the inspectors considered the equipment and safety function of the offsite AC power system as unavailable, and the loss of this equipment or function by itself during the external initiating event it was intended to mitigate would degrade one or more trains of a system that supports a risk significant system or function requiring performance of a detailed risk evaluation.
A senior reactor analyst performed a detailed risk evaluation considering the impacts on both affected cornerstones. For the initiating events cornerstone impact, the analyst added a basic event to fault tree OEP-NAN-S04, 13.8 KV Bus NAN-S04 Fails, that considered that a heavy rain event would result in water intrusion into the Unit 2 13.8 kV switchgear cubicle, 2E-NAN-S04A. The analyst assumed that the frequency of a heavy rain event was 3.1E-1/year based on point precipitation frequency estimates of 1 inch in 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> for Tonopah, Arizona, taken from the National Weather Service Hydrometeorological Design Studies Center (https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_map_cont.html?bkmrk=az). This change resulted in an increase in the frequency of an event initiated by the loss of one train of an engineered safety features bus from 2.94E-3/year to 4.32E-3/year, and an increase in core damage frequency of 3.2E-7/year.
The analyst then reviewed the increase in core damage frequency from the Mitigating Systems Cornerstone by reviewing the impact of the unavailability of an engineered safety features bus for Units 1 and 3. The analyst set basic event ACP-TFM-FC-NBNX04 to TRUE to model the unavailability of transformer NBN-X04 as a surrogate event for a conservative exposure time of 1 week. This analysis estimated an increase of core damage frequency of 4.2E-8/year. Combining these two results yielded an estimate of the increase in core damage frequency of 3.6E-7/year, characterizing the issue as having very low safety significance (Green). Dominant core damage sequences were losses of AC and DC buses mitigated by remaining offsite power availability. These results were run on the Palo Verde SPAR model, Version 8.82, using SAPHIRE, Version 8.2.11. External events were considered in the change made for the initiating events portion of the analysis and were qualitatively estimated to be insignificant for the mitigating systems portion. The analyst noted that none of the dominant core damage frequency sequences were significant contributors to large early release frequency and therefore considered core damage frequency as the best representation of the risk impact of the finding.
Cross-Cutting Aspect: Not Present Performance. No cross-cutting aspect was assigned to this finding because the inspectors determined the finding did not reflect present licensee performance.
Enforcement:
Inspectors did not identify a violation of regulatory requirements associated with this finding.
Licensee-Identified Non-Cited Violation 71153 This violation of very low safety significance was identified by the licensee and has been entered into the licensee corrective action program and is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Violation: Renewed facility operating license No. NPF-74, condition 2.C.(2), requires, in part, that APS shall operate the facility in accordance with the technical specifications. Technical specification limiting condition of operation 3.3.12 states two channels of [boron dilution alarm system] shall be operable. Contrary to above, on April 9, 2024, after declaring both channels of the boron dilution alarm system inoperable, the licensee did not operate the facility in accordance with the technical specifications. Specifically, the licensee did not complete the required actions of technical specifications limiting condition of operation 3.3.12 conditions A and B in the required completion times and did not enter technical specification limiting condition of operation 3.3.12 condition C to suspend all operations involving positive reactivity additions.
Screening: The licensees failure to meet the required actions and completion times for technical specifications limiting condition of operation 3.3.12 following the loss of the boron dilution alarm system was a performance deficiency. Specifically, after declaring both channels of the boron dilution alarm system inoperable on April 9, 2024, the licensee failed to sample the reactor coolant system boron concentration per procedure 40ST-9ZZ24, Boron Dilution Alarm System (BDAS) Inoperable, revision 17, and as a result, failed to meet the required actions and completion times for technical specifications limiting condition of operation 3.3.12.
The inspectors assessed the significance of the finding using Exhibit 3, Mitigating Systems Screening Questions, of Inspection Manual Chapter 0609 Appendix G, Appendix 1, Shutdown Operations Significance Determination Process Phase 1 Initial Screening and Characterization of Findings. The inspectors assumed that the finding was not a design or qualification issue, that a loss of system safety function did not occur, that reactor coolant system level indication was not degraded, that the finding did not involve an open vent path, that the finding did not involve external events, and that fire mitigation equipment protection was not affected, and screened the issue to Green.
Significance/Severity: Green.
Corrective Action References: Condition report 24-03817 Minor Violation 71153 Failure to Follow Procedures Results in an Invalid Start of the Unit 3 Emergency Diesel Generator Minor Violation: During the Unit 3 refueling outage, 3R24, a clearance was established for maintenance on a spray pond manhole. The clearance included racking out the circuit breaker for the B spray pond pump and placing the mode control switch for the B diesel generator in the OFF position, to prevent the equipment from starting. When the control room restored the clearance on April 27, 2024, the B spray pond breaker was racked in, and the mode control switch for the B diesel generator was placed in REMOTE, without clearing a sealed in loss of power signal present in the diesel generator control cabinet. This resulted in the invalid actuation of the Unit 3 B emergency diesel generator followed by the valid actuation of the B spray pond pump.
During the restoration of the maintenance, operators in the control room did not recognize that a loss of power signal was sealed in and should have been reset per step 6.4.30 of procedure, 40OP-9SA02, De-energization of BOP ESFAS, revision 26, with the direction to reset the B emergency diesel generator by placing the diesel generator in standby per 40OP-9DG02, Emergency Diesel Generator B, revision 81.
Screening: The failure to follow procedures to restore the Unit 3 B emergency diesel generator is a performance deficiency. Specifically, the licensee failed to reset a loss of power signal by placing the B emergency diesel generator in standby per operations procedures, which resulted in an invalid start of the B emergency diesel generator.
The performance deficiency was minor because it could not be reasonably viewed as a precursor to a significant event; would not have the potential to lead to a more significant safety concern if left uncorrected; and while it was associated with the Human Performance attribute of the Mitigating Systems Cornerstone, it did not adversely affect the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). Specifically, the licensees failure to follow procedures to place the Unit 3 B emergency diesel generator in standby, resulted in the invalid start of the B emergency diesel generator and valid start of the B spray pond pump, placing the two systems in the required safety-related lineup.
Additionally, the B emergency diesel generator and B spray pond pump were not required to be operable per technical specifications in Mode 6 or credited for shutdown risk.
Technical Specification 5.4.1.a, Procedures, states in part, that written procedures shall be established, implemented, and maintained covering the applicable procedures listed in Regulatory Guide 1.33, Quality Assurance Program Requirements, revision 2, Appendix A, February 1978. Regulatory Guide 1.33, revision 2, Appendix A, Section 9.a, Procedures for Performing Maintenance, requires, in part, that maintenance that can affect the performance of safety-related equipment should be properly pre-planned and performed in accordance with written procedures, documented instructions, or drawings appropriate to the circumstances.
Contrary to the above, on April 27, 2024, the licensee failed to perform maintenance that can affect the performance of safety-related equipment in accordance with written procedures appropriate to the circumstances. Specifically, when restoring the Unit 3 B emergency diesel generator from maintenance, the licensee failed to perform the reset of the loss of power signal, in accordance with written procedure, 40OP-9SA02, De-energization of BOP ESFAS, revision 26.
Enforcement:
This failure to comply with Technical Specification 5.4.1.a constitutes a minor violation that is not subject to enforcement action in accordance with the NRCs Enforcement Policy. The licensee entered this issue into the corrective action program under Condition Report 24-04580.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On October 2, 2024, the inspectors presented the Palo Verde 71111.11 inspection results to Cary Harbor, Senior Vice President, Site Operations, and other members of the licensee staff.
- On October 22, 2024, the inspectors presented the integrated inspection results to Cary Harbor, Senior Vice President, Site Operations, and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Corrective Action
Documents
24-07924
Drawings
2-E-PGA-0001
Single Line Diagram, 480V Class 1E Power System Load
Center 2E-PGA-L31
Drawings
2-E-PGA-0003
Single Line Diagram, 480V Class 1E Power System Load
Center 2E-PGA-L33
Drawings
2-E-PGA-0005
Single Line Diagram, 480V Class 1E Power System Load
Center 2E-PGA-L35
Drawings
2-E-PHA-0001
Single Line Diagram, 480V Class 1E Power System Motor
Control Center 2E-PHA-M31
Drawings
2-E-PHA-0003
Single Line Diagram, 480V Class 1E Power System Motor
Control Center 2E-PHA-M33
Drawings
2-E-PHA-0005
Single Line Diagram, 480V Class 1E Power System Motor
Control Center 2E-PHA-M35
Drawings
2-E-PHA-0007
Single Line Diagram, 480V Class 1E Power System Motor
Control Center 2E-PHA-M37
Corrective Action
Documents
24-07125
Drawings
01-M-FPP-002
P & I Diagram Fire Protection System
Fire Plans
Pre-Fire Strategies Manual
Miscellaneous
Simulator Open Modifications List
08/7/2024
Miscellaneous
Simulator Closed Modifications List
08/7/2024
Miscellaneous
Simulator Oversight Committee Minutes 1st Quarter 2023
03/14/2023
Miscellaneous
Simulator Oversight Committee Minutes 1st Quarter 2024
03/12/2024
Miscellaneous
Simulator Oversight Committee Minutes 3rd Quarter 2023
09/14/2023
Miscellaneous
23 Simulator Core Testing Data Package
11/16/2023
Miscellaneous
24 Week 1 RO Written Examination
08/8/2024
Miscellaneous
24 Week 1 SRO Written Examination
08/8/2024
Miscellaneous
License Operator Continuing Training Program Description
Miscellaneous
23 Simulator A Transient Test Package
10/11/2023
Miscellaneous
23 Simulator B Transient Test Package
10/4/2023
Miscellaneous
23 Simulator A Malfunctions Test Package
2/6/2023
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Miscellaneous
23 Simulator B Malfunctions Test Package
10/11/2023
Miscellaneous
24 Simulator A Malfunctions Test Package
06/17/2024
Miscellaneous
24 Simulator B Malfunctions Test Package
06/18/2024
Miscellaneous
Simulator to Unit Differences Report
07/17/2024
Miscellaneous
23 Annual Operating Test Remediation Package
09/15/2023
Miscellaneous
24 LOCT Cycles 1 & 4 Remediation Package
07/25/2024
Miscellaneous
JPM A2
Determine the appropriate radiological release status for an
E-Plan event
Miscellaneous
JPM A3
Determine the Protective Action Recommendation (PAR) for
an Emergency Plan Event
Miscellaneous
JPM A4
Respond to an event requiring entry into the Excessive RCS
Leakrate AOP
Miscellaneous
JPM A5
Respond to an event requiring entry into the Excessive RCS
Leakrate AOP
Miscellaneous
Conduct shift operations
Miscellaneous
JPM P5
Manually isolate Steam Generator Blowdown valves
Miscellaneous
JPM P6
Respond to a Control Room Fire
Miscellaneous
JPM P7
Respond to an event requiring entry into LOOP/LOFC ORP
Miscellaneous
JPM S2
Respond to an event requiring entry into the SGTR ORP
Miscellaneous
JPM S7
Respond to an event requiring entry into the LOCA ORP
Miscellaneous
JPM S8
Perform AFAS Check/Reset
Miscellaneous
JPM S9
Respond to an RCS to NC Leak
Miscellaneous
SES-0-05-J-01
Licensed Operator Continuing Training SES #17
Miscellaneous
SES-0-07-H-08
Licensed Operator Continuing Training SES #5
Miscellaneous
SES-0-09-S-06
Licensed Operator Continuing Training SES #8
Miscellaneous
SES-0-09-V-01
Licensed Operator Continuing Training SES #18
Miscellaneous
Simulator Reports
4582, 4592, 4597, 4598, 4229, 4243, 4267, 4289, 4375,
4391, 4649, 4703, 4729, 4754, 4763, 4775, 4799, 4818,
4831, 4832, 4728, 4298, 4333, 4212, 4414, 4566, 4585,
4716, 4726, 4720 4572, 4343, 4358, 4611, 4450, 4291
08/7/2024
Procedures
Operator Licensing and Requalification Process
Procedures
LOCT Annual Operating Exam Sample Plan Development
Procedures
NRC Examination Security
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Procedures
Simulator Configuration
Procedures
NET-009
Core Physics Test
11/16/2023
Procedures
OST001 (73ST-
9AF01)
AFN-P01 Surveillance Test
10/18/2022
Miscellaneous
SES-0-09-M-08
Palo Verde Nuclear Generating Station Licensed Operator
Continuing Training Exam Scenario
08/30/2024
Engineering
Evaluations
23-10254-010
Unit 1 Pressurizer Thermowell Nozzle Leak - Level 1 SCAQ
Root Cause Analysis Report
Miscellaneous
K-640591-RP-
0001
Palo Verde Generating Station Unit 1 Pressurizer Nozzle
Weld Examination
Miscellaneous
Phoenix Risk Monitor - Unit 1, Plant State as of 08/27/2024
11:00 AM
Miscellaneous
Protected Equipment for BOP ESFAS sequencer A
08/28/2024
Procedures
Management of Critical Evolutions and Infrequently
Performed Tests or Evolutions
Procedures
Online Integrated Risk
Procedures
Protected Equipment
Procedures
Assessment and Management of Risk When Performing
Maintenance in Modes 1 and 2
Work Orders
5650260
Calculations
13-MC-HA-0052
Auxiliary Building Essential Cooling System Heat Load
Calculation - Appendix X
Calculations
13-MC-JH-263
Control Room Pressure Boundary Allowable Open Area
Calculations
13-NC-ZJ-200
Control Room HVAC Parameters
Corrective Action
Documents
19-01016, 24-02037, 24-07766, 24-03456, 24-07870, 22-
13143, 24-4277, 24-5924, 24-03908, 18-18549, 21-11022,
24-01866, 24-01883, 24-08725, 24-08852, 24-03849, 22-
06446, 24-08852
Corrective Action
Documents
Condition Report/Disposition Request 310199
Corrective Action
Documents
Resulting from
54885
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Inspection
Drawings
03-M-SIP-001
Safety Injection & Shutdown Cooling System
Drawings
08KPX053294
Mechanical Seal Assembly
C
Engineering
Changes
Engineering Design Change 2024-00177
Engineering
Changes
Engineering Design Change 2009-00891
Engineering
Evaluations
Engineering Evaluation Request 86-HJ-041 and 86-HJ-042
Miscellaneous
PVNGS Design Basis Manual - Safety Injection System
Miscellaneous
Technical Specification 3.3.12 Boron Dilution Alarm System
(BDAS), Amendment 138
Miscellaneous
Technical Specification 3.9.2 Nuclear Instrumentation,
Amendment 138
Miscellaneous
Level 3 Evaluation Report 24-01883-001
03/27/2024
Miscellaneous
PVNGS Design Basis Manual - Diesel Generator, Class 1 E
Standby Generation, Fuel Oil Storage and Transfer System
Miscellaneous
PVNGS Design Basis Manual - Essential Chilled Water
System
Miscellaneous
PVNGS Design Basis Manual - Auxiliary Feedwater System
Miscellaneous
13-MC-HA-199
Auxiliary Feedwater Pump Train A, Units 1, 2, and 3 max
allowable steam leak into AFW pump room A
Miscellaneous
13-MC-SI-0250
Safety Injection, Containment Spray, and Shutdown Cooling
System Pump NPSH Evaluations
Miscellaneous
13-MC-ZZ-00622
Pipe Break Location/Exclusion Calculation
Miscellaneous
13-MS-A70
Separation/Hazards Evaluation Study For The Palo Verde
Motor Driven AFW B Pump Room
Miscellaneous
0011
American Air Filter Installation, Operation, and Maintenance
Instruction for Air Handling Units
Miscellaneous
0015
American Air Filter Instruction Manual For Model N Air
Handling Units for Nuclear Environmental Systems
Miscellaneous
SDOC N001-
0902-00005
Seismic Qualification Reports - NSSS PE Equipment -
Multi-Earthquake Fatigue Analysis
Procedures
Containment Spray Pump Disassembly and Assembly
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Procedures
Excore Startup Channel and Boron Dilution Alarm System
Calibration
Procedures
Panel B02A Alarm Responses
Procedures
Operations Operability Determination Process
Procedures
Essential Chilled Water Train A
Procedures
Boron Dilution System Inoperable
Procedures
Class 1E Diesel Generator Load Rejection 24 Hour Rated
Load and Hot Start Test Train A
Procedures
Class 1E Diesel Generator Load Rejection 24 Hour Rated
Load and Hot Start Test Train B
Procedures
Class 1E Diesel Generator and Integrated Safeguards Test
Train A
Procedures
BASIS
Procedure Basis Document - Class 1E Diesel Generator and
Integrated Safeguards Test Train A
35a
Work Orders
5470681, 5644198, 5496474, 4728823, MM 3118138,
STWO 5405200, 5565996, 5503044, 5617375
Work Orders
Engineering Work Orders 18-18549-002, 21-11022-004, and
24-01866-002
Calculations
13-MC-EC-0252
EC System Water Requirements and Chiller Sizing
Corrective Action
Documents
24-06516, 24-08687, 24-08725, 24-04484
Engineering
Changes
Engineering Design Change 2004-00693
Miscellaneous
PVNGS Design Basis Manual - Essential Chilled Water
System
Miscellaneous
PVGS Diverse and Flexible Coping Strategies (FLEX)
Program
Miscellaneous
01-E-SAF-004
Control Wire Diagram Engineered Safety Features Actuation
System BOP-ESFAS Intertying Circuits Train A
Miscellaneous
13-M018-00720
Overspeed Shutdown Butterfly Valve
Miscellaneous
00051
Cooper Energy Instruction Manual for KSV Turbocharged
Diesel Generating Unit for Nuclear Power Plant Emergency
Stand-by Service
Miscellaneous
Control Room AFU Airflow Capacity and Pressurization Test
20a
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Miscellaneous
FT-089
Function Test Control of Bertan Power Supply
2
Miscellaneous
FT-124
Functional Test Control of Pioneer Magnetics DC-DC Power
Supply 28 VDC at 21.4 amps
Miscellaneous
VTD-G063-00002
General Atomic - Sorrento Division-Instruction Manual for
Balance of Plant Engineered Safety Features Actuation
System
Procedures
FLEX RWT Transfer Pump Inspections and Tests
Procedures
Cleaning, Inspection, and Testing of the Class 1E Diesel
Generator, rev 5273ST-9DG08, Class 1E Diesel Generator
Load Rejection, 24 Hour Rated Load and Hot Start Test
Train
Procedures
Control Room AFU Airflow Capacity and Pressurization Test
Procedures
BDAS Functional Test
Procedures
Excore Startup Channel and Boron Dilution Alarm System
Calibration
Procedures
Flex Support Guidelines
Procedures
Procedures
Essential Chilled Water and Ventilation Systems Inoperable
Actions Surveillance
Procedures
Essential Chilled Water Pumps - Inservice Test
Work Orders
5517378, 5303327, 5650260, 5274146, 5284689, 5496357,
5503044, 5498274
Corrective Action
Documents
24-08488, 24-08496, 24-09439
Miscellaneous
2404 - Drill, Emergency Preparedness Manual
08/13/2024
Procedures
Emergency Preparedness Drill and Exercise Program
71151
Calculations
13-NS-C075
Palo Verde MSPI Basis Document
71151
Miscellaneous
NRC Action Matrix PI Data Results for Palo Verde Unit 1
Second Quarter 2024
71151
Miscellaneous
NRC Action Matrix PI Data Results for Palo Verde Unit 2
Second Quarter 2024
71151
Miscellaneous
NRC Action Matrix PI Data Results for Palo Verde Unit 3
Second Quarter 2024
71151
Miscellaneous
Report Identification Number and Title Redacted 1, INPO
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Industry Reporting and Information System (IRIS) Report for
MSPI Monitored Component Failure
71151
Miscellaneous
Report Identification Number and Title Redacted 2, IRIS
Report for MSPI Monitored Component Failure
71151
Procedures
Regulatory Assessment Performance Indicator Guideline
Corrective Action
Documents
11-00156, 21-13031, 23-07576, 24-02828, 24-02829, 24-
03817, 24-06221, 24-04580
Miscellaneous
Level 2 Cause Analysis Report 24-02828-011
Miscellaneous
Equipment Reliability Engineering Template 2827064
Miscellaneous
Level 2 Cause Analysis Report 24-04580-004
Miscellaneous
PVNGS Design Basis Manual - Diesel Generator, Class 1E
Standby Generation, Fuel Oil Storage and Transfer System
Miscellaneous
Level 2 Cause Analysis Report 24-03817-003
Miscellaneous
Engineering Evaluation 18-14337-001
Miscellaneous
13-MC-SS-0201
Primary Sampling volume and Recirculation Flow Rates
Miscellaneous
13-VTD-G080-
0394-1
Vendor Technical Document - General Electric Instructions
for Metal-Clad Switchgear Types M26 and M36
05/27/1993
Procedures
Reactivity Management Program
Procedures
Inspection/Cleaning of 13.8kV and 4.16kV Switchgear
Procedures
Conduct of Operations
Procedures
Conduct of Operations
Procedures
Operations Technical Documents
Procedures
Procedures
Procedures
Boron Dilution Alarm System Inoperable
Procedures
Conduct of Chemistry
Procedures
Primary Chemistry Shutdown and Startup Guidelines
Procedures
Primary Sampling Instructions
Procedures
Engineering Work Orders and Evaluations
Work Orders
253921, 5611279, 5253682