IR 05000445/2023003
| ML23297A249 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 10/25/2023 |
| From: | Greg Werner NRC/RGN-IV/DORS/PBB |
| To: | Peters K Vistra Operations Company |
| References | |
| IR 2023003 | |
| Download: ML23297A249 (25) | |
Text
October 25, 2023
SUBJECT:
COMANCHE PEAK NUCLEAR POWER PLANT, UNITS 1 AND 2 -
INTEGRATED INSPECTION REPORT 05000445/2023003 AND 05000446/2023003
Dear Ken Peters:
On September 30, 2023, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Comanche Peak Nuclear Power Plant, Units 1 and 2. On October 12, 2023, the NRC inspectors discussed the results of this inspection with Steven Sewell, Site Vice President, and other members of your staff. The results of this inspection are documented in the enclosed report.
Two findings of very low safety significance (Green) are documented in this report. 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 Comanche Peak Nuclear Power Plant, Units 1 and 2.
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 Comanche Peak Nuclear Power Plant, Units 1 and 2. This letter, its enclosure, and your response (if any) will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with Title 10 of the Code of Federal Regulations 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely, Gregory E. Werner, Chief Reactor Projects Branch B Division of Operating Reactor Safety Docket Nos. 05000445, 05000446 License Nos. NPF-87, NPF-89 Enclosure:
As stated cc w/ encl: Distribution via LISTSERV Signed by Werner, Gregory on 10/25/23
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Comanche Peak Nuclear Power Plant,
Units 1 and 2, 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 Establish Adequate Procedures for Oversight of Vendor Activities on Safety-related Systems.
Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green NCV 05000446/2023003-01 Open/Closed
[H.14] -
Conservative Bias 71111.08P The inspectors identified a Green, non-cited violation of 10 CFR Part 50, Appendix B,
Criterion IX, Control of Special Processes, for failure to establish measures to assure that special processes such as mechanical stress improvement are controlled and accomplished by qualified personnel using qualified procedures in accordance with applicable codes, standards, specifications, criteria, and other special requirements. Contrary to this, the licensee allowed the vendor to make physical changes to contour rings for the mechanical stress improvement process box press units without evaluating these changes to the design control measures commensurate with those applied to the original equipment design.
Inadequate Procedures Lead to Seal Failure on A Filter Housing Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green NCV 05000445/2023003-02 Open/Closed
[P.5] -
Operating Experience 71152A The inspector identified a finding and associated Green, non-cited violation of Technical Specification 5.4.1 for failing to have a procedure(s) appropriate to the circumstances for replacing a filter and restoring a reactor coolant pump seal cooling filter to service.
Additional Tracking Items
None.
PLANT STATUS
Unit 1 began the inspection period ascending to 100 percent power from 78 percent power following repair of main feedpump 1-02. Unit 2 operated at or near 100 percent power for the entire inspection report.
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) (4 Samples)
The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:
- (1) Unit 2, train B diesel generator starting air system on August 23.
- (2) Unit 2, turbine driven auxiliary feedwater pump and train B motor driven auxiliary feedwater pump on August 30, 2023.
- (3) Unit 1, train A safety injection system on September 7, 2023
- (4) Unit 1, train B safety chiller system on September 18, 2023
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (5 Samples)
The inspectors evaluated the implementation of the fire protection program by conducting a walkdown and performing a review to verify program compliance, equipment functionality, material condition, and operational readiness of the following fire areas:
- (1) Unit 1, auxiliary building charging pump rooms on July 6, 2023
- (2) Unit 2, auxiliary building charging pump rooms on July 6, 2023
- (3) Unit 1, safeguards building elevation 773 on September 5, 2023
- (4) Unit 2, auxiliary building on September 5, 2023
- (5) Unit 2, cable spreading room on September 8, 2023
Fire Brigade Drill Performance Sample (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated the onsite fire brigade training and performance during an unannounced fire drill on July 20, 2023.
71111.06 - Flood Protection Measures
Flooding Sample (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated internal flooding mitigation protections in both Units 1 and 2 for the safety chiller system located within rooms 115A and 115B.
===71111.08P - Inservice Inspection Activities (PWR) The inspectors verified that the reactor coolant system (RCS) 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 from May 1 to 11, 2023.
PWR Inservice Inspection Activities Sample - Nondestructive Examination and Welding Activities (IP Section 03.01)===
The inspectors verified that the following nondestructive examination and welding activities were performed appropriately:
- (1) Ultrasonic Examination
- residual heat removal, TCX-1-4101-12, elbow to pipe
- safety injection, TCX-1-4301-9, pipe to elbow
- safety injection, TCX-1-4301-10, pipe to elbow
- containment spray, TCX-2-2536-7, pipe to elbow Magnetic Particle Examination
- steam generator 4, TCX-2-1100-4-11, nozzle to vessel Dye Penetrant Examination
- containment spray, TCX-2-2576-H1, 4 welded attachments Visual Examination
- containment spray, TCX-2-2576-H5, hanger
- main steam, TCX-2-2400-H1, hanger
- residual heat removal, CC-2-AB-012-H15, hanger
- residual heat removal, TCX-2-2501-H11, hanger
- residual heat removal, TCX-2-2501-H14, hanger Welding Activities
- gas tungsten arc welding
- auxiliary feedwater, through wall leak repair on 1-01 motor driven auxiliary feedwater pump recirculation line downstream of CP1-AFORBO-01 PWR Inservice Inspection Activities Sample - Vessel Upper Head Penetration Inspection
Activities (IP Section 03.02) (1 Sample)
The inspectors verified that the license conducted the following vessel upper head penetration inspections and addressed any identified defects appropriately:
(1)
- Reactor vessel upper head, penetration 1 to 9, thermal sleeve wear check
- Reactor vessel upper head, penetration 14 to 21, thermal sleeve wear check
- Reactor vessel upper head, penetration 30 to 61, thermal sleeve wear check
- Reactor vessel upper head, penetration 66 to 73, thermal sleeve wear check 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)
- 2014-013333
- 2018-003490
- 2020-003068
- 2022-001784
- 2022-002065
- 2022-002987
- 2022-000367
- 2022-002069
- 2022-003052
- 2022-008373
- 2023-001501
- 2023-000810 PWR Inservice Inspection Activities Sample - Steam Generator Tube Inspection Activities (Section 03.04) (1 Sample)
The inspectors verified that the licensee is monitoring the steam generator tube integrity appropriately through a review of the following examinations:
(1)
- steam generators 1-4
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 14, 2023, to September 21, 2023.
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 and evaluated operator simulator training on steam generator tube rupture on July 18, 2023.
71111.12 - Maintenance Effectiveness
Maintenance Effectiveness (IP Section 03.01) (2 Samples)
The inspectors evaluated the effectiveness of maintenance to ensure the following structures, systems, and components (SSCs) remain capable of performing their intended function:
(1)safeguards building ventilation (2)auxiliary building heating, ventilation, air conditioning for exceeding performance criteria on March 11, 2021.
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (2 Samples)
The inspectors evaluated the accuracy and completeness of risk assessments for the following planned and emergent work activities to ensure configuration changes and appropriate work controls were addressed:
(1)freeze seal for 2-8511B, charging system alternate minimum flow valve on September 13, 2023 (2)planned safety chiller outage on September 19, 2023
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (6 Samples)
The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:
- (1) Unit 2, ventilation operability due to elevated ventilation exhaust temperatures in Unit 2 safeguards building
- (2) Unit 2, power range nuclear instrument due to step increase in indicted flux (3)component cooling water pump 2-01 with tygon tubing left in bearing oil chamber (4)main steam isolation valves with air blowing out of pneumatic pump (5)emergency core cooling system while impacted by reactor coolant pump (RCP) seal filter failure (6)functionality of main turbine lube oil with a lube oil cooler leak
71111.18 - Plant Modifications
Temporary Modifications and/or Permanent Modifications (IP Section 03.01 and/or 03.02) (1 Sample)
The inspectors evaluated the following temporary or permanent modifications:
- (1) Unit 1, train B heater drain pump temporary modification to allow oil to flow on pump trip on September 8, 2023
71111.24 - Testing and Maintenance of Equipment Important to Risk
The inspectors evaluated the following testing and maintenance activities to verify system operability and/or functionality:
Post-Maintenance Testing (PMT) (IP Section 03.01) (2 Samples)
- (1) Unit 1, RCP seal injection filter change on July 19, 2023.
- (2) Unit 1, safety chiller 1-05 compressor replacement/reinstallation on September 24, 2023.
Inservice Testing (IST) (IP Section 03.01) (2 Samples)
- (1) Unit 2, train B safety injection pump inservice test on September 5, 2023
- (2) Unit 2, train B residual heat removal pump inservice test on September 7, 2023
71114.01 - Exercise Evaluation
Inspection Review (IP Section 02.01-02.11) (1 Sample)
- (1) The inspectors evaluated the biennial emergency plan exercise conducted on July 26, 2023. The exercise scenario simulated a station service water pump motor fire followed by a condensate pump trip, anticipated transient without scam with actions in the control room successful in tripping the unit, and a loss of coolant accident with fuel failure. During the scenario, a subsequent valve failure caused a radiological release. As conditions degraded during the scenario, the licensee developed protective actions recommendations for the public. The licensee completed its critique process for the exercise on August 23, 2023, and the inspectors subsequently evaluated the effectiveness of the critique process to identify performance weaknesses and deficiencies to ensure they were entered into the corrective action program for resolution.
71114.04 - Emergency Action Level and Emergency Plan Changes
Inspection Review (IP Section 02.01-02.03) (1 Sample)
- (1) The inspectors evaluated the following submitted Emergency Action Level and Emergency Plan changes.
- Emergency Plan Revision 46 - effective September 1, 2022
- Emergency Plan Revision 47 - effective March 16, 2023
- Emergency Plan Revision 48 - effective July 5, 2023 This evaluation does not constitute NRC approval.
71114.06 - Drill Evaluation
Drill/Training Evolution Observation (IP Section 03.02) (2 Samples)
The inspectors evaluated:
- (1) The inspectors observed a simulator training session with emergency action level declaration and notification on September 11, 2023.
- (2) The inspectors observed a site wide emergency planning drill on September 27,
RADIATION SAFETY
71124.06 - Radioactive Gaseous and Liquid Effluent Treatment
Walkdowns and Observations (IP Section 03.01) (3 Samples)
The inspectors evaluated the following radioactive effluent systems during walkdowns:
- (1) Unit 1, auxiliary building ventilation system discharge to main plant vent stack
- (2) Unit 2, auxiliary building ventilation system discharge to main plant vent stack
- (3) Units 1 and 2, liquid waste processing system discharge to circulating water system
Sampling and Analysis (IP Section 03.02) (4 Samples)
Inspectors evaluated the following effluent samples, sampling processes and compensatory samples:
- (1) Unit 1, tritium gas sample for plant vent stack on August 8, 2023
- (2) Unit 1, noble gas sample for plant vent stack on August 8, 2023
- (3) Unit 2, iodine cartridge sample for plant vent stack on August 8, 2023
- (4) Unit 2, particulate filter sample for plant vent stack on August 8, 2023
Dose Calculations (IP Section 03.03) (2 Samples)
The inspectors evaluated the following dose calculations:
- (1) Dose calculations associated with liquid release permits:
L2021-019, L2021-031, L2022-015, L2022-027, L2023-010, and L2023-022
- (2) Dose calculations associated with gaseous release permits:
G2021-082, G2021-083, G2022-076, G2022-087, G2023-073, and G2023-086 Abnormal Discharges (IP Section 03.04)
The inspectors evaluated the inspection period and identified no abnormal discharges to review.
71124.07 - Radiological Environmental Monitoring Program
Environmental Monitoring Equipment and Sampling (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated environmental monitoring equipment and observed collection of environmental samples.
Radiological Environmental Monitoring Program (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated the implementation of the licensees radiological environmental monitoring program.
GPI Implementation (IP Section 03.03) (1 Sample)
- (1) The inspectors evaluated the licensees implementation of the Groundwater Protection Initiative program to identify incomplete or discontinued program elements.
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, 2022, through June 30, 2023)
- (2) Unit 2 (July 1, 2022, through June 30, 2023)
MS07: High Pressure Injection Systems (IP Section 02.06) (2 Samples)
- (1) Unit 1 (July 1, 2022, through June 30, 2023)
- (2) Unit 2 (July 1, 2022, through June 30, 2023)
MS09: Residual Heat Removal Systems (IP Section 02.08) (2 Samples)
- (1) Unit 1 (July 1, 2022, through June 30, 2023)
- (2) Unit 2, (July 1, 2022, through June 30, 2023)
BI02: RCS Leak Rate Sample (IP Section 02.11) (2 Samples)
- (1) Unit 1 (July 1, 2022, through June 30, 2023)
- (2) Unit 2 (July 1, 2022, through June 30, 2023)
EP01: Drill/Exercise Performance (DEP) Sample (IP Section 02.12) (1 Sample)
- (1) July 1, 2022, through June 30, 2023 EP02: Emergency Response Organization (ERO) Drill Participation (IP Section 02.13) (1 Sample)
- (1) July 1, 2022, through June 30, 2023 EP03: Alert and Notification System (ANS) Reliability Sample (IP Section 02.14) (1 Sample)
- (1) July 1, 2022, through June 30, 2023
71152A - Annual Follow-up Problem Identification and Resolution Annual Follow-up of Selected Issues (Section 03.03)
The inspectors reviewed the licensees implementation of its corrective action program related to the following issues:
(1)
- The inspectors reviewed failure of an O-ring in a RCP sealing cooling filter that resulted in loss of RCP seal cooling to two RCPs.
71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02)
- (1) The inspectors reviewed human performance issues that have occurred during 2023.
The inspectors noted multiple examples of minor deviations in site requirements that included late return of test equipment, failure to secure fire doors and food wrappers in radiologically controlled areas. Although of minor safety significance, these issues reveal lax standards of some licensee staff. In addition, identification of food wrappers in the radiologically controlled area and door were identified by NRC staff. This indicates weaknesses in peer-to-peer coaching or a lack of documenting minor issues.
INSPECTION RESULTS
Failure To Establish Adequate Procedures for Oversight of Vendor Activities on Safety-related Systems.
Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green NCV 05000446/2023003-01 Open/Closed
[H.14] -
Conservative Bias 71111.08P The inspectors identified a Green, non-cited violation of 10 CFR Part 50, Appendix B, Criterion IX, Control of Special Processes, for failure to establish measures to assure that special processes such as mechanical stress improvement are controlled and accomplished by qualified personnel using qualified procedures in accordance with applicable codes, standards, specifications, criteria, and other special requirements. Contrary to this, the licensee allowed the vendor to make physical changes to contour rings for the mechanical stress improvement process (MSIP) box press units without evaluating these changes to the design control measures commensurate with those applied to the original equipment design.
Description:
During the Fall 2021 refueling outage, the licensee attempted to perform the MSIP on the Unit 2 reactor vessel nozzles. This process used hydraulic box presses to apply circumferential pressure on the RCS hot and cold legs sufficient to compress the pipe at the nozzle. To achieve proper compression, hydraulic rams are pressurized to tens of thousands of pounds per square inch to apply compressive forces to the pipe in the vicinity of the weld.
During the attempt on hot leg 2 on October 20, 2021, both legs of the box press frame failed catastrophically resulting in numerous gouges/indentations on the hot leg piping. Contract workers had pressurized the hydraulics to near full pressure when both legs of the box press failed. The resulting release of pressure severely damaged the tooling and created multiple gouges on the hot leg. As part of recovery, the licensee evaluated each of the damaged areas and remediated the indentations to ensure removal of any stress risers. Post remediation measurement and analysis of the pipe revealed a substantial reduction in margin to the ASME code required minimum wall thickness. The licensee performed an operability determination, including engineering stress analysis to establish a basis for operability. The licensee stopped MSIP evolutions while evaluating the impact of the failure and considering potential causes of the failure. Although the licensee could not determine a cause in the near term, the licensee decided to proceed with MSIP on the cold leg nozzles under the rationale that the cold leg equipment was more robust than the equipment that had failed during the hot leg MSIP.
On October 23, 2021, during MSIP on cold leg 1, another box press failed. At the time of the failure, the licensee had attained about 90 percent of full hydraulic pressure. Review of the failure revealed the box press failed in a similar location/manner to the hot leg failure. With the multiple box press failures, the licensee opted to end further MSIP activities until the cause of the failures could be determined.
To implement MSIP, the vendor modified a clamp design that had been used effectively at other facilities. The redesigned contour rings offset the MSIP application plane inside the clamp assembly to within required parameters developed in the finite element analysis. The vendor modeled the new designs, independent of the overall assembly, and performed a fatigue analysis to confirm both would withstand the typical loads during MSIP application.
However, the vendor determined that this approach failed to evaluate all the interactions among the various components and piping used as part of MSIP. Although the vendors Quality Manual and procedures provided guidance on design preparation and verification including design, analysis, and testing requirements for safety related equipment, the vendor failed to apply them to the redesign of the contour rings. The vendor determined that the MSIP design changes were implemented using deficient processes and procedures to evaluate and document the impact. Because the licensee was not providing the required oversight of the vendors involved, the inadequate processes and procedures enabled these design changes that directly caused the failure of the MSIP presses and damage to the RCS.
Subsequent modeling using finite element analysis predicted a failure of the tooling consistent with the observed failure. Therefore, a robust design review, as required by the vendor procedures would have predicted stresses exceeding allowable values, thus providing insight that could have prevented these failures from occurring. By not requiring the vendor to follow their design review process, the licensee failed to meet the requirements of the Comanche Peak Nuclear Power Plant Quality Assurance Manual, revision 24, section 9.1 which states that the licensee shall establish measures to control special processes. These special processes shall be accomplished under specified and controlled conditions by qualified personnel using qualified procedures and equipment in accordance with applicable codes, standards, specifications, criteria, or other special requirements. A robust design review, as required by the licensee's quality assurance manual and the vendor's procedures would have predicted stresses exceeding allowable values, thus providing insight that could have prevented these failures from occurring. Additionally, the redesigned MSIP equipment was only tested to the application procedural limit, \\ leaving no margin between qualification and application limits and no tolerance for instrument uncertainties. The licensee elected to continue with the MSIP process without understanding the cause of the first MSIP press failure, resulting in the failure of the second MSIP and additional damage to the RCS.
A finite element analysis model performed as part of the root cause investigation indicated that the offset contour ring design caused the clamp to rotate, generating an unanticipated and unanalyzed acentric load through the MSIP tooling assembly. The reaction applied an unanalyzed load to the other parts of the MSIP tooling assembly contributing to the failure.
Significant engineering analysis was required to demonstrate that the RCS remained operable. The actual loads due to the failed MSIP exceeded the code allowable stress limit but were less than the allowable faulted loads for the reactor vessel design specification per Westinghouse Specification 952540, revision 1.
Corrective Actions: A root cause analysis was performed by the vendor, and an organization effectiveness investigation was performed by the licensee to evaluate and address shortfalls in the process controls, design, training, and decision making. This included a review and necessary updates to engineering guidance related to vendor oversight for major plant initiatives. To improve safety, quality and schedule execution in future outages, the station will use a team approach to investigate these issues. This review included a look at the licensee's use of industry operating experience when preparing for outages and how the station looks at preparation, proficiency and mitigation strategies with vendors and provides the guidance for vendor oversight.
Corrective Action References: CR-2021-006952, CR-2021-007070, CR-2021-7061, TR-2023-000211
Performance Assessment:
Performance Deficiency: The licensees failure to establish measures to assure that the mechanical stress improvement process is controlled and accomplished using properly qualified equipment as required by Comanche Peak Nuclear Power Plant Quality Assurance Manual, revision 24 is a performance deficiency. Specifically, section 9.1 requires that special processes shall be accomplished under specified and controlled conditions by qualified personnel using qualified procedures and equipment in accordance with applicable codes, standards, specifications, criteria, or other special requirements.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Equipment Performance attribute of the Initiating Events cornerstone and adversely affected the cornerstone objective to limit the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. Specifically, equipment not qualified and tested in accordance with the licensees quality assurance manual and the vendors quality assurance program was used to perform MSIP on the RCS nozzles. Failure of the tooling resulted in damage to the class 1 pressure boundary and subjected the RCS to stress that exceeded ASME code general allowed load limits.
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 the finding was of very low safety significance (Green) because:
- (1) it was not a design deficiency;
- (2) it did not represent a loss of system and/or function;
- (3) it did not represent an actual loss of function of at least a single train for longer than its technical specification allowed outage time; and
- (4) it did not result in the loss of a high safety significant non-technical specification train.
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 to proceed, rather than unsafe to stop. Contrary to this, the licensee allowed the vendor to proceed with redesign and deployment of the new contour rings and continue MSIP evolutions with inadequate testing and understanding of the failure mechanism. This resulted in damage to the RCS and reduction in margin to minimum allowable wall thickness on the affected hot and cold leg piping of the RCS.
Enforcement:
Violation: Title 10 CFR Part 50, Appendix B, Criterion IX, Control of Special Processes, requires, in part, that the licensee establish measures to assure that special processes are controlled and accomplished by qualified personnel using qualified procedures in accordance with applicable codes, standards, specifications, criteria, and other special requirements.
Comanche Peak Nuclear Power Plant Quality Assurance Manual, revision 24, section 9.1 requires that special processes shall be accomplished under specified and controlled conditions by qualified personnel using qualified procedures and equipment in accordance with applicable codes, standards, specifications, criteria, or other special requirements.
Contrary to the above, prior to October 23, 2021, the licensee failed to maintain measures to assure that the design changes to the tooling used to perform the MSIP were controlled and accomplished by qualified personnel using qualified procedures in accordance with applicable codes, standards, specifications, criteria, and other special requirements. Specifically, the licensee failed to assure that the design changes that modified MSIP press used in the special process were properly controlled and accomplished in accordance with the design change control requirements.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Inadequate Procedures Lead to Seal Failure on A Filter Housing Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green NCV 05000445/2023003-02 Open/Closed
[P.5] -
Operating Experience 71152A The inspector identified a finding and associated Green non-cited violation of Technical Specification 5.4.1 for failing to have a procedure(s) appropriate to the circumstances for replacing a filter and restoring a RCP seal cooling filter to service.
Description:
On July 18, 2023, the licensee replaced filter 1-02 in the RCP seal water injection line due to rising differential pressure across the filter. Following replacement, the operators began restoration of the filter to service using procedure SOP-103A, "Chemical Volume Control System." Upon opening the inlet valve to the filter housing, control room operators noted seal injection flow lowering and could not recover seal flow via adjusting of 1C-0182, RCP water pressure controller. The reactor operator noted a drop in pressurizer level as well. The reactor operators called the field nuclear equipment operator (NEO) and directed the NEO to close the filter vent valve. About 30 seconds later, the reactor operator directed the NEO to close the filter inlet valve and ensure the outlet and drain vales were closed. The NEO isolated the filter and stopped inventory transient. During this event, RCS inventory lost about 170 gallons, pressurizer level dropped 60 percent to 57 percent and RCP seal flow dropped to less than 1 gallon per minute per pump. Procedure SOP-103A did not have steps in the procedure to verify leak tightness of the filter housing when returning to service.
The licensee determined that the leak resulted from failure of the filter lid O-ring. The mechanics stated that during installation the O-ring can become misaligned during reassembly and that alignment cannot be easily checked during the reassembly process, resulting on leakage. When asked by the inspectors, the mechanics indicated that leaks have happened during previous filter replacements that also required rework and replacement of the O-ring.
The inspectors searched the licensee's corrective action program and non-cap tracking database but could not located documentation that O-rings had previously become misaligned. The licensee conducted a similar search with the same results. The inspectors reviewed vendor documentation as well as site procedures for post-work testing requirements. The inspectors identified that both documents specified a visual inspection for leaks at the flange, however, the work order 23-2777278 did not include the visual inspection; therefore, the instruction was not adequate. The seal filters are in a floor vault that is covered by a removable concrete plug and during the replacement, the licensee installed the concrete plug over the filter assembly thus preventing a visual inspection of the filter housing for leaks.
The inspectors determined that the licensee failed to enter the previous O-ring failures into the corrective action program as required by procedure STA-421, "Control of Issue Reports."
Corrective Actions: The licensee immediate actions included isolation of the filter and replacement of the failed O-ring. Subsequent actions included adding this event to the pre-job brief database and entering the event into the corrective action program.
Corrective Action References: CR-2023-5124, CR-2023-51531
Performance Assessment:
Performance Deficiency: The licensee failure to implement and maintain procedures for replacement and returning to service RCP seal water filters was a performance deficiency.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Procedure Quality attribute of the Initiating Events cornerstone and adversely affected the cornerstone objective to limit the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. Specifically, work order 23-277278, and procedure SOP-103A collectively failed to prevent losses of RCS inventory and RCP seal flow.
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 screened the finding using IMC 0609 exhibit 1, dated, November 30, 2020.
Because the finding challenged the RCP seals, which is a loss of coolant accident initiator, and the finding impacted a system used to mitigate a loss of coolant accident, the inspectors determined a detailed risk evaluation was required. A regional senior reactor analyst performed the detailed risk evaluation and assumed that a maintenance error led to a total loss of RCP seal injection and that the maintenance error was recoverable 50 percent of the time. Using the Comanche Peak SPAR model, version 8.81, ran on SAPHIRE, version 8.2.8, the analyst added and logically "ANDed" 2 basic events under fault tree LOSC-1, "Seal Injection is Unavailable," to model the occurrence of a maintenance error and the ability to recover from that maintenance error. The analyst conservatively assumed that the exposure time for the error was 1 day. Applying these assumptions yielded an estimate of the increase in core damage frequency of 1.4E-8/year, making the safety significance very low (Green).
Events where component cooling water was lost comprised the dominant core damage sequences in the high-pressure injection and auxiliary feedwater systems remained available for mitigation.
Cross-Cutting Aspect: P.5 - Operating Experience: The organization systematically and effectively collects, evaluates, and implements relevant internal and external operating experience in a timely manner. The inspectors determined that internal operating experience indicated that the O-ring has failed on several previous filter changes; however, this experience had not been entered into the corrective action program.
Enforcement:
Violation: Technical Specification 5.4.1 requires that written procedures shall be established, implemented, and maintained covering applicable procedures recommended in Regulatory Guide 1.33, revision 2, appendix A, February 1978. Regulatory Guide 1.33 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 this requirement, work order 23-2777278, and procedure SOP-103A collectively were not appropriate to the circumstances. Specifically, on July 18, 2023, when restoring the RCP seal injection filter to a normal lineup, the work order and the procedure being used did not have appropriate written instructions, resulting in losses of RCS inventory and RCP seal flow.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On August 10, 2023, the inspectors presented the public radiation safety inspection results to Steven Sewell, Site Vice President, and other members of the licensee staff.
- On October 4, 2023, the inspectors presented the Comanche Peak Unit 2 Inservice Inspection results to J. Lloyd, Senior Director, Engineering & Regulatory Affairs, and other members of the licensee staff.
- On October 5, 2023, the inspectors presented the biennial emergency preparedness exercise inspection results to Al Marzloff, Plant Manager, and other members of the licensee staff.
- On October 12, 2023, the inspectors presented the integrated inspection results to Steven Sewell, Site Vice President, and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Procedures
SOP-201B
Safety Injection System
Procedures
SOP-304B
Auxiliary Feedwater System
Procedures
SOP-304B-AF-
V02
Train B MDAFW Pump Lineup
Procedures
SOP-304B-AF-
V03
TDAFWP Lineup
Procedures
SOP-609B-DG-
V02
Train B DG Air System Valve Lineup
Procedures
SOP-815B
Safety Chilled Water System
Miscellaneous
Drill 23-15-02 Scenario
07/20/2023
Procedures
CPNPP/FPR
Comanche Peak Nuclear Power Plant Fire Protection Report
Unit 1 and Unit 2
Procedures
FPI 101A
Unit 1 Safeguards Building Elevation 790
Procedures
FPI-101A
Unit 1 Safeguards building elevation 773'-0" Train A & B -
Procedures
FPI-101B
Unit 2 Safeguards building elevation 773'-0" A & B RHR, SI
and Containment Spray Pump Rooms
Procedures
FPI-102B
Unit 2 Safeguards Building Elevation 790
Procedures
FPI-403
Auxiliary Building Elevation 810'-6"
Corrective Action
Documents
CR-YYYY-NNNN
TR-YYYY-NNNN
2004-001456, 2009-000794, 2020-008364, 2022-002987,
21-006774, 2022-003052, 2021-006832, 2022-000786,
21-006859, 2022-001391, 2020-006898, 2022-002769,
22-003783, 2022-004216, 2021-008097, 2021-007550,
22-000367, 2022-005376, 2021-006299, 2022-002559,
22-004896, 2022-004630, 2022-005029, 2021-007806,
22-002065, 2022-000787, 2021-006607, 2021-008291,
22-002069, 2021-008067, 2022-003295, 2022-000786,
22-006938, 2022-007500, 2022-006559, 2022-008555,
22-008373, 2022-006936, 2023-000810, 2023-001501,
23-001699, CR-2023-002755,
TR-2022-006827, TR-2022-008643, TR-2022-000165,
TR-2022-001241, TR-2023-000211,
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
IR-YYYY-NNNN
23-002755, 2020-006898
Corrective Action
Documents
Resulting from
Inspection
CR-YYYY-NNNN
IR-YYYY-NNNN
TR-YYYY-NNNN
23-005185,
23-003711, 2023-003715, 2023-003716, 2023-003717,
23-003718, 2023-003719, 2023-003720, 2023-003722,
23-000211
Engineering
Evaluations
EV-CR-2009-
000794-00-2
Engineering discovered a coffee colored stain in the reactor
cavity tell-tale trough
04/29/2009
Engineering
Evaluations
EV-TR-2023-
000211-1
Response to NRC Question on U2 MSIP Tool Event &
Analyses
01/13/2023
Miscellaneous
Associated work
order: 21-373898,
Procedure: TX-
ISI-8, Report No:
VT-3-Visual Examination of Pipe Hanger, Support of
Restraint
Miscellaneous
LTR-SDA-21-084
Comanche Peak Unit 2 Reactor Vessel Hot Leg and Cold
Leg Dissimilar Metal Welds PWSCC Operability Based on
MSIP Application and Inspections per Code Case N-770-5
10/31/2021
Miscellaneous
TCX-PP000-CN-
PX-000002
Comanche Peak Unit 2 Operability Assessment of the
Reactor Coolant Piping and Support System Due to the
MSIP Tool Failures
Procedures
TX-ISI-IWE
Metal containment visual Examination
Work Orders
21-582757
PD CHRG PMP 2-01 SUCT VNT CHK VLV
Welding documents 220208, 220209,220210,220211
05/03/2023
Corrective Action
Documents
CR-YYYY-NNNN
23-4574, 2021-1820
Corrective Action
Documents
CR-YYYY-NNNN
23-04763
Corrective Action
Documents
CR-YYYY-NNNN
23-4378, 2023-5791,2023-5576
Corrective Action
Documents
IR-YYYY-NNNN
23-5522
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Corrective Action
Documents
TR-YYYY-NNNN
23-5981
Drawings
M2-0302
Flow Diagram-Ventilation Safeguards and Electrical Area
Engineering
Changes
FDA-2023-
000043
Provide connection to heater drain pump 1-02 to allow for
flow if pump trips
Miscellaneous
Work schedule report for 2RF20 for shift operations and
maintenance team 1.
April and
May 2023
Miscellaneous
Work force reports of hours worked for Westinghouse
April 17 thru
May 27,
23
Drawings
m1-0255
Chemical and Volume Control System Charging and Positive
Displacement Pump Trains
Procedures
OPT-203B
Residual Heat Removal System Testing
Procedures
OPT-204B
Safety Injection System Testing
Work Orders
23-277278
Work Orders
Unit 1 safety chiller 1-05 compressor replacement
Corrective Action
Documents
CR-YYYY-NNNN
21-001627, 2021-003405, 2021-003396, 2021-003398,
21-005340, 2021-008501, 2021-008503, 2022-004836,
22-005181, 2022-006005, 2022-006007, 2022-006006,
22-007168, 2023-001209, 2023-001437, 2023-001394,
21-005512, 2021-008514, 2021-003239, 2021-003715,
21-005014, 2023-001620, 2022-007495, 2022-007693,
23-001395, 2022-008803,
Corrective Action
Documents
CR-YYYY-NNNN
22-008975, 2022-008715, 2023-004166, 2023-003562,
23-002780, 2023-002761, 2023-004348, 2022-008144,
23-003960, 2023-004840, 2023-007340
Corrective Action
Documents
TR-YYYY-NNNN
23-002377, 2023-002380, 2023-002381, 2023-002383
Corrective Action
Documents
Resulting from
Inspection
IR-YYYY-NNNN
23-006923
Procedures
Exercise Report 11-06-2019
07/12/2022
Procedures
Exercise Report Red Team 12/15/2021
07/12/2022
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Procedures
Exercise Report Blue Team 08/04/2021
2/22/2021
Procedures
Exercise Report Green Team 05/12/2021
07/08/2021
Procedures
Exercise Report Gold Team 03/03/2021
07/12/2022
Procedures
Exercise Report Gold Team 02/16/2022
07/12/2022
Procedures
Exercise Report Green Team 06/22/2022
10/12/2022
Procedures
Exercise Report Green Team 07/27/2022
10/12/2022
Procedures
Exercise Report Red Team 11/30/2022
01/11/2023
Procedures
Exercise Report Blue Team 02/22/2023
05/04/2023
Procedures
Comanche Peak Nuclear Power Plant Emergency Plan
Procedures
EPP-109
Duties and Responsibilities of the Emergency
Coordinator/Recovery Manager
Procedures
EPP-201
Assessment of Emergency Action Levels Emergency
Classification and Plan Activation
Procedures
EPP-202
Emergency Communications Systems and Equipment
Procedures
EPP-203
Notifications
EPP-203
Procedures
EPP-204
Activation and Operation of the Technical Support Center
(TSC)
Procedures
EPP-205
Activation and Operation of the Operations Support Center
(OSC)
Procedures
EPP-206
Activation and Operation of the Emergency Operations
Facility (EOF)
Procedures
EPP-303
Operation of Computer Based Emergency Dose Assessment
System
Procedures
EPP-304
Protective Action Recommendations
Procedures
EPP-306
Use of Thyroid Blocking Agents
Procedures
EPP-309
Onsite/In-Plant Radiological Surveys and Offsite
Radiological Monitoring
Procedures
EPP-314
Evacuation and Accountability
Miscellaneous
50.54(q) Screening and Evaluation Documents for
Emergency Plan Revision
Miscellaneous
50.54(q) Screening and Evaluation Documents for
Emergency Plan Revision 48
Procedures
Comanche Peak Nuclear Power Plant Emergency Plan
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Procedures
Comanche Peak Nuclear Power Plant Emergency Plan
Procedures
EPP-123
CFR 50.54(q) Screening and Evaluation of Changes to
Emergency Plan Documentation
Miscellaneous
Notification Message Form
0946
09/11/2023
Miscellaneous
Notification Message Form
0750
09/11/2023
Miscellaneous
LO46.E23.PRA
Cycle 23-5 Practice Scenario
Corrective Action
Documents
CR-YYYY-NNNN
21-003323, 2022-007381
Corrective Action
Documents
TR-YYYY-NNNN
20-007580, 2021-000682, 2021-000846, 2022-000027,
22-000622, 2022-001065, 2022-001442, 2023-000039,
23-001105, 2023-004906
Corrective Action
Documents
Resulting from
Inspection
IR-YYYY-NNNN
23-005672, 2023-0005681, 2023-005683
Miscellaneous
20
Annual Radioactive Effluent Release Report
03/29/2021
Miscellaneous
21
Annual Radioactive Effluent Release Report
04/09/2022
Miscellaneous
22
Annual Radioactive Effluent Release Report
03/30/2023
Miscellaneous
23
Land Use Census
06/08/2023
Miscellaneous
4th Quarter 2021
Results of Radiochemistry Cross Check Program
04/19/2022
Miscellaneous
Offsite Dose Calculation Manual
Procedures
CHM-170
Liquid and Gaseous Effluent Program
Procedures
CLI-741
Setpoint Modification and DRMS Pre-Release Surveillance
Procedures
CLI-745
Radioactive Effluent Post-Release Permit Processing and
Surveillance Tracking
Procedures
CLI-774
Wide Range Gas Monitor Filter Replacement
Procedures
CLI-777
Use of Gaseous Waste Sampling Equipment
Procedures
COP-816
Plant Ventilation
Procedures
PPT-SX-7509A
ESF Filter Unit Test - CPX-VAFUPK-15
Procedures
STA-603
Control of Station Radioactive Effluents
Radiation
Surveys
Gaseous Effluent
Permits
G2021-007, G2021-008, G2021-045, G2021-073,
G2021-082, G2021-083, G2021-122, G2021-123,
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
G2021-139, G2021-190, G2021-191, G2021-206,
G2021-212, G2022-024, G2022-047, G2022-048,
G2022-074, G2022-076, G2022-087, G2022-108,
G2022-109, G2022-139, G2022-183, G2022-184,
G2022-219, G2023-031, G2023-032, G2023-034,
G2023-061, G2023-073, G2023-086, G2023-091,
G2023-092
Radiation
Surveys
Liquid Effluent
Permits
L2021-005, L2022-010, L2023-005, L2021-019, L2022-015,
L2023-010, L2021-031, L2022-027, L2023-022, L2021-047,
L2022-045, L2023-033, L2021-057, L2022-055, L2021-062,
L2022-062
Radiation
Surveys
M-20230702-1
CCW heat exchanger room, auxiliary building 790' elevation
07/02/2023
Self-Assessments EVAL-2021-006
Chemistry/ Environmental/ Effluent/Radioactive Waste Audit
04/25/2022
Corrective Action
Documents
CR-YYYY-NNNN
21-003323, 2020-001474, 2022-008211, 2021-007878
Corrective Action
Documents
TR-YYYY-NNNN
20-002247, 2020-004597, 2021-000581, 2022-000484,
21-003892, 2022-003827, 2020-001878, 2020-001904,
22-001873, 2022-003871
Miscellaneous
21
Annual Radiological Environmental Operating Report
04/12/2022
Miscellaneous
22
Annual Radiological Environmental Operating Report
03/28/2023
Miscellaneous
23
GPI Plan and Status
07/01/2023
Procedures
INC-4923X
Channel Calibration Backup Tower Air Ambient Temperature
Channel 4134
Procedures
INC-7682X
Channel Calibration Primary 60M Tower Wind Speed
Channel 4117
Procedures
INC-7685X
Channel Calibration Primary 60m Tower Wind Direction
Channel 4115
Procedures
RPI-710
Radiological Environmental Monitoring, Sampling, and
Analysis Program
Procedures
RPI-713
Collection, Preparation, and Shipment of Radiological
Environmental Samples
Procedures
RPI-714
Land Use Census
Procedures
STA-654
Groundwater Protection Program
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Radiation
Surveys
549194
Soil Sediment Gamma Isotopic
08/06/2021
Radiation
Surveys
564474
Food Product Gamma Isotopic
01/05/2022
Radiation
Surveys
566896
Fish Tritium Sample
01/13/2022
Radiation
Surveys
605457
Broad Leaf Gamma Isotopic and Iodine
01/27/2023
Radiation
Surveys
609143
Quarterly Gamma Isotopic of Air Samples
2/22/2023
Self-Assessments 2019
EPRI Groundwater Protection Program
06/23/2020
Self-Assessments 2022
On-Site Assessment Report for Radiation Detection
Company
05/21/2023
Self-Assessments Eval-2021-006
Chemistry/ Environmental/ Effluent/Radioactive Waste Audit
03/03/2022
Work Orders
2-465494
Meteorological Data System Backup Tower 10 Meter
Elevation Wind Speed Loop 4128
03/27/2023
Work Orders
2-465656
Meteorological Data System Backup Tower 10 Meter Level
Wind Direction Loop 4126
03/27/2023
71151
Miscellaneous
Alert and Notification Test Data 3Q2022 - 2Q2023
71151
Miscellaneous
Key Emergency Response Organization Personnel Drill
Participation Data 3Q2022 - 2Q2023
71151
Miscellaneous
Drill and Exercise Performance Data 3Q2022 - 2Q2023
71151
Procedures
SG-20
Staff Guideline 20 NRC Performance Indicators
Corrective Action
Documents
CR-YYYY-NNNN
21-3228
Corrective Action
Documents
CR-YYYY-NNNN
23-2947
Work Orders
2-07855