IR 05000445/2023004
| ML24024A192 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 01/29/2024 |
| From: | Greg Werner NRC Region 4 |
| To: | Peters K Vistra Operations Company |
| References | |
| IR 2023004 | |
| Download: ML24024A192 (21) | |
Text
January 29, 2024
SUBJECT:
COMANCHE PEAK NUCLEAR POWER PLANT, UNITS 1 AND 2 -
INTEGRATED INSPECTION REPORT 05000445/2023004 AND 05000446/2023004
Dear Ken Peters:
On December 31, 2023, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Comanche Peak Nuclear Power Plant, Units 1 and 2. On January 11, 2024, 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.
Three 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 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 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
Inspection Report
Docket Numbers:
05000445 and 05000446
License Numbers:
Report Numbers:
05000445/2023004 and 05000446/2023004
Enterprise Identifier:
I-2023-004-0000
Licensee:
Vistra Operations Company
Facility:
Comanche Peak Nuclear Power Plant, Units 1 and 2
Location:
Glen Rose, TX 76043
Inspection Dates:
October 1, 2023, to December 31, 2023
Inspectors:
D. Antonangeli, Resident Inspector
J. Drake, Senior Reactor Inspector
J. Ellegood, Senior Resident Inspector
D. Proulx, Senior Project Engineer
Approved By:
Gregory E. Werner, Chief
Reactor Projects Branch B
Division of Operating Reactor Safety
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 Restrain Freon Bottles in Safety Chiller Room Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000445/2023004-01 Open/Closed
[H.2] - Field Presence 71111.15 The inspectors identified a Green finding and associated non-cited violation of 10 CFR 50,
Appendix B, Criterion V, Instructions, Procedures and Drawings, for the licensees failure to implement a procedure affecting quality. Specifically, the licensee failed to follow procedure STA-661, Non-Plant Equipment Storage and Use Inside Seismic Category 1 Structures, revision 5, by failing to restrain or correctly position four Freon cylinders and associated cart stored near the Unit 1 safety chiller train A.
Failure to Secure a Lock High Radiation Area to Prevent Unauthorized Access Cornerstone Significance Cross-Cutting Aspect Report Section Occupational Radiation Safety Green NCV 05000445/2023004-02 Open/
Closed
[H.2] - Field Presence 71111.20 The inspectors identified a Green finding and associated non-cited violation of Technical Specification 5.7.2(a) for the failure to properly lock to prevent unauthorized entry to a high radiation area with dose rates greater than 1 rem/hr at 30 cm, often referred to as a locked high radiation area. Specifically, the locked high radiation area barrier to the fuel transfer canal was not properly locked and could be easily moved aside and therefore easily circumvented.
Ineffective Reliability Monitoring of Main Feedwater Pump 1-02 Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green FIN 05000445/2023004-03 Open/Closed
[P.2] -
Evaluation 71152A The inspectors reviewed a self-revealed Green finding without a violation for failure to appropriately evaluate and correct corrosion products in the main feedwater pump control oil system. As a result, on June 16, 2023, main feedwater pump 1-02 tripped causing a Unit 1 reactor trip. Specifically, the main feedwater pump tripped due to corrosion products in the control oil system of the pump. Review of data available prior to the trip revealed precursor indications that would have afforded the licensee the ability to perform a controlled down power to repair the pump.
Additional Tracking Items
None.
PLANT STATUS
Unit 1 started the inspection period at 100 percent power and remained at or near 100 percent until the licensee shut down the unit on October 15, 2023, for refueling outage 1RFO23. On November 12, 2023, the licensee restarted Unit 1 and returned to 100 percent power on November 16. Unit 1 remained at or near 100 percent power for the remainder of the inspection period.
Unit 2 operated at or near 100 percent power for the entire inspection period.
INSPECTION SCOPES
Inspections were conducted using the appropriate portions of the inspection procedures (IPs) in effect at the beginning of the inspection unless otherwise noted. Currently approved IPs with their attached revision histories are located on the public website at http://www.nrc.gov/reading-rm/doc-collections/insp-manual/inspection-procedure/index.html. Samples were declared complete when the IP requirements most appropriate to the inspection activity were met consistent with Inspection Manual Chapter (IMC) 2515, Light-Water Reactor Inspection Program - Operations Phase. The inspectors performed activities described in IMC 2515, Appendix D, Plant Status, observed risk significant activities, and completed on-site portions of IPs. The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel to assess licensee performance and compliance with Commission rules and regulations, license conditions, site procedures, and standards.
REACTOR SAFETY
71111.01 - Adverse Weather Protection
Seasonal Extreme Weather Sample (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated readiness for seasonal extreme weather conditions prior to the onset of cold weather for the following systems:
- diesel generators
- main steam system
- main feedwater system
Impending Severe Weather Sample (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated the adequacy of the overall preparations to protect risk
-significant systems from impending severe weather consisting of predicted thunderstorms and wind gusts on November 30, 2023.
71111.04 - Equipment Alignment
Partial Walkdown Sample (IP Section 03.01) (2 Samples)
The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:
- (1) Unit 1, train B component cooling water system on October 18, 2023
- (2) Unit 1, safety injection train B on November 21, 2023
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (7 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, battery rooms and charging rooms on November 21, 2023
- (2) Unit 2, battery rooms and charging rooms on December 4, 2023 (3)auxiliary building 790-foot elevation on December 8, 2023
- (4) Unit 2, emergency diesel room on December 11, 2023
- (5) Unit 2, safeguards building 852-foot elevation on December 12, 2023
- (6) Unit 2, train A switchgear room, safeguards building 810-foot elevation on December 13, 2023
- (7) Unit 1, electrical equipment room, safeguards building 832-foot elevation on December 13, 2023
===71111.08P - Inservice Inspection Activities (PWR) The inspectors verified that the reactor coolant system boundary, reactor vessel internals, risk-significant piping system boundaries, and containment boundary are appropriately monitored for degradation and that repairs and replacements were appropriately fabricated, examined and accepted by reviewing the following activities from October 16 to November 30, 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
- reactor coolant, TBX-1-4101-3, elbow to pipe
- reactor coolant, TBX-1-4101-4, elbow to pipe
- reactor coolant, TBX-1-4101-5, elbow to pipe
- reactor coolant, TBX-1-4101-6, elbow to pipe Dye Penetrant Examination
- reactor coolant, TBX-1-4109-6, pipe to elbow Visual # Examination
- auxiliary feedwater, AF-1-SB-001-H1, anchor
- auxiliary feedwater, AF-1-SB-001-H2, strut
- auxiliary feedwater, AF-1-SB-001-H3, spring can
- safety injection, TBX-2-2561-H3, spring can
- safety injection, TBX-2-2561-H3, anchor Welding Activities
- Gas tungsten arc welding o
charging, DC-1-09-P-P-line-1993, WIB-307 o
charging, DC-1-09-P-P-line-1993, WIB-403 o
charging, DC-1-09-P-P-line-1993, WIB-404 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 head, penetrations 1 through 78, vent line A-B001, and vent line C-D001 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)
- condition report 2023-007406 U-2 condensate storage tank and refueling water storage tank pipe tunnel deposits
- condition report 2023-007406 work order initiation for clean and non-destructive examination
- condition report 2023-007069 1RF23 mode 3 boric acid corrosion control program walkdown results and evaluations
- condition report 2023-007403 1SI-0015 deposits PWR Inservice Inspection Activities Sample - Steam Generator Tube Inspection Activities (Section 03.04)
No inspections of steam generator tubes were required this outage.
71111.11Q - Licensed Operator Requalification Program and Licensed Operator Performance
Licensed Operator Performance in the Actual Plant/Main Control Room (IP Section 03.01) (2 Samples)
- (1) The inspectors observed and evaluated licensed operator performance in the control room during Unit 1 shutdown and cooldown for a planned outage on October 15, 2023.
- (2) The inspectors observed and evaluated licensed operator performance in the control room during vacuum fill on November 6, 2023.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed and evaluated a simulator scenario involving a seismic event and a steam generator tube rupture on November 28, 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) Unit 2, containment structure based on suspected cracks identified on October 28, 2023 (2)diesel generator 2-01 trip due to tachometer failure on October 31, 2023
Quality Control (IP Section 03.02) (1 Sample)
The inspectors evaluated the effectiveness of maintenance and quality control activities to ensure the following SSC remains capable of performing its intended function:
- (1) Unit 1, train A safety chiller replacement/refurbishment the week of October 1, 2023
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (4 Samples)
The inspectors evaluated the accuracy and completeness of risk assessments for the following planned and emergent work activities to ensure configuration changes and appropriate work controls were addressed:
- (1) Unit 1 outage risk assessment (2)mitigating actions for yellow risk for containment closure on October 17, 2023 (3)defense in depth actions in place on October 31, 2023 (4)risk associated with vacuum fill and mid-loop operations on November 6 and 7, 2023
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (4 Samples)
The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:
(1)prestart up assessment of open deficiencies (2)operability of motor driven auxiliary feedwater 2-02 due to seal gland fastener thread engagement (3)past operability of safety injection pump 1-02 due to degraded bearing.
(4)past operability assessment of Unit 1 train A safety chiller in the presence of unrestrained Freon bottles
71111.18 - Plant Modifications
Temporary Modifications and/or Permanent Modifications (IP Section 03.01 and/or 03.02) (2 Samples)
The inspectors evaluated the following temporary or permanent modifications:
- (1) Unit 2, temporary modification installing jumper around cell number 10 of train B battery CP2-EPBTED-04 on November 8, 2023
- (2) Unit 1, resolve the condensate motor (CP1-COAPCP-01M) bus bars are too short by fabricating longer bus bar leads on November 8, 2023.
71111.20 - Refueling and Other Outage Activities
Refueling/Other Outage Sample (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated refueling outage 1RFO23 from October 15 to November 13, 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) (7 Samples)
(1)post cleaning of reactor cavity for foreign material exclusion prior to flood up on October 19, 2023.
(2)routine maintenance on air operated valve, 1-HV-4710, on October 28, 2023.
(3)maintenance of component cooling water heat exchanger 1-02 on October 25, 2023 (4)diesel generator 1-02 testing on November 1, 2023 (5)re-tensioning of reactor vessel head nuts to check for proper elongation on November 9, 2023 (6)core reload verification by low power physics testing on November 12 and 13, 2023.
(7)turbine plant cooling water pump 1-01 motor breaker inspection and cleaning on December 20,2023
Surveillance Testing (IP Section 03.01) (2 Samples)
(1)test of Unit 1 polar crane on October 25, 2023
- (2) Unit 1 train A integrated test sequence on October 21, 2023
Inservice Testing (IST) (IP Section 03.01) (1 Sample)
- (1) Unit 1 air operated valve, 1-HV-4711, on October 28, 2023
Containment Isolation Valve (CIV) Testing (IP Section 03.01) (1 Sample)
- (1) Unit 1 reactor coolant drain tank 1-01 level control valve, observed local leak rate testing on October 19, 2023
Diverse and Flexible Coping Strategies (FLEX) Testing (IP Section 03.02) (1 Sample)
(1)testing of FLEX emergency light towers and FLEX emergency 500 kW diesel generators, on October 5,
OTHER ACTIVITIES - BASELINE
===71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:
MS08: Heat Removal Systems (IP Section 02.07)===
- (1) Unit 1 (October 1, 2022, through September 30, 2023)
- (2) Unit 2 (October 1, 2022, through September 30, 2023)
MS10: Cooling Water Support Systems (IP Section 02.09) (2 Samples)
- (1) Unit 1 (October 1, 2022, through September 30, 2023)
- (2) Unit 2 (October 1, 2022, through September 30, 2023)
BI01: Reactor Coolant System (RCS) Specific Activity Sample (IP Section 02.10) (2 Samples)
- (1) Unit 1 (July 1, 2022, through June 30, 2023)
- (2) Unit 2 (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)emergency diesel generator 2-01 tachometer failure per condition report 2023-
005914 (2)main feed pump trip resulting in a reactor trip per condition report 2023-4448 71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02)
- (1) The inspectors reviewed the licensees corrective action program for potential adverse trends in housekeeping that might be indicative of more significant safety issues, such as fire protection or seismic issues. The inspectors observed a negative trend in licensee performance with respect to demobilization from the refueling outage work activities as well as general cleanliness. After the refueling outage, the inspectors identified numerous items that were not removed nor properly secured.
One issue related to Freon bottle storage in a safety chiller room was inspected under IP 71111.15, Operability Determinations, and a non-cited violation is included in this report.
INSPECTION RESULTS
Failure to Restrain Freon Bottles in Safety Chiller Room Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000445/2023004-01 Open/Closed
[H.2] - Field Presence 71111.15 The inspectors identified a Green finding and associated non-cited violation of 10 CFR 50, Appendix B, Criterion V, Instructions, Procedures and Drawings, for the licensees failure to implement a procedure affecting quality. Specifically, the licensee failed to follow procedure STA-661, Non-Plant Equipment Storage and Use Inside Seismic Category 1 Structures, revision 5, by failing to restrain or correctly position four Freon cylinders and associated cart stored near the Unit 1 safety chiller train A.
Description:
On November 16, 2023, during a tour of the auxiliary building the inspectors noted that four Freon cylinders and a supporting cart were stored in the Unit 1 train A safety chiller room. These cylinders had a listed weight of 370 lbs. each and were 59 inches tall. The four cylinders and the supporting cart were in close proximity to safety-related electrical conduit and instrument tubing that could have failed upon impact following a seismic event.
None of the cylinders was restrained to prevent sliding/toppling following a seismic event, which could challenge the operability of the Unit 1 train A safety chiller, a risk significant system.
Procedure STA-661, section 6.8 required objects stored in seismic structures to be at least 6 inches from targets or restrained. At least two of the Freon bottles and the cart were within 6 inches of plant equipment. The inspectors determined that the as-found condition of at least two of the cylinders and the cart did not meet procedure STA-661.
Upon notification, the licensee entered this issue into their corrective action program as condition report 2023-008227 to be evaluated by engineering. During the engineering walkdown of November 16, 2023, the licensee determined that the condition of the cylinders did not meet procedure STA-661. The licensees immediate corrective action was to strap (bundle) the bottles into pairs of two on November 16, 2023, without attaching the bundles to a structural support. This did not meet procedure STA-661, which required storage more than 6 inches from equipment or restraint to preclude sliding. The inspectors continued to question the presence of the bottles in the train A safety chiller room given the seismic concerns, and the licensee removed the four bottles and cart from the room to a safe storage area on December 13, 2023.
Because the Freon cylinders and cart were in close proximity to critical equipment associated with the Unit 1 train A safety chiller, the inspectors considered this condition to challenge the operability of the train during a seismic event. Technical Specification (TS) 3.7.19 states that with one safety chilled water system train inoperable, restore the train to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, or implement the risk informed completion time program, or be in Mode 3 within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. This condition existed for 27 days; and thus, exceeded the TS action statement.
Corrective Actions: The licensee removed the four Freon bottles and cart from the train A safety chiller room.
Corrective Action References: condition report 2023-008227
Performance Assessment:
Performance Deficiency: The licensees failure to implement a procedure that required proper spacing or restraint of four Freon bottles and cart in the Seismic Category 1 Unit 1 train A safety chiller room was a performance deficiency.
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 failure to restrain or properly place four Freon bottles and cart in the Unit 1 train A safety chiller room could have reasonably caused the train to be inoperable during a seismic event. The four cylinders and cart were in close proximity to safety-related electrical conduit and instrument tubing and could have caused failure by impact following a seismic event.
Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power. Using Exhibit 2 Mitigating Systems Screening Questions, Section A.3, the inspectors determined that a detailed risk evaluation was required because the condition represented a potential loss of the probabilistic risk assessment function of one train of a multi-train system for greater than the TS allowed outage time. A senior reactor analyst performed the analysis and determined the increase in core damage frequency was 1.2E-9/year, making the significance very low (Green). For this evaluation, the analyst added seismic failure modeling to fault tree SCW-A, Safety Chilled Water System Loop A Unavailable in the Comanche Peak SPAR model, revision 8.81 (run on SAPHIRE, version 8.2.9). The analyst used surrogate fragility values of a 4160V breaker to estimate the chiller fragility for the base case and then assumed the unsecured bottles would cause failure of the chiller during all seismic events during the 27-day exposure time. The redundant chiller train remained available for mitigation of the dominant seismic sequences where the vulnerable chiller train was lost.
Cross-Cutting Aspect: H.2 - Field Presence: Leaders are commonly seen in the work areas of the plant observing, coaching, and reinforcing standards and expectations. Deviations from standards and expectations are corrected promptly. Senior managers ensure supervisory and management oversight of work activities, including contractors and supplemental personnel.
Specifically, the inappropriately stored Freon bottles were allowed to remain in the area for several weeks, without the leadership team identifying and correcting the failure to meet the standard.
Enforcement:
Violation: Title 10 CFR 50, Appendix B, Criterion V, Instructions, Procedures and Drawings, states, in part, that activities affecting quality shall be prescribed by procedures appropriate to the circumstances and shall be accomplished in accordance with these procedures.
Procedure STA-661, Non-Plant Equipment Storage and Use Inside Seismic Category 1 Structures, revision 5, a procedure affecting quality, stated in section 6.4.1 equipment may be stored in a seismic category one structure provided there are no targets within the zone of influence. Section 6.8 established a zone of influence of at least 6 inches for the Freon bottles and cart or restraint to limit movement.
Contrary to above, from November 16 to December 12, 2023, the licensee failed to accomplish a quality-related procedure appropriate to the circumstances. Specifically, the licensee stored Freon bottles and a cart in close proximity to the Seismic Category 1 Unit 1 safety chiller A.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Failure to Secure a Lock High Radiation Area to Prevent Unauthorized Access Cornerstone Significance Cross-Cutting Aspect Report Section Occupational Radiation Safety Green NCV 05000445/2023004-02 Open/
Closed
[H.2] - Field Presence 71111.20 The inspectors identified a Green finding and associated non-cited violation of Technical Specification 5.7.2(a) for the failure to properly lock to prevent unauthorized entry to a high radiation area with dose rates greater than 1 rem/hr at 30 cm, often referred to as a locked high radiation area. Specifically, the locked high radiation area barrier to the fuel transfer canal was not properly locked and could be easily moved aside and therefore easily circumvented.
Description:
On November 7, 2023, during the Unit 1 containment closure inspection, the inspectors challenged a posted locked high radiation area (LHRA) barrier to the fuel transfer canal to verify it was properly locked. The licensee utilized a piece of sheet metal locked by wire cable to cover the upper rungs of an installed ladder leading to the fuel transfer canal.
The inspectors questioned the appropriateness of the LHRA barrier, and a qualified health physics technician was able to easily move the LHRA barrier by hand to allow access to the LHRA.
The inspectors notified radiation protection staff as well as site management. In response, licensee staff properly locked the barrier. On a subsequent tour of containment, the inspectors noted that the barrier could not be bypassed without use of tools.
While reviewing this issue, the inspectors requested and reviewed the latest survey of the fuel transfer canal. Survey M-20231104-3 identified one location where dose rates exceeded 1.55 rem/hour at thirty centimeters. The inspectors concluded that the as found condition of the barrier did not meet the requirements of TS 5.7.2(a), which requires for high radiation areas with dose rates greater than 1 rem/hour at 30 cm that each entryway to such an area shall be provided with a locked or continuously guarded door or gate that prevents unauthorized entry.
Corrective Actions: The licensee immediately took actions to properly lock the LHRA barrier.
Also, the licensee entered the issue into the corrective action program to determine any additional actions.
Corrective Action References: condition report 2023-007980
Performance Assessment:
Performance Deficiency: The failure to secure a LHRA to prevent unauthorized access in accordance with their TSs is a performance deficiency.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Human Performance attribute of the Occupational Radiation Safety cornerstone and adversely affected the cornerstone objective to ensure the adequate protection of the worker health and safety from exposure to radiation from radioactive material during routine civilian nuclear reactor operation. Specifically, the fuel transfer canal LHRA entryway was not properly locked and could be easily circumvented.
Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix C, Occupational Radiation Safety SDP. The inspectors determined the finding had very low safety significance (Green) because:
- (1) it was not associated with ALARA planning and work controls,
- (2) it was not an overexposure,
- (3) there was no substantial potential for overexposure, and
- (4) the ability to assess dose was not compromised.
Cross-Cutting Aspect: H.2 - Field Presence: Leaders are commonly seen in the work areas of the plant observing, coaching, and reinforcing standards and expectations. Deviations from standards and expectations are corrected promptly. Senior managers ensure supervisory and management oversight of work activities, including contractors and supplemental personnel.
Specifically, when the LHRA barrier was installed, individuals did not validate that the barrier could not be moved aside by hand.
Enforcement:
Violation: Technical Specification 5.7.2(a) requires, in part, for high radiation areas with dose rates greater than 1 rem/hour at 30 cm, that each entryway to such an area shall be provided with a locked or continuously guarded door or gate that prevents unauthorized entry.
Contrary to the above, on November 7, 2023, the licensee failed to have the entryway to a high radiation area with dose rates greater than 1 rem/hr at 30 cm, properly locked or to have a continuously guarded door or gate that prevented unauthorized entry. Specifically, inspectors found that the high radiation area barrier that was intended to prevent access to the area was easily movable by hand.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Ineffective Reliability Monitoring of Main Feedwater Pump 1-02 Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green FIN 05000445/2023004-03
[P.2] -
Evaluation 71152A Open/Closed The inspectors reviewed a self-revealed Green finding without a violation for failure to appropriately evaluate and correct corrosion products in the main feedwater pump control oil system. As a result, on June 16, 2023, main feedwater pump 1-02 tripped causing a Unit 1 reactor trip. Specifically, the main feedwater pump tripped due to corrosion products in the control oil system of the pump. Review of data available prior to the trip revealed precursor indications that would have afforded the licensee the ability to perform a controlled down power to repair the pump.
Description:
Over the past several years, the licensee has experienced numerous control oil issues with the main feedwater pumps. These issues occurred as a result of water entrainment into the lube/control oil system for the pumps, resulting in corrosion of carbon steel piping. This corrosion has broken loose from the carbon steel piping, which degraded the operation of the control oil system.
In 2022, the NRC issued a finding (FIN-05000445/2022002-02) for licensee maintenance practices that allowed an out-of-specification tolerance of the main feedwater pump shaft seal. This allowed water from the turbine side of the bearing to enter the oil system. In addition, the licensee has acknowledged that poor performance of the oil seal system has allowed water to enter the oil system. Although the licensee took actions to monitor and remove water from the oil system, performance monitoring to account for corrosion products caused by the water omitted several available data points that could have indicated degraded performance of the pump. As part of corrective actions for the 2021 trip, the licensee developed an adverse condition monitoring plan that focused on monitoring of water in the oil.
This plan neglected to address corrosion product that had already been introduced into the control oil portion of the system. The design of the system precludes elimination of particulate in the control oil portion since filters are located upstream of this section. Therefore, corrosion products generated in the control oil portion become foreign material that can prevent proper operation of the system.
Licensee procedures for adverse condition monitoring plans and equipment reliability established requirements for monitoring parameters of critical components, which included components that could lead to a plant trip, such that actions could be taken to preclude or minimize adverse consequences. Procedure STA-748, Equipment Monitoring Process, revision 6 stated: "Performance monitoring is used to establish performance criteria and monitoring parameters for important system functions and critical components." However, the licensee failed to establish performance criteria and monitoring parameters that could have identified degraded performance of the control oil system on the main feedwater pump, a critical component. On May 15, 2022, the licensee noted water droplets were in the gland seal area. Subsequent testing on May 23 identified water in the lube oil sump. On August 18, 2022, the licensee established an adverse condition monitoring plan (ACMP) in response to the water intrusion. Procedure STI-144.04, Adverse Condition Monitoring Plan, revision 1 step 6.1.8 stated "A Licensed Operator review is required in the development of an ACMP to ensure that the appropriate operational parameters and actions are selected. This will ensure that operational challenges are properly addressed." However, operations staff failed to ensure parameters that could indicate degraded performance were monitored.
In the licensee's causal evaluation, the licensee identified the following: There were multiple ACMPs developed, but there was no comprehensive action plan; effective trending of available data was not established; and the ACMPs did not evaluate all data. Of note, the licensee recently upgraded the feed pump turbine control system, which provided significant monitoring capabilities. Graphs of the servo output for main feedwater pump 1-02 show significant variation approximately 20 days before the plant trip. In comparison, main feedwater pump 1-01 graphs showed a significantly more stable servo output.
Corrective Actions: The licensee replaced the servo as an immediate action and flushed the control oil portion of the system. Subsequent actions include additional site focus on equipment reliability and increased engineering focus on equipment trending.
Corrective Action References: condition report 2023-4448
Performance Assessment:
Performance Deficiency: The licensee's failure to monitor critical parameters on the Unit 1 main feedwater pumps as required by site procedures for equipment monitoring and ACMPs was a performance deficiency.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Equipment Performance attribute of the Initiating Events cornerstone and adversely affected the cornerstone objective to limit the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. Specifically, the main feedwater pump 1-02 experienced a degraded control oil system which led to a plant trip.
Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power. Using exhibit 1 dated November 30, 2020, the inspectors screened the finding as green because it was a transient initiator that did not cause a loss of mitigating equipment.
Cross-Cutting Aspect: P.2 - Evaluation: The organization thoroughly evaluates issues to ensure that resolutions address causes and extent of conditions commensurate with their safety significance. The licensee failed to thoroughly evaluate the condition of water in the main feedwater pump oil system and failed to establish trending to identify degradation before it became more significant.
Enforcement:
Inspectors did not identify a violation of regulatory requirements associated with this finding.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On November 30, 2023, the inspectors presented the Unit 1 inservice inspection exit meeting inspection results to Steven Sewell, Site Vice President, and other members of the licensee staff.
- On January 11, 2024, 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-502A
Component Cooling Water System
Procedures
SOP-502A-CC-
V02
Valve Lineup - Train B
Miscellaneous
Comanche Peak Nuclear Power Plant Fire Protection Report
Miscellaneous
Comanche Peak Nuclear Power Plant Final Safety Analysis
Report
2
Corrective Action
Documents
CR-YYYY-NNNN
2019-000300, 2019-004334, 2020-007823, 2022-000786,
22-002987, 2022-003052, 2022-003055, 2022-003074,
22-003295, 2022-003607, 2022-003783, 2022-003786,
22-004216, 2022-004630, 2022-004896, 2022-005029,
22-005376, 2022-006559, 2022-006597, 2022-006936,
22-006938, 2022-006987, 2022-007500, 2022-008373,
22-008729, 2022-008745, 2023-000235, 2023-001501,
23-001574, 2023-001692, 2023-001699, 2023-002024,
23-002308, 2023-002456, 2023-002681, 2023-002690,
23-002736, 2023-002913, 2023-002947, 2023-003032,
23-003376, 2023-003933, 2023-004188, 2023-004212,
23-004337, 2023-005185, 2023-006143, 2023-006380,
23-006539, 0223-007069, 2023-007239, 2023-007244,
23-007403, 2023-007406
Corrective Action
Documents
Resulting from
Inspection
CR-YYYY-NNNN
23-007239, 2023-007240, 2023-007241, 2023-007244,
23-007245, 2023-007257
Miscellaneous
Unit 1 Bare metal visual inspection on the Unit 1 reactor
vessel head
10/21/2023
Procedures
EPG - 9.08
Reactor Vessel Closure Head Visual Examination
Procedures
STA-737
Boric Acid Corrosion Detection and Evaluation
Procedures
STI-737.01
Boric Acid Corrosion Detection and Evaluation
Procedures
TPVEN_TX-ISI-
Liquid Penetrant Examination for CPSES
Procedures
TPVEN_TX-ISI-
210
Ultrasonic Examination Procedure for Welds in Ferritic Steel
Vessels
Procedures
TPVEN_TX-ISI-
301
Ultrasonic Examination of Ferritic Piping Welds
Procedures
TPVEN_TX-ISI-
2
Ultrasonic Examination Procedure of Austenitic Piping Welds
Procedures
TPVEN_TX-ISI-8
VT-1 and VT-3 Visual Examination Procedure
Procedures
TPVEN_TX-ISI-
Metal Containment Visual Examination
Procedures
TPVEN_WDI-
STD-1007
Generic Procedure for Ultrasonic Examination of Weld
Overlay Similar and Dissimilar Metal Welds Using PDI-UT-8
Work Orders
Work Orders
5967387, 5761540, 22-227193, 5517123
Corrective Action
Documents
CR-YYYY-NNNN
23-7569
Corrective Action
Documents
TR-YYYY-NNNN
22-2161
Miscellaneous
SAR# 6S713618
procurement documents for various parts for safety chiller
compressor
10/18/1991
NDE Reports
SPR 22
IWL Final Report Unit 2
05/02/2022
Procedures
ECE-6.02-01
Procurement Levels
Procedures
ECE-6.02-02
Engineering Review of Procurement Documents
Procedures
ECE-6.08
Determination of Shelf Life
Work Orders
23-379172
Corrective Action
Documents
TR-YYYY-NNNN
23-6422
Miscellaneous
1RF-23 Level 1 Schedule
C
Miscellaneous
1RF23 Level 2 Schedule
C
Miscellaneous
AI-TR-2023-
000001-13
Probabilistic Risk Assessment for 1RF23 Outage Schedule
Revision 2 Level C Risk Assessment
09/13/2023
Corrective Action
Documents
CR-YYYY-NNNN
23-7270, 2023-7281, 2023-7405, 2023-7523,
23-007949, 2023-008277
Engineering
Changes
FDA-2023-
000027-01-00
Jumper around cell #10 of battery CP2-EPBTED-04
05/04/2023
Engineering
Changes
FDA-2023-
000078-01-00
Resolve the Condensate Replacement Motor T-Leads
(CP1-COAPCP-01M) issue identified in TR-2023-007848
Corrective Action
Documents
CR-YYYY-NNNN
23-7222
Procedures
IPO-002A
Plant Startup from Hot Standby
Corrective Action
Documents
CR-YYYY-NNNN
23-007168, 2023-007862, 2023-7214
Procedures
MSE-S0-6301
6.9 KV Air Circuit Breaker Inspection and Cleaning
Procedures
OPT-430A
Train A Integrated Test Sequence
Procedures
SOP-609A
Diesel Generator System
Work Orders
23-284411, 23-314379, 23-9301, 22-222505, 22-507201,
23-283663, 22-241565, 22-261909, 21-839244, 22-267787
71151
Miscellaneous
Unit 1 and Unit 2 dose equivalent iodine results July 1, 2022,
through June 30, 2023
71151
Miscellaneous
Units 1 and 2 margin reports for heat removal systems and
cooling water systems.
Corrective Action
Documents
Corrective Action
Documents
CR-YYYY-NNNN
23-005914, 2023-4448
Miscellaneous
Adverse Condition Monitoring Plan for 1A and 1B Main
Feedwater Pump Water Intrusion into the Lube Oil System
05/14/2022
Procedures
SOP-302A
Feedwater System
Procedures
STA-748
Equipment Reliability Process
Procedures
STI-144.04
Adverse Condition Monitoring Plan
0,1,2 and 3