IR 05000498/2024002
| ML24219A065 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 08/09/2024 |
| From: | Patricia Vossmar NRC/RGN-IV/DORS/PBA |
| To: | Harshaw K South Texas |
| References | |
| IR2024002 | |
| Download: ML24219A065 (27) | |
Text
August 09, 2024
SUBJECT:
SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION, UNITS 1 AND 2 - INTEGRATED INSPECTION REPORT 05000498/2024002 AND 05000499/2024002
Dear Kimberly A. Harshaw:
On June 30, 2024, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at South Texas Project Electric Generating Station, Units 1 and 2. On July 11, 2024, the NRC inspectors discussed the results of this inspection with you and other members of your staff.
The results of this inspection are documented in the enclosed report.
One finding of very low safety significance (Green) is documented in this report. This finding involved a violation of NRC requirements. 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 violation or the significance or severity of the violation 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 South Texas Project Electric Generating Station, 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 South Texas Project Electric Generating Station, 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, Patricia J. Vossmar, Chief Reactor Projects Branch A Division of Operating Reactor Safety Docket Nos. 05000498,05000499 License Nos. NPF-76,NPF-80
Enclosure:
As stated
Inspection Report
Docket Numbers:
05000498 and 05000499
License Numbers:
Report Numbers:
05000498/2024002 and 05000499/2024002
Enterprise Identifier:
I-2024-002-0011
Licensee:
STP Nuclear Operating Company
Facility:
South Texas Project Electric Generating Station, Units 1 and 2
Location:
Wadsworth, TX 77483
Inspection Dates:
April 1, 2024, to June 30, 2024
Inspectors:
B. Baca, Health Physicist
J. Drake, Senior Reactor Inspector
L. Flores, Resident Inspector
V. Lee, Project Engineer
S. Lichvar, Technical Assistant
J. O'Donnell, Senior Health Physicist
J. Vera, Senior Resident Inspector
Approved By:
Patricia J. Vossmar, Chief
Reactor Projects Branch A
Division of Operating Reactor Safety
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at South Texas Project Electric Generating Station, 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
Improper entry into a high radiation area Cornerstone Significance Cross-Cutting Aspect Report Section Occupational Radiation Safety Green NCV 05000499/2024002-01 Open/Closed
[H.14] -
Conservative Bias 71124.01 The inspectors reviewed a self-revealed Green finding and associated non-cited violation of Technical Specification 6.8.1 for an improper entry into a Unit 2 high radiation area.
Specifically, a radiation worker was not authorized to enter the high radiation area and did not follow the radiation work permit instructions upon receiving a dose rate alarm.
Additional Tracking Items
Type Issue Number Title Report Section Status LER 05000498/2023-004-01 Condition Prohibited by Technical Specifications Due to Inoperable Train of Essential Chilled Water 71153 Closed
PLANT STATUS
Unit 1 began the inspection period at rated thermal power and remained there for the inspection period.
Unit 2 began the inspection period in refueling outage 2RE23. The main generator breaker was closed on May 11, 2024, ending the refueling outage. On May 12, 2024, the Unit 1 turbine was manually tripped due to a turbine supervisory alarm on low pressure turbine No. 3, and rated thermal power was lowered to 13 percent. Later, on May 12, 2024, the unit automatically tripped due to a partial loss of offsite power caused by unit auxiliary transformer lockout and entered forced outage 2F2401 to perform repairs. The main generator breaker was closed on May 19, 2024, ending forced outage 2F2401. The unit returned to rated thermal power on May 22, 2024, and remained there until June 18, 2024, when the turbine was taken offline, and reactor power was lowered to about 19 percent to support forced outage 2F2402. The outage was necessary to repair a steam leak on a line to a pressure transmitter used for control of steam dump valves.
The repairs were completed, and the main generator breaker was closed on June 19, 2024, ending forced outage 2F2402. The unit returned to rated thermal power on June 19, 2024, and remained there for the remainder 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
71111.01 - Adverse Weather Protection
Seasonal Extreme Weather Sample (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated readiness for seasonal extreme weather conditions prior to the onset of seasonal hot temperatures for the following systems:
- emergency diesel generator the week of June 10, 2024
- essential cooling water system the week of June 10, 2024.
71111.04 - Equipment Alignment
Partial Walkdown Sample (IP Section 03.01) (3 Samples)
The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:
- (1) Unit 2, spent fuel pool cooling - outage on April 5, 2024
- (2) Unit 1, train A essential cooling water system following maintenance on June 13, 2024
- (3) Unit 2, train D auxiliary feedwater system on June 17, 2024
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (5 Samples)
The inspectors evaluated the implementation of the fire protection program by conducting a walkdown and performing a review to verify program compliance, equipment functionality, material condition, and operational readiness of the following fire areas:
- (1) Unit 2, reactor coolant pump oil collection system on April 20, 2024
- (2) Unit 2, fuel handling building safety injection cubicle and electrical chase, train B, fire zone Z306 on May 21, 2024
- (3) Unit 1, electrical auxiliary building, switchgear room, train A, fire zone Z004 on June 11, 2024
- (4) Unit 1, electrical auxiliaries building, auxiliary shutdown area, fire zone Z071 on June 11, 2024
- (5) Unit 2, electrical auxiliaries building, cable spreading room train B fire zone 0407 on June 14, 2024
Fire Brigade Drill Performance Sample (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated the onsite fire brigade training and performance during a simulated fire at the fire pump house on June 24, 2024.
71111.06 - Flood Protection Measures
Flooding Sample (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated external flooding mitigation protections in the flood protection measures for postulated failure of main cooling reservoir on May 10, 2024.
===71111.08P - Inservice Inspection Activities (PWR) The inspectors verified that the reactor coolant system boundary, reactor vessel internals, risk-significant piping system boundaries, and containment boundary are appropriately monitored for degradation and that repairs and replacements were appropriately fabricated, examined and accepted by reviewing the following activities in Unit 2 during refueling outage 2R23 from April 1 to April 5, 2024.
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 system, thermal fatigue line No: 2"-RC-1419-BB1, elbow to pipe, weld 3
- Reactor coolant system, 12-RC-2312-BB1, pipe to elbow, weld 6
- Reactor coolant system, 12-RC-2312-BB1, pipe to elbow, weld 5 Dye Penetrant Examination
- Reactor coolant system, 2"-RC-1418-BB1, weld FW0113 Visual Examination
- VT-1, Reactor coolant system, 2"-RC-1418-BB1, weld FW0113
- VT-3, Containment liner (335-340 DEG) /CC-LINER-MB-1
- VT-3, Containment liner (240-360 DEG) /CC-LINER-MB-1 Welding Activities
Reactor coolant system, 2"-RC-1418-BB1, weld FW0113 PWR Inservice Inspection Activities Sample - Vessel Upper Head Penetration Inspection
Activities (IP Section 03.02) (1 Sample)
The inspectors verified that the licensee conducted the following vessel upper head penetration inspections and addressed any identified defects appropriately:
- (1) The inspectors reviewed video of reactor vessel head penetrations 1-10, 27-35, 75, 76. Penetration 75 annulus was obscured by residue from a known core exit thermocouple nozzle assembly leak. The licensee was granted a relief (ML24101A008) for the code inspection for this nozzle, cleaned the annulus area, and will inspect again next refuel outage.
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 screenings and evaluations:
- (1) Boric acid evaluations and screenings:
- 22-9731, Hi Head Safety Injection Pump 2C Discharge to Loop 2C Hot Leg Isolation Valve
- 22-10516, RHR (Residual heat removal) 2A heat exchanger
- 22-12188, Flange for level indicator LI-0108 located downstream of valve CV-0315
- 23-3065, Reactor coolant Drain Tank Heat Exchanger WL-NHX-101A pipe cap, and pipe flange
- 23-4469, 3R172TCV0333, Boric Acid Tank 2A Charging Pump Suction Isolation Valve
- 23-4533, 3R172TCV0352B Boric Acid Filter Bypass Valve
- 23-4753, 2N122NPA201A High Head Safety Injection Pump 2A
- 23-4758, N2CSFI0815 Containment Spray Pump 2A Test Line Flow Indicator
- 23-10544, SFPC (spent fuel pool cooling) Pump 2A inboard seal PWR Inservice Inspection Activities Sample - Steam Generator Tube Inspection Activities (Section 03.04)
No steam generator tube inspections required this refuel 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) (1 Sample)
- (1) The inspectors observed and evaluated licensed operator performance in the Unit 2 control room during startup after a refueling outage on May 11, 2024, and during a shutdown on June 17, 2024.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed and evaluated performance during just-in-time training for control room operators on June 15, 2024.
71111.12 - Maintenance Effectiveness
Maintenance Effectiveness (IP Section 03.01) (3 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, outage structural walkdowns in containment on April 6, 2024
- (2) Unit 2, emergency diesel generator cylinder air start valves on May 2, 2024
- (3) Unit 1 and unit 2 essential cooling water self-cleaning strainer leaks and low as-found material conditions during lube/inspect on May 15, 2024
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (5 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 2, electrical distribution system configuration changes following loss of offsite power on May 12, 2024
- (2) Unit 2, risk associated with reactor coolant system drain for reactor coolant pump 2B seal replacement during forced outage on May 15, 2024
- (3) Unit 1, white risk for planned maintenance the week of May 20, 2024
- (4) Unit 2, risk associated with forced outage to perform steam leak repairs on June 19, 2024,
- (5) Unit 2, risk associated with continued forced outage after main generator breaker lockout on June 21, 2024
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (5 Samples)
The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:
- (1) Unit 2, train A high head safety injection pump surveillance failure during outage on April 7, 2024
- (2) Unit 2, train B emergency diesel generator switchboard ground and high voltage alarms on May 6, 2024
- (3) Unit 2, train C essential cooling water self-cleaning strainer drum low as-found wall thickness on May15, 2024
- (4) Unit 2, essential chiller 22C operability for temperature adjustments on May 15, 2024
- (5) Unit 2, reactor vessel level indication system sheath operability on June 22, 2024
71111.20 - Refueling and Other Outage Activities
Refueling/Other Outage Sample (IP Section 03.01) (2 Samples)
- (1) The inspectors evaluated the Unit 2 refueling outage 2RE23 activities from April 1 to May 11, 2024.
- (2) The inspectors evaluated the Unit 2 forced outage due to loss of offsite power activities on May 13, 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) (6 Samples)
- (1) Unit 2, train R reactor trip breaker testing on April 8, 2024
- (2) Unit 2, train A high head safety injection pump following orifice modification on April 11, 2024
- (3) Unit 2, train C emergency diesel generator following lube oil filter replacement on April 16, 2024
- (4) Unit 2, automatic control rod drop timing test on May 8, 2024
- (5) Unit 2, low power physics testing on May 9, 2024
- (6) Unit 2, personnel airlock door testing following maintenance on June 26, 2024
Surveillance Testing (IP Section 03.01) (3 Samples)
- (1) Unit 2, train C emergency diesel generator engineered safety features actuation test for a loss offsite power on April 2, 2024
- (2) Unit 2, diesel 21 surveillance on May 3, 2024
- (3) Unit 1, train B low head safety injection pump in-service test on June 27, 2024
Inservice Testing (IST) (IP Section 03.01) (2 Samples)
- (1) Unit 2, train B low head safety injection comprehensive pump test on April 2, 2024
- (2) Unit 2, train B high head safety injection comprehensive pump test on April 2, 2024
Containment Isolation Valve (CIV) Testing (IP Section 03.01) (1 Sample)
- (1) Unit 2, local leak rate testing for M-55 residual heat removal pump 2B to reactor water storage tank on June 21, 2024
71114.06 - Drill Evaluation
Additional Drill and/or Training Evolution (1 Sample)
The inspectors evaluated:
- (1) Blue team tabletop on May 29, 2024
71114.08 - Exercise Evaluation - Scenario Review
Inspection Review (IP Section 02.01 - 02.04) (1 Sample)
- (1) The inspectors reviewed the licensee's preliminary exercise that was submitted to the NRC on May 15, 2024 (ML24136A286 and -287), for the exercise scheduled on July 17, 2024. The inspectors discussed the preliminary scenario comments with M. Hill, Manager, Emergency Preparedness, and other members of the emergency preparedness staff on June 12, 2024. The inspectors' review does not constitute NRC approval of the scenario.
RADIATION SAFETY
71124.01 - Radiological Hazard Assessment and Exposure Controls
Radiological Hazard Assessment (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated how the licensee identifies the magnitude and extent of radiation levels and the concentrations and quantities of radioactive materials and how the licensee assesses radiological hazards.
Instructions to Workers (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated how the licensee instructs workers on plant-related radiological hazards and the radiation protection requirements intended to protect workers from those hazards.
Contamination and Radioactive Material Control (IP Section 03.03) (2 Samples)
The inspectors observed/evaluated the following licensee processes for monitoring and controlling contamination and radioactive material:
- (1) Radiation workers exiting the Unit 2 radiological controlled area and use of the small article monitor for personal items.
- (2) Radiation protection technicians performing personnel and equipment screening surveys after exiting a contaminated area in the fuel handling building.
Radiological Hazards Control and Work Coverage (IP Section 03.04) (5 Samples)
The inspectors evaluated the licensee's control of radiological hazards for the following radiological work:
- (1) Radiation work permit (RWP) 24-2501, "Routine Maintenance and Plant Support,"
revision 0, task 2 in a high radiation area (HRA)
- (2) RWP 24-2502, "2RE23 - Radiation Protection Functions," revision 0, task 3 for radiation protection routines and support in locked high radiation areas (LHRA)
- (3) RWP 24-2510, "2RE23 - Maintenance and Support in Rm 001, 003, and 307,"
revision 0, task 3 for routine maintenance in LHRAs of reactor control building rooms 003 & 307
- (4) RWP 24-2520, "2RE23 - Refueling Activities," revision 0, task 22 for maintenance and support of refueling activities in HRAs
- (5) RWP 24-3531, "2RE23 - D Loop Cut Out and Replace," revision 0, task 1 for 'D' loop drainpipe replacement and associated activities in an HRA High Radiation Area and Very High Radiation Area Controls (IP Section 03.05) (5 Samples)
The inspectors evaluated licensee controls of the following HRAs and very high radiation areas:
- (2) Unit 2 RCB-011-001 under vessel very high radiation area
- (3) Unit 2 RCB-011-004 inside secondary shield wall HRA
- (4) Unit 2 FHB-030-103 very high radiation area during fuel transfer
- (5) Unit 2 RCB-037-307 regenerative heat exchanger LHRA Radiation Worker Performance and Radiation Protection Technician Proficiency (IP Section 03.06) (1 Sample)
- (1) The inspectors evaluated radiation worker and radiation protection technician performance as it pertains to radiation protection requirements.
71124.03 - In-Plant Airborne Radioactivity Control and Mitigation
Permanent Ventilation Systems (IP Section 03.01) (2 Samples)
The inspectors evaluated the configuration of the following permanently installed ventilation systems:
- (1) Unit 1 control room cleanup unit - train C (1-HE-VXV-003)
- (2) Unit 1 technical support center makeup air filtration (1-HE-VXV-001)
Temporary Ventilation Systems (IP Section 03.02) (2 Samples)
The inspectors evaluated the configuration of the following temporary ventilation systems:
- (1) Unit 2 D loop drain line pipe elbow cut out ventilation with spark arrestor
- (2) Unit 2 reactor vessel head temporary ventilation
Use of Respiratory Protection Devices (IP Section 03.03) (1 Sample)
- (1) The inspectors evaluated the licensees use of respiratory protection devices.
Self-Contained Breathing Apparatus for Emergency Use (IP Section 03.04) (1 Sample)
- (1) The inspectors evaluated the licensees use and maintenance of self-contained breathing apparatuses.
71124.08 - Radioactive Solid Waste Processing & Radioactive Material Handling, Storage, &
Transportation
Shipment Preparation (IP Section 03.04)
- (1) The inspectors observed the preparation of radioactive shipment STP-2-24-012 of one box containing reactor coolant pump motor air coolers on April 1,
OTHER ACTIVITIES - BASELINE
===71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:
MS05: Safety System Functional Failures (SSFFs) Sample (IP Section 02.04)===
- (1) Unit 1 (April 1, 2023, through March 31, 2024)
- (2) Unit 2 (April 1, 2023, through March 31, 2024)
BI01: Reactor Coolant System (RCS) Specific Activity Sample (IP Section 02.10) (2 Samples)
- (1) Unit 1 (April 1, 2023, through March 31, 2024)
- (2) Unit 2 (April 1, 2023, through March 31, 2024)
BI02: RCS Leak Rate Sample (IP Section 02.11) (2 Samples)
- (1) Unit 1 (April 1, 2023, through March 31, 2024)
- (2) Unit 2 (April 1, 2023, through March 31, 2024)
OR01: Occupational Exposure Control Effectiveness Sample (IP Section 02.15) (1 Sample)
- (1) January 1, 2023, through December 31, 2023 PR01: Radiological Effluent Technical Specifications/Offsite Dose Calculation Manual Radiological Effluent Occurrences (RETS/ODCM) Radiological Effluent Occurrences Sample (IP Section 02.16) (1 Sample)
- (1) January 1, 2023, through December 31, 2023
71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02)
- (1) The inspectors reviewed the licensees corrective action program to identify potential trends in nuclear fundamentals that might be indicative of a more significant safety issue.
71153 - Follow Up of Events and Notices of Enforcement Discretion Event Follow up (IP Section 03.01)
- (1) The inspectors evaluated the Unit 2 automatic reactor trip due to a partial loss of offsite power on May 12, 2024.
Event Report (IP Section 03.02) (1 Sample)
The inspectors evaluated the following licensees event reporting determination to ensure it complied with reporting requirements.
- (1) LER 05000498/2023-004-01, "Unit 1, Supplement to Condition Prohibited by Technical Specifications Due to Inoperable Train of Essential Chilled Water" (ADAMS Accession No. ML24116A317). The inspectors reviewed the updated LER submittal.
The previous LER submittal was reviewed in Inspection Report 05000498/2024001.
The inspection conclusions associated with this LER are documented in Inspection Report 05000498/2024001 under Inspection Results Section 71153 as NCV 05000498/2024001-02. This LER is Closed.
INSPECTION RESULTS
Improper entry into a high radiation area Cornerstone Significance Cross-Cutting Aspect Report Section Occupational Radiation Safety Green NCV 05000499/2024002-01 Open/Closed
[H.14] -
Conservative Bias 71124.01 The inspectors reviewed a self-revealed Green finding and associated non-cited violation of Technical Specification 6.8.1 for an improper entry into a Unit 2 high radiation area.
Specifically, a radiation worker was not authorized to enter the high radiation area and did not follow the radiation work permit instructions upon receiving a dose rate alarm.
Description:
On April 1, 2024, a radiation worker made an improper entry into a high radiation area (HRA) inside room 201A (bio shield) contrary to the radiation work permit (RWP) and associated task instructions.
A work group was assigned to locate a component on the bio shield 37-foot elevation. The work group consisted of a licensee radiation worker and a small group of contractors. The work group was briefed to enter containment and the bio shield under RWP 24-2501, 2RE23 - Routine Maintenance and Plant Support, task 2, which permitted or authorized entry into an HRA. However, after the work group received their radiological briefing, the radiation worker logged into the radiologically controlled area (RCA) under RWP 24-2501, 2RE23 - Routine Maintenance and Plant Support, task 1, which did not permit or authorize entry into an HRA. The worker had no intent of entering the HRA and informed them that he would wait outside the HRA for the contractors to confirm the component location.
After the contractors entered the HRA and after an undetermined amount of time with no feedback from the contractors locating the component, the radiation worker that signed onto task 1 of RWP 24-2501 entered the HRA to assist the contractors. While inside the HRA, the workers dosimeter went into a dose rate alarm and alarmed for 22 seconds. The worker did not promptly exit the RCA and did not report the dose rate alarm to radiation protection.
Radiation protection was notified of the dose rate alarm by an automated Sentinel system email. The exposure control section of RWP 24-2501, task 1, stated that if at any time the self-reading dosimeter should alarm on dose or an unanticipated dose rate alarm occurs, place work in a safe condition, leave the work area, and notify radiation protection.
Although the initial work brief failed to identify the need for all workers to be on task 2 for RWP 24-2501, the radiation worker did not adhere to the RWP and task instructions to not enter areas they were not authorized to enter, did not exit the RCA upon receipt of a dose rate alarm, and did not immediately report the dose rate alarm to radiation protection upon exit of the RCA.
Corrective Actions: The licensee initiated corrective actions to promptly restrict the radiation workers access to the RCA, investigated the event, performed a prompt human performance checklist, and issued a station communication reinforcing radiation protection worker expectations and procedure adherence, i.e. radiation work permit, radiological postings, and barriers.
Corrective Action References: The condition was entered into the licensees corrective action program as CR 24-3185.
Performance Assessment:
Performance Deficiency: An improper entry into an HRA is a performance deficiency.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Program & Process 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, improperly entering an HRA and failure to leave the area upon receiving a dose rate alarm led to the radiation worker receiving additional, unintended exposure to radiation.
Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix C, Occupational Radiation Safety SDP. The finding was determined to be of very low safety significance (Green) because the finding was not:
- (1) related to as low as is reasonably achievable (ALARA) planning,
- (2) did not involve an overexposure,
- (3) did not involve a substantial potential for overexposure, and
- (4) the ability to assess dose was not compromised.
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 radiation worker decided to go on a more restrictive RWP task but later decided that they needed to be in the HRA work area to assist the work group to locate a component. The radiation worker did not consider if their actions were safe in order to proceed rather than unsafe in order to stop.
Enforcement:
Violation: Technical Specification 6.8.1 stated written procedures shall be established, implemented, and maintained covering activities referenced in Regulatory Guide 1.33, appendix A, revision 2. Regulatory Guide 1.33, appendix A, section 7 e.
- (1) lists procedures for access control to radiation areas including a radiation work permit system.
Specifically, RWP 24-2501, 2RE23 - Routine Maintenance and Plant Support, revision 0, task 1, permitted access to high contamination areas and radiation areas; it did not permit access to HRAs. The RWPs exposure control section instructed that if at any time a worker received an unanticipated dose rate alarm, place work in a safe condition, leave the work area, and notify radiation protection.
Contrary to the above, on April 1, 2024, a radiation worker failed to follow their assigned RWP requirements when they entered a bio shield HRA, received an unanticipated dose rate alarm, did not promptly leave the work area, nor notify radiation protection of the dose rate alarm. Specifically, RWP 24-2501, task 1, restricted access to only radiation areas and stated that if the worker received a dose rate alarm, the worker was required to place their work in a safe condition, leave the work area, and notify radiation protection.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Observation: Semi-Annual Trend Review - Radiation Protection and Foreign Material Exclusion 71152S The inspectors reviewed the licensees corrective action program, performance indicators, condition reports (CRs), and other documentation available to help identify performance trends that might indicate the existence of a more significant safety issue. The inspectors verified that the licensee was taking corrective actions to address the identified adverse trends. The inspectors did not review any cross-cutting themes because none existed at the site. The inspectors noted negative trends in nuclear fundamentals that resulted in human performance errors. The most salient trends were in the areas of radiation protection and foreign material exclusion (FME)/dropped objects which were most evidenced during the Unit 2 refueling outage, which occurred between March 22, and May 19, 2024.
The lists below showcase selected examples of events that illustrate the error trends.
Radiation Protection:
- CR 2024-3173: individual left their self-reading dosimeter in the dress out area and proceeded into the Reactor Containment Building work location
- CR 2024-3183: individual ran their self-reading dosimeter through the east gatehouse X-Ray machine
- CR 2024-3185: individual exited Unit 2 radiologically controlled area with a Rate Alarm of 32 millirem per hour on a set point of 25 millirem per hour
- CR 2024-3246: employee exited the Unit 2 radiologically controlled area via the emergency exit bypass door. Door is posted Radiological Controlled Area Boundary - Emergency Exit Only
- CR 2024-3407: a security officer inadvertently crossed the radiological boundary on the ground level of the equipment hatch
- CR 2024-3655: individual bypassed the high rad gate Foreign material exclusion/dropped objects:
- CR 2024-2795: during the refueling outage seismic restraint removal activity, a pair of channel-lock pliers were dropped into the cavity
- CR 2024-3086: dropped 3/8" hex nut on the east end of the main generator
- CR 2024-3258: while loosening the main generator turbine end rotor support, two associated brass shims (taped together), fell into the 10 oil drain line
- CR 2024-3395: a Siemens wrench (60MM) dropped from the HP enclosure valve work to a scaffold located on the TGB 55. The dropped wrench was not reported
- CR 2024-3565: Hex key (Allen wrench) was not identified to be stuck in tool prior to bringing into FME zone. Item was dislodged while in cavity.
- CR 2024-3753: during tightening of bore ring hardware in Unit 2 main generator, a 3/8" bolt from the zone 1 (turbine end) access panel was dropped
- CR 2024-3775: dropped dust cap into cavity. It did not have an aircraft cable lanyard attached. Item was retrieved
- CR 2024-4088: FME coordinator identified two hand tools without lanyards and not logged inside a FME zone 1 The licensee corrected each of the conditions at the time of discovery and is implementing additional actions to prevent further issues. These include a set of randomized questions to be required to be answered correctly in order to grant access to the radiologically controlled area, new gate control readers in the dress out area exit to ensure personnel dont forget their self-reading dosimeters, and additional management field presence checking for proper behaviors. More coaching on FME practices and more field observations are expected to raise performance during the next outage scheduled for October
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On April 5, 2024, the inspectors presented the occupational radiation safety inspection results to Rachel Jackson, Vice President of General Counsel, and other members of the licensee staff.
- On May 16, 2024, the inspectors presented the exit meeting for Unit 2 in-service inspection results to Kimberly A. Harshaw, Acting President, Chief Executive Officer and Chief Nuclear Officer and other members of the licensee staff.
- On June 12, 2024, the inspectors presented the emergency preparedness exercise scenario inspection results to Marc Hill, Manager, Emergency Preparedness and other members of the licensee staff.
- On July 11, 2024, the inspectors presented the integrated inspection results to Kimberly A. Harshaw, Acting President, Chief Executive Officer and Chief Nuclear Officer, and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Corrective Action
Documents
CR-YYYY-NNNN
23-7558, 2022-9710, 2024-4314, 2024-5715
5Q159MB1023
Standby Diesel Generator System
Miscellaneous
5R289MB01006
Essential Cooling Water System
0001
Essential Cooling Water Operations
Procedures
PHG-002
Summer Peak Period Readiness
5R289F05038#1
Piping and Instrument Diagram Essential Cooling Water
System Train 1A
Drawings
5S142F00024
Piping and Instrument Diagram Auxiliary Feedwater
0001
Essential Cooling Water Operations
Procedures
Spent Fuel Pool Cooling and Cleanup System
Corrective Action
Documents
CR-YYYY-NNNN
24-4477
Fire Preplan Electrical Auxiliary Building Cable
Spreading/Power Cabling Area, Train B
Fire Plans
Fire Pump House
Miscellaneous
Training logs
Fire brigade member qualification logs
Fire Pre-plan Electrical Auxiliaries Building ESF Switchgear
Room Train A
Fire Preplan Electrical Auxiliaries Building, Auxiliary
Shutdown Area
Fire Preplan Fuel Handling Building Train C SI/CSS Cubicle
STPEGS Fire Brigade
Procedures
Control of Transient Fire Loads and Use of Combustible and
Flammable Liquids and Gases
Procedures
Natural or Destructive Phenomena Guidelines
Corrective Action
Documents
CR-YYYY-NNNN
21-10813, 2022-10588, 2024-2324, 2024-2899,24-722, 2024-711, 2023-3109, 2023-3295, 2023-10544,
23-10207, 2023-9490, 2023-8816, 2023-8798,
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
23-8789, 2023-8033, 2023-4758, 2023-4753, 2023-4533,
23-4469, 2023-3065, 2023-3058, 2022-9731, 2023-3273,
23-2869, 2023-1894, 2024-2324, 2024-2243, 2024-683,24-563, 2024-412, 2023-11198, 2023-10723,
23-10699, 2023-738, 2022-12188, 2022-11809,
22-10516, 2023-10451, 2023-6608, 2023-5683,
23-3363, 2022-12178
Corrective Action
Documents
Resulting from
Inspection
CR-YYYY-NNNN
24-3232, 2024-3241, 2024-3309
010 5-01 0
251WNA
Replacement Reactor Vessel Head Project Closure Head
and Nozzle Assembly
0105-
0100241WNA
Replacement Reactor Vessel Head Project Closure Head
Outline Drawing
0105-
0100248WNA
Replacement Reactor Vessel Head Project Closure Head
Penetration Position
0105-
0100249WNA
Replacement Reactor Vessel Head Project Closure Head
Penetration Position
Top Head Insulation
Drawings
Top Head Insulation
South Texas Project Units 1 and 2 Periodic Update of Code
Case N-716-1 Application
NOC-AE-
19003684
South Texas Project Unit 1 and 2, Docket No. STN 50-498
and STN 50-499 Proposed Alternative to ASME Boiler &
Pressure Vessel Code Section Xl Requirements for
Repair/Replacement of Essential Cooling Water (ECW)
System Class 3 Buried Piping in accordance with 10 CFR 50.55a(z)(1) (Relief Request RR-ENG-3-24)
09/26/2016
NSD-ENG-EP-
345
Procedure for Installing the "Canopy-Less" Core Exit
Thermocouple Nozzle Assembly (CETNA)
SG-CDMP-19-21
South Texas 1RE22 Steam Generator Degradation
Assessment
Miscellaneous
SG-CDMP-22-16
South Texas 2RE22 Steam Generator Degradation
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Assessment
SG-CDMP-22-23
South Texas Unit 2 Steam Generator Condition Monitoring
for Cycle 22 and Final Operational Assessment for Cycles
23, 24, 25, 26, and 27
UTI # 065
thermal fatigue: pipe to elbow 2-RC-2418-BBl WELD 3
UTI # PDI-UT-2
thermal fatigue-pipe to elbow, 8-RH-1106-KB2 WELD 5&6
VTC-2O23-OL2
reactor coolant pressurizer base PRB1
VTIWE-2022-003
containment liner (240-360 DEG) /CC-LINER-MB-1
NDE Reports
VTIWE-2022-014
containment liner (335-340 DEG) /CC-LINER-MB-1
0PEP10ZA0010
0PEP10ZA0017
Magnetic Particle
0PEP10ZA0023
Visual Component Supports
0PEP10ZA0024
VT1 and VT3
Chemical Control Program
ASME Section XI Repair/Replacement Activities
RCS Pressure Boundary Inspection for Boric Acid Leaks
Boric Acid Corrosion Control Program
Control of Transient Fire Loads and Use of Combustible and
Flammable Liquids and Gases
Station Self-Assessment Program
0001
General Welding Requirements
0001A
ASME Repair/Replacement Welding Requirements
0001B
ASME/ANSI B31.1 Welding Requirements
0001C
AWS/HVAC Welding Requirements
0001D
Welding Documentation Requirements
Procedures
0002
Welding Procedure Specification Preparation and
Qualification
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
0003
Welder Qualification and Certification
0004
Control of Filler Materials
0005
Control of Post Weld Heat Treatment
0006
Arc Wire Thermal Spray Coatings
0018A
Non-Rapid Refueling Mechanical Support
0001
Essential Cooling Water Operations
TR 1025145
Boric Acid Corrosion Guidebook
Procedures
Reactor Startup
Corrective Action
Documents
CR-YYYY-NNNN
23-7146, 2023-10344, 2024-522, 2024-1738, 2024-1682,
21-4865
OQAP
Operational Quality Assurance Plan
Miscellaneous
Purchase Orders
160608, 219683, 168246
Procedures
Procurement of Material
Work Orders
Work
Authorization
Number
2617, 563866
Corrective Action
Documents
CR-YYYY-NNNN
24-4882, 2024-4076
Drawings
00000E0AAAA
Single Line Diagram Main One Line Diagram Unit No. 1 &2
Probabilistic Risk Assessment Risk Ranking
Protected Components
Risk Management Actions (RMAs)
AC Electrical Distribution Breaker Lineup
Transformer Normal Breaker and Switch Lineup
Plant Cooldown
Procedures
00A1
Motor Control Center E1A1(E2A1) Bus Outage
Calculations
PC5001
Piping Minimum Wall Thickness Calculation Essential
05/09/1989
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Colling Water
THX-EW071-TM-
CX-000001
South Texas Project Unit 2 (THX) Heated Junction
Thermocouple (HJTC) Probe - Justification for Continued
Operation with Tube Degradation
Corrective Action
Documents
CR-YYYY-NNNN
24-3077, 2022-10618, 2019-12309, 2021-3505,
21-4916, 2024-1738, 2024-1682,2024-1891,24-522, 2020-760, 2024-3909, 2024-3851
Drawings
5N129F05013#2
Piping and Instrumentation Diagram Safety Injection System
Essential Chiller Operation
High Head Safety Injection Pump Flow Rate Measurement
Standby Diesel Generator 6 Year Inspection
Procedures
Standby Diesel Generator 6 Year Electrical Inspection
Work Orders
Work
Authorization
Number
563866, 635587, 576371, 578263, 672913, 676278,
677659, 679959, 706587
Reactor Startup
Plant Startup to 100%
24
Plant Cooldown
Procedures
Core Refueling
Corrective Action
Documents
CR-YYYY-NNNN
24-3751
Miscellaneous
Plant Operations
Logs
Temporary Log sheet ESF DG 23 Lube oil filter D/P
04/18/2024
Initial Criticality and Low Power Physics Testing using
RhoPRO
Standby Diesel 12(23) LOOP - ESF Actuation Test
Low Head Safety Injection Pump 1B(2B) Inservice Test
ECCS Valve Checklist
High Head Safety Injection Pump Flow Rate Measurement
Low Head Safety Injection Pump 1B(2B) Comprehensive
Pump Test
High Head Safety Injection Pump 1B(2B) Comprehensive
Pump Test
Procedures
Train R Reactor Trip Breaker TADOT
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
0006R
Automatic Multiple Rod Drop Time Measurement
Personnel Airlock Pneumatic Seal System Pressure Drop
Test
Local Leak Rate Test Calculations, Guidelines, and Program
Work Orders
Work
Authorization
Number
668861, 655480, 668863, 665481, 622115, 667327,
669255, 685271, 685272, 669704, 685302, 685303,
685304, 685305, 685306, 685307, 685308, 651053,
651525, 702949, 654071, 654058
NOC-AE-
2003893
South Texas Project Units 1 and 2; Docket Nos. STN 50-
498; STN 50-499; 2022 NRC/FEMA Evaluated Exercise
Scenario Manual
5/18/2022
Miscellaneous
NOC-AE-
24004041
South Texas Project, Units 1 and 2; Dockets Nos. STN 50-
498, STN 50-499; 2024 NRC/FEMA Evaluated Exercise
Scenario Manual
5/15/2024
Emergency Notifications
South Texas Project Electric Generating Station (STPEGS)
Emergency Action Level Technical Bases Manual
Procedures
Protective Action Recommendation (PAR) Strategies
11/19/2021
ALARA Plans
24-1432-9
2RE23 D loop drain cutout
03/27/2024
Corrective Action
Documents
CR-YYYY-NNNN
23-2558, 2023-2798, 2023-2906, 2023-3045, 2023-3335,
23-3343, 2023-3447, 2023-3571, 2023-3580, 2023-3736,
23-3774, 2023-3896, 2023-3952, 2023-4452, 2023-5482,
23-5506, 2023-5685, 2023-6667, 2023-7058, 2023-7286,
23-7508, 2023-9212, 2023-9308, 2023-9539, 2023-9814,
23-10368, 2024-836, 2024-928, 2024-1465, 2024-2028,
24-2450, 2024-2731, 2024-2768, 2024-2877, 2024-2992,
24-3173
Spent Fuel Pool Storage and Work
Radiological Access Controls/Standards
Radioactive Material Control Program
Job Coverage
Radiation and Contamination Surveys
Procedures
Radiological Postings and Labeling
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Radiological Air Sampling
0016A
Radiological Air Sampling at STP
Access Controls for High Radiation Areas
Access Controls for High Radiation Areas
Radiation Work Permits/Radiological Work ALARA Reviews
Radiological Risk Management
Maintenance of HEPA Vacuum Cleaners and Portable
Ventilation Units
Control of HEPA Vacuum Cleaners and Portable Ventilation
Units
Transuranics Analysis
28108
Inside secondary shield wall (2-RCB+019-201)
03/29/2024
28286
'D' cross over leg (2-RCB+019-201)
04/03/2024
AS 25909
Air Sample: Routine - Room 207 (2-RCB+019)
03/24/2024
AS 25944
Air Sample: Job Coverage - top of reactor head
03/26/2024
Radiation
Surveys
AS 25953
Air Sample: Back up sample - reactor head
03/26/2024
23 Radiation Protection Formal Self-Assessment Findings
Report
10/25/2023
Self-Assessments
Formal HP Program Self-Assessment 2024
2/08/2024
Corrective Action
Documents
CR-YYYY-NNNN
22-10532, 2023-573, 2023-2619, 2023-5288, 2023-7709,
23-9705, 2024-40, 2024-938, 2024-2717, 2024-2862,
24-2920, 2024-2921
Corrective Action
Documents
Resulting from
Inspection
CR-YYYY-NNNN
24-3296, 2024-3298
List of respirators for emergency use at STP by location,
quantity, and size.
230221017-00
TRI Air Testing Laboratory Report for IA11 - Unit 1
instrument air compressor #11
2/22/2023
230223006-00
TRI Air Testing Laboratory Report for IA12 - Unit 1
instrument air compressor #12
2/24/2023
Miscellaneous
230223116-00
TRI Air Testing Laboratory Report for IA13 - Unit 1
2/24/2023
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
instrument air compressor #13
230228133-00
TRI Air Testing Laboratory Report for IA14 - Unit 1
instrument air compressor #14
03/01/2023
230309068-00
TRI Air Testing Laboratory Report for U1BA - Unit 1
breathing air compressor
03/10/2023
230316018-00
TRI Air Testing Laboratory Report for Atlas Copco PTS 1600
mobile air compressor
03/17/2023
231106078-00
TRI Air Testing Laboratory Report for IA11 - Unit 1
instrument air compressor Sullair 375HH 375CFM-17 mobile
compressor
11/07/2023
MAB, TSC and RCB HVAC In-Place HEPA Filter Leak Test
Respiratory Protection Program
Non-Technical Specification Monitor Set Points
Maintenance, Inspection, and Storage of Respiratory
Protection Equipment
Procedures
Air Quality Evaluation for Compressors or Pressurized Gas
Cylinders
Self-Assessments CR-24-40
Formal HP Program Self-Assessment 2024
2/08/2024
Shipping Records
STP-2-24-012
Shipment of radioactive material, excepted package-limited
quantity of material, 7,
reactor coolant pump moto air coolers
04/01/2024
23
Annual Environmental Operating Report
April 2024
Miscellaneous
24
Radioactive Effluent Release Report - Draft
April 2024
71151
Procedures
AD-0008
Collection of NRC Performance Indicator Data - Public
Radiation Safety Cornerstone
5