IR 05000498/2024002

Integrated Inspection Report 05000498/2024002 and 05000499/2024002

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: NPF-76 and NPF-80

Report Numbers: 05000498/2024002 and 05000499/2024002

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

Enclosure

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 Report Aspect Section Occupational Green [H.14] - 71124.01 Radiation Safety NCV 05000499/2024002-01 Conservative Open/Closed Bias 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 71153 Closed Technical Specifications Due to Inoperable Train of Essential Chilled Water

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.

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

• Essential cooling water, ECW pump IC discharge vent line 3" EW-1400-WT3 weld

• 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

• Weld process, gas tungsten arc weld o 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

• 22-11809, 8T242TLW0517, Open Loop Seal Water Header Blowdown Valve

• 22-12188, Flange for level indicator LI-0108 located downstream of valve CV-0315

• 23-3058, CVCS Alternate Charging to RCS loop 1C cold Leg MOV 1-CV-0006 valve stem

• 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

• 23-10207, 2-CV-FCV-0111B CVCS blended flow to VCT flow control valve

• 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.

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:

(1) Unit 2 RCB-002-003 incore instrument (TIP) room 003 LHRA

(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 Report Aspect Section Occupational Green [H.14] - 71124.01 Radiation Safety NCV 05000499/2024002-01 Conservative Open/Closed Bias 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 71152S Material Exclusion 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 Type Designation Description or Title Revision or

Procedure Date

71111.01 Corrective Action CR-YYYY-NNNN 2023-7558, 2022-9710, 2024-4314, 2024-5715

Documents

Miscellaneous 5Q159MB1023 Standby Diesel Generator System 4

5R289MB01006 Essential Cooling Water System 9

Procedures 0POP02-EW-Essential Cooling Water Operations 87

0001

PHG-002 Summer Peak Period Readiness 1

71111.04 Drawings 5R289F05038#1 Piping and Instrument Diagram Essential Cooling Water 21

System Train 1A

5S142F00024 Piping and Instrument Diagram Auxiliary Feedwater 13

Procedures 0POP02-AF-0001 Auxiliary Feedwater 60

0POP02-EW-Essential Cooling Water Operations 87

0001

0POP02-FC-0001 Spent Fuel Pool Cooling and Cleanup System 99

71111.05 Corrective Action CR-YYYY-NNNN 2024-4477

Documents

Fire Plans 0EAB31-FP-0047 Fire Preplan Electrical Auxiliary Building Cable 7

Spreading/Power Cabling Area, Train B

0FPH59-FP-0080 Fire Pump House 2

Miscellaneous Training logs Fire brigade member qualification logs

Procedures 0EAB02-FP-0004 Fire Pre-plan Electrical Auxiliaries Building ESF Switchgear 4

Room Train A

0EAB07-FP-0071 Fire Preplan Electrical Auxiliaries Building, Auxiliary 4

Shutdown Area

0FHB35-FP-0305 Fire Preplan Fuel Handling Building Train C SI/CSS Cubicle3

0PGP03-ZF-0011 STPEGS Fire Brigade 20

0PGP03-ZF-0019 Control of Transient Fire Loads and Use of Combustible and 20

Flammable Liquids and Gases

71111.06 Procedures 0POP04-ZO-0002 Natural or Destructive Phenomena Guidelines 62

71111.08P Corrective Action CR-YYYY-NNNN 2021-10813, 2022-10588, 2024-2324, 2024-2899,

Documents 2024-722, 2024-711, 2023-3109, 2023-3295, 2023-10544,

23-10207, 2023-9490, 2023-8816, 2023-8798,

Inspection Type Designation Description or Title Revision or

Procedure 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 CR-YYYY-NNNN 2024-3232, 2024-3241, 2024-3309

Documents

Resulting from

Inspection

Drawings 010 5-01 0 Replacement Reactor Vessel Head Project Closure Head 2

251WNA and Nozzle Assembly

0105-Replacement Reactor Vessel Head Project Closure Head 2

0100241WNA Outline Drawing

0105-Replacement Reactor Vessel Head Project Closure Head 2

0100248WNA Penetration Position

0105-Replacement Reactor Vessel Head Project Closure Head 1

0100249WNA Penetration Position

RT-49924-RTH Top Head Insulation 8

RT-49926-RTH Top Head Insulation 2

Miscellaneous South Texas Project Units 1 and 2 Periodic Update of Code 0

Case N-716-1 Application

NOC-AE-South Texas Project Unit 1 and 2, Docket No. STN 50-498 09/26/2016

19003684 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)

NSD-ENG-EP-Procedure for Installing the "Canopy-Less" Core Exit 8

345 Thermocouple Nozzle Assembly (CETNA)

SG-CDMP-19-21 South Texas 1RE22 Steam Generator Degradation 0

Assessment

SG-CDMP-22-16 South Texas 2RE22 Steam Generator Degradation 1

Inspection Type Designation Description or Title Revision or

Procedure Date

Assessment

SG-CDMP-22-23 South Texas Unit 2 Steam Generator Condition Monitoring 1

for Cycle 22 and Final Operational Assessment for Cycles

23, 24, 25, 26, and 27

NDE Reports UTI # 065 thermal fatigue: pipe to elbow 2-RC-2418-BBl WELD 3 0

UTI # PDI-UT-2 thermal fatigue-pipe to elbow, 8-RH-1106-KB2 WELD 5&6 1

VTC-2O23-OL2 reactor coolant pressurizer base PRB1 0

VTIWE-2022-003 containment liner (240-360 DEG) /CC-LINER-MB-1 0

VTIWE-2022-014 containment liner (335-340 DEG) /CC-LINER-MB-1 0

Procedures 0PEP10ZA0010 Liquid Penetrant 9

0PEP10ZA0017 Magnetic Particle 7

0PEP10ZA0023 Visual Component Supports 8

0PEP10ZA0024 VT1 and VT3 6

0PGP03-ZA-0141 Chemical Control Program 6

0PGP03-ZE-0027 ASME Section XI Repair/Replacement Activities 32

0PGP03-ZE-0033 RCS Pressure Boundary Inspection for Boric Acid Leaks 14

0PGP03-ZE-0133 Boric Acid Corrosion Control Program 13

0PGP03-ZF-0019 Control of Transient Fire Loads and Use of Combustible and 20

Flammable Liquids and Gases

0PGP03-ZX-0003 Station Self-Assessment Program 15

0PMP02-ZW-General Welding Requirements 12

0001

0PMP02-ZW-ASME Repair/Replacement Welding Requirements 3

0001A

0PMP02-ZW-ASME/ANSI B31.1 Welding Requirements 2

0001B

0PMP02-ZW-AWS/HVAC Welding Requirements 1

0001C

0PMP02-ZW-Welding Documentation Requirements 2

0001D

0PMP02-ZW-Welding Procedure Specification Preparation and 8

0002 Qualification

Inspection Type Designation Description or Title Revision or

Procedure Date

0PMP02-ZW-Welder Qualification and Certification 12

0003

0PMP02-ZW-Control of Filler Materials 20

0004

0PMP02-ZW-Control of Post Weld Heat Treatment 6

0005

0PMP02-ZW-Arc Wire Thermal Spray Coatings 2

0006

0PMP04-RX-Non-Rapid Refueling Mechanical Support 26

0018A

0POP02-EW-Essential Cooling Water Operations 86

0001

TR 1025145 Boric Acid Corrosion Guidebook 2

71111.11Q Procedures 0POP03-ZG-0004 Reactor Startup 52

71111.12 Corrective Action CR-YYYY-NNNN 2023-7146, 2023-10344, 2024-522, 2024-1738, 2024-1682,

Documents 2021-4865

Miscellaneous OQAP Operational Quality Assurance Plan 26

Purchase Orders 160608, 219683, 168246

Procedures 0PGP03-ZP-0011 Procurement of Material 30

Work Orders Work 622617, 563866

Authorization

Number

71111.13 Corrective Action CR-YYYY-NNNN 2024-4882, 2024-4076

Documents

Drawings 00000E0AAAA Single Line Diagram Main One Line Diagram Unit No. 1 &2 30

Procedures 0PGP01-ZA-0304 Probabilistic Risk Assessment Risk Ranking 12

0PGP03-ZO-0055 Protected Components 18

0POP01-ZO-0006 Risk Management Actions (RMAs) 28

0POP02-AE-0001 AC Electrical Distribution Breaker Lineup 36

0POP02-AE-0002 Transformer Normal Breaker and Switch Lineup 79

0POP03-ZG-0007 Plant Cooldown 99

0POP06-PM-Motor Control Center E1A1(E2A1) Bus Outage 11

00A1

71111.15 Calculations PC5001 Piping Minimum Wall Thickness Calculation Essential 05/09/1989

Inspection Type Designation Description or Title Revision or

Procedure Date

Colling Water

THX-EW071-TM-South Texas Project Unit 2 (THX) Heated Junction 0

CX-000001 Thermocouple (HJTC) Probe - Justification for Continued

Operation with Tube Degradation

Corrective Action CR-YYYY-NNNN 2024-3077, 2022-10618, 2019-12309, 2021-3505,

Documents 2021-4916, 2024-1738, 2024-1682,2024-1891,24-522, 2020-760, 2024-3909, 2024-3851

Drawings 5N129F05013#2 Piping and Instrumentation Diagram Safety Injection System35

Procedures 0POP02-CH-0005 Essential Chiller Operation 79

0PSP03-SI-0026 High Head Safety Injection Pump Flow Rate Measurement 5

0PSP04-DG-0002 Standby Diesel Generator 6 Year Inspection 29

0PSP06-DG-0006 Standby Diesel Generator 6 Year Electrical Inspection 17

Work Orders Work 563866, 635587, 576371, 578263, 672913, 676278,

Authorization 677659, 679959, 706587

Number

71111.20 Procedures 0POP03-ZG-0004 Reactor Startup 52

0POP03-ZG-0005 Plant Startup to 100% 124

0POP03-ZG-0007 Plant Cooldown 99

0POP08-FH-0009 Core Refueling 55

71111.24 Corrective Action CR-YYYY-NNNN 2024-3751

Documents

Miscellaneous Plant Operations Temporary Log sheet ESF DG 23 Lube oil filter D/P 04/18/2024

Logs

Procedures 0PEP02-ZX-0022 Initial Criticality and Low Power Physics Testing using 5

RhoPRO

0PSP03-DG-0015 Standby Diesel 12(23) LOOP - ESF Actuation Test 49

0PSP03-SI-0002 Low Head Safety Injection Pump 1B(2B) Inservice Test 19

0PSP03-SI-0014 ECCS Valve Checklist 22

0PSP03-SI-0026 High Head Safety Injection Pump Flow Rate Measurement 5

0PSP03-SI-0040 Low Head Safety Injection Pump 1B(2B) Comprehensive 10

Pump Test

0PSP03-SI-0043 High Head Safety Injection Pump 1B(2B) Comprehensive 12

Pump Test

0PSP03-SP-Train R Reactor Trip Breaker TADOT 37

Inspection Type Designation Description or Title Revision or

Procedure Date

0006R

0PSP10-DM-0003 Automatic Multiple Rod Drop Time Measurement 30

0PSP11-XC-0009 Personnel Airlock Pneumatic Seal System Pressure Drop 20

Test

0PSP11-ZA-0005 Local Leak Rate Test Calculations, Guidelines, and Program21

Work Orders Work 668861, 655480, 668863, 665481, 622115, 667327,

Authorization 669255, 685271, 685272, 669704, 685302, 685303,

Number 685304, 685305, 685306, 685307, 685308, 651053,

651525, 702949, 654071, 654058

71114.08 Miscellaneous NOC-AE-South Texas Project Units 1 and 2; Docket Nos. STN 50- 5/18/2022

2003893 498; STN 50-499; 2022 NRC/FEMA Evaluated Exercise

Scenario Manual

NOC-AE-South Texas Project, Units 1 and 2; Dockets Nos. STN 50- 5/15/2024

24004041 498, STN 50-499; 2024 NRC/FEMA Evaluated Exercise

Scenario Manual

Procedures 0EPR01-IP-0002 Emergency Notifications 1

EP-0003.000 South Texas Project Electric Generating Station (STPEGS) 0

Emergency Action Level Technical Bases Manual

EP-0005.000 Protective Action Recommendation (PAR) Strategies 11/19/2021

71124.01 ALARA Plans 24-1432-9 2RE23 D loop drain cutout 03/27/2024

Corrective Action CR-YYYY-NNNN 2023-2558, 2023-2798, 2023-2906, 2023-3045, 2023-3335,

Documents 2023-3343, 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

Procedures 0PEP02-ZM-0009 Spent Fuel Pool Storage and Work 10

0PGP03-ZR-0051 Radiological Access Controls/Standards 49

0PGP03-ZR-0053 Radioactive Material Control Program 21

0PRP01-ZA-0042 Job Coverage 3

0PRP04-ZR-0013 Radiation and Contamination Surveys 44

0PRP04-ZR-0015 Radiological Postings and Labeling 42

Inspection Type Designation Description or Title Revision or

Procedure Date

0PRP04-ZR-0016 Radiological Air Sampling 37

0PRP04-ZR-Radiological Air Sampling at STP 0

0016A

0PRP04-ZR-0019 Access Controls for High Radiation Areas 4

0PRP04-ZR-0019 Access Controls for High Radiation Areas 5

0PRP07-ZR-0010 Radiation Work Permits/Radiological Work ALARA Reviews 41

0PRP07-ZR-0034 Radiological Risk Management 7

0PRP08-ZR-0014 Maintenance of HEPA Vacuum Cleaners and Portable 27

Ventilation Units

0PRP08-ZR-0022 Control of HEPA Vacuum Cleaners and Portable Ventilation 4

Units

0PRP10-ZL-0032 Transuranics Analysis 2

Radiation 128108 Inside secondary shield wall (2-RCB+019-201) 03/29/2024

Surveys 128286 '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

AS 25953 Air Sample: Back up sample - reactor head 03/26/2024

Self-Assessments 2023 Radiation Protection Formal Self-Assessment Findings 10/25/2023

Report

Formal HP Program Self-Assessment 2024 02/08/2024

71124.03 Corrective Action CR-YYYY-NNNN 2022-10532, 2023-573, 2023-2619, 2023-5288, 2023-7709,

Documents 2023-9705, 2024-40, 2024-938, 2024-2717, 2024-2862,

24-2920, 2024-2921

Corrective Action CR-YYYY-NNNN 2024-3296, 2024-3298

Documents

Resulting from

Inspection

Miscellaneous List of respirators for emergency use at STP by location,

quantity, and size.

230221017-00 TRI Air Testing Laboratory Report for IA11 - Unit 1 02/22/2023

instrument air compressor #11

230223006-00 TRI Air Testing Laboratory Report for IA12 - Unit 1 02/24/2023

instrument air compressor #12

230223116-00 TRI Air Testing Laboratory Report for IA13 - Unit 1 02/24/2023

Inspection Type Designation Description or Title Revision or

Procedure Date

instrument air compressor #13

230228133-00 TRI Air Testing Laboratory Report for IA14 - Unit 1 03/01/2023

instrument air compressor #14

230309068-00 TRI Air Testing Laboratory Report for U1BA - Unit 1 03/10/2023

breathing air compressor

230316018-00 TRI Air Testing Laboratory Report for Atlas Copco PTS 1600 03/17/2023

mobile air compressor

231106078-00 TRI Air Testing Laboratory Report for IA11 - Unit 1 11/07/2023

instrument air compressor Sullair 375HH 375CFM-17 mobile

compressor

Procedures 0PEP05-ZH-0008 MAB, TSC and RCB HVAC In-Place HEPA Filter Leak Test 9

0PGP03-ZR-0054 Respiratory Protection Program 23

0PRP05-RA-0025 Non-Technical Specification Monitor Set Points 9

0PRP06-ZR-0005 Maintenance, Inspection, and Storage of Respiratory 21

Protection Equipment

0PRP06-ZR-0008 Air Quality Evaluation for Compressors or Pressurized Gas 6

Cylinders

Self-Assessments CR-24-40 Formal HP Program Self-Assessment 2024 02/08/2024

71124.08 Shipping Records STP-2-24-012 Shipment of radioactive material, excepted package-limited 04/01/2024

quantity of material, 7,

reactor coolant pump moto air coolers

71151 Miscellaneous 2023 Annual Environmental Operating Report April 2024

24 Radioactive Effluent Release Report - Draft April 2024

Procedures AD-0008 Collection of NRC Performance Indicator Data - Public 5

Radiation Safety Cornerstone

23