IR 05000498/2024012
| ML24326A153 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 11/25/2024 |
| From: | Greg Warnick NRC/RGN-IV/DORS/EB2 |
| To: | Harshaw K South Texas |
| References | |
| EPID I-2024-012-0004 IR 2024012 | |
| Download: ML24326A153 (1) | |
Text
November 25, 2024
SUBJECT:
SOUTH TEXAS PROJECT, UNIT 1 - LICENSE RENEWAL PHASE 1 INSPECTION REPORT 05000498/2024012
Dear Kimberly A. Harshaw:
On October 31, 2024, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at South Texas Project, Unit 1 and 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.
No findings or violations of more than minor significance were identified during this inspection.
This letter, its enclosure, and your response (if any) will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with Title 10 of the Code of Federal Regulations 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely, Gregory G. Warnick, Chief Engineering Branch 2 Division of Operating Reactor Safety Docket No. 05000498 License No. NPF-76
Enclosure:
As stated
Inspection Report
Docket No:
05000498
License No:
Report No:
Enterprise Identifier:
I-2024-012-0004
Licensee:
STP Nuclear Operating Company
Facility:
South Texas Project, Unit 1
Location:
Wadsworth, TX
Inspection Dates:
October 27 - 31, 2024
Inspectors:
G. Pick, Senior Reactor Inspector
C. Smith, Senior Reactor Inspector
Approved By:
Gregory G. Warnick, Chief
Engineering Branch 2
Division of Operating Reactor Safety
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting a license renewal phase 1 inspection at South Texas Project, Unit 1, 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
No findings or violations of more than minor significance were identified.
Additional Tracking Items
None.
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 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.
OTHER ACTIVITIES
- TEMPORARY INSTRUCTIONS, INFREQUENT AND ABNORMAL
===71003 - Post-Approval Site Inspection for License Renewal The inspectors evaluated the material condition of South Texas Project, Unit 1, in October 2024 while the plant was shut down for a scheduled refueling outage. This allowed the inspectors to evaluate the material condition of inaccessible areas prior to entry into the period of extended operation and to evaluate licensee implementation of aging management activities. The period of extended operation is the additional 20 years beyond the original 40-year licensed term and begins after midnight on August 20, 2027.
In addition, the inspectors evaluated whether the licensee:
- (1) completed the necessary actions to comply with the license condition and commitments related to aging management; and (2)implemented programs that agreed with those approved in the safety evaluation report and described in the updated final safety analysis report. NRC issued the safety evaluation report, Safety Evaluation Report Related to the License Renewal of South Texas Project, Units 1 and 2 [ADAMS No. ML17146B242] in June 2017. Specific activities evaluated during this inspection are described in the following paragraphs.
The inspectors walked down normally inaccessible areas of the facility looking at the structures, systems, and components for signs of aging, such as corrosion on piping and supports, corrosion of cable trays, water intrusion, cracking, and spalling of concrete.
Post-Approval Site Inspection for License Renewal===
- (1) Plant Condition Monitoring Walkdowns Specific structures, systems, and components walked down and evaluated during this inspection included:
- reactor containment building - multiple elevations
- containment liner
- reactor cool pump oil collection tanks
- reactor containment fan cooling units
- reactor containment tendon gallery
- component cooling water heat exchanger rooms
- component cooling water pump and chiller rooms
- turbine generator building switchgear room
- positive displacement pump room
- diesel cleanup polisher skid
- fire pump house
- standby diesel generator 1-1
- masonry walls in auxiliary and turbine generator building During the walk downs of the areas, the inspectors did not identify any signs of aging that affected the structures, systems, or components.
(2)19A.1.2 Water Chemistry and Commitment 1 This existing mitigation program manages aging effects for loss of material, cracking, reduction of heat transfer, and wall thinning in primary and secondary water system components. The program controls the chemistry in the primary and secondary water based on relevant industry standards.
Commitment 1 specified:
- Enhance program procedures to require increasing the sampling frequency for the primary and secondary water systems whenever corrective actions are taken for an abnormal chemistry parameter that exceeds an action level and continue this increased sampling until the desired condition has been achieved.
The inspectors reviewed the aging management program basis document, implementing procedures, and chemistry trends. The inspectors verified that procedures provide instructions and specifications for chemistry parameters, impurities and additives, sampling and analysis frequencies, and corrective actions for out-of-specification primary and secondary water chemistry. The inspectors verified the control of selected parameters for both primary and secondary chemistry.
The inspectors verified that the licensee revised the appropriate chemistry procedures to identify that they should not be changed without contacting the license renewal coordinator. The licensee included the requirement to increase the sampling frequency whenever abnormal chemistry parameters exceed action levels, as specified in commitment 1.
Based on the review of the procedures, records and discussion with licensee personnel, the inspectors did not identify any findings or violations of more than minor significance for this aging management program.
(3)19A.1.11 Inspection of Overhead Heavy Load and Light Load (Related to Refueling) Handling Systems and Commitment 6 This existing program manages aging effects for loss of material for all cranes, trolley and hoist structural components, fuel handling equipment and applicable rails within the scope of license renewal. The licensee verifies the structural integrity of the components. The inspection requirements are consistent with the guidance provided NUREG-0612, Control of Heavy Loads at Nuclear Power Plants.
Commitment 6 specified:
- Enhance the program procedures to inspect crane structural members for loss of material caused by corrosion and rail wear.
The inspectors reviewed the aging management program basis document, work orders, condition reports, and implementing procedures, as well as interviewed the program owner. The inspectors verified that the licensee had included statements related to inspecting for rail wear and corrosion in the annual inspection portion of the implementing procedures, as required by commitment 6. From review of completed work activities, the inspectors confirmed that the preventive maintenance documents described being implemented as part of license renewal and had reviewed for corrosion and rail wear. The licensee began evaluating for rail wear and corrosion during inspections several years prior to entering the period of extended operation.
Based on the review of the documents and discussions with licensee personnel, the inspectors did not identify any findings or violations of more than minor significance associated with this aging management program.
(4)19A.1.14 Fuel Oil Chemistry Aging Management Program and Commitment 9 This existing program manages loss of material on the internal surface of components in the safety-related standby diesel generator fuel oil storage and transfer system, diesel fire pump fuel oil system, lighting diesel generator system, and balance of plant fuel oil system. The program includes:
1. surveillance and monitoring procedures for maintaining fuel oil quality by
controlling contaminants in accordance with the Technical Specifications and ASTM Standards D1796 or D4176, D6217 or D7321, and sampled in accordance with D4057,
2. periodic draining of water from fuel oil tanks,
3. visual inspection of internal surfaces during periodic draining and cleaning,
4. ultrasonic wall thickness or pulsed eddy current wall thickness measurement
of fuel oil tank bottoms during periodic draining and cleaning, and
5. inspections of new fuel oil before introduction into the fuel oil tanks.
Specifically addressing the standby diesel generator, only the safety-related fuel oil storage and transfer system are included in the one-time inspections (i.e. storage tanks and associated safety related piping).
Commitment 9 specified:
Enhance the program procedures to:
- Check and remove the accumulated water from the in-scope tanks and diesel generators. A minimum frequency for water removal from the fuel oil tanks will be included in the procedure.
- Include 10-year periodic draining, cleaning, and inspection for corrosion of the in-scope tanks and diesel generators.
- Require periodic testing of the in-scope tanks for microbiological organisms.
- Require analysis for water, biological activity, sediment, and particulate contamination of the in-scope tanks quarterly.
- Conduct ultrasonic testing or pulsed eddy current thickness examination to detect corrosion-related wall thinning once on the in-scope tanks.
- Incorporate the sampling and testing of the diesel fire pump fuel oil storage tanks for particulate contamination and water; incorporate the trending of water, particulate contamination, and microbiological activity in the in-scope tanks.
The inspectors reviewed the aging management program basis document, implementing procedures, documents related to completed program activities, and held discussions with site personnel. Specifically, the inspectors verified the fuel quality chemistry analyses for new diesel fuel, diesel tank inspection results, trends, performed a walkdown of the accessible portions of the diesel generators and their associated tanks and discussed the program with the system engineers.
The inspectors confirmed the licensee completed the required commitments and implemented the procedures associated with this program prior to the period of extended operation.
Based on the review of the procedures, records, and discussions with licensee personnel, the inspectors did not identify any findings or violations of more than minor significance for this aging management program.
(5)19A.1.21 Flux Thimble Tubes and Commitment 16 This existing program manages aging effects for loss of material by performing wall thickness eddy current inspection of flux thimble tubes that form part of the reactor coolant system pressure boundary. The pressure boundary includes the length of the tube inside the reactor vessel out to the seal fittings on the seal table outside the reactor vessel. Eddy current inspection is performed on the portion of the tubes inside the reactor vessel.
Commitment 16 specified:
Enhance the program to generate a new procedure that includes provisions to:
- Examine flux thimble tubes that form part of the reactor coolant system pressure boundary. Schedule the inspections each outage, which may be deferred using an evaluation of the actual wear rate.
- Evaluate flux thimble tube wear and perform corrective actions based on the evaluation.
- Trend wall thickness measurements and calculate wear rates after each inspection.
- Take corrective actions to reposition, cap or replace the tube, if the predicted wear is projected to exceed the established acceptance criterion prior to the next outage.
- Describe the testing and analysis methodology and acceptance criteria of a maximum of 80 percent through wall loss.
- Remove flux thimbles from service to ensure the integrity of the reactor coolant system pressure boundary that cannot be inspected over the tube length, that are subject to wear caused by restriction or other defects, or that cannot be demonstrated satisfactory for continued service.
The inspectors reviewed the aging management program basis document, work orders, examination reports, engineering evaluations, condition reports, and implementing procedures, as well as interviewed the program owner. The licensee developed procedure 0PGP04-ZE-0314, Flux Thimble Tube Wear Program, revision 0, to implement the program. The procedure described implementation of the aging management actions and included all enhancements described in commitment 16. The inspectors determined that the licensee performed the eddy current testing every 3 years on each unit.
From review of completed work orders and condition report engineering evaluations, the inspectors determined that the licensee had evaluated the flux thimble tube wear for each unit to manage the effects of aging. The licensee included actions required by IE Bulletin 88-09, Thimble Tube Thinning in Westinghouse Reactors. The licensee had been performing the eddy current testing every 3 years on each unit based on wear predictions. Prior to 2017, the licensee scheduled the flux thimble tube eddy current evaluations every 18 months and, if wear predictions demonstrated 80 percent would not be exceeded for 3 years, implemented a preventive maintenance task waiver that resulted in operating for 36 months between eddy current examinations.
In 2015 and 2017, condition reports 15-23353 and 16-12548 changed the preventive task frequency from 18 to 36 months for Unit 1 and Unit 2, respectively. From review of completed work orders after these dates, the inspectors determined that the licensee continued to evaluate the wear rate to ensure acceptance criteria would not be exceeded at both 18 months and 36 months. If the wear would exceed 80 percent during the upcoming operating period, the licensee capped or plugged the affected flux thimble tube. Similarly, if the predicted wear would exceed 80 percent between 18 and 36 months, the licensee implemented corrective actions to remove the affected flux thimble tube during the outage that would occur in 18 months. The inspectors determined that the licensee had not updated their updated final safety analysis report supplement to reflect the change in frequency to 36 months. The licensee documented the need to change the updated final safety analysis report supplement in condition report 24-10692.
Based on the review of the documents and discussions with licensee personnel, the inspectors did not identify any findings or violations of more than minor significance associated with this aging management program.
(6)19A.1.28 IWL Containment Post Tensioning and Commitment 22 This existing program manages aging effects of the concrete containment building caused by cracking, loss of bond, loss of material (i.e., spalling or scaling), and increase in porosity and permeability. The program also manages the loss of tendon prestress in the post-tensioning system. The program uses periodic visual inspections of the structure and testing of the post tensioning in the cables.
Commitment 22 specified:
- Enhance the ASME Section XI, Subsection IWL program procedures to incorporate the 2004 edition of ASME Section XI, Subsection IWL (no addenda), supplemented with the applicable requirements of 10 CFR 50.55a(b)(2).
The inspectors reviewed the aging management program basis document, implementing procedures, design specifications, work orders, inspection results, calculations and relief requests, as well as interviewed the program owner. The inspectors verified that the licensee had implemented the reference to the 2004 edition of the ASME code in procedure 0PSP09-TD-0001, Containment Tendon Test/End Anchorage and Adjacent Concrete Inspection, revision 5, as specified in commitment 22.
The inspectors confirmed that the aging management basis document described the inspections related to ASME Section XI, Subsection IWL program from section 19A.1.28, the testing required in section 19A.2.3, Concrete Containment and the time-limited aging analysis projections specified in section 19A.3.4, Concrete Containment Tendon Prestress. Procedure 0PSP09-TD-0001 prescribed the frequency and testing requirements for implementing the inspections and testing in coordination with specification 4C23HCS0001, Specification for Inservice Surveillance of Containment Post-Tensioning System, revision 11. The inspectors identified that section 19A.1.28 in the updated final safety analysis report only described the physical inspection attributes required by Subsection IWL and did not discuss the other included sections that they implemented in the aging management program basis document. The licensee initiated condition report 24-10963 to revise the updated final safety analysis report to reflect how they actually implemented the aging management program.
The inspectors determined that this program managed the effects of aging by inspecting the concrete surfaces and tendon interfaces every 5 years for both units.
Each unit receives liftoff force testing of randomly selected hoop and vertical tendons every 10 years for each unit. The licensee evaluated the amount of loss of tendon prestress for the period of extended operation by confirming that the average lift-off forces of the vertical and hoop tendon groups remain above their minimum required values, as required by the design basis of the containment building and of its post-tensioning system. The inspectors verified that the licensee randomly selected samples for each test; calculated the predicted lower limit lines for the vertical and hoop tendon groups to 60 years; developed a plot of the measured results against time that included the predicted lower limit, minimum required value, and trend lines; and performed a regression analysis consistent with the requirements of Information Notice 99-10, Degradation of Prestressing Tendon Systems in Prestressed Concrete Containments, revision 1, attachment 3, Comparison and Trending of Prestressing Forces.
The inspectors determined that the licensee had received relief from the testing of the Unit 2 tendons at 35 years, which would result in testing of the Unit 2 tendons at the 45th year of operation (20 years between Unit 2 tests). During interviews, the inspectors determined that the licensee planned to perform tendon testing of both units at the 40th year when Unit 1 is scheduled for testing and Unit 2 would be at 15 years since the last test. If the liftoff testing has favorable results, the licensee planned to use this data to seek another relief request for Unit 2 from the testing required at the 45th year.
Based on the review of the documents and discussions with licensee personnel, the inspectors did not identify any findings or violations of more than minor significance associated with this aging management program.
(7)19A.1.31 Masonry Walls and Commitment 36 This existing program manages aging effects related to cracking of masonry walls, as well as degradation of the structural steel restraint systems. The licensee administered this as part of the structures monitoring program and implemented the guidance provided in IE Bulletin 80-11, Masonry Wall Design and Information Notice 87-67, Lessons Learned from Regional Inspections of Licensee Actions in Response to NRC IE Bulletin 80-11.
Commitment 36 specified:
Enhance the program procedures to specify that the inspection frequency will be in accordance with ACI 349.3R, Evaluation of Existing Nuclear Safety-Related Concrete Structures, table 6.1, Frequency of Inspection, which specifies:
- For below-grade structures and structures in controlled interior environment (except inside primary containment), all accessible areas of both units will be inspected every 10 years.
- For all other structures (including inside primary containment), all accessible areas of both units will be inspected every 5 years.
The inspectors reviewed the aging management program basis document, implementing procedures, work orders, and completed inspection results, as well as interviewed the program owner. The inspectors walked down selected masonry block walls in the mechanical auxiliary building and the turbine building. The inspectors confirmed that procedure 0PEP04-ZE-0001, Structures Monitoring Program, revision 7, included an inspection form for masonry walls. The inspectors determined that the licensee had added specific statements related to the frequency of inspections as specified in commitment 36. The licensee had included non-category I masonry walls in scope for license renewal to satisfy updated final safety analysis report commitments related to fire protection requirements.
Based on the review of the documents and discussions with licensee personnel, the inspectors did not identify any findings or violations of more than minor significance associated with this aging management program.
INSPECTION RESULTS
No findings were identified.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On October 31, 2024, the inspectors presented the license renewal phase 1 inspection results to Kimberly Harshaw and other members of the licensee staff.
DOCUMENTS REVIEWED
The inspectors closed the following commitments related to aging management programs: 1, 6, 9, 16, 22, and 36.
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Calculations
REP-1140-511
Regression Analysis for the Unit 1 30th Year Tendon
Surveillance at South Texas Project Nuclear Power Plant
Corrective Action
Documents
CR-
10-17171, 10-23251, 10-23258, 10-23597, 11-19937, 16-
2548
Corrective Action
Documents
Resulting from
Inspection
CR 24-
10703,10706,10729,10750,10751,10799,10962,10963
Concrete - Mechanical & Electrical Auxiliary Building
Removeable Concrete Block Walls Plan and Elevation
Architectural Miscellaneous Details, Unit 1
Architectural Miscellaneous Details, Unit 1
Architectural - Turbine Generator Building Floor Plan EL 29'-
Unit 1
Architectural - Turbine Generator Building Mezzanine Floor
EL 55'-0 Unit 1
sheet 2
Architectural - Turbine Generator Building Plan EL 31'-0
Switchgear Room/Battery Room
sheet 1
Architectural - Turbine Generator Building Miscellaneous
Details and Operator Station
Drawings
9M132A01041
Architectural - Mechanical & Electrical Auxiliary Building
Enlarged Floor Plan El 41'-0 Personnel Access Control Area
13-13139-1
Determine Estimated Wear Rate of Unit 2 Flux Thimbles for
months and 3 years
15-23352-1
Determine Estimated Wear Rate of Unit 1 Flux Thimbles for
months and 3 years
16-2156-1
2018 Structures Monitoring Program Inspections
18-11941-1
Determine Estimated Wear Rate of Unit 1 Flux Thimbles for 3
years
71003
Engineering
Evaluations
19-11336-1
Determine Estimated Wear Rate of Unit 2 Flux Thimbles for 3
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
years
21-10621-1
Determine Estimated Wear Rate of Unit 1 Flux Thimbles for 3
years
2-10154-1
Determine Estimated Wear Rate of Unit 2 Flux Thimbles for 3
years
2-210-9
Four Conditions from 35th year Tendon Surveillance Require
Evaluation
7/24/2024
18-8955-1
Update UFSAR Section 1 9
- A. 1.2, Water Chemistry.
specifying that STP adopts the latest revision of the PWR
Primary and Secondary Water Chemistry Guidelines.
4C23HCS0001
Specification for Inservice Surveillance of Containment Post-
Tensioning System
Chapter 11
Primary Chemistry Strategic Water Chemistry Plan
Chapter 12
Secondary Chemistry Optimization Plan
LRI.19A.1.11
Inspection of Overhead Heavy Load and Light Load (Related
to Refueling) Handling Systems Program
LRI.19A.1.2
Water Chemistry Aging Management Program
LRI.19A.1.21
Flux Thimble Tube Inspection Aging Management Program
LRI.19A.1.28
Containment Post Tensioning System Aging Management
Program
LRI.19A.1.31
Masonry Wall Program
LRl.19A.1.14
Fuel Oil Chemistry Aging Management Program
MTLS-06-131
Westinghouse Supplement to EPRI PWR Primary Water
Chemistry Guidelines
NOC-AE-
23004000
Supplement to Proposed Alternate Frequency to Containment
Unbonded Post-Tensioning System Inservice Inspection
(Relief Request RR-ENG-4-06) (EPID: L-2023-LLR-0004)
2/14/2023
Miscellaneous
Bottom Mounted Instrumentation Flux Thimble Wear
1/1991
REP-1140-510
Final Report for the Containment Structure Tendon
Surveillance at South Texas Project Nuclear Power Plant Unit
and Unit 2
NDE Reports
REP-1196-510
Final Report for the 2024 IWL Containment Concrete
Inspection at South Texas Project Unit 1 & Unit 2
Procedures
Plant Chemistry Specifications
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Sampling and Treatment of the Fuel Oil System
Structures Monitoring
0012
Plant Systems Chemistry Control
0043
Fuel Oil Monitoring Program
0003A
Inspection of Hoists
0003B
Inspection for Jib Cranes
0003C
Inspection for Single Hoist Cranes
0003D
Inspection for Multi-Hoist Cranes
0003E
Inspection for Non-Electrified Monorail Hoist (Mechanical)
0003F
Inspection for Electrified Monorail Hoists
0002
Emergency Diesel Generator 12(22)
Diesel Fuel Oil Particulate Testing
Containment Tendon Test / End Anchorage and Adjacent
Concrete Inspection
MRS-GEN-1304
Generic Flux Thimble Eddy Current (FTEC) Field Procedure
Using the Corestar System 8.1
Work Orders
WAN
557246, 557326, 582027, 621359, 627868, 647330, 671341,
2561, 673528, 673961, 677035, 677282, 683955, 683966,
691747, 693226, 693227