IR 05000282/2023004
| ML24032A095 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 02/01/2024 |
| From: | Hironori Peterson NRC/RGN-III/DORS/RPB3 |
| To: | Conboy T Northern States Power Company, Minnesota |
| References | |
| IR 2023004 | |
| Download: ML24032A095 (1) | |
Text
SUBJECT:
PRAIRIE ISLAND NUCLEAR GENERATING PLANT - INTEGRATED INSPECTION REPORT 05000282/2023004 AND 05000306/2023004
Dear Thomas Conboy:
On December 31, 2023, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Prairie Island Nuclear Generating Plant. On January 10, 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.
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, Hironori Peterson, Chief Reactor Projects Branch 3 Division of Operating Reactor Safety Docket Nos. 05000282 and 05000306 License Nos. DPR-42 and DPR-60
Enclosure:
As stated
Inspection Report
Docket Numbers:
05000282 and 05000306
License Numbers:
Report Numbers:
05000282/2023004 and 05000306/2023004
Enterprise Identifier:
I-2023-004-0056
Licensee:
Northern States Power Company
Facility:
Prairie Island Nuclear Generating Plant
Location:
Welch, MN
Inspection Dates:
October 01, 2023, to December 31, 2023
Inspectors:
R. Elliott, Senior Project Engineer
E. Fernandez, Senior Reactor Inspector
K. Pusateri, Resident Inspector
J. Reed, Health Physicist
D. Tesar, Senior Resident Inspector
Approved By:
Hironori Peterson, Chief
Reactor Projects Branch 3
Division of Operating Reactor Safety
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Prairie Island Nuclear Generating Plant, 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.
PLANT STATUS
Unit 1 entered the inspection period at full-rated thermal power and operated at or near full-rated thermal power until October 19, 2023. At 11:10 a.m. on October 19, 2023, Unit 1 experienced an automatic turbine and reactor trip. Unit 1 remained shut down for the remainder of the inspection period.
Unit 2 was at approximately 91 percent of rated thermal power in coastdown at the start of the inspection period. On October 6, 2023, Unit 2 was taken offline for a refueling outage, and remained shut down 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
71111.04 - Equipment Alignment
Partial Walkdown Sample (IP Section 03.01) (2 Samples)
The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:
- (1) Unit 2 residual heat removal system - pit area on October 2, 2023 (2)22 diesel-driven cooling water pump (protected equipment) on November 22, 2023
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (4 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) Fire Zone 12, relay and cable spreading room Units 1 and 2, on October 30, 2023
- (2) Fire Zone 35, 21 & 22 battery rooms Unit 2, on November 8, 2023
- (3) Fire Zone 42, 52 & 54 Unit 2 reactor building, on November 15, 2023
- (4) Fire Zone 97, D6 480V switchgear 221 and 222 room, on November 21, 2023
===71111.08P - Inservice Inspection Activities (PWR) The inspectors verified that the reactor coolant system boundary, reactor vessel internals, risk-significant piping system boundaries, and containment boundary are appropriately monitored for degradation and that repairs and replacements were appropriately fabricated, examined, and accepted by reviewing the following activities:
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, Weld W-14, Bent Pipe to Bent Pipe Weld
- Reactor Coolant System, Weld W-6, Elbow to Reducer Weld
- Reactor Coolant System, Weld W-5, Valve to Elbow Weld Visual VT-3 Examination
- Reactor Coolant System, Reactor Vessel, 10-Year Reactor Vessel Inservice Inspection (ISI) American Society of Mechanical Engineers (ASME)Section XI Visual Examination Volumetric or Surface Examination Records and Associated Evaluations for Relevant Indications from the Previous Outage That the Licensee Analytically Evaluated and Accepted for Continued Service
- Action Request (AR) 1408630, Reactor Coolant System, 257-051 21 RX Vessel, Indications in Baffle to Former Bolting Welding Activities
- Weld Process, Reactor Coolant System, CV 31228, Replacement of the LOOP A to Pressurizer CV 31228 Bypass Valve PWR Inservice Inspection Activities Sample - Boric Acid Corrosion Control Inspection Activities (IP Section 03.03) (1 Sample)
The inspectors verified the licensee is managing the boric acid corrosion control program through a review of the following evaluations:
(1)
- Issue ID 501000057584, Reactor Coolant System, 2RC-8-13, Leak Identified at Welded 90 Degree Swagelok Compression Fitting/Elbow on Pressurizer Vent
- Issue ID 501000067304, Chemical & Volume Control, 2VC-11-142, Leak Identified on Body to Bonnet Gasket on Boric Acid Batch Tank to Boric Acid Storage Tank Transfer Valve
- Issue ID 501000069713, Chemical & Volume Control, CV-31214, Identified a 3 Drop Per Minute Leak from Valve CV-31214 Onto 2VC-21-16
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 control room during post Unit 1 trip and cooldown on October 19, 2023.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed and evaluated licensed operator requalification training on November 7, 2023.
71111.12 - Maintenance Effectiveness
Maintenance Effectiveness (IP Section 03.01) (1 Sample)
The inspectors evaluated the effectiveness of maintenance to ensure the following structures, systems, and components (SSCs) remain capable of performing their intended function:
- (1) Transmission and distribution bus inspections and preventive maintenance on November 1, 2023
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (2 Samples)
The inspectors evaluated the accuracy and completeness of risk assessments for the following planned and emergent work activities to ensure configuration changes and appropriate work controls were addressed:
- (1) Unit 2 residual heat removal bypass repair and 2RY transformer lockout on October 2, 2023
- (2) Safe shutdown analysis review and protected equipment walkdowns during Unit 2 Yellow risk window for lowered inventory in the reactor coolant system on October 9, 2023
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (1 Sample 2 Partials)
The inspectors evaluated the licensees justifications and actions associated with the following operability determinations and functionality assessments:
(1)1N41 inoperability on October 12, 2023 (2)
(Partial)
Reactor coolant system evaluation for Technical Specification 3.4.3 on October 25, 2023 (3)
(Partial)
Source range nuclear instrument seismic qualification on December 5, 2023
71111.18 - Plant Modifications
Temporary Modifications and/or Permanent Modifications (IP Section 03.01 and/or 03.02) (2 Samples)
The inspectors evaluated the following temporary or permanent modifications:
(1)1R control power T-mod
- (2) D6 governor modification project
71111.20 - Refueling and Other Outage Activities
Refueling/Other Outage Sample (IP Section 03.01) (2 Partials)
(1)
(Partial)
The inspectors evaluated Unit 2 refueling outage (2R33) activities from October 6, 2023, to December 31, 2023.
(2)
(Partial)
The inspectors evaluated Unit 1 forced outage (P1FO1) activities from October 19, 2023, to December 31, 2023.
71111.24 - Testing and Maintenance of Equipment Important to Risk
The inspectors evaluated the following testing and maintenance activities to verify system operability and/or functionality:
Post-Maintenance Testing (PMT) (IP Section 03.01) (10 Samples)
- (1) Fuel oil storage tank vault piping replacements for D5 and D6 emergency diesel generators on October 16, 2023
- (2) B cooling water header valve replacement requiring risk-informed completion time on October 18, 2023
- (4) Bus 21 test tripping per PE-021 on November 29, 2023
- (5) WO 700099074, SP 2092E 2SI-6-4 Open Flow Test (PMT), on December 5, 2023
- (6) WO 700131925, SP 2286 Sump A Pump Discharge Containment Isolation Valve Quarterly Test - Sump A PMT, on December 10, 2023
- (7) WO 700105593, PMT for 21 MDAFW [motor-driven auxiliary feedwater] Pump, on December 12, 2023
- (8) Surveillance Procedure (SP) 2083B, Integrated Safety Injection Surveillance Test, on December 19, 2023
- (9) SP 2070, Reactor Coolant System Integrity Test - 2SI-6-4 (closed) PMT, on December 20, 2023
- (10) WO 700087037, PMT for U2 Main Feed and Bypass Control Valves Re-baseline, on December 28, 2023 Surveillance Testing (IP Section 03.01) (1 Sample 1 Partial)
- (1) Local leak rate test (LLRT) of 21 and 22 containment vacuum breakers on December 15, 2023 (2)
(Partial)
LLRT total leak rate for Unit 2 2R33 refueling outage on December 15, 2023
Inservice Testing (IST) (IP Section 03.01) (1 Sample)
71114.04 - Emergency Action Level and Emergency Plan Changes
Inspection Review (IP Section 02.01-02.03) (1 Sample)
- (1) The inspectors completed an evaluation of emergency action level (EAL) and emergency plan changes on December 13, 2023. For the inspection period from July 1, 2022, through June 30, 2023, the licensee did not make any changes to the site emergency plan and EAL bases/matrix documents. The inspectors independently reviewed the current revisions of these documents to verify no changes were completed.
This evaluation does not constitute NRC approval.
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) Workers exiting the site protected area utilizing portal monitors
- (2) Workers utilizing the tool and equipment monitors as well as the whole-body contamination monitors while exiting the radiologically controlled area during the Unit 2 refueling outage
Radiological Hazards Control and Work Coverage (IP Section 03.04) (4 Samples)
The inspectors evaluated the licensees control of radiological hazards for the following radiological work:
- (1) Reactor head lift
- (2) Reactor coolant pump seal replacement
- (3) Baffle bolt replacement (4)2SI-6-4 valve work High Radiation Area and Very High Radiation Area Controls (IP Section 03.05) (3 Samples)
The inspectors evaluated licensee controls of the following high radiation areas (HRAs) and very high radiation areas (VHRAs):
- (1) Unit 2 - reactor head stand and enclosure
- (2) Unit 2 - containment C sump
- (3) Unit 2 - containment fuel transfer tunnel 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.
OTHER ACTIVITIES - BASELINE
===71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:
BI01: Reactor Coolant System (RCS) Specific Activity Sample (IP Section 02.10)===
- (1) Unit 1 (October 1, 2022, through August 30, 2023)
- (2) Unit 2 (October 1, 2022, through August 30, 2023)
OR01: Occupational Exposure Control Effectiveness Sample (IP Section 02.15) (1 Sample)
- (1) October 1, 2022, through August 30, 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) October 1, 2022, through August 30, 2023
71152A - Annual Follow-up Problem Identification and Resolution Annual Follow-up of Selected Issues (Section 03.03)
- (1) CAP 501000075913 fix-it-now (FIN) team notification of probabilistic risk assessment (PRA) update to control room on December 1, 2023 71153 - Follow Up of Events and Notices of Enforcement Discretion Event Follow up (IP Section 03.01) (1 Partial)
(1)
(Partial)
The inspectors evaluated the Unit 1 trip on October 19,
INSPECTION RESULTS
Observation: Plant Configuration Changes Affecting PRA Not Communicated to Control Room Operators 71152A The inspectors assessed NRC-identified CAP 501000075913 titled, PRA Not Updated as Required, for an annual follow-up sample to determine whether corrective actions were commensurate with the safety significance of the issue. The licensee was performing planned D1 emergency diesel generator (EDG) maintenance work which rendered the D1 EDG inoperable per Technical Specifications, but it remained PRA-available. The FIN team briefed the Unit 1 shift supervisor that FIN would be performing work on the 122-fuel oil storage transfer (FOST) pump. However, the lockout/tagout used in the field removed power to both the 121 and 122 FOST pumps, which rendered the D1 diesel generator unavailable. The control room operators were unaware that the availability of D1 EDG had changed, and therefore released other scheduled risk-significant work while the D1 EDG was unavailable. Once the Unit 1 shift supervisor was informed of the issue, operators immediately updated the model to the correct plant configuration and recalculated the actual Unit 1 risk. It was determined that, although the risk level had increased, risk remained Green per the online risk monitor software. The licensee entered the issue into CAP. The CAP drove the licensee to conduct a human performance event investigation, which determined that the failure to communicate the change in plant status to the control room was a human performance error. Corrective actions in the CAP included a FIN department stand down and lessons learned from the event shared with the FIN team. Inspectors determined actions were commensurate with the safety significance of the issue. No findings or violations of more than minor significance were identified.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On January 10, 2024, the inspectors presented the integrated inspection results to Thomas Conboy, Site Vice President, and other members of the licensee staff.
- On October 23, 2023, the inspectors presented the inservice inspection results to Jason Loeffler, Director, Site Performance and Operations Support, and other members of the licensee staff.
- On October 25, 2023, the inspectors presented the radiation protection baseline inspection results to Thomas Conboy, Site Vice President, and other members of the licensee staff.
- On December 13, 2023, the inspectors presented the emergency action level and emergency plan change review inspection results to Timothy Borgen, Plant Manager, and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Detection Zone
Relay & Cable Spreading Room Units 1 & 2
Detection Zone
& 22 Battery Rooms
Detection Zone
Reactor Building Unit 2 El. 697'
Fire Plans
Detection Zone
D5/D6 Diesel Building
Corrective Action
Documents
Resulting from
Inspection
501000077902
Ultrasonic Examination of a Valve-to-Pipe Weld at 2SI-9-6
(Summary #501689-RI-N716) was a Limited Examination
Due to Being a Single Sided Exam
10/18/2023
PI-2R33-UT-001
NDE Report for Ultrasonic Examination (UT) of RC System
Valve to Elbow Weld W-5
10/18/2023
PI-2R33-UT-007
NDE Report for Ultrasonic Examination (UT) of RC System
Elbow to Reducer Weld W-6
10/14/2023
NDE Reports
PI-2R33-UT-015
NDE Report for Ultrasonic Examination (UT) of RC System
Bent Pipe to Bent Pipe Weld W-14
10/14/2023
FP-PE-NDE-401
Ultrasonic Examination of Ferritic Pipe
Welds - Supplement 3
FP-PE-NDE-402
Ultrasonic Examination of Austenitic Pipe
Welds - Supplement 2
WDI-PJF-349545-
EPP-001
Prairie Island Nuclear Power Plant, Unit 2 MRP-227 1-A,
Reactor Vessel Lower Internals Visual and 10 Year RVISI
ASME Section XI Visual Examination Program Plan
Procedures
WDI-STD-088
Underwater Remote Visual Examination of Reactor Vessel
Internals
PE 0009
4kV Switchgear Preventive Maintenance
PE 0022-01T
4.16kV Bus 22 Cubicle 1 2M Aux Transformer Electrical
Maintenance - Test Tripping
Procedures
PE 4822
480V Transformer PM
Work Orders
700078678
PE-222M-XFMR Refl Insp
11/04/2023
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
700078678-0020
PMT/RTS 222M/XFMR
700130029-0420
Install Substation Control of 8H13 and 8H14
2D20.2.BUS1
Plant Alignment for 345 kV Bus 1 Isol/Rest
FP-OP-REP-01
2000028901, Event Reporting and Notification Process
Procedures
SP 2118
Verifying Paths from the Grid to U-2 Buses
Corrective Action
Documents
501000079469
NIS Mode 3 4 5 Seismic Qual Resolution
11/29/2023
Engineering
Evaluations
DBD SYS-38A
Design Basis Document for the Emergency Diesel Generator
System
2000020872
Unit 2 Fuel Oil Storage Tank Volume/Configuration
Requirements During 2R33 RFO
Miscellaneous
NSAL-00-016
Nuclear Safety Advisory Letter - Rod Withdrawal from
Subcritical Protection in Lower Modes
2/04/2000
Procedures
D58.2.9
Unit 2 Reactor Vessel Head Removal
700079840
SP 2083B Int SI Tst - Sim Loss Offsite Pwr
700087109-0080
Install EQ Splices on CV-31102 I/P Converter
700098136
SP 2072.41B-LLRT-41B (NO. 22 Vacuum Bkr)
700098271
SP 2072.41A-LLRT-41A (21 Vacuum Bkr)
700099074
501000057644, 2SI-6-4 Leakage During SP 2070
700099074
2SI-6-4 RTS Open During SP 2092E
700100220
SP 2070 - Rx Coolant Sys Integrity Tst
Work Orders
700110954-0040
Replace Fuel Oil Storage Tank Piping - 4-2FO-42,
4-2FO-43 & 4-2FO-44
Emergency Preparedness Coordinator 50.54(Q)
Qualification Records (Spreadsheet)
05/10/2023
Miscellaneous
FL-BEP-EPT-
001M
Conduct a 50.54(Q) Review (Training Guide)
F3-2
Classification of Emergencies
Procedures
F3-2.1
Emergency Action Level Technical Bases
501000077529
Poor Rad Worker Behaviors - 22 RCP Seal
10/10/2023
501000077729
BFB Container Surveys
10/15/2023
Corrective Action
Documents
501000077778
Personnel Contamination
10/16/2023
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
501000077857
NRC Health Physics Observations
10/17/2023
501000077881
Rad Shipment Manifest Not Updated
10/17/2023
501000077926
NRC Health Physics Observations
10/18/2023
501000077986
Documentation for HEPA Vacuum
10/20/2023
Corrective Action
Documents
Resulting from
Inspection
501000078022
Airborne Response not per RWP 232042
10/20/2023
Miscellaneous
Sentinel ED
Alarm report
List of Electronic Dosimeter Alarms for 2023
10/17/2023
FP-RP-NISP-03
Radiological Air Sampling
FP-RP-NISP-05
Access Controls for High Radiation Areas
FP-RP-NISP-08
Use and Control Hepa Filtration and Vacuum Equipment
FP-RP-SEN-02
Radiological Work Planning and Controls
RPIP 1123
Alpha Characterization Smears
Procedures
RPIP 1204
Evaluation of Airborne Radioactivity
PI-I-20231016-13
Job Coverage - Decon Building
10/16/2023
PI-M-20231006-7
2R33 U2 CTMT Initial
10/06/2023
PI-M-20231006-9
2R33 Initial Entry 755' and 735'
10/06/2023
Radiation
Surveys
PI-M-20231016-4
RCP Seal Removal
10/15/2023
RWP 232020
2R33 - RCP WORK
RWP 232026
2R33 - 2SI-6-4 Valve Work
RWP 232040
100% Work In-Progress Review for RWP 232040
10/14/2023
RWP 232042
2R33 - Reactor (RX) Head Disassembly / Reassembly
Radiation Work
Permits (RWPs)
RWP 232082
2R33 - Baffle Former Bolt Replacement
Corrective Action
Documents
LER 2023-001-00
Reactor Trip, Auxiliary Feedwater and Emergency Service
Water System Actuation Due to Electrical Transient in
DC Control Power Cables
10/19/2023
Engineering
Evaluations
608000001132
RCS Evaluation for Technical Specification 3.4.3
0