IR 05000237/2023004
| ML24033A161 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 02/02/2024 |
| From: | Robert Ruiz NRC/RGN-III/DORS/RPB1 |
| To: | Rhoades D Constellation Energy Generation, Constellation Nuclear |
| References | |
| IR 2023004 | |
| Download: ML24033A161 (1) | |
Text
SUBJECT:
DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3-INTEGRATED INSPECTION REPORT 05000237/2023004 AND 05000249/2023004
Dear David Rhoades:
On December 31, 2023, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Dresden Nuclear Power Station, Units 2 and 3. On January 16, 2024, the NRC inspectors discussed the results of this inspection with C. Joseph, Site Vice President, 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, Robert Ruiz, Chief Reactor Projects Branch 1 Division of Operating Reactor Safety Docket Nos. 05000237 and 05000249 License Nos. DPR-19 and DPR-25
Enclosure:
As stated
Inspection Report
Docket Numbers:
05000237 and 05000249
License Numbers:
Report Numbers:
05000237/2023004 and 05000249/2023004
Enterprise Identifier:
I2023004-0050
Licensee:
Constellation Energy Generation, LLC
Facility:
Dresden Nuclear Power Station, Units 2 and 3
Location:
Morris, IL
Inspection Dates:
October 01, 2023 to December 31, 2023
Inspectors:
M. Domke, Reactor Inspector
J. Kutlesa, Emergency Preparedness Inspector
M. Porfirio, Illinois Emergency Management Agency
J. Reed, Health Physicist
C. St. Peters, Resident Inspector
J. Steffes, Senior Resident Inspector
Approved By:
Robert Ruiz, Chief
Reactor Projects Branch 1
Division of Operating Reactor Safety
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Dresden Nuclear Power Station, Units 2 and 3, 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
Type Issue Number Title Report Section Status URI 05000237, 05000249/202300401 2/3 Emergency Diesel Generator Output Breaker Opened During Surveillance Testing 71152A Open
PLANT STATUS
Unit 2 began the inspection period in coast down to prepare for refueling outage D2R28.
On October 29, 2023, the unit was shut down to commence D2R28. The unit was synchronized to the grid on November 17, 2023, and ascended to full power the next day.
On November 25, 2023, reactor power was lowered to 69 percent to perform rod pattern adjustment. The unit was returned to full power on November 26, 2023. On December 9, 2023, reactor power was lowered to 64 percent to perform rod pattern adjustment. The unit was returned to full power the next day and remained at or near full power for the remained of the inspection period.
Unit 3 began the inspection period at rated thermal power. On December 30, 2023, reactor power was lowered to 81 percent to perform a rod pattern adjustment. The unit was returned to full power on December 31, 2023, and remained at or near full power 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 onsite 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
Complete Walkdown Sample (IP Section 03.02) (1 Sample)
- (1) The inspectors evaluated system configurations during a complete walkdown of the Unit 2 core spray system on November 3-December 20, 2023.
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (1 Sample)
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 8.2.5B, Unit 2 Low Pressure Heater Bays Elev. 517' on November 2, 2023
71111.07A - Heat Exchanger/Sink Performance
Annual Review (IP Section 03.01) (1 Sample)
The inspectors evaluated readiness and performance of:
- (1) Unit 2 2A low pressure coolant injection heat exchanger
71111.08G - Inservice Inspection Activities (BWR)
BWR Inservice Inspection Activities Sample - Nondestructive Examination and Welding
Activities (IP Section 03.01)
The inspectors evaluated boiling-water reactor nondestructive testing and welding activities by observing and reviewing the following activities from October 30, 2023, to November 7, 2023.
(1)
1. Volumetric, automated, phased array ultrasonic examination of augmented
IGSCC category D jet pump instrumentation nozzle reducer-toreducer weld 2/1/JPIA/N20A5
2. Volumetric, manual, phased array ultrasonic examination of augmented
IGSCC category D isolation condenser, safe end-tonozzle weld, 2/2/1302B12/127
3. Volumetric, manual, phased array ultrasonic examination of augmented
IGSCC category D shutdown cooling pipe-tovalve weld, 2/1/1001B16/1610(A)
4. Volumetric, manual, conventional ultrasonic examination of thermal fatigue
category RA low pressure coolant injection pipe-topipe weld, 2/1/150616/16K4
5. Visual examination, VT3, of ASME class 1 strut support on reactor head
spray piping, 2/1/03042.5/M1167D1
6. Replacement activities for ASME class 2 pressure boundary welds for Unit 2
standby liquid control fittings completed in work order (WO) 05017094
7. Replacement activities for ASME class 2 pressure boundary welds for Unit 2
emergency core cooling jockey pump piping completed in WO 05142586
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 shutdown on October 29, 2023, and startup on November 15, 2023, for refueling outage D2R28.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
- (1) The inspectors observed and evaluated licensed crew performance in the simulator during scenarios LT SEG 2302A and LT SEG 2302B on October 18, 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) Unit 2 isolation condenser valve 21301-3
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (7 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) Elevated fire risk due to planned work on the 480V MCC breaker for MOV 21501-20B on October 5, 2023
- (2) Emergent activities and troubleshooting for Unit 3 drywell cooler C tripping on October 12-16, 2023
- (3) Review of plant aggregate risk and risk management actions for the week of October 16, 2023, while Unit 2 isolation condenser and 2A circulating water pump were unavailable
- (4) Review of plant aggregate risk and risk management actions for the week of October 23, 2023, while 2/3 service water pump and Division II low pressure coolant injection were unavailable
- (5) Review of plant aggregate risk and risk management actions while the 231 vital bus was unavailable
- (6) Plant aggregate risk and risk management actions review while Unit 3 offsite power transformer lost control power on November 28-29, 2023
- (7) Emergent activities and troubleshooting for the Unit 2 B core spray following a failure of the 2B pump to start during a routine surveillance, on December 12, 2023
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (3 Samples)
The inspectors evaluated the licensees justifications and actions associated with the following operability determinations and functionality assessments:
- (1) Unit 2 station blackout diesel generator functionality review following coolant leak as noted in CR 4706892
- (2) Unit 3 offgas system review following high radiation alarm as documented in CR 4719418
- (3) Unit 3 high pressure coolant injection (HPCI) functionality review following inability to complete HPCI fast start as documented in CR 4720435
71111.20 - Refueling and Other Outage Activities
Refueling/Other Outage Sample (IP Section 03.01) (1 Sample)
- (1) The inspectors evaluated refueling outage D2R28 activities from October 29-November 17, 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) Control room emergency ventilation system fragnet post-maintenance testing, the week of September 25, 2023
- (2) Replacement of U3 main steam line D low pressure isolation switch 30261-30D and subsequent test, on October 5, 2023
- (3) Replacement of U2 reactor protection system relay 20590-101A and subsequent test, per WO 1283609
- (4) Calibration following replacement of Unit 2 reactor high pressure scram pressure transmitter 20263-55B, per WO 1404115
- (5) Calibration following replacement of Unit 2 reactor high pressure scram pressure transmitter 20263-55D, per WO 1404120
- (6) Local leak rate test following valve maintenance on 1A main steam isolation valve, per WO 5028130
- (7) Local leak rate test following valve maintenance on 2C main steam isolation valve, per WO 5028128
- (8) Integrated leak rate test on November 13-14, 2023
- (9) Hydrostatic testing on November 12, 2023
- (10) HPCI steam supply valve inspection and diagnostic testing following valve repack, per WO 4750831
Surveillance Testing (IP Section 03.01) (1 Sample)
- (1) U2 Division I under voltage testing on November 6, 2023
Containment Isolation Valve (CIV) Testing (IP Section 03.01) (1 Sample)
- (1) Reactor water cleanup inlet isolation valves on November 1, 2023
Reactor Coolant System Leakage Detection Testing (IP Section 03.01) (1 Sample)
- (1) Unit 2 drywell unidentified leakage increase from October 25-November 15, 2023
71114.04 - Emergency Action Level and Emergency Plan Changes
Inspection Review (IP Section 02.0102.03) (1 Sample)
- (1) The inspectors evaluated the following submitted Emergency Action Level and Emergency Plan changes.
§50.54(q) Program Evaluation/Assessment Review Evaluation No.: 2158:
Emergency Action Levels for Dresden Station: EPAA1004 Addendum 3, Revision 13 of November 20, 2021
- EPAA1004, Addendum 3: Emergency Action Levels for Dresden Station, Revision 13
- EPDR1000: Dresden Station Radiological Emergency Plan, Revision 0
- EPAA1004, Addendum 1: Dresden Station OnShift Staffing Technical Basis, Revision 2
- EPAA1004, Addendum 2: Evacuation Time Estimates for Dresden Generating Station Plume Exposure Pathway Emergency Planning Zone (KLD TR - 634, rev. 0), Revision 01
- EPAA1004, Radiological Emergency Plan Annex for Dresden Station, Revision 39 This evaluation does not constitute NRC approval.
71114.06 - Drill Evaluation
Drill/Training Evolution Observation (IP Section 03.02) (1 Sample)
The inspectors evaluated:
- (1) Focused area drill on December 7,
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) Licensee surveys of potentially contaminated material leaving the radiologically controlled area (RCA)
- (2) Workers exiting the RCA during a 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) Drywell core spray work
- (2) Drywell shielding activities
- (3) Turbine building sand blasting activities
- (4) Refuel floor activities 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 and very high radiation areas (VHRAs):
- (1) Unit 3 high pressure heater room
- (2) Unit 2 reactor head stand
- (3) Unit 2 RBEDT room 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 - InPlant Airborne Radioactivity Control and Mitigation
Use of Respiratory Protection Devices (IP Section 03.03) (1 Sample)
- (1) The inspectors evaluated the licensees use of respiratory protection devices.
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 2 (October 1, 2022 through September 30, 2023)
- (2) Unit 3 (October 1, 2022 through September 30, 2023)
BI01: Reactor Coolant System (RCS) Specific Activity Sample (IP Section 02.10) (2 Samples)
- (1) Unit 2 (June 1, 2022 through August 31, 2023)
- (2) Unit 3 (June 1, 2022 through August 31, 2023)
OR01: Occupational Exposure Control Effectiveness Sample (IP Section 02.15) (1 Sample)
- (1) June 1, 2022 through August 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) June 1, 2022 through August 31, 2023
71152A - Annual Follow-up Problem Identification and Resolution Annual Follow-up of Selected Issues (Section 03.03)
The inspectors reviewed the licensees implementation of its corrective action program related to the following issues:
(1)2/3 emergency diesel generator output breaker opened during surveillance testing
71152S - Semiannual Trend Problem Identification and Resolution Semiannual Trend Review (Section 03.02)
- (1) The inspectors reviewed the licensees corrective action program for potential adverse trends in procedure use and adherence that might be indicative of a more significant safety issue.
INSPECTION RESULTS
Unresolved Item (Open)2/3 Emergency Diesel Generator Output Breaker Opened During Surveillance Testing URI 05000237,05000249/202300401 71152A
Description:
At 12:55 a.m. Central on January 30, 2023, the 2/3 emergency diesel generator (EDG) was declared inoperable to perform monthly operability surveillance testing. The licensee performed a low idle local start of the EDG, closed in 2/3 diesel output breaker to bus 331 and achieved full load at 1:46 a.m. At 3:06 a.m., the 2/3 EDG breaker to bus 331 tripped open unexpectedly. The EDG responded as expected and achieved idle conditions. At 3:10 a.m., the 2/3 EDG was placed in a secured status, declared inoperable and unavailable and troubleshooting efforts commenced.
During troubleshooting the licensee discovered a loose banana jack in the 2/3 EDG local control panel which is mounted to the side of the 2/3 EDG at TB25C. The licensee was able to tighten the banana jack five turns. The loose banana jack resulted in control circuitry wiring being loose and caused the open circuit conditions observed during unloaded diesel run troubleshooting. Once the banana jack was tightened and the control wiring properly secured, the 2/3 EDG successfully passed the monthly operability surveillance test and was restored to an operable and available status at 4:22 p.m. on February 1, 2023.
The inspectors determined that the banana jack at TB25C had become lose over time from vibrations during diesel operation. This in turn, caused the underlying wiring to become unsecured, resulting in a loss of continuity and causing voltage fluctuations. The fluctuating voltage affected the excitation circuitry and could cause a loss of excitation voltage, preventing the diesel generator from functioning. During the January 30 testing, these voltage fluctuations caused the output breaker to open as a protective measure. During emergency operation, such as a loss of offsite power event, this breaker protective feature is blocked, and the breaker will remain closed; however, the voltage fluctuations could still result in a loss of excitation, and therefore the diesel could not be counted on to reliably function.
During normal operation, relay VSR would pick up, seal in, and energize relays ER and EXC.
The EXC relay contacts ensure proper operation of the excitation circuitry. The voltage fluctuations could result in a loss of voltage to all three relays and, due to the open EXC relay, the loss of the excitor reflashing current. The loss of the reflashing current energized relay RTDG 2/3 and the associated contact caused the output breaker to trip. During an emergency start, such as from a loss of offsite power, the RTDG 2/3 relay is blocked, and the breaker would remain closed. However, the VSR, ER and EXC relays would function as normal, and a loss of excitation could occur preventing the EDG from functioning.
Inspector review identified that the banana jack had been installed on March 26, 2019, under work order 466527806, 2/3 10 Year EDG Time Delay Relay (TDR3) Replacement, in accordance with procedure DIP 210028, Banana Jack Adapter Installation, Revision 15.
Procedure DIP 210028 specified the banana jack installed at terminal block TB25C terminal point 12 torqued snug tight. On July 31, 2020, the licensee documented in condition report 4360154, Procedure Revisions Required - Corporate Torque HIT Actions, that procedure use of torque snug tight was no longer acceptable direction for tightening components and specifically identified that procedure DIP 210028 required revision.
The inspectors determined from further review of CR 4360154 that the licensee had changed torque requirements for the installation of banana jacks from a required torque value to snug tight, when procedure DIP 210028, Banana Jack Adapter Installation, Revision 12 was issued on March 23, 2012. The inspectors reviewed condition reports 957053 Banana Jack Defective, Did Not Install for Pre Outage, 1094898 Banana Jacks Adapters are Defective, Cannot Torque, 1104972 Cannot Achieve Torque Value of Banana Jack, and 1110756 Torque Specs in Procedure Are Not Correct, generated between August 24, 2009, and September 8, 2010, which documented material deficiency issues noted during banana jack installation while attempting to torque the banana jacks to the procedurally required value.
Specifically, the licensee encountered an issue where the plastic hex nut bonded to the banana jack metal part would strip and spin freely during torquing evolutions.
Condition report 1110756 action item 2 was created to review recommended torque values of 10-12 in-lbs as recommended by Vendor against Dresden Design Criteria. The licensee documented that Pomona had originally recommended the 1516 inlbs torque as the maximum torque based on Calculation CMED048403, Evaluation of Pomona Banana Jack Adapters for Terminal Blocks Identified in CECo EM Standards. CMED048403 calculated and documented required thread engagement to ensure the banana jack did not impact system function when installed. The inspectors noted that CMED048403 documented the torque value for #832 screws as 16 inlbs and that the Pomona recommended torque values for adapters were also applicable for existing terminal screws. The inspectors determined that an evaluation against original design requirements had not been provided nor an evaluation of minimum torque requirement established.
The inspectors reviewed alternate part replacement evaluation M19961190-003 which was referenced associated with the establishment of procedure DIP 210028, Revision 0, and documented the review of CMED057854 for the use of banana jack adapters have been analyzed as being better or equal to the original terminal screws for all areas of the plant with exceptions. CMED057854, Calcs. For Eval. the Use of Banana Jack Adapters in Harsh Environments, Revision 1, which stated, in part, that the function of these [Pomona terminal strip banana jack] adapters is to maintain the continuity of the electrical circuit where they are located. This is performed by the threaded portion of the adapter which replaces the screw in a terminal strip. Per CMED-048403 the metal portion of the subject adapters has been evaluated and found to meet the requirements of CECo Standard M-EM-0012. Also, the recommended torque values for the adapters are applicable to the existing terminal screws.
Finally, it was concluded that there is no significant effect on the qualification of the terminal block. Therefore, the properly installed adapters will maintain the continuity of the electrical circuit where they are located. See CMED-048403 for torque and minimum thread engagement requirements.
The licensee reviewed NC0057, Torque Requirements, Revision 2, and chose to change banana jack installation to snug tight based on Section 2.6.2 and 2.4.2 because of the material deficiency concerns encountered during maintenance. Section 2.6.2 stated, Unless otherwise specified on the Electrical Installation Documents, lug connections at terminal blocks shall be tightened snug tight as defined in 2.4.2 (For hardware less than 1/4 in diameter). Section 2.4.2 (For hardware less than 1/4 in diameter) stated, The tightness attained by the force necessary to bring a fastener into acceptable contact/alignment and set the fastener (nut, bolt, screw, etc.) so that is will not loosen by itself. The inspectors determined that the licensee had established the torque value of 15-16 inlbs. based on design analysis and vendor recommendation but had not been provided a similar analysis for the reduction in torque requirement to snug tight to ensure proper thread engagement and therefore circuit continuity were maintained.
The inspectors determined that the licensee did not perform a review of plant equipment which had banana jacks installed in accordance with the superseded snug tight instructions, to determine if these jacks still securely held the underlying wiring. As a result, the banana jacks installed on the 2/3 EDG had loosened over time from diesel operation, causing the underlying wires to become unsecured. The unsecured wires resulted in a loss of continuity causing voltage fluctuations which could affect the operability of the diesel. The licensee performed torque checks on the banana jacks installed on the Unit 2 and 3 diesels and determined that they were secure and met the current requirement of procedure DIP 210028.
Planned Closure Actions: The inspectors previous review identified an issue of concern with respect to design control. In order to determine whether the issue of concern is a performance deficiency or violation, the inspectors plan to review the original design documents associated with the terminal screws and terminal blocks prior to banana jack installation. Additionally, the inspectors will review the process, procedures and documents the licensee used to evaluate the design change from terminal screws to banana jacks.
Finally, the inspectors will request and review all documents generated for use of commercially available parts in a quality application.
Licensee Actions: Corrective actions included, but were not limited to, securing the excitation circuitry wires by installing the banana jack at TB25C to required torque in accordance with procedural requirements and reperforming an operability run of the 2/3 EDG, and performing an extent of condition review for similar conditions on the other two EDGs, as well as the station blackout diesels.
Corrective Action References: CR 4551179 2/3 EDG Output Breaker Trip, CR 4687009 NRC Question: 2/3 EDG Banana Jacks, CR 4691063 U2 Extent of Condition Review from IR 4551179, CR 4691067 U3 Extent of Condition Review from IR 4551179, CR 4692803 U2 SBO Banana Jack Extent of Condition Walkdown, and CR 4692804 U3 SBO Banana Jack Extent of Condition Walkdown.
Observation: Procedure Use and Adherence Trend Review 71152S The inspectors performed a semiannual review of issues entered into the corrective action program and a cognitive review of plant observations over the period of July 1, 2023, to December 31, 2023, to identify any potential trends that might indicate the existence of a more significant safety issue. In the second half of 2023, the NRC inspectors identified several potential examples of issues with procedure use and adherence.
On July 7, 2023, the inspectors observed operators in the field perform actions during a quarterly surveillance on the diesel generator cooling water pump that should have been marked as N/A, or not applicable. The site identified that those particular steps were not marked as N/A in accordance with procedure HUAA104101, Procedure Use and Adherence. In addition, the site did not include any indication these steps were performed in the record of the surveillance. The inspectors noted the equipment operator entered stop work criteria, and the main control room and infield equipment operators determined the step was not required and should have been N/Ad. The licensee documented the inspectors observation on July 12, 2023, in CR 4690019, NRC ID: Documentation for DOS 660008 Incomplete, performed a fact finding, and issued a site wide human performance (HU) alert to share learnings from the event.
On November 29, 2023, a site employee did not provide the correct reference distance for the U3 HPCI fast initiation start in accordance with the procedure DOS 230007, High Pressure Coolant Injection Fast Initiation. Step E.16. The system engineering was to provide the reference distance that was recorded in step E.16. The reference distance was that measured from the top of gland follower to the bottom of the anti-rotation bar on MO 32301-10, the HPCI test return valve. Valve MO 32301-10 is adjusted to a provided reference distance that will allow the HPCI turbine to demonstrate functionality of its safety function and achieve predefined criteria listed in procedure DOS 230007. The inspectors held discussions with the site where they were informed that the reference distance provided was not for the correct unit, and a peer check was not obtained before the data was provided.
The incorrect value resulted in the site backing out of the surveillance due to expected conditions not being obtained, the surveillance not being credited and rescheduled. The licensee documented this event in CR 4720435 on November 29, 2023. The site noted in discussions with the inspectors that changes are planned to formalize the need for a peer check of the supplied reference distance value and that a fact finding had been performed to better understand the cause.
The inspectors also reviewed CR 4722873, L4 C&TD2R28 LLT/O Restoration Instruction Improvements, generated on December 11, 2023. The site had identified that some tagouts left the restoration instructions to the discretion of the supervisor rather than a prescribed specific lineup. Specifically, containment cooling service water (CCSW) feed to control room emergency ventilation (CREV) refrigeration condensing unit was left to the discretion of the unit supervisor and identified during establishment of the lineup for the CREVs surveillance.
Additionally, the system valve checklist leaves the lineup to the discretion of the unit supervisor. In this event, CREVs was not aligned to the preferred division, Division 2, of CCSW. CCSW provides backup emergency cooling to the Train B refrigeration condensing unit and by proactively aligning to the preferred division of CCSW during restoration; making additional manipulations when initiating CREVs can be avoided. Actions from this CR included, but were not limited to, lining up CREVs to the preferred division, revising DOP 0040M3/M4 to included preferred and alternate lineup, and evaluating creating a standard for use of as required in tagout restoration steps.
The inspectors noted that challenges in procedure use and adherence could present challenges to plant operation and equipment. However, for each potential example identified in the previous paragraphs, the site has taken steps and actions to address and attempt to prevent recurrence. The inspectors did not identify any findings or violations associated with the inspection activities.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On January 16, 2024, the inspectors presented the integrated inspection results to C. Joseph, Site Vice President, and other members of the licensee staff.
- On November 3, 2023, the inspectors presented the radiation protection inspection results to P Boyle, Site Vice President, and other members of the licensee staff.
- On November 7, 2023, the inspectors presented the inservice inspection results to R. McCulloch, and other members of the licensee staff.
- On December 20, 2023, the inspectors presented the emergency action level and emergency plan changes inspection results to A. Clements, Emergency Preparedness Manager, and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
Drawings
M27
Diagram of Core Spray Piping
AAO
Procedures
DOP 1400M1
Unit 2 Core Spray System
Fire Plans
135 U2TB38
FZ 8.2.5B Unit 2 Low Pressure Heater Bays
Elev. 517'
AsFound Pictures
2/14/2023
Miscellaneous
As Left Pictures
2/14/2023
NDE Reports
D2R28 2A LPCI Heat Exchanger Eddy Current Examination
Final Report
11/02/2023
CYDR120413
Cooling and Service Water Chemical Injection Systems
CYDR1204131
Raw Water Chemical Feed Equipment Repair and
Preventative Maintenance Program
Procedures
DOS 150002
Containment Cooling Service Water Pump Test and
Inservice Test (IST)
Work Orders
05305118
D2 Perform HX Thermal Performance
09/28/2023
04470925
Missed General Visual Exam on ASME Class
MC Valve 28526
01/10/2022
04471230
D2R28 CCSW Piping Replacements
01/11/2022
04534285
D3R27 VT3 ASME Class 3 Support Indications in Crib
House
11/02/2022
04537253
Steam Leak on Unit 2 High Pressure Core Injection Drain
Pot Piping at LS22365
11/16/2022
04550381
Inspect Suction Piping to Valve 23932-500
01/25/2023
Corrective Action
Documents
04714132
D2R28 -ISI Exam Relevant Condition on M1167D1
Support
10/31/2023
D2R28APR04
UT Examination Summary Sheet
11/06/2023
UT Calibration/Examination
10/31/2023
UT Calibration/Examination
11/03/2023
UT Calibration/Examination
11/03/2023
NDE Reports
UT Calibration/Examination
11/04/2023
Procedures
EPRI-DMW-PA1
Procedure for Manual Phased Array Ultrasonic Examination
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
ERAA335016
VT3 Visual Examination of Component Supports,
Attachments and Interiors of Reactor Vessels
GEH-PDI-UT2
PDI Generic Procedure for the Ultrasonic Examination of
Austenitic Pipe Welds
GEH-UT258
Procedure for Automated Phased Array Ultrasonic
Examination of Austenitic and Ferritic Similar Metal Piping
Welds with the Topaz
GEH-UT261
Procedure for Automated Ultrasonic Flaw Depth Sizing in
Austenitic and Ferritic Piping Welds with the Topaz
05017094
Need a WO to Replace S4AMC Coded
SBLC Fittings for 2B Train
11/14/2021
Work Orders
05142586
Degraded Piping Off the 21401-4 Jockey Pump
05/04/2022
Miscellaneous
D2R28 Load Profile
10/25/2023
DGP 0101
Unit Startup
208
DGP 0201
Unit Shutdown
177
NFAB720F-1
Control Rod Sequence Review and Approval Sheet
10/26/2023
NFAB720F-1
Control Rod Sequence Review and Approval Sheet
11/14/2023
NFDR7211004
Dresden Unit 2 Rod Sequence
OPAB3001003
ReMa Plan D229001: Unit 2 Startup from All Rods In to
<25% CTP
11/14/2023
Procedures
OPAB3001003
ReMa Plan D228023: Shutdown for D2R28
10/29/2023
4141412
MOV 21301-3 AsFound Stroke Length High
05/25/2018
Corrective Action
Documents
4456931
Unit 2 Iso Condenser 21301-3 Valve Stroke Length
10/29/2021
2073
Unit 2 Isolation Condenser Valve 21301-3 Opening Setting
Adjustment
2531
Isolation Condenser Expected Heat Removal with 100%
Initial Carryover Fraction Performance
Engineering
Changes
635437
21301-3 Valve Stroke Length Exceeded-Historical
Operability Review
4716611
EM D2 RFL Com MOV Elect Insp & Diagnostic Test 21301-
10/17/2023
Work Orders
256862
OP Support MOV 21301-3 Diagnostic + PMT
10/18/2023
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
4708978
Unexpected Alarm 9235 E4, U3 Drywell Clr Blower Trip
10/12/2023
4719393
TR32 Transfer Switch Source Available Lights Off
11/23/2023
Corrective Action
Documents
23005
2B Core Spray Pump Fail to Start
2/12/2023
Engineering
Changes
639998
Predictions for U3 Drywell Temperature with a Loss of 3C
Drywell Cooler Fan
Work Week Highlights Week of 10/2/2023
10/05/2023
Miscellaneous
Work Week Highlights Week of 10/23/23 to 10/30/23
10/24/2023
DEP 004027
Megger and Bridge Testing and Acceptance Criteria
MAAA716234
FIN Team Process
OPAA107
Integrated Risk Management
OPAA108111
Adverse Condition Monitoring and Contingency Plan
OPAA108117
Protected Equipment List
10/25/2023
OPDR201012-
1001
Dresden OnLine Fire Risk Management
Procedures
WCAA1011006
OnLine Risk Management and Assessment
2588501
Assist Operations in Breaker Swap Bus 241 Cub 10
2/12/2023
Work Orders
2588503
T/S & Repair (C/S 21401-B) 2B Core Spray PP, 21430-
308B (C/S 21401-B) 2B Core Spray PP
Bus 241
2/12/2023
4719661
Operations Crew 3 Clock Reset. Troubleshooting Gland
Seal Condenser Vacuum and Offgas Rads
11/26/2023
Corrective Action
Documents
20435
Unable to Complete U3 HPCI Fast Start per
DOS 230007
11/29/2023
DOS 230003
High Pressure Coolant Injection System Operability and
Quarterly IST Verification Test
20
Procedures
DOS 230007
High Pressure Coolant Injection Fast Initiation Test
4712420
Fatigue Assessment
10/25/2023
Corrective Action
Documents
4714371
Fatigue Assessment for Vehicle Incident
11/01/2023
Engineering
Evaluations
640153
D2R28 (FME) Lost Parts Analysis for Reactor Vessel and
Connected Systems
Schedule Reports for Operations 10/2023-11/2023
11/14/2023
Miscellaneous
23013
Temporary State Estimator Alarm Setpoints During D2R28
09/22/2023
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
TSP 2023034
Temporary Contact Shielding Permit
11/01/2023
DMP 580018
Load Handling of Heavy Loads and Lifting Devices
DOP 100003
Shutdown Cooling Mode of Operation
DOP 190003
Reactor Cavity, Dryer/Separator Storage Pit and Fuel Pool
Level Control
DOP 650008
Bus 241 to Bus 341 Tie Breaker Operation
DOP 650030
Bus 231 to Bus 331 Tie Breaker Operation
ERAA330001
Section XI Pressure Testing
ERAA335015-
2103
VT2 Visual Examination in Accordance with
ASME 2013 Edition
MAAA716022
MAAB756600
Reactor Disassembly
MAAB756601
Reactor Assembly
MADR756600
Dresden Reactor Disassembly
MADR756601
Reactor Assembly
NFAA3301001
Core Verification
Procedures
OPAA108108
Startup Checklist
Corrective Action
Documents
4705708
Unit 2 Entered OPDR108111-1003 for Drywell Floor Drain
Leakage
09/28/2023
Miscellaneous
Adverse
Condition
Monitoring and
Contingency Plan
Unit 2 Drywell Floor Drain Sump InLeakage
09/28/2023
DOS 020101
Unit 2 RPV ASME B & PV Code 1000 PSI System Leakage
Test
DOS 575004
Control Room Train B HVAC and Air Filtration Unit
Surveillance
Procedures
DOS 660006
Bus Undervoltage and ECCS Integrated Functional Test for
Unit 2/3 Diesel Generator to Unit 2
283609
D2 NDO PM RPS 20590-101A Logic Replace Relay
11/09/2023
1308233
Primary Containment (ILRT) Integrated Leak Rate Test
11/14/2023
Work Orders
1375034
Ops PMT 2/35741-48A, CCSW Supply Valve Per DOS
160004
09/28/2023
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
1687812
Op PMT Leak Check 2/35741-071, Valve Relief
CR HVaC Ref Cond
09/28/2023
248640
AsFound Local Leak Rate Test for Reactor Water Clean Up
Inlet Primary Containment Isolation Valves
11/02/2023
296745
OPS PMT Verify No Leaks at System Pressure
09/27/2023
5354746
IMD Replace PS 30261-30D U3 Main Steam Line D Low
Press Isolation
10/06/2023
5381021
D 2/3 Quarterly TS/com Valve Timing IST
09/28/2023
Calculations
Evaluation No.:
2158
§50.54(q) Program Evaluation/Assessment Review
Evaluation No.: 2158: Emergency Action Levels for
Dresden Station: EPAA1004 Addendum 3
EPAA1004
Radiological Emergency Plan Annex for Dresden Station
EPAA1004
Addendum 3
Emergency Action Levels for Dresden Station
EPAA1004,
Addendum 1
Dresden Station OnShift Staffing Technical Basis
EPAA1004,
Addendum 2
Evacuation Time Estimates for Dresden Generating Station
Plume Exposure Pathway Emergency Planning Zone (KLD
TR - 634, Rev. 0)
Procedures
EPDR1000
Dresden Station Radiological Emergency Plan
Miscellaneous
4Q2023FAD
Focused Area Drill
2/07/2023
04557060
Fixed Contamination Found Inside Conestoga Trailer
2/23/2023
04692976
Floor Drain Elevated Dose Rates
07/26/2023
Corrective Action
Documents
04698004
Variance Between DLR and ED Dose
08/17/2023
Miscellaneous
23 Alpha
Assessment
RPAA302 Alpha Level Assessment
08/25/2023
NISP-RP005
Access Controls for High Radiation Areas
RPAA3761001
Radiological Posting, Labeling and Marking Standards
RPAA460
Controls for High and Locked High Radiation Areas
Procedures
RPAA460001
Controls for Very High Radiation Areas
23203636
Unit 2 REBDT Room
10/17/2023
23204548
Reactor Cavity Pre-Decon Survey
01/30/2023
Radiation
Surveys
23204554
Drywell Basement
10/30/2023
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
23204556
CRD Platform
10/30/2023
23204753
20-64A Piping Cutout
11/01/2023
23204753
Air Sample of 2220-64A Piping Cut Out
11/01/2023
DR0223-00503
D2R28 Drywell Small Scope
DR0223-00505
D2R28 Drywell Temporary Shielding
DR0223-00805
D2R28 Turbine and Generator Sand Blasting Activities
Radiation Work
Permits (RWPs)
DR0223-00906
D2R28 Cavity Decon
04451037
Nuclear Oversite Radiation Protection Audit
11/30/2021
Self-Assessments
467522303
10/23/2023
Procedures
RPAA440
Respiratory Protection Program
71151
Miscellaneous
Data Verification Package for Safety System Functional
Failure Performance Indicator, Unit 2 and Unit 3
10/01/2022-
09/30/2023
20435
Unable to Complete U3 HPCI Fast Start per DOS 230007
11/29/2023
Corrective Action
Documents
22873
L4 C&TD2R28 LLT/O Restoration Instruction
Improvements
2/11/2023
Corrective Action
Documents
Resulting from
Inspection
4690019
NRC ID: Documentation for DOS 660008 Incomplete
07/07/2023
HUAA104101
Procedure Use and Adherence
Procedures
RMAA1011008
Processing and Storage of Records
533460039
OPD Div 1 CS Fill/Vent System Following Maintenance
11/17/2023
533460040
OPD Div 2 CS Fill/Vent/Run System Following Maintenance
11/17/2023
Work Orders
533460042
OPD HPCI Fill/Vent Following Maintenance
11/17/2023