IR 05000237/2021004

Integrated Inspection Report 05000237/2021004 and 05000249/2021004

ML22038A195
Person / Time
Site:	Dresden
Issue date:	02/07/2022
From:	Kenneth Riemer NRC/RGN-III/DRP/B1
To:	Rhoades D Constellation Energy Generation, Constellation Nuclear
References
IR 2021004
Download: ML22038A195 (32)

Text

February 7, 2022

SUBJECT:

DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 - INTEGRATED INSPECTION REPORT 05000237/2021004 AND 05000249/2021004

Dear Mr. Rhoades:

On December 31, 2021, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Dresden Nuclear Power Station, Units 2 and 3. On January 20, 2022, the NRC inspectors discussed the results of this inspection with Mr. P. Boyle, Site Vice President, and other members of your staff. The results of this inspection are documented in the enclosed report.

One Severity Level IV violation without an associated finding is documented in this report. We are treating this violation as a non-cited violation (NCV) consistent with Section 2.3.2 of the Enforcement Policy.

No NRC-identified or self-revealing findings were identified during this inspection.

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 III; the Director, Office of Enforcement; and the NRC Resident Inspector at Dresden Nuclear Power Station, Units 2 and 3. 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, Signed by Riemer, Kenneth on 02/07/22 Kenneth R. Riemer, Chief Branch 1 Division of Reactor Projects Docket Nos. 05000237 and 05000249 License Nos. DPR-19 and DPR-25

Enclosure:

As stated

Inspection Report

Docket Numbers: 05000237 and 05000249 License Numbers: DPR-19 and DPR-25 Report Numbers: 05000237/2021004 and 05000249/2021004 Enterprise Identifier: I-2021-004-0090 Licensee: Constellation Energy Generation, LLC Facility: Dresden Nuclear Power Station, Units 2 and 3 Location: Morris, IL Inspection Dates: October 01, 2021 to December 31, 2021 Inspectors: A. Nguyen, Senior Resident Inspector M. Domke, Reactor Inspector G. Edwards, Senior Health Physicist R. Elliott, Resident Inspector J. Neurauter, Senior Reactor Inspector M. Porfiirio, Illinois Emergency Management Agency L. Torres, Nuclear Safety Engineer, Illinois Emergency Management Agency R. Trelka, Reactor Inspector Approved By: Kenneth R. Riemer, Chief Branch 1 Division of Reactor Projects Enclosure

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

Ultimate Heat Sink Licensing and Design Basis Changed without NRC Approval Cornerstone Severity Cross-Cutting Report Aspect Section Not Applicable Severity Level IV Not Applicable 71152 NCV 05000237,05000249/2021004-01 Open/Closed The inspectors identified a Severity Level IV non-cited violation of 10 CFR 50.59(c)(2)(ii) due to the licensee's failure to obtain a license amendment prior to implementing a proposed change which resulted in a more than minimal increase in the likelihood of occurrence of a malfunction of a structure, system, or component important to safety previously evaluated in the final safety analysis report (as updated). Specifically, the licensee implemented Updated Final Safety Evaluation Report change DFL 12-007, which incorrectly eliminated a seismically induced failure of the Dresden lock and dam, the failure of other non-seismically qualified equipment, and a concurrent loss of offsite power from the plant's licensing and design basis without Agency approval.

Additional Tracking Items

Type Issue Number Title Report Section Status LER 05000249/2021001-00 LER 2021-001-00 for 71153 Closed Dresden Nuclear Power Station, Unit 3, Reactor Scram due to Main Power Transformer Failure

PLANT STATUS

Unit 2 began the inspection period coasting down in preparation for refueling outage D2R27.

Unit 2 was shut down for D2R27 on November 8, 2021. Unit 2 went critical on November 21, 2021, and synched to the grid on November 22, 2021, to exit D2R27. The unit achieved rated thermal power on November 24, 2021. Unit 2 conducted a downpower to around 70 percent rated thermal power on December 11, 2021, for control rod sequence exchanges coming out of the refueling outage. The unit was returned to rated thermal power on December 12, 2021 and remained at or near rated thermal power for the remainder of the inspection period.

Unit 3 began the inspection period at rated thermal power. Unit 3 experienced an automatic turbine trip and reactor scram on October 16, 2021. The unit remained shut down to fix a failed main power transformer associated with the trip during forced outage D3F53. Unit 3 went critical on October 30, 2021 and synched to the grid on November 2, 2021. Unit 3 achieved rated thermal power on November 3, 2021. On November 18, 2021, Unit 3 experienced a fire in the control power cabinet of the main power transformer. The unit was taken offline to affect repairs. The unit synched to the grid on November 20, 2021 and returned to rated thermal power on November 21, 2021. The unit remained at or near rated thermal 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, conducted routine reviews using IP 71152, Problem Identification and Resolution, 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.

On February 1, 2022, the operating license for Dresden held by Exelon Generation Company, LLC was transferred to Constellation Energy Generation, LLC (Constellation) as documented in the associated license amendments (ML22021B660). While some or all of the inspection documented in this report was performed while the license was held by Exelon Generation Company, LLC, this report will refer to the licensee as Constellation throughout.

71111.01 - Adverse Weather Protection

External Flooding Sample (IP Section 03.03) (1 Sample)

(1) The inspectors evaluated that flood protection barriers, mitigation plans, procedures, and equipment are consistent with the licensees design requirements and risk analysis assumptions for coping with external flooding on October 15, 2021.

71111.04 - Equipment Alignment

Partial Walkdown Sample (IP Section 03.01) (5 Samples)

The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:

(1) Unit 3 shutdown cooling system on October 20, 2021, during D3F53

(2) Unit 2/3 emergency diesel generator (EDG) on October 20-21, 2021

(3) Unit 2 fuel pool cooling system on November 12, 2021, during D2R27

(4) Unit 2 shutdown cooling system on November 15, 2021, during D2R27

(5) Unit 2 and Unit 3 electrical power systems during crosstie alignments for D2R27 on November 11 and 14, 2021

71111.05 - Fire Protection

Fire Area Walkdown and Inspection Sample (IP Section 03.01) (7 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 8.2.5E, Unit 3 reactor feed pumps elevation 517' on October 20, 2021

(2) Fire Zone 9.0.C, Unit 2/3 swing diesel generator room elevation 517' on October 20, 2021

(3) Fire Zone 8.2.1B, Unit 3 condensate pumps elevation 469' on October 21, 2021

(4) Fire Zone 1.1.2.5.A, Unit 2 isolation condenser area elevation 589' on November 1, 2021

(5) Fire Zone 8.2.6B, Unit 2 low pressure heater bays elevation 538' and Fire Zone 8.2.5B Unit 2 low pressure heater bays elevation 517' on November 9, 2021

(6) Fire Zone 8.2.5.A, Unit 2 switchgear and motor control center elevation 517' and Fire Zone 8.2.6.A, Unit 2 switchgear area elevation 534' on November 12, 2021

(7) Fire Zone 8.2.6.C, Unit 2/3 lube oil reservoir area elevation 534' and Fire Zone 8.2.6.C, Unit 2/3 heat exchanger area elevation 534' on November 14, 2021

71111.06 - Flood Protection Measures

Inspection Activities - Internal Flooding (IP Section 03.01) (1 Sample)

The inspectors evaluated internal flooding mitigation protections in the:

(1) Unit 2 containment cooling service water pump vault

71111.08G - Inservice Inspection Activities (BWR)

BWR Inservice Inspection Activities Sample - Nondestructive Examination and Welding

Activities (IP Section 03.01)

(1) The inspectors verified that the reactor coolant system boundary, reactor vessel internals, risk-significant piping system boundaries, and containment boundary were appropriately monitored for degradation and that repairs and replacements were appropriately fabricated, examined, and accepted by reviewing the following activities from November 8, 2021, to November 18, 2021:

03.01.a - Nondestructive Examination and Welding Activities.

1. Ultrasonic examination (UT) of two low pressure coolant injection piping system welds, American Society of Mechanical Engineers (ASME) category R-A, Item R1.20, elbow-pipe weld, component 2/2/1502-24/24-2 and pipe-elbow weld, component 2/2/1502-24/24-3 on drawing ISI-202 2. UT of isolation condenser nozzle to shell weld, ASME category C-B, item C2.21, component 2/2/1302B-12/12-8 on drawing ISI-201 3. Magnetic particle examination (MT) of isolation condenser nozzle to shell weld, ASME category C-B, item C2.21, component 2/2/1302B-12/12-8 on drawing ISI-201 4. MT examination of reactor pressure vessel skirt weld, ASME category B-K, component 2/1/RPV LWR HD/M-1175D-5(IWA)5. Visual examination (VT-1) of reactor pressure vessel flange bolting, ASME category B-G-1, item B6.10, component 2/1/RPV UPP HD/HD NUTS (92)6. Visual examination (VT-3) of two containment cooling service water system piping supports, ASME category F-A, item F1.30, component 2/3/1514-16/M-1164D-133 and component 2/3/1514-16/M-1164D-265 on drawing ISI-300, sheet 4 7. EC 629967, D2R26 - engineering evaluation for moisture barrier and drywell liner degradation (NDE Report 19-627 / AR 04294208 and NDE report 19-711 / AR 04295748)8. EC 629936, Dresden Unit 2 reactor pressure vessel top head flaw evaluation, Fall 2019 - D2R26 (GE UT NDE Report AVR-20 / AR 04294489)9. Replacement of Unit 2 standby liquid control system piping and fittings, welds 1 through 34 (Work Order 04829744-01)10. Replacement of reactor pressure vessel head vent flange on line 2-0215-1-A, Weld-1 (Work Order 04977143-01)11. Inspect and repair weld on Unit 2 2B upper low pressure coolant injection heat exchanger (Work Order 04739314-01)

71111.11Q - Licensed Operator Requalification Program and Licensed Operator Performance

Licensed Operator Performance in the Actual Plant/Main Control Room (IP Section 03.01)

(3 Samples)

(1) The inspectors observed and evaluated licensed operator performance in the control room during Unit 3 reactor startup from forced outage D3F53 on October 30, 2021.

(2) The inspectors observed and evaluated licensed operator performance in the control room during Unit 2 reactor shutdown and re-start activities from refueling outage D2R27 on November 7, 20, and 22, 2021.

(3) The inspectors observed and evaluated licensed operator performance in the control room during an emergent downpower on Unit 3 due to repairs needed to the main power transformer on November 18, 2021. The inspectors also observed and evaluated licensed operator performance in the control room during the Unit 3 power ascension activities and main generator synch to the grid on November 20, 2021.

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) Main steam system

(2) Circulating water system

(3) EDG air start system

71111.13 - Maintenance Risk Assessments and Emergent Work Control

Risk Assessment and Management Sample (IP Section 03.01) (6 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 3 emergent work and elevated risk for forced outage D3F53 for main power transformer 3 fire on October 16-30, 2021

(2) Unit 3 elevated radiological risk due to intermediate range monitor 13 removal from the reactor for replacement on October 26, 2021

(3) Unit 2 elevated risk for two lowered inventory windows during D2R27, on November 9 and 17, 2021

(4) Unit 2 and Unit 3 elevated risk due to Division I and Division II 4 kilovolt electrical power crossties during D2R27 on November 11 and 13, 2021

(5) Unit 2 and Unit 3 elevated risk for out of service window for transformer 22, on November 16, 2021

(6) Unit 3 elevated risk and emergent work on main power transformer 3, on November 18, 2021

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 3 EDG failure to start due to moisture in air start motor

(2) 3C reactor feedwater pump loose parts evaluation for discharge valve pin failure

(3) Evaluation of Unit 2 scram valve diaphragms for use beyond recommended service life

(4) Unit 2 main steam isolation valves (MSIVs) historical operability evaluations for failures identified during outage testing

(5) Unit 2 reactor water cleanup pump room floor penetration degradation

71111.18 - Plant Modifications

Temporary Modifications and/or Permanent Modifications (IP Section 03.01 and/or 03.02)

(1 Sample)

The inspectors evaluated the following temporary or permanent modifications:

(1) Engineering Change 635573, temporary change to main power transformer 3 winding hot spot temperature indicator due to degraded heating function

71111.19 - Post-Maintenance Testing

Post-Maintenance Test Sample (IP Section 03.01) (10 Samples)

The inspectors evaluated the following post-maintenance test activities to verify system operability and functionality:

(1) Unit 3 EDG operability run following replacement of air start regulator, relay valve, and upper motor on October 21, 2021, per WO 5187735-01

(2) Validation of pipe integrity following containment cooling service water pipe elbow leak repairs on October 26, 2021, per WO 5197721-05

(3) Intermediate range monitor (IRM) functional and acceptance testing after Unit 3 IRM 13 and 15 replacements during D3F53 on October 26, 2021

(4) IRM functional and acceptance testing after Unit 2 IRM repairs during D2R27 on November 8-11, 2021

(5) Unit 2 reactor coolant pressure boundary 10-year system leakage test in accordance with ASME section XI on November 19, 2021, per WO 05001122-03

(6) DOS 6600-07, Testing low pressure coolant injection swing bus protective relays and auto transfer function, after replacement of time delay relay for MCC 28-7/29-7 failure to auto swap on November 20, 2021

(7) Unit 3 reactor recirculation pump seal replacements during D3F53 per WO 5118338 and WO 5169343

(8) Unit 2 isolation condenser '2' and '3' valve repairs which verified stroke length 2- 1301- 3 per WO 04974818-01

(9) Unit 2 reactor protection system relay, 2-0595-140B, replacement after found chattering during startup from refueling outage, per WO 5205029

(10) DOS 0250-02, full closure timing and exercising of main steam isolation valves, after timing adjustments for Unit 2 MSIVs during D2R27, November 12-21, 2021

71111.20 - Refueling and Other Outage Activities

Refueling/Other Outage Sample (IP Section 03.01) (2 Samples)

(1) The inspectors evaluated refueling outage D2R27 activities from November 7, 2021, to November 22, 2021.

(2) The inspectors evaluated forced outage D3F53 activities for main power transformer 3 failure from October 16, 2021, to November 2, 2021.

71111.22 - Surveillance Testing

The inspectors evaluated the following surveillance tests:

Surveillance Tests (other) (IP Section 03.01)

(1) DOS 6600-05, Bus Undervoltage and Emergency Core Cooling System Integrated Functional Test for Unit 2 EDG on November 10, 2021

RCS Leakage Detection Testing (IP Section 03.01) (1 Sample)

(1) Increased Drywell Leakage during startup from D2R27 on November 22, 2021

Containment Isolation Valve Testing (IP Section 03.01) (1 Sample)

(1) DOS 0250-02, Full Closure Timing and Exercising of MSIVs on November 8,

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) (3 Samples)

The inspectors observed/evaluated the following licensee processes for monitoring and controlling contamination and radioactive material:

(1) The inspectors observed workers exiting the radiological controlled area at Unit 2 during a refueling outage

(2) The inspectors observed licensee surveys of potentially contaminated material leaving the radiological controlled area

(3) The inspectors observed work area staging for inspection/repairs of the Unit 2 low pressure turbine blade sandblasting

Radiological Hazards Control and Work Coverage (IP Section 03.04) (3 Samples)

The inspectors evaluated the licensee's control of radiological hazards for the following radiological work:

(1) The inspectors observed low pressure turbine blade sandblasting repairs/inspections during the fall 2021 outage (Radiation Work Permit DR-02-21-00805 and associated ALARA documentation)

(2) The inspectors observed main steam line isolation valve maintenance activities during the fall 2021 outage (Radiation Work Permit DR-02-21-00509 and associated ALARA documentation)

(3) The inspectors observed drywell snubber inspection activities during the fall 2021 outage (Radiation Work Permit DR-02-21-00520 and associated ALARA documentation)

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:

(1) Unit 2 drywell general areas

(2) Unit 2 refuel floor (platform over the reactor cavity)

(3) Unit 2 turbine work area 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.

71124.02 - Occupational ALARA Planning and Controls

Verification of Dose Estimates and Exposure Tracking Systems (IP Section 03.02) (3 Samples)

The inspectors evaluated dose estimates and exposure tracking for the following activities:

(1) The inspectors evaluated items associated with Radiation Work Permit LA-02-21-00520 and associated ALARA documentation for D2R27 drywell snubber inspections during the fall 2021 outage

(2) The inspectors evaluated items associated with Radiation Work Permit LA-02-21-00509 and associated ALARA documentation for D2R27 drywell main steam isolation repairs/inspections during the fall 2021 outage

(3) The inspectors evaluated items associated with Radiation Work Permit LA-02-21-00513 and associated ALARA documentation for D2R27 drywell under vessel control rod drive exchange activities during the fall 2021 outage

Implementation of ALARA and Radiological Work Controls (IP Section 03.03) (3 Samples)

The inspectors reviewed as low as reasonably achievable practices and radiological work controls for the following activities:

(1) The inspectors evaluated items associated with Radiation Work Permit LA- 02- 21- 00520 and associated ALARA documentation for D2R27 drywell snubber inspections during the fall 2021 outage

(2) The inspectors evaluated items associated with Radiation Work Permit LA- 02- 21- 00805 and associated ALARA documentation for D2R27 turbine building sandblasting activities during the fall 2021 outage

(3) The inspectors evaluated items associated with Radiation Work Permit LA- 02- 21- 00807 and associated ALARA documentation for D2R27 turbine building moisture separator activities during the fall 2021 outage

Radiation Worker Performance (IP Section 03.04) (1 Sample)

(1) The inspectors evaluated radiation worker and radiation protection technician performance during work activities.

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, 2020 through September 30, 2021)

(2) Unit 3 (October 1, 2020 through September 30, 2021)

BI01: Reactor Coolant System (RCS) Specific Activity Sample (IP Section 02.10) (2 Samples)

(1) Unit 2 (September 1, 2020 through October 31, 2021)

(2) Unit 3 (September 1, 2020 through October 31, 2021)

BI02: RCS Leak Rate Sample (IP Section 02.11) (2 Samples)

(1) Unit 2 (October 1, 2020 through September 30, 2021)

(2) Unit 3 (October 1, 2020 through September 30, 2021)

OR01: Occupational Exposure Control Effectiveness Sample (IP Section 02.15) (1 Sample)

(1) September 1, 2020 through October 31, 2021 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) September 1, 2020 through October 31, 2021

71152 - Problem Identification and Resolution (PI&R)

Semiannual Trend Review (IP Section 02.02) (1 Sample)

(1) The inspectors reviewed the licensees corrective action program for potential adverse trends in equipment reliability that might be indicative of a more significant safety issue.

Annual Follow-Up of Selected Issues (IP Section 02.03) (1 Sample)

The inspectors reviewed the licensees implementation of its corrective action program related to the following issues:

(1) Resolution of issue of concern regarding design and licensing bases changes to the ultimate heat sink

71153 - Follow-Up of Events and Notices of Enforcement Discretion Event Follow-Up (IP Section 03.01)

(1) The inspectors evaluated main power transformer 3 failure and the licensees response on October 16, 2021

(2) The inspectors evaluated a small fire in main power transformer 3 control power cabinet and the licensees response on November 18, 2021

Event Report (IP Section 03.02) (1 Sample)

The inspectors evaluated the following licensee event reports (LERs):

(1) LER 05000249/2021-001-00, Unit 3 Reactor Scram due to Main Power Transformer Failure, ADAMS Accession No. ML21355A306. The inspectors determined that it was not reasonable to foresee or correct the cause discussed in the LER, therefore no performance deficiency was identified. The inspectors did not identify a violation of NRC requirements.

INSPECTION RESULTS

Ultimate Heat Sink Licensing and Design Basis Changed without NRC Approval Cornerstone Severity Cross-Cutting Report Aspect Section Not Severity Level IV Not 71152 Applicable NCV 05000237,05000249/2021004-01 Applicable Open/Closed The inspectors identified a Severity Level IV non-cited violation of 10 CFR 50.59(c)(2)(ii), due to the licensee's failure to obtain a license amendment prior to implementing a proposed change which resulted in a more than minimal increase in the likelihood of occurrence of a malfunction of a structure, system, or component important to safety previously evaluated in the final safety analysis report (as updated). Specifically, the licensee implemented Updated Final Safety Evaluation Report change DFL 12-007 which incorrectly eliminated a seismically induced failure of the Dresden lock and dam, the failure of other non-seismically qualified equipment, and a concurrent loss of offsite power from the plant's licensing and design basis without Agency approval.

Description:

The normal heat sink for Dresden Station is the Kankakee river. Upon a postulated catastrophic failure of the Dresden lock and dam, the normal plant heat sink would become unavailable because the river level would fall below the high point of the intake and discharge canals. The decreasing river level would cause water to be trapped in both canals between each canals high point and the plant. The water trapped in the intake canal above the suction of the diesel generator cooling water (DGCW) pumps is credited as the ultimate heat sink (UHS) available water volume following a failure of the lock and dam, as described in Updated Final Safety Analysis Report (UFSAR) Section 9.2.5.3.1. This water is supplied to the shell side of the isolation condensers (ICs) for a specific number of days to support bringing and maintaining the reactors to a hot shutdown condition. Once the water in the intake canal is near depletion, the UHS must be replenished with water to support maintaining the reactors in a hot shutdown condition for 30 days following a catastrophic lock and dam failure.

While performing the triennial UHS inspection, the inspectors identified several deficiencies with the assumed available UHS water inventory. These deficiencies resulted in a Green Finding and a Non-Cited Violation (NCV) of 10 CFR 50, Appendix B, Criterion III, Design Control, for the licensees failure to verify or check the adequacy of the UHS and the DGCW system design for a loss of lock and dam scenario. The inspectors also identified an Apparent Violation (AV) of 10 CFR 50.59, Changes, Tests and Experiments, for the licensees failure to have a written evaluation which provided the bases for determining a change made, pursuant to 10 CFR 50.59(c) did not require a license amendment (EA-20-053). The NRC documented these items in NRC Inspection Report 05000237/2020012 and 05000249/2020012 (ML20140A181). In addition, the NRC provided the licensee with an opportunity to respond to the AV by attending a pre-decisional Enforcement Conference or providing a written response.

The licensee provided a written response to the AV via letter dated July 2, 2020 (ML20184A260). The NRC reviewed the information provided by the licensee but did not use it to disposition the AV as a Severity Level IV NCV of 10 CFR 50.59 (see NRC Inspection Report 05000237/2020090 and 05000249/2020090). However, while reviewing the information provided by the licensee, the NRC identified an issue of concern with 10 CFR 50.59 Evaluation 2020-02-001, Update to UFSAR Section 9.2.5.3.1, DOA 0010-01, and DTS 4450-04, Revision 1. Specifically, Evaluation 2020-02-001 resulted in the licensee adopting a new loss of lock and dam strategy which relied on the use of water from multiple, non-seismically qualified tanks and piping to replenish the UHS following a loss of the lock and dam. This concerned the inspectors since the plants original licensing and design basis included a loss of the lock and dam due to a seismic event coincident with a loss of offsite power (LOOP), which would result in non-seismically qualified equipment being unavailable.

At the time, the NRC determined follow-up actions and additional inspection would be needed to review this new issue of concern.

The NRC performed an in-depth review of Evaluation 2020-02-001 and the Dresden design and licensing bases. The NRC found the information and bases provided in Evaluation 2020-02-001 was partially based on a previous UFSAR change which modified the site's licensing bases. Specifically, the licensee implemented UFSAR change DFL 12-007 on March 29, 2012, to "clarify that a large break LOCA [loss of coolant accident] coincident with a seismic event that fails the DRESDEN Lock and Dam is not part of the licensing bases". To implement UFSAR change DFL 12-007 the licensee performed 50.59 screening 2012-0067, and modified various UFSAR sections including:

9.2.5.3.1 - "Dam Failure During Normal Plant Operation" - This section traces its creation to the original licensing process for Dresden; 9.2.5.3.2 - "Dam Failure Coincident with a Large Break LOCA" - This was the primary intended section to be modified by DFL 12-007; and 9.2.5.3.3 - "Seismically Induced Dresden Dam Failure Coupled with a Small Break LOCA" - This section appears to trace its origins to the Individual Plant External Event Evaluation (IPEEE). The licensee considers the information discussed in this section as beyond design basis information. The inspectors made no conclusion on this specific licensee assertion.

The change to UFSAR Section 9.2.5.3.1 was the focus of the NRCs review since it serves as one of the key sections describing the design and licensing basis for the Dresden UHS.

Section 9.2.5.3.1 also describes the impact of a LOOP on the UHS. For reasons which are not clear, the licensee modified the first sentence of UFSAR Section 9.2.5.3.1 to indicate that no seismic activity was considered concurrent with the lock and dam failure described in this section. Specifically, the first sentence of UFSAR Section 9.2.5.3.1 was modified via UFSAR change DFL 12-007 by adding the underlined words below:

If a catastrophic failure of the Dresden lock and dam occurred with no seismic activity, both Units 2 and 3 could be safely shut down.

This modification effectively removed a seismically induced lock and dam failure concurrent with a LOOP from the site's design and licensing bases. This concerned the inspectors because the removal of this information from the sites licensing and design basis resulted in the licensee being able to use water stored in non-seismically qualified tanks to cool the plant following a lock and dam failure. The inspectors also determined 50.59 screening 2012-0067 failed to provide the bases for why the change to UFSAR Section 9.2.5.3.1 would not be considered adverse and require a 50.59 Evaluation, or a license amendment.

Nuclear Energy Institute (NEI) 96-07, Revision 1, "Guidelines for 10 CFR 50.59 Implementation," Section 4.2, "Screenings," discusses the types of changes which would "screen in" (i.e., require a 50.59 evaluation) when performing a 50.59 screening. Per this section, changes which degrade the seismic qualification of a structure, system, or component (SSC) can affect the UFSAR described function. The inspectors concluded the licensees decision to remove a seismically induced catastrophic lock and dam failure from the licensing basis was an adverse change and required a 50.59 Evaluation because it degraded the overall seismic qualification of the UHS and its ability to support safe shutdown of the reactor(s) following a seismically induced lock and dam failure coincident with a LOOP.

Additionally, NEI 96-07, Section 4.3, "Evaluation Process," provides guidance to determine if a proposed change under evaluation requires a license amendment. Section 4.3.2 states that changes in design requirements for earthquakes should be treated as potentially affecting the likelihood of malfunction of an SSC important to safety. Example 3 from the same section provides that changes which do not satisfy the seismic design bases requirements are to be considered changes that constitute a more than a minimal increase in the likelihood of a malfunction of an SSC important to safety. As a result, the inspectors were concerned the licensee had implemented a change to the plant, as discussed in 50.59 screening 2012-0067, without obtaining a license amendment.

To address the NRC's concern, the licensee prepared a November 2020 document titled, "Position Paper - Dresden UHS 2012 UFSAR Change - 9.2.5.3.1 Non-Seismic," to support the conclusions of 50.59 Evaluation 2020-02-001 and 50.59 screening 2012-0067. The licensee's conclusion provided in the position paper was as follows:

"The Dresden Licensing Basis in response to a loss of Lock and Dam includes strategies to cope with a non-seismic catastrophic failure of the Dresden Lock and Dam (UFSAR Section 9.2.5.3.1) and a seismically induced failure of the Dresden Lock and Dam with a coincident LOOP and a small break LOCA on one unit (UFSAR Section 9.2.5.3.3). UFSAR Section 9.2.5.3.1 traces back to Reference 1 and Section 9.2.5.3.3 is a result of the IPEEE. Throughout the Licensing Basis history, in response to a loss of Lock and Dam event, Dresden has been able to effectively establish UHS make-up from diverse sources (e.g., onsite, off-site, seismic, and non-seismic SSCs). DFL 12-007 attempted to clarify Dresden's Licensing Basis but was ineffective in both documenting the basis for the change and also the impact review. This has been identified as part of IR [Issue Report] 04384954."

(NOTE: Reference 1 is a February 28, 1969 licensee response to a request for information regarding Final Safety Analysis Report, Amendment Number 9 for Unit 2 and Amendment Number 10 for Unit 3)

The inspectors determined a majority of the differing licensing basis views between the NRC and the licensee regarding a Dresden lock and dam failure centered around the use of the phrases "catastrophic failure" vs. "seismic induced failure". The inspectors performed an extensive licensing basis review and found the licensing bases origins for the loss of lock and dam scenario started during initial licensing for Dresden Units 2 and 3. On October 16, 1968, while processing license amendment 9/10 (for Units 2 and 3 respectively) the Atomic Energy Commission (AEC), the predecessor of the NRC, asked the licensee to complete a safety evaluation assuming the lock and dam failed as a result of an earthquake which disabled all Class II systems (e.g., non-seismic systems). Additionally, the AEC specifically requested the licensee to: "Provide an evaluation of the ability of Units 2 and 3 to cope with the effects of an earthquake during normal operation which causes coincident failures of the dam, all Class II systems, and off-site electrical power. How would the consequences be affected by the availability of off-site power?".

In its 2020 position paper, the licensee acknowledges their February 28, 1969 response to the AECs request (this response is the same Reference 1 and Reference 47 noted within this writeup). In addition, the licensee agrees the AECs subsequent acceptance of the information provided to the AEC in response to the request established the loss of lock and dam licensing basis from that point forward. The licensee also noted the response to this scenario served as the basis for what is now UFSAR Section 9.2.5.3.1. However, the licensee contends the scenario discussed with the AEC in 1969 was a "catastrophic failure" which allowed the utilization of non-Class I equipment including equipment located off-site rather than a seismically induced failure.

The inspectors and the licensee disagree on the interpretation of the October 16, 1968 correspondence. The licensee's February 28, 1969 reply referred to the event in question as a "catastrophic failure of the Dresden Dam and Lock." In the context of the response, the inspectors determined the licensee's use of "catastrophic" also encompassed seismically induced lock and dam failures due to the licensees claim that only Class I structures or portions of systems which could meet Class I requirements were available for use following a catastrophic failure of the lock and dam. The licensees reply also specifically stated Class II systems would not be available following a catastrophic lock and dam failure. Additionally, the response established a plant shutdown could be performed while on the emergency diesels (i.e., a LOOP). The licensees response to the AEC specifically stated:

"If catastrophic failure of the Dresden Dam and Lock were to take place, it is still possible to effect a safe shutdown on all three units. The Class I sections of Class II systems were only considered in bringing the plant to a safe condition. It is immaterial whether the shutdown is carried out on normal auxiliary power or on the diesel generators."

The licensee response provided above was subsequently approved by the AEC and incorporated into the Provisional Operating License (POL) which was issued on December 22, 1969. Therefore, the inspectors concluded that: 1) a seismically induced failure of the Dresden Lock and Dam coincident with a LOOP was part of the site's original design and licensing bases; 2) the structures credited to mitigate the event would be Class I and/or parts of Class II systems, which could meet the requirements of a Class I system and be sectionalized/isolated from the failed parts of the system; and 3) the term "catastrophic failure" encompassed a seismically induced failure of the lock and dam.

The licensees November 2020 position paper also referenced a Technical Evaluation Report (TER), TER-C5257-421 "Hydrological Consideration - Dresden 2," performed by Franklin Research Center (an NRC consultant) as part of the Systematic Evaluation Program (SEP).

The licensee's position paper stated the NRC had reviewed the TER and generally concurred with the reports evaluation, conclusions, and recommendations. The licensee reasoned that Franklin Research Center understood FSAR Amendments 9 and 10 described a "catastrophic failure" of the lock and dam, not a "seismically induced structural failure." To support this position, the licensee cited the beginning of TER Section 3.4.3.1, "Vulnerability of the UHS to Failure of the Dresden Lock and Dam," which stated:

"The failure of the Dresden lock and dam can be postulated to occur due to catastrophic structural failure or seismically induced structural failure. Although both of these events are considered by the Licensee to be low probability events, consideration of these events is consistent with topic review criteria. In Reference 47, the licensee provided an evaluation of a catastrophic failure of the Dresden lock and dam. That evaluation concluded that Dresden Units 2 and 3 can be safely shut down and maintained in that condition." (NOTE: Reference 47 is also the February 28, 1969 licensee response to a request for information regarding Final Safety Analysis Report, Amendment Number 9 for Unit 2 and Amendment Number 10 for Unit 3)

The inspectors disagreed with the licensees interpretation of the TER because the report appears to break the lock and dam failure into two separate scenarios (catastrophic structural failure or seismically induced structural failure). The licensee interpreted the beginning of TER Section 3.4.3.1 as implying Reference 47 (the original licensing bases) was only meant to address a "catastrophic structural failure" of the lock and dam. The NRC disagrees with this interpretation. In addition, further reading of TER Section 3.4.3.1 shows the authors of the TER believed use of the phrase catastrophic structural failure in Reference 47 included a seismically induced failure as seen by the following statement:

"The availability of makeup water to the isolation condensers is dependent upon the nature of the initiating event. If the dam failed due to catastrophic structural failure, then make up could be provided by any of the three sources previously mentioned. If the dam failure was caused by seismic phenomena with concomitant effects such as failure of other non-seismic structures and loss of offsite power, then make up water must come from a seismically qualified source. In Reference 47, the Licensee indicated that the demineralized water tank and the contaminated demineralized water tank were not designed to withstand seismic phenomena and therefore would not be available."

Section 3.4.3.1 of the TER goes on to quote the Reference 47 discussion that the Fire Protection system is Class II, but portions of the system which can meet the requirements of Class I can be sectionalized from the failed portions of the system following a catastrophic structural failure of the lock and dam. Based upon this information, the inspectors concluded the TER reiterated the original design and licensing bases which included a seismically induced lock and dam failure, failure of non-seismically qualified SSCs, and a coincident LOOP.

Another point brought forth by the licensee was the origin of UFSAR Section 9.2.5.3.3 - "Seismically Induced Dresden Dam Failure Coupled with a Small Break LOCA.

Specifically, the licensee believes the origins of this section are related to the IPEEE and represents a beyond design bases event. As a discussion on the origins of Section 9.2.5.3.3 is not germane to the discussion of UFSAR Section 9.2.5.3.1 and whether a seismically induced failure of the Dresden lock and dam is part of the plants licensing and design bases, the inspectors did not evaluate or make any conclusions regarding the licensees position on UFSAR Section 9.2.5.3.3.

The licensees November 2020 position paper also addressed the stations 2001 Extended Power Uprate (EPU) licensing efforts. The licensee contends that EPU-related discussions regarding a seismically induced lock and dam failure were related to information from the IPEEE document. The licensee also claimed that throughout their licensing bases history regarding a loss of the lock and dam, the site has been able to establish makeup to the isolation condensers (ICs) using diverse sources including on-site or off-site sources which may or may not be seismically qualified. The inspectors acknowledge that during the EPU licensing process there were discussions regarding the IPEEE as part of the NRCs EPU licensing efforts. However, the IPEEE was part of a larger discussion on items such as external events. The inspectors found there were also discussions during the EPU UHS licensing process referencing back to the SEP and TER, and a discussion about the need to use the emergency diesel generators during a loss of lock and dam event (which implies a LOOP has occurred). Through a review of EPU-related correspondence, the inspectors found that many of the seismic and IPEEE discussions were specific to the availability of credited make-up sources to the isolation condenser (IC). During EPU licensing activities, the NRC noted the licensee did not have a seismically qualified shell side make-up path/source to the IC. However, the NRC also noted the licensee had committed to develop a make-up path to the IC which met the 0.3 g seismic capacity as part of the IPEEE.

Regardless, via licensing correspondence between the licensee and the NRC, it was acknowledged that shell side make-up sources for the IC were not seismically qualified. On September 26, 2001, via letter RS-01-208 to the NRC, the licensee stated, "The sources of makeup water to the IC shell side are not seismically qualified, but given the redundancy and diversity of these sources, there is a high confidence that at least one source will be available following a seismic event." The NRC acknowledged this position when it issued the Safety Evaluation for the EPU license amendment (ML013540187 & ML013620048). Specifically, in Section 6.4.5, "Ultimate Heat Sink," under the topic "Replenishment of the UHS," the NRC stated:

"Both DNPS [Dresden Nuclear Power Station] units can be simultaneously brought to hot shutdown and maintained in that condition for 30 days using the IC following EPU.

The sources of makeup water are not seismically qualified but, considering the redundancy and diversity of the sources, there is a high confidence that at least one source [emphasis added] will be available following a design basis event, including seismic events that could cause dam failure. Based on the review of the licensee's rationale and evaluation, the staff agrees with the licensee's conclusion that the ability of the DNPS UHS to support operations at the proposed EPU conditions is acceptable."

The inspectors noted the use, by the licensee and the NRC, of the phrase, "at least one source will be available," when referring to the make-up sources to the IC following a seismic event including seismic events that could cause a dam failure. As a result, the inspectors agree the site's current licensing bases allows for crediting non-seismic sources of shell side water make-up to the ICs. The key caveat of the approval to use non-seismically qualified make-up sources was the consideration of redundant and diverse sources. This allowed the licensee to assume one of the many sources would survive the seismic event which fails the lock and dam. However, the assumption that multiple or all non-seismic sources would survive (as assumed in the licensees 2012 and 2020 50.59 documents discussed earlier)would represent a change to the approved design and licensing bases.

Based on the research performed and summarized above, the inspectors concluded a seismically induced failure of the Dresden Lock and Dam, with failure of other non-seismically qualified structures/components, and a concurrent LOOP is part of Dresden's design and licensing bases. In addition, using the guidance provided by NEI 96-07, the inspectors concluded the change to UFSAR Section 9.2.5.3.1 effectively changed the sites design and licensing bases and required a license amendment.

Corrective Actions: The licensee is evaluating the violation to determine the appropriate corrective actions.

Corrective Action References: CR 04384954; NRC: 50.59 Basis Clarification CR 04389007; Receipt of NRC UHS Inspection Report CR 04468520; NRC Review of UHS and UFSAR 9.2.5.3.1

Performance Assessment:

The NRC determined that this violation was associated with a previously documented finding assessed using the significance determination process.

Enforcement:

The ROPs significance determination process does not specifically consider the regulatory process impact in its assessment of licensee performance. Therefore, it is necessary to address this violation, which impedes the NRCs ability to regulate using traditional enforcement to adequately deter non-compliance.

Severity: Severity Level IV. This was determined using the example available in Section 6.1.d.2. of the Enforcement Policy (January 15, 2020). Specifically, the associated condition was previously evaluated and resulted in a Green Finding (05000237,05000249/2020012-01).

Violation: Title 10 CFR 50.59(c)(2)(ii) states, in part, that a licensee shall obtain a license amendment pursuant to 10 CFR 50.90 prior to implementing a proposed change, test, or experiment if the change, test, or experiment would result in more than a minimal increase in the likelihood of occurrence of a malfunction of a structure, system, or component (SSC)important to safety previously evaluated in the final safety analysis report (as updated).

UFSAR 9.2.5.3.1, "Dam Failure During Normal Plant Operations," describes many of the key design and licensing bases when postulating a failure of the Dresden Lock and Dam.

Contrary to the above, as of March 29, 2012, the licensee failed to obtain a license amendment prior to implementing a proposed change which resulted in a more than minimal increase in the likelihood of occurrence of a malfunction of an SSC important to safety previously evaluated in the final safety analysis report (as updated). Specifically, prior to implementing UFSAR change DFL 12-007, only a 50.59 screening (2012-0067) was performed. However, the portion of change DFL 12-007 which modified UFSAR Section 9.2.5.3.1 effectively and incorrectly eliminated from the site's design and licensing bases a seismic event which resulted in the failure of the Dresden lock and dam, failure of other non-seismically qualified SSCs, and a concurrent LOOP.

Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.

Observation: Equipment Reliability Trend 71152 The inspectors performed a semiannual review of issues entered into the corrective action program (CAP) and a cognitive review of plant observations over the period of June 1, 2021, to December 31, 2021, to identify any potential trends that might indicate the existence of a more significant safety issue. Based on these reviews, the inspectors concluded that there had been a decline in equipment reliability throughout 2021 that had resulted in a number of operational issues. The inspectors conducted further evaluation of the issues to determine if the underlying causes and contributors to the equipment issues were well-understood and addressed with the licensee's corrective actions and improvement plans. The inspectors identified gaps in the thoroughness of licensee evaluation of issues, consideration of the extent of condition and causes, and evaluation of previous occurrences of the issues. In many cases, the issues had been previously identified by plant personnel or through equipment failures/degradation, however, the inspectors noted planned corrective actions had not been sufficiently prioritized or implemented to fully resolve the deficiencies. In a few other instances, the impact of a change to the SSC's preventive maintenance strategy or modification to the design or monitoring of a system wasn't fully understood to completely evaluate all potential impacts of the change; and in some cases, led to equipment failures/degradations. The inspectors discussed the specific issues with the licensee and highlighted the potential underlying causes (behavioral components) to ensure that the trend was fully understood, and actions were being developed to ensure the holistic issue was being addressed as part of the equipment reliability improvement plan for 2022.

The following are some of the equipment performance issues that were included in this trend:

Unit 3 condenser flow reversal valves failed to function Unit 3 replacement main power transformer put into service without functional deluge system, Serveron system, and hydrogen/moisture monitoring system Unit 2 and 3 reactor recirculation pump seal degradation and operational/design issues Unit 2 mechanical vacuum pump valve lineup causing Unit 3 alarms Leakage in the Unit 2 and Unit 3 low pressure heater bays from the fire protection system Leakage from the Unit 2 and Unit 3 containment cooling service water piping Unit 2 isolation condenser '3' valve failed its acceptance criteria Unit 3 emergency diesel generator failure to start due to moisture in the air start system Potential operator workaround and burden for manual operation of the hydrogen addition system

EXIT MEETINGS AND DEBRIEFS

The inspectors verified no proprietary information was retained or documented in this report.

On January 20, 2022, the inspectors presented the integrated inspection results to Mr. P. Boyle, Site Vice President, and other members of the licensee staff.

On November 15, 2021, the inspectors presented the radiation protection inspection results to Mr. P. Karaba, Site Vice President, and other members of the licensee staff.

On November 18, 2021, the inspectors presented the in-service inspection results to Mr. M. Budelier, Component Program Engineering Manager, and other members of the licensee staff.

On December 21, 2021, the inspectors presented the Technical Debrief & Exit: Ultimate Heat Sink Licensing and Design Basis Changed without NRC Approval inspection results to Mr. J. Biegelson, Engineering Director, and other members of the licensee staff.

DOCUMENTS REVIEWED

Inspection Type Designation Description or Title Revision or

Procedure Date

71111.04 Drawings 12E-2328 Emergency Power System O

Engineering 635007 Alternate Decay Heat Removal (ADHR) Qualification for 0

Evaluations D2R27

Procedures DOP 1000-M1 Unit 2 Shutdown Cooling System Checklist 09

DOP 1000-M1/E1 Unit 3 Shutdown Cooling Checklist 14

DOP 1900-M1 Unit 2 Fuel Pool Cooling System Checklist 17

DOP 6600-E2 Unit 2/3 Standby Diesel Generator 6

DOP 6600-M2 Unit 2/3 Emergency Diesel Generator Checklist 29

DOP 6700-19 Bus 29 Outage 17

DOP-6600-04 Diesel Generator 2/3 Preparation for Standby Operation 32

71111.05 Fire Plans 115 U2RB-12 FZ 1.1.2.5.A Unit 2 Isolation Condenser Area Elevation 589' 02

135 U2TB-38 FZ 8.2.5 B Unit 2 Low Pressure Heater Bays Elevation 517' 02

148 U2TB-50 FZ 8.2.6B Unit 2 Low Pressure Heater Bays Elevation 538' 02

157 U3TB-68 Unit 3 Condensate Pumps Elevation 469', FZ 8.2.1B 04

161 U3TB-72 Unit 3 Reactor Feed Pumps Elevation 517', FZ 8.2.5E 03

184 2/3 EDG Unit 2/3 Swing Diesel Generator Room Elevation 517' 6

Procedures CC-AA-501-1027 Hot Work Precautions and Safety Practices 02

OP-AA-201-004 Fire Prevention for Hot Work 17

71111.06 Corrective Action 1242555 Degraded Piping Upstream of Check Valve 07/21/2011

Documents 1312212 Need WR: CCSW VLT Drain CHK VLV Replace with 01/11/2012

SR COMP

Procedures DOS 1500-21 CCSW Pump Vault Watertight Door Leak Test 01

DOS 4400-01 Containment Cooling Service Water Vault Room Floor Drain 13

DTP 70 Evaluation of CCSW Pump Vault Flood Protection Leakage 02

Test Results

Work Orders 1403807 Repair/Replace Check Valve 2-4999-75 Leaked 1.2 GPM 11/16/2011

677050 8Y PM Perform Check Inspection 2-4999-75 01/14/2012

888212 8Y Actuator Assembly Overhaul 2-4999-74 08/05/2016

71111.08G Calculations Calculation 8.5.0- Minimum Required Containment Thickness at Sand Pocket 1

Inspection Type Designation Description or Title Revision or

Procedure Date

Corrective Action AR 00139424 Support Drawing M-1164D-265 Does Not Match As-Built 01/13/2003

Documents Configuration

AR 00860977 BWRVIP-205, Bottom Head Drain Line I&E Guideline 12/29/2008

AR 04280111 FME: Refuel Floor / Dryer Separator Pit Walk Down 10/18/2019

AR 04292243 NDE VT-3: Noted Heavy Rust / Corrosion During Exam 10/29/2019

AR 04292561 FME on Unit 2 Reactor Pressure Vessel Steam Dryer 10/30/2019

AR 04293016 IVVI: Historical FME Discovered on Jet Pump 18 - Vessel 10/31/2019

Side

AR 04294208 D2R26, Drywell Basement Moisture Barrier Relevant 11/03/2019

Conditions

AR 04294489 D2R26 Reactor Pressure Vessel to Flange Weld 2-SC4-FLG 11/04/2019

Ultrasonic Examination (UT) Results

AR 04295748 D2R26, Unit 2 Drywell Basement Primary Containment 11/08/2019

Metallic Liner VT-1 Exam Results

AR 04459474 D2R27 FAC Inspection Deferrals 11/08/2021

AR 04460717 Support Drawing M-1164D-265 Does Not Match As-built 11/13/2021

Configuration

Drawings ISI-201 Inservice Inspection Class II Isolation Condenser Piping H

ISI-202 Inservice Inspection Class II Low Pressure Coolant Injection F

Piping

ISI-300, Sheet 4 Inservice Inspection Class III Containment Cooling Service D

Water Piping

M-1164D-133 Hanger Mark No. M-1164D-133 1

M-1164D-265 Hanger Mark No. M-1164D-265 1

Engineering EC 629936 Dresden Unit 2 Reactor Pressure Vessel Top Head Flaw 11/10/2019

Changes Evaluation, Fall 2019-D2R26

EC 629967 D2R26, Engineering Evaluation for Moisture Barrier and 0

Drywell Liner Degradation

EC 635538 Structural Evaluation of Degraded Support 0

Miscellaneous RRP 2-19-087 Repair Replacement Plan: Replace 1 Flange on Line 11/06/2019

2-0215-1-A

RRP-19-067 Repair Replacement Plan: Replacement of Unit 2 Standby 09/20/2019

Liquid Control Piping and Fittings

WPS 8-8-GTSM ASME Welding Procedure Specification Record (QW-482) 6

Inspection Type Designation Description or Title Revision or

Procedure Date

NDE Reports D2R27-IWE-003 2/DW Basement Containment Liner Interface (E-C) 11/15/2021

D2R27-MT-004 Magnetic Particle Examination (MT): Component 11/10/2021

2/2/1302B-12/12-8

D2R27-UT-006 UT Calibration / Examination: Component 2/2/1502-24/24-2 11/09/2021

D2R27-UT-007 UT Calibration / Examination: Component 2/2/1502-24/24-3 11/09/2021

D2R27-UT-020 UT Calibration / Examination: Component 11/10/2021

2/2/1302B-12/12-8

D2R27-VT-022 Visual Examination of Pipe Hanger, Support 11/09/2021

2/3/1514-16/M-1164D-133

D2R27-VT-025 Visual Examination of Pipe Hanger, Support 11/09/2021

2/3/1514-16/M-1164D-265

GE UT AVR-20 Upper Shell to Flange Circumferential Weld, Component 10/31/2019

2/1/RPV SHELL/2-SC4-FLG

PT 19-682 Liquid Penetrant Examination: Final Welds #2, 5, 6, 9, 10, 11/06/2019

11, 12, 13, 14, 18, 19, 22, 23, and 24 (Weld Map 1) and #30

and 31 (Weld Map 2)

PT-19-713 Liquid Penetrant Examination: Final Welds #1, 4, 7, 18A, 20, 11/08/2019

24A, 30, 31, and 34 (Weld Map 1)

Report 19-627 General Visual Examination of Drywell Basement Moisture 11/03/2019

Barrier

Report 19-711 VT-1 Examination of Drywell Basement Moisture Barrier 11/08/2019

Report 19-717 Liquid Penetrant Examination: Weld 1 11/09/2019

Report 19-725 Liquid Penetrant Examination: Weld 1 11/11/2019

VT-2 19-191 System Leakage Test WO 04829744-06 11/10/2019

VT-2 19-192 System Leakage Test WO 04829744-04 11/10/2019

Procedures ER-AA-335-002 Liquid Penetrant (PT) Examination 12

ER-AA-335-003 Magnetic Particle (MT) Examination 10

ER-AA-335-014 VT-1 Visual Examination 11

ER-AA-335-016 VT-3 Visual Examination of Component Supports, 13

Attachments and Interiors of Reactor Vessels

GEH-PDI-UT-1 PDI Generic Procedure for the Ultrasonic Examination of 12.1

Ferritic Welds

Work Orders WO 01202827-01 Perform NDE of Dresden Unit 2 Reactor Pressure Vessel 10/30/2011

Bottom Head Drain Line Per BWRVIP-205

Inspection Type Designation Description or Title Revision or

Procedure Date

WO 04739314-01 Inspect and Repair Weld, D2 2B Low Pressure Coolant 10/09/2019

Injection Heat Exchanger

WO 04829744-01 Replace Piping and Fittings for Unit 2 Standby Liquid Control 10/30/2019

System

WO 04977143-01 Replace Reactor Pressure Vessel Head Piping Flange 11/10/2019

71111.11Q Corrective Action 4453407 IRM 15 Spike Causes Half SCRAM on Unit 3 10/16/2021

Documents 4455742 OE Benchmarks: RR Seal Low Pressure Operations 10/26/2021

4457124 DOP 0202-01 Recirculation System Startup Enhancement 10/30/2021

4457556 D3F53 Contingencies for RR Seal Temperature Oscillations 11/01/2021

During Startup

4461397 Critique of Unit 2 Shutdown for D2R27 11/08/2021

4462221 Unit 2 Mechanical Vacuum Pump Valve Lineup Causes 11/20/2021

Unit 3 Alarms

4462376 Unexpected Alarm 902-5, C-10, Channel A IRM Hi Hi/INOP 11/21/2021

4462436 Unit 2 DEHC <Z> VPRO Board Failed 11/21/2021

Procedures DGP 01-01 Unit Startup 201

DGP 02-01 Unit Shutdown 175

DOP 0202-01 Reactor Recirculation System Startup 83

71111.12 Corrective Action 4425857 Unit 3 'A' Main Steam Line Inboard MSIV Partially Closed 05/26/2021

Documents 4454158 U3 EDG Failure to Start 10/20/2021

4455521 Contingent WO for U2 EDG 10/25/2021

4456355 Ops Crew 3 Clock Reset 10/27/2021

4459334 2B MSIV Close Time was Slow 11/08/2021

4461934 2C MSIV 1B Limit Switch Found Failed 11/16/2021

4464799 Unit 3 Condenser Flow Reversal Second Half Incomplete 12/04/2021

Miscellaneous System Health Report and Action Plan: Main Steam 12/15/2021

System Health Report and Action Plan: Circulating Water 12/17/2021

Work Orders 1835285 U3 EDG Failed to Start 01/16/2016

5187735-01 OP D3 1M TS Unit Diesel Generator Operability 10/21/2021

5197601 U3 EDG Failure to Start 10/25/2021

71111.13 Corrective Action 4453735 Unexpected Unit 2 EDG Trouble Alarm 10/18/2021

Documents 4454942 Unit 3 IRM 13 Drive Cable Broken, Detector Stuck 10/20/2021

4455272 Running Unit Signs Not Posted During D3F53 10/24/2021

Inspection Type Designation Description or Title Revision or

Procedure Date

4460035 Entered DOA 4700-01, Instrument Air System Failure 11/10/2021

4460245 MCC 29-7/28-7 did not Auto Swap during DOP 6700-19 11/11/2021

4461231 Unit 2 EDG Room Fire Door Inoperable 11/16/2021

4461692 Cavity Drain Down Critical Path Delay 11/17/2021

Miscellaneous Protected Equipment Lists for D2R27 11/7/2021 -

11/18/2021

Protected Division II 4kV X-Tie (Bus 24-1 from Bus 34) 11/13/2021

Equipment List

Procedures DOA 6500-01 4kV Bus Failure 19

DOP 1900-03 Reactor Cavity, Dryer/Separator Storage Pit and Fuel Pool 60

Level Control

DOP 6700-19 Bus 29 Outage 17

71111.15 Corrective Action 182973 Aged Scram Valves Diaphragms Almost Installed 10/17/2003

Documents 4454158 U3 EDG Failure to Start 10/20/2021

4454248 Foreign Material Loss of Integrity 10/20/2021

4454754 Degraded Shaft on 3C RFP 10/22/2021

4462836 Air Void Identified on U2 2B Core Spray Piping 11/23/2021

4464422 IR 4459334 2B MSIV Historical Operability 11/08/2021

4467276 IR 4461934 2C MSIV 1B RPS Level Switch Historical 12/17/2021

Operability Review

Corrective Action 4461642 NRC ID: Unit 2 Elevation 545' Reactor Water Cleanup 11/17/2021

Documents Pump Room Floor Penetration Collar Broken

Resulting from

Inspection

Drawings M-14 Diagram of Reactor Feed Piping MC

M-30, Sheet 1 Diagram of Reactor Water Clean-Up System AAQ

Engineering 371911 Acceptance Criteria for Venting of the LPCI and Core Spray 00

Changes Systems

Engineering 404118 Unrecoverable Foreign Material in the Feed Water System 0

Evaluations from the 3-3208-C Feed Water Discharge Check Valve

Procedures ER-AA-2009 Managing Gas Accumulation 04

ER-DR-200-101 Periodic Monitoring for Gas Accumulation in ECCS Systems 08

Work Orders 5041757 D2R27 Overhaul HCUs 11/15/2021

Inspection Type Designation Description or Title Revision or

Procedure Date

71111.19 Corrective Action 4453049 DOA 0202-05 Seal Failure Entered due to 3A Recirc Pump 10/14/2021

Documents Seal #2

4454158 U3 EDG Failed to Start 10/20/2021

4455402 Pressure Spike During Performance of DMP 0202-01 10/25/2021

4457765 Unit 3 MPT 3 Deluge Test Deferred 11/01/2021

4458145 Unable to Adjust IRM 17 Pre-Amp 11/02/2021

4458161 IRM 15 Spiking 11/02/2021

4458892 Unit 2 IRM 14 Loss of Power 11/05/2021

4459059 Unexpected Alarm due to Unit 3 IRM 15 Spiking 11/06/2021

4459337 1A MSIV Does Not Meet Closing Time Acceptance Criteria 11/08/2021

4459339 1B MSIV Did Not Meet Closing Time Acceptance Criteria 11/08/2021

4459340 1C MSIV Did Not Meet Closing Time Acceptance Criteria 11/08/2021

4459347 1D MSIV Did Not Meet Closing Time Acceptance Criteria 11/08/2021

4459372 IRM 12 Trip Unit Failed 11/08/2021

4459416 2A MSIV Did Not Meet Closing Time Acceptance Criteria 11/08/2021

4459439 2D MSIV Did Not Meet Acceptance Criteria for Closing Time 11/08/2021

4460248 Unit 2 2B MSIV Stroked Satisfactorily 11/11/2021

4460387 D2R27 NDE VT-3 of 2-1301-2 Valve Indicated Wear/Erosion 11/12/2021

4460660 D2R27 SBLC VT-2 Leak Test 2-1199-103 Valve Packing 11/13/2021

Leak

4460816 Relay 2-0595-140B Found Chattering 11/14/2021

4461079 IRM 16 Degraded Cable 11/15/2021

4461948 2-0302-13B-8A U2 CRD SYS B STAB Insert Valve Leak 11/19/2021

4461991 D2R27 RCPB Class 1 System Leakage Test Results 11/19/2021

4462021 D2R27 Hydro Leak Downstream of 2-0299-113A 40DPM 11/19/2021

4462237 D2R27 Leak From 2-2301-53 RV in U2 HPCI Room 5 DPM 11/20/2021

4462311 2B MSIV Leakage from Manifold O-Rings 11/21/2021

4462391 RPS Relay 2-0590-101A Chattering 11/21/2021

Engineering 452583 Isolation Condenser Reactor Inlet Isolation Valve -Review 00

Changes Differences Between Installed and Replacement Motor and

Determine Impact on Protective Devices

NDE Reports21-179 D2R27 Class 1 System Leakage Test 11/19/2021

Procedures DES 0200-38 MSIV Level Switch Adjustment and SCRAM Setpoint Check 18

Inspection Type Designation Description or Title Revision or

Procedure Date

DOP 0250-03 MSIV Timing Adjustment 09

DOS 0250-02 Full Closure Timing and Exercising of Main Steam Isolation 39

Valves

DOS 0700-02 IRM Downscale Rod Block Functional Test 19

DOS 0700-04 IRM Detector Position Rod Block Functional Test 17

DOS 0700-05 IRM Upscale and Inoperative Functional Testing 15

Work Orders 1401689 Unit 2 IRM 15 Detector Work in D2R27 11/11/2021

4978538 2C Outboard MSIV 10% Close Limit Switch 11/17/2021

5042126 Test LPCI Swing Bus Relays 11/21/2021

5054251 2B Outboard MSIV 10% Close Limit Switch Test 11/16/2021

5104554 Unit 3 IRM 13 Troubleshooting 10/26/2021

5115618 Unit 2 IRM 13 Failed Upscale 11/15/2021

5118338 Unit 3 Forced Outage Reactor Recirculation Pump Seal 10/24/2021

Replacement (3A)

5159849 Unit 3 IRM 15 is Spiking 10/26/2021

5169343 Unit 3 Forced Outage 3B Reactor Recirculation Pump Seal 10/24/2021

Replacement

5187735 Unit 3 Diesel Generator Operability 10/21/2021

5197601 U3 EDG Failure to Start 10/21/2021

202864 Unit 2 IRM 12 Trip Unit Failed 11/08/2021

204465 MCC 29-7/28-8 did not Auto Swap During DOP 6700-19 11/20/2021

205029 Relay 2-0595-140B Chattering 11/17/2021

207058 Replace 2B MSIV Manifold O-Rings 11/21/2021

71111.20 Corrective Action 4453451, Work Hour Limits Waiver 10/16/2021

Documents 4453448,

4453450

4453492 Initial Unit 3 Drywell Entry Walkdown and Inspection for 10/17/2021

D3F53

4454913 Unit 3 DEHC Uninterruptible Power Supply in Alarm 10/22/2021

4455396 Rod Out Block did not Alarm with 2 HCUs in Trouble State 10/25/2021

4456019 Unit 3 CRD HCU 30-39 SSPV Buzzing 10/27/2021

4456681 MPT 3 Oil Level Appears Higher than Desired 10/28/2021

4458864 RPT Outage Schedule WHR Tracking 10/18/2021

Inspection Type Designation Description or Title Revision or

Procedure Date

4460756 D2R27 Check Valve, 2-4799-281A Failed IST Leak Test 11/14/2021

(Target Rock)

4461096 D2R27: Intercept Valve Servos Failed Null Bias Check 11/15/2021

4471322 IMD FLS Work Hour Rule Violation 10/18/2021

4471324 IMD FLS Work Hour Rule Violation 11/07/2021

Corrective Action 4454371 NRC ID: 3-3102-B, 3C2 Feedwater Heater Extraction 10/20/2021

Documents Shutoff MOV Leak

Resulting from 4456569 NRC Identified: Unit 3 Drywell Closeout Questions 10/27/2021

Inspection 4459470 X-Area Secondary Containment Boot Seal Inspection 11/08/2021

4461139 Carbon Dioxide Hose Reel Header Charged 11/16/2021

Miscellaneous D2R27: Dresden Unit 2 Refueling Outage Shutdown Safety 02

Plan

Procedures DFP 0800-07 Fuel Movement During Refueling Operations 42

DOP 0201-04 Reactor Pressure Vessel Water Inventory Control 15

DOP 1000-03 Shutdown Cooling Mode of Operation 85

DOS 1000-02 Alternate Decay Heat Removal Using Shutdown Cooling and 22

Fuel Pool Cooling

DOS 1600-19 Suppression Chamber Closeout Inspection 03

OU-DR-104 Shutdown Safety Management Program 23

Work Orders 4992555 Primary Containment Type B and C Leakage Rate Test 11/07/2021

Summation

71111.22 Work Orders 4738556 Bus 24-1 Undervoltage and ECCS Integrated Functional 11/10/2021

Test

5186675 Diesel Generator Fast Start Operability Surveillance 11/10/2021

71124.01 Procedures NISP-RP-002 Radiation and Contamination Surveys 1

NISP-RP-003 Radiological Air Sampling 1

NISP-RP-005 Access Control for High Radiation Areas 1

Radiation Work DR-02-21-00509 Drywell Main Steam Isolation Valve (MSIV) Activities 0

Permits (RWPs) DR-02-21-00520 Drywell Snubber Activities 0

DR-02-21-00805 Turbine Sandblasting Activities 0

71124.02 ALARA Plans DR-02-21-00513 Drywell Under Vessel Control Rod Drive Exchange 0

DR-02-21-00805 Turbine Building Sandblasting Activities 0

DR-02-21-00807 Turbine Building Moisture Separator Activities 0

Inspection Type Designation Description or Title Revision or

Procedure Date

71151 Miscellaneous Monthly Data Elements for NRC Reactor Coolant System 09/01/2020 -

(RCS) Specific Activity 10/31/2021

Monthly Data Elements for NRC Occupational Exposure 09/01/2020 -

Control Effectiveness Sample 10/31/2021

Data Validation Package for RCS Leak Rate Performance 12/31/2021

Indicator, Unit 2 and Unit 3

Data Validation Package for Safety System Functional 12/31/2021

Failure Performance Indicator, Unit 2 and Unit 3

Monthly Data Elements for NRC Radiological Effluent 09/01/2020 -

Technical Specifications/Offsite Dose Calculation Manual 10/31/2021

Radiological Effluent Occurrences (RETS/ODCM)

Radiological Effluent Occurrences Sample

71152 Corrective Action 04384954 NRC: 50.59 Basis Clarification 11/17/2020

Documents 04389007 Receipt of NRC UHS Inspection Report 12/09/2020

4404120 Unit 2 Low Pressure Heater Bay Fire Protection Header 02/01/2021

Degradation

4455742 OE Benchmarks: Reactor Recirculation Seal Low Pressure 10/26/2021

Operations

4457765 Unit 3 Main Power Transformer Deluge Test Deferred 11/01/2021

4457770 Unit 3 MPT Calisto Hydrogen and Moisture Monitor 11/01/2021

4457771 Unit 3 MPT Serveron Gas-in-Oil Analyzer 11/01/2021

4460238 System Flush Scheduled for Outage not Performed 11/10/2021

4460648 As-found LLRT for 2-2301-45 could not be Performed 11/13/2021

4462206 D2R27 Missed VT-2 PMT of 2-1105A Standby Liquid Control 11/20/2021

Relief Valve

4462221 Unit 2 Mechanical Vacuum Pump Valve Lineup Causes Unit 11/20/2021

Alarms

4462253 D2R27 Unit 2 Main Power Transformer Oil Leak and Sudden 11/20/2021

Pressure Relay Light not Illuminated

4462327 MPT 3 49-1/49-2 Winding Temperature Gauges Elements 11/21/2021

Swapped

4470532 EC 401945 did not Address NERC Standard PRC-019-2 01/07/2022

Impacts

4470925 Missed General Visual Exam on ASME Class MC Valve, 01/10/2022

Inspection Type Designation Description or Title Revision or

Procedure Date

2-8526

4471214 Repair of Unit 3 Heater Bay Fire Protection Header 01/11/2022

4471230 D2R28 CCSW Piping Replacements 01/11/2022

Corrective Action 04468520 NRC Review of UHS and UFSAR 9.2.5.3.1 12/28/2021

Documents

Resulting from

Inspection

Engineering DFL 12-007 UFSAR Change 12-007 and 50.59 Screening 2012-0067 03/28/2012

Changes

Miscellaneous RS-01-208 Additional Information Supporting the License Amendment 09/26/2001

Request to Permit Uprated Power Operation at Dresden

Nuclear Power Station

71153 Corrective Action 4453508 Security - Emergency Response to Site in PA 10/16/2021

Documents 4453866 Critique for Transformer 3 Failure and Unit 3 SCRAM 10/19/2021

4454286 EP Critique / Lessons Learned from Unusual Event 10/16/2021

Declaration

4454768 Critique of Fire Brigade Response to MPT-3 Fire 10/22/2021

4461720 Transformer 3 Trouble 11/18/2021

Engineering 635573 Temporary Change: Main Power Transformer 3, 01

Changes 3-6200-49-2, due to Degraded Heating Function

Miscellaneous Operations Logs 11/18/2021

Event Summary Report of Emergency Declared at the 10/16/2021

Exelon [Constellation] Dresden Station

Operations Logs 10/16/2021

Procedures DEOP 0100-00 Reactor Pressure Vessel Control 13

DGP 02-03 Reactor SCRAM 117

DOA 0010-10 Fire/Explosion 27

EP-AA-1004, Emergency Action Levels for Dresden Station 11

Addendum 3

OP-AA-108-114 Post Transient Review 13

Work Orders 5206323 Transformer 3 Trouble 11/22/2021

29