IR 05000327/2021003

Integrated Inspection Report 05000327/2021003 and 05000328/2021003 and Apparent Violation and Exercise of Enforcement Discretion

ML21314A097
Person / Time
Site:	Sequoyah   (DPR-077, DPR-079)
Issue date:	11/10/2021
From:	Tom Stephen NRC/RGN-II/DRP/RPB5
To:	Jim Barstow Tennessee Valley Authority
References
EA-21-106 IR 2021003
Download: ML21314A097 (26)

Text

November 10, 2021

SUBJECT:

SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 - INTEGRATED INSPECTION REPORT 05000327/2021003 AND 05000328/2021003 AND APPARENT VIOLATION AND EXERCISE OF ENFORCEMENT DISCRETION

Dear Mr. Barstow:

On September 30, 2021, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Sequoyah Nuclear Plant, Units 1 and 2. On October 27, 2021, the NRC inspectors discussed the results of this inspection with Mr. Tom Marshall and other members of your staff.

The results of this inspection are documented in the enclosed report.

Section 71114.04 of the enclosed report discusses a finding with an associated apparent violation for which the NRC has not yet reached a preliminary significance determination. The failure to maintain the effectiveness of an emergency plan to meet the requirements of Title 10 CFR Part 50.47(b)(4) and Part 50 Appendix E to have a standardized EAL scheme with adequate methods, systems, and equipment in use based on facility system and effluent parameters for assessing and monitoring actual or potential offsite consequences of a radiological emergency, was a performance deficiency.

We intend to issue our final safety significance determination and enforcement decision, in writing, within 90 days from the date of this letter. The NRCs significance determination process (SDP) is designed to encourage an open dialogue between your staff and the NRC; however, neither the dialogue nor the written information you provide should affect the timeliness of our final determination. We ask that you promptly provide any relevant information that you would like us to consider in making our determination. We are currently evaluating the significance of this finding and will notify you in a separate correspondence once we have completed our preliminary significance review. You will be given an additional opportunity to provide additional information prior to our final significance determination unless our review concludes that the finding has very low safety significance (i.e., Green). Two findings of very low safety significance (Green) are documented in this report. Two of these findings involved violations of NRC requirements. We are treating these violations as non-cited violations (NCVs) consistent with Section 2.3.2 of the Enforcement Policy.

If you contest the violations or the significance or severity of the violations 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 II; the Director, Office of Enforcement; and the NRC Resident Inspector at Sequoyah, Units 1 and 2.

If you disagree with a cross-cutting aspect assignment in this report, you should provide a response within 30 days of the date of this inspection report, with the basis for your disagreement, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region II; and the NRC Resident Inspector at Sequoyah, Units 1 and 2.

This letter, its enclosure, and your response (if any) will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with Title 10 of the Code of Federal Regulations 2.390, Public Inspections, Exemptions, Requests for Withholding.

Sincerely,

/RA/

Thomas A. Stephen, Chief Reactor Projects Branch 5 Division of Reactor Projects

Docket Nos. 05000327 and 05000328 License Nos. DPR-77 and DPR-79

Enclosure:

As stated

Inspection Report

Docket Numbers:

05000327 and 05000328

License Numbers:

DPR-77 and DPR-79

Report Numbers:

05000327/2021003 and 05000328/2021003

Licensee:

Tennessee Valley Authority

Facility:

Sequoyah Nuclear Plant, Units 1 and 2

Location:

Soddy Daisy, TN 37379

Inspection Dates:

July 01, 2021 to September 30, 2021

Inspectors:

N. Childs, Resident Inspector

W. Deschaine, Senior Resident Inspector

S. Downey, Senior Reactor Inspector

C. Fontana, Emergency Preparedness Inspector

D. Hardage, Senior Resident Inspector

K. Miller, Resident Inspector

A. Nielsen, Senior Health Physicist

W. Pursley, Health Physicist

S. Sanchez, Senior Emergency Preparedness Insp

J. Walker, Emergency Response Inspector

Approved By:

Thomas A. Stephen, Chief

Reactor Projects Branch 5

Division of Reactor Projects

SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Sequoyah Nuclear Plant, Units 1 and 2, in accordance with the Reactor Oversight Process. The Reactor Oversight Process is the NRCs program for overseeing the safe operation of commercial nuclear power reactors. Refer to https://www.nrc.gov/reactors/operating/oversight.html for more information.

List of Findings and Violations

Herculite tarp used as a barrier to protect the 2A emergency diesel generator battery from foreign material intrusion during maintenance.

Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000328/2021003-01 Open/Closed

[P.3] -

Resolution 71111.15 A NRC identified Green finding and associated non-cited violation (NCV) of Sequoyah Unit 2 Technical Specification 5.5.15, Battery Monitoring and Maintenance Program, was identified when the licensee installed a tarp over the 2A-A diesel generator battery. The use of the tarp invalidated battery ventilation requirements to prevent the buildup of an explosive mixture of hydrogen gas.

Failure to Ensure Accurate Instrumentation Threshold Values Are Used for Certain Emergency Classifications Cornerstone Significance/Severity Cross-Cutting Aspect Report Section Emergency Preparedness Pending Apparent Violation AV 05000327,05000328/2021003-02 Open

[H.4] -

Teamwork 71114.04 An Apparent Violation (AV) of Title 10 CFR Part 50.54(q)(2), Title 10 CFR Part 50.47(b)(4)and Title 10 CFR Part 50, Appendix E,Section IV.B was identified for failure to maintain the effectiveness of their emergency plan and a standard emergency classification scheme based on facility system parameters from July 3, 2018 to March 5, 2021. Specifically, the licensees emergency classification scheme for system malfunctions during cold initiating conditions CG1 & CS1, contained threshold values which were overly conservative and could result in an over-classification and unnecessary protective action recommendations to the public.

Failure to Maintain the Capability to Analyze Highly Radioactive Samples in the Onsite Count Room Cornerstone Significance Cross-Cutting Aspect Report Section Public Radiation Safety Green NCV 05000327,05000328/2021003-03 Open/Closed

[H.3] - Change Management 71124.06 The inspectors identified a Green finding and associated NCV of Sequoyah Technical Specification 5.4.1.c, Procedures, when the licensee failed to implement a quality assurance procedure related to the analysis of high activity effluent samples.

Additional Tracking Items

Type Issue Number Title Report Section Status EDG EA-21-106 Failure to Comply with 10 CFR 37 for the Protection of Disused Steam Generators Stored in a Concrete Storage Module 71124.08 Closed LER 05000327/2021-001-00 LER 2021-001-00 for Sequoya Nuclear Plant, Unit 1, Reactor Trip on High Neutron Flux Rate Due to Dropped Control Rods 71153 Closed

PLANT STATUS

Unit 1 began the inspection period at rated thermal power (RTP). On August 6, 2021, the unit was shutdown to repair a steam leak on an extraction line off the high pressure turbine. The unit was returned to RTP on August 10, 2021 and remained at or near RTP for the remainder of the inspection period.

Unit 2 began the inspection period at RTP. On September 1, 2021, the unit began reducing power for end of life (EOL) coastdown. EOL coastdown continued the remainder of the quarter and the unit was at 76 percent RTP at the end 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 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.

Starting on March 20, 2020, in response to the National Emergency declared by the President of the United States on the public health risks of the coronavirus (COVID-19), resident and regional inspectors were directed to begin telework and to remotely access licensee information using available technology. During this time, the resident inspectors performed periodic site visits each week, increasing the amount of time on site as local COVID-19 conditions permitted.

As part of their onsite activities, resident inspectors conducted plant status activities as described in IMC 2515, Appendix D; observed risk significant activities; and completed on site portions of IPs. In addition, resident and regional baseline inspections were evaluated to determine if all or a portion of the objectives and requirements stated in the IP could be performed remotely. If the inspections could be performed remotely, they were conducted per the applicable IP. In some cases, portions of an IP were completed remotely and on site. The inspections documented below met the objectives and requirements for completion of the IP.

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 July 2, 2021.

71111.04 - Equipment Alignment

Partial Walkdown Sample (IP Section 03.01) (3 Samples)

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

(1) A main control room (MCR) chiller/air handling unit and 1A diesel generator handswitch and feeder from 1A shutdown board with B MCR chiller degraded due to high vibrations on July 15, 2021 (2)2A residual heat removal (RHR) system with the 2B RHR pump out of service for planned maintenance on August 25, 2021

(3) U2 train A emergency core cooling system pumps with 2B-B centrifugal charging pump out of service for planned maintenance on September 21, 2021

Complete Walkdown Sample (IP Section 03.02) (1 Sample)

(1) The inspectors evaluated system configurations during a complete walkdown of the Unit 2 auxiliary feedwater (AFW) system on July 13, 2021.

71111.05 - Fire Protection

Fire Area Walkdown and Inspection Sample (IP Section 03.01) (6 Samples)

The inspectors evaluated the implementation of the fire protection program by conducting a walkdown and performing a review to verify program compliance, equipment functionality, material condition, and operational readiness of the following fire areas:

(1) Unit 1 and Unit 2 Auxiliary Building, Elevation 669 on July 21, 2021

(2) Unit 1 and Unit 2 Auxiliary Building, Elevation 749 (Non-RCA) on July 22, 2021

(3) Unit 1 Auxiliary Building, Elevation 690 on August 7, 2021

(4) Unit 2 Auxiliary Building, Elevation 690 on August 15, 2021

(5) Unit 1 and Unit 2 Auxiliary Building, Elevation 759 on September 13, 2021

(6) Unit 1 and Unit 2 Auxiliary Building, Elevation 734 (U-X) on September 15, 2021

71111.06 - Flood Protection Measures

Inspection Activities - Internal Flooding (IP Section 03.01) (2 Samples)

The inspectors evaluated internal flooding mitigation protections in the:

(1) 1B2 and 2A2 480V shutdown board rooms (2)125V vital battery board rooms (I thru IV)

===71111.07SIX - Heat Sink Performance

Ultimate Heat Sink Containment Device and Dam (IP Section 03.05)===

The inspectors the sexennial review of the following Ultimate Heat Sink Containment Device from August 2, 2021 to August 6, 2021:

(1) Essential Raw Cooling Water (ERCW) Channel, Section 03.05. Specifically, Section 03.05.a. was performed.

===71111.07T - Heat Sink Performance The inspectors evaluated heat exchanger/sink performance on the following components from August 2, 2021 to August 6, 2021:

Heat Exchanger (Service Water Cooled) (IP Section 03.02)===

The inspectors evaluated heat exchanger/sink performance on the following:

(1) Safety Injection Pump Lube Oil Cooler 2A-A (SQN-2-CLR-063-0138)

Heat Exchanger (Closed Loop) (IP Section 03.03) (1 Sample)

(1) RHR Heat Exchangers 1A & 2A (SQN-1-HEX-074-0015, SQN-2-HEX-074-0015)

Ultimate Heat Sink (IP Section 03.04) (1 Sample)

(1) ERCW System, Section 03.04. Specifically, Sections 03.04.b and 03.04.d were completed.

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 MCR during Unit 1 shutdown on August 5, 2021, and reactor startup on August 8, 2021.

Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)

(1) The inspectors observed and evaluated a simulator examination scenario on September 6, 2021.

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) Review of Maintenance Rule Fifteenth Periodic Assessment Report (Units 1, 2, and Common), approved on September 2, 2021

71111.13 - Maintenance Risk Assessments and Emergent Work Control

Risk Assessment and Management Sample (IP Section 03.01) (3 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 1 and 2, week of July 18 - 24, 2021, including protection equipment reviews for scheduled maintenance on the 1A emergency diesel generator (EDG), and 1A safety injection pump.

(2) Unit 1 and 2, August 5 - 11, 2021, including protection equipment reviews for scheduled maintenance on the 2A EDG, vital invertor 1-II, 1B AFW pump and planned maintenance outage on Unit 1 to repair a steam leak just off the turbine casing.

(3) Unit 1 and 2, August 22 - 28, 2021, including protection equipment reviews for scheduled maintenance on the 1B EDG, 2B RHR pump, 2B component cooling system pump.

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) Power operated relief valve 1-68-340A stroke time exceeds requirements (CR

===1692192)

(2) C-B essential raw cooling water (ERCW) screen wash pump develops insufficient head (CR 1710144)

(3)2-TR-61-138 ice bed temperature recorder values in error (CR 1709839)

(4) Herculite covering 2A-A DG battery (CR 1708706)

(5) Auxiliary building secondary containment enclosure challenge due to miscommunication of standard in TI-16 (CR 1715829)

71111.18 - Plant Modifications

Temporary Modifications and/or Permanent Modifications (IP Section 03.01 and/or 03.02) (2 Samples)

The inspectors evaluated the following temporary or permanent modifications:

(1) Design Equivalent Change Package SQN-21-022, Centrifugal Charging Pump Injection Tank Inlet Valve (1-FCV-63-39) Stem Modification

(2) Design Equivalent Change Package SQN-19-460, Emergence Diesel Generator Building Fire Damper Removal

71111.19 - Post-Maintenance Testing

Post-Maintenance Test Sample (IP Section 03.01)===

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

(1) Work Order (WO) 121504825, 1-VLV-067-0513A, EDG 1A-A ERCW supply check valve inspection on July 21, 2021

(2) WO 122223769, Repair steam leak on the high pressure turbine on August 11, 2021

(3) WO 120664269, Replace HFA relays in 6.9 kV shutdown board 2B-B on September 21, 2021

71111.22 - Surveillance Testing

The inspectors evaluated the following surveillance tests:

Surveillance Tests (other) (IP Section 03.01)

(1)0-SI-EBT-250-100.3, 125 Vdc Vital Battery and Battery Charger Annual Inspection on July 14, 2021 (2)0-SO-360-3, 6900V FLEX Diesel Generator, diesel generator 3B full load test on August 27, 2021 (3)1-SI-OPS-202-621.A, Periodic Functional Test of Voltage Relay on 6.9kV shutdown board 1A-A, on September 14, 2021

FLEX Testing (IP Section 03.02) (1 Sample)

(1)0-SO-360-225, 480V FLEX Diesel Generator, diesel generator B full load test, on August 13, 2021

71114.01 - Exercise Evaluation

Inspection Review (IP Section 02.01-02.11) (1 Sample)

(1) The inspectors evaluated the conduct of the biennial emergency plan exercise during the week of September 6, 2021. The exercise scenario simulated a reported high reactor coolant system (RCS) dose equivalent iodine for Unit 1, which met the threshold for declaration of an Unusual Event. A short time later, a power operated relief valve on the Unit 1 pressurizer failed open, which met the conditions for declaration of an Alert. A rise in Unit 1 containment radiation monitors met the conditions for declaration of a Site Area Emergency due to the loss of two barriers (RCS & fuel clad). Lastly, a large decrease in Unit 1 containment pressure met the conditions for declaration of a General Emergency, thereby allowing the Offsite Response Organizations to demonstrate their ability to implement emergency actions. This exercise scenario also included a beyond design basis demonstration related to a decreasing spent fuel pool water level.

71114.04 - Emergency Action Level and Emergency Plan Changes

Inspection Review (IP Section 02.01-02.03) (1 Sample)

(1) The inspectors evaluated submitted Emergency Action Level, Emergency Plan, and Emergency Plan Implementing Procedure changes during the week of September 6, 2021. 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) Emergency preparedness drill conducted on August 11, 2021

71114.08 - Exercise Evaluation Scenario Review

Inspection Review (IP Section 02.01 - 02.04) (1 Sample)

(1) The inspectors reviewed and evaluated in-office, the proposed scenario for the biennial emergency plan exercise at least 30 days prior to the day of the exercise.

71124.06 - Radioactive Gaseous and Liquid Effluent Treatment

Walkdowns and Observations (IP Section 03.01) (5 Samples)

The inspectors evaluated the following radioactive effluent systems during walkdowns:

(1) Unit 1, Auxiliary Building Ventilation System Discharge System

(2) Service Building Ventilation System

(3) Unit 1, Condenser Vacuum Exhaust System

(4) Unit 2 Steam Generator Blowdown System

(5) Unit 1 ERCW system

Sampling and Analysis (IP Section 03.02) (3 Samples)

(1) Inspectors evaluated effluent sampling for the Unit 1 Upper Containment Depressurization.

(2) Inspectors evaluated effluent sampling for the Unit 2 Lower Containment Depressurization.

(3) Inspectors evaluated effluent sampling for the Auxiliary Building Ventilation System

Dose Calculations (IP Section 03.03) (2 Samples)

The inspectors evaluated the following dose calculations:

(1) Gaseous Waste Release Permit #2021794.031.240.G, Unit 2 Containment Vent

(2) Liquid Waste Release Permit #2021828.007.557.L, Waste Monitor Tank

71124.08 - Radioactive Solid Waste Processing & Radioactive Material Handling, Storage, &

Transportation

Radioactive Material Storage (IP Section 03.01)

(1) Inspectors evaluated the licensees performance in controlling, labelling and securing radioactive materials.

Radioactive Waste System Walkdown (IP Section 03.02) (1 Sample)

(1) Inspectors walked down accessible portions of the solid radioactive waste systems and evaluated system configuration and functionality.

Waste Characterization and Classification (IP Section 03.03) (2 Samples)

The inspectors evaluated the licensees characterization and classification of radioactive waste.

(1)10 CFR Part 61 waste stream evaluation - Dry Active Waste 4/25/20

(2) Waste stream evaluation for resin liner PO690656-21, 6/24/20

Shipment Preparation (IP Section 03.04) (1 Sample)

(1) The inspectors observed that a shipment containing radioactive material is prepared according to requirements.

Shipping Records (IP Section 03.05) (4 Samples)

The inspectors evaluated the following non-excepted radioactive material shipments through a record review:

(1) SNP 20-1201, Type B, Resin

(2) SNP 20-0201, Type B, Resin

(3) SNP 19-1111, Type A, Outage Equipment

(4) SNP 21-0401, Type B, Filters

OTHER ACTIVITIES - BASELINE

===71151 - Performance Indicator Verification

The inspectors verified licensee performance indicators submittals listed below:

MS05: Safety System Functional Failures (SSFFs) Sample (IP Section 02.04)===

(1) Unit 1 (July 2020 through June 2021)

(2) Unit 2 (July 2020 through June 2021)

MS06: Emergency AC Power Systems (IP Section 02.05) (2 Samples)

(1) Unit 1 (July 2020 through June 2021)

(2) Unit 2 (July 2020 through June 2021)

MS07: High Pressure Injection Systems (IP Section 02.06) (2 Samples)

(1) Unit 1 (July 2020 through June 2021)

(2) Unit 2 (July 2020 through June 2021)

MS08: Heat Removal Systems (IP Section 02.07) (2 Samples)

(1) Unit 1 (July 2020 through June 2021)

(2) Unit 2 (July 2020 through June 2021)

MS09: Residual Heat Removal Systems (IP Section 02.08) (2 Samples)

(1) Unit 1 (July 2020 through June 2021)

(2) Unit 2 (July 2020 through June 2021)

MS10: Cooling Water Support Systems (IP Section 02.09) (2 Samples)

(1) Unit 1 (July 2020 through June 2021)

(2) Unit 2 (July 2020 through June 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) June 30, 2020 through June 30, 2021

EP01: Drill/Exercise Performance (DEP) Sample (IP Section 02.12) (1 Sample)

(1) Unit 1 (July 1, 2020, through June 30, 2021)

Unit 2 (July 1, 2020, through June 30, 2021)

EP02: Emergency Response Organization (ERO) Drill Participation (IP Section 02.13) (1 Sample)

(1) Unit 1 (July 1, 2020, through June 30, 2021)

Unit 2 (July 1, 2020, through June 30, 2021)

EP03: Alert And Notification System (ANS) Reliability Sample (IP Section 02.14) (1 Sample)

(1) Unit 1 (July 1, 2020, through June 30, 2021)

Unit 2 (July 1, 2020, through June 30, 2021)

71152 - Problem Identification and Resolution

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) Defect identified in concrete slab underneath Unit 1 Reactor Cavity/Equipment Pit Area

71153 - Follow Up of Events and Notices of Enforcement Discretion Event Report (IP Section 03.02)

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

(1) LER 05000327/2021-001-00, Reactor Trip on High Neutron Flux Rate Due to Dropped Control Rods. ADAMS accession: ML21202A441. 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 also concluded that no violation of NRC requirements occurred.

INSPECTION RESULTS

Herculite tarp used as a barrier to protect the 2A emergency diesel generator battery from foreign material intrusion during maintenance.

Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems

Green NCV 05000328/2021003-01 Open/Closed

[P.3] -

Resolution 71111.15 A NRC identified Green finding and associated non-cited violation (NCV) of Sequoyah Unit 2 Technical Specification 5.5.15, Battery Monitoring and Maintenance Program, was identified when the licensee installed a tarp over the 2A-A diesel generator battery. The use of the tarp invalidated battery ventilation requirements to prevent the buildup of an explosive mixture of hydrogen gas.

Description:

On July 20, 2021 the inspectors identified herculite on top of the 2A-A diesel generator battery and notified the work control center. The herculite had been installed earlier that morning to provide protection for the battery in preparation for upcoming maintenance to install conduit for battery charger replacement. The covering was draped over the battery bank creating a tented volume that could trap gases produced by the battery bank while being charged. This could allow the buildup of an explosive gas mixture under the tarp. The licensee removed the herculite from 2A-A diesel generator battery later that afternoon.

The herculite material used to cover the battery is waterproof. Manufacturer testing provided a 13.7 grams/m²/day water vapor transmission rate per ASTM E398-13. No specific test for hydrogen gas transmission rate exists. While the herculite is not impermeable to gases it does adversely impact ventilation in the immediate area of the battery that was covered by the material.

During the time the condition existed (July 20, 2021 at 11:00 until July 20, 2021 at 12:45) the battery charger was in float mode. Based on the maximum battery charger voltage of 135 volts allowed in operator rounds, the licensee concluded a maximum of 0.45 ft3 of Hydrogen could have been generated and that hydrogen pockets under the herculite could have been at or above the Lower Explosive Limits of hydrogen in air.

Corrective Actions: The herculite was removed July 20, 2021 at 12:45.

Corrective Action References: CR 1708706

Performance Assessment:

Performance Deficiency: The licensees use of a herculite tarp as a barrier to protect the 2A-A diesel generator battery from foreign material intrusion during maintenance was a performance deficiency. Specifically, the use of the tarp invalidates vender technical manual requirements for adequate battery ventilation to prevent the buildup of an explosive mixture of hydrogen gas.

Screening: The inspectors determined the performance deficiency was more than minor because if left uncorrected, it would have the potential to lead to a more significant safety concern. Specifically, the subsequent engineering evaluation confirmed the potential for buildup of an explosive mixture of hydrogen gas under the tarp and thus an explosive event which could render the EDG unavailable during accident mitigation.

Significance: The inspectors assessed the significance of the finding using Appendix A, The Significance Determination Process (SDP) for Findings At-Power. Using Exhibit 2, Mitigating Systems Screening Questions, the inspectors determined that the finding screened to Green because the finding did not result in the loss of operability or PRA function of the 2A-A diesel generator battery.

Cross-Cutting Aspect: P.3 - Resolution: The organization takes effective corrective actions to address issues in a timely manner commensurate with their safety significance. The use of herculite as a covering during maintenance activities in the vicinity of station batteries had been previous identified as adverse practice by the licensee's Nuclear Safety Review Board in December 2018 and by the NRC in March 2020. The corrective actions taken by the licensee to discontinue this practice included post of signage at the battery stating "If a Foreign Material Exclusion (FME) Cover is to be used over these batteries, it must be a permeable cloth type to prevent hydrogen accumulation under the cover." The sign was not effective in preventing the installation of herculite as a FME barrier.

Enforcement:

Violation: Sequoyah Unit 2 Technical Specification 5.5.15, Battery Monitoring and Maintenance Program, requires the program be in accordance with IEEE Standard 450-2002, IEE Recommended Practice for Maintenance, Testing, and Replacement of Vented Lead-Acid Batteries for Stationary Applications. IEEE Standard 450-2002 requires, in part, "The following protective procedures shall be observed during maintenance: e) Ensure that battery area ventilation is operating per its design." Contrary to this requirement, on July 20, 2021 at 11:00 the licensee install an herculite tarp over the 2A-A diesel generator battery which obstructed the battery's ventilation. The tarp was removed and normal ventilation restored on July 20, 2021 at 12:45.

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

Failure to Ensure Accurate Instrumentation Threshold Values Are Used for Certain Emergency Classifications Cornerstone Significance/Severity Cross-Cutting Aspect Report Section Emergency Preparedness

Pending Apparent Violation AV 05000327,05000328/2021003-02 Open

[H.4] -

Teamwork 71114.04 An Apparent Violation (AV) of Title 10 CFR Part 50.54(q)(2), Title 10 CFR Part 50.47(b)(4)and Title 10 CFR Part 50, Appendix E,Section IV.B was identified for failure to maintain the effectiveness of their emergency plan and a standard emergency classification scheme based on facility system parameters from July 3, 2018 to March 5, 2021. Specifically, the licensees emergency classification scheme for system malfunctions during cold initiating conditions CG1 & CS1, contained threshold values which were overly conservative and could result in an over-classification and unnecessary protective action recommendations to the public.

Description:

On July 3, 2018, the licensee implemented the NRC-approved NEI 99-01 Revision 6 emergency action level (EAL) scheme. This new scheme utilizes a design output value from calculation SQS20110 Revision 37 for emergency classification based on reactor vessel level indication system (RVLIS) percentage values. However, the RVLIS value utilized was incorrect because the design output, used by Emergency Preparedness (EP), was not the value calculated in the actual calculation. The actual value calculated from SQS20110 Rev. 37 was 60% on RVLIS, but the design output table (used by EP) contained a value of 64%. In October 2020, the Sequoyah (SQN) Design Engineering group began working on the Engineering Change Package (ECP) and Risk Review for SQN-20-1219 to update the design output portion of calculation SQS20110. During the updates to the calculation, the licensee identified a latent error with the RVLIS lower range value (top of the reactor core). However, the licensee did not enter the issue into the corrective action program or inform the responsible department (EP). Not until February 22, 2021, was it recognized by the Operations Training Department that there was a difference between the calculation design output table and the EAL threshold value. Condition Report (CR) 1673364 was written to document this issue, and the EAL was corrected on March 5, 2021. Eventually, another CR was written to initiate a causal evaluation (CR 1676064).

The inspectors reviewed the compiled information describing timeframes, types of errors, and the impact of those errors, to help understand the significance of the errors. T he licensees ability to declare emergencies based on facility system parameter values was degraded because event classification using RVLIS would be delayed under certain cold initiating conditions (Mode 5 and 6). The RVLIS threshold values were overly conservative and therefore, would cause a General Emergency to be declared early and unnecessary protective action recommendations (PARs) be made to the public.

Corrective Actions: The licensee entered the issue into the corrective action program on February 3, 2021. Other actions taken by the licensee were to correct the error and initiate a root cause evaluation.

Corrective Action References: Condition Report (CR) 1673364 and 1676064.

Performance Assessment:

Performance Deficiency: The failure to maintain the effectiveness of an emergency plan to meet the requirements of Title 10 CFR Part 50.47(b)(4) and Part 50 Appendix E to have a standardized EAL scheme with adequate methods, systems, and equipment in use based on facility system and effluent parameters for assessing and monitoring actual or potential offsite consequences of a radiological emergency, was a performance deficiency.

Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Procedure Quality attribute of the Emergency Preparedness cornerstone and adversely affected the cornerstone objective to ensure that the licensee is capable of implementing adequate measures to protect the health and safety of the public in the event of a radiological emergency. Specifically, for a decreasing RVLIS under certain plant conditions, an EAL over-classification could occur and result in unnecessary PARs for the public.

Significance: The inspectors assessed the significance of the finding using Appendix B, Emergency Preparedness SDP. This issue is awaiting preliminary assessment by a significance enforcement review panel (SERP).

Cross-Cutting Aspect: H.4 - Teamwork: Individuals and work groups communicate and coordinate their activities within and across organizational boundaries to ensure nuclear safety is maintained. The cause of the finding was determined to be associated with a cross-cutting aspect in the Teamwork component of the Human Performance area because the licensee failed to ensure individuals and work groups communicate and coordinate their activities within and across organizational boundaries to ensure nuclear safety is maintained. Specifically, Engineering did not ensure the appropriate group (Emergency Preparedness) was informed of changes being made to system parameters that affected EAL threshold values. [H.4]

Enforcement:

Violation: Title 10 CFR Part 50.54(q)(2) requires that a holder of a nuclear power reactor operating license under this part, shall follow and maintain the effectiveness of an emergency plan that meets the requirements in Appendix E to this part and the planning standards of 10 CFR 50.47(b). Title 10 CFR Part 50.47(b)(4) requires a standard emergency classification and action level scheme, the bases of which include facility system and effluent parameters, is in use by the nuclear facility licensee, and State and local response plans call for reliance on information provided by facility licensees for determinations of minimum initial offsite response measures. Title 10 CFR Part 50, Appendix E,Section IV.B., Assessment Actions, requires in part, that the means to be used for determining the magnitude of, and for continuously assessing the impact of, the release of radioactive materials shall be described, including EALs that are to be used as criteria for determining the need for notification and participation of local and State agencies, the Commission, and other federal agencies, and the EALs that are to be used for determining when and what type of protective measures should be considered within and outside the site boundary to protect health and safety. The EALs shall be based on in-plant conditions and instrumentation, in addition to onsite and offsite monitoring.

Contrary to the above, since July 3, 2018, until March 5, 2021, the licensee failed to maintain the effectiveness of their emergency plan and a standard emergency classification scheme based on facility system parameters. Specifically, the licensees emergency classification scheme for system malfunctions during cold initiating conditions CG1 & CS1, contained threshold values which were overly conservative and could result in an over-classification and unnecessary protective action recommendations to the public. The failure to maintain the effectiveness of an emergency plan to meet the requirements of 10 CFR Part 50.47(b)(4) and Part 50 Appendix E, pending final determination, is identified as AV 05000327, 328/2021003-XX, Inaccurate Instrumentation Values Results in Overly Conservative EAL Threshold Values.

Enforcement Action: This violation is being treated as an AV violation pending a final significance (enforcement) determination.

Failure to Maintain the Capability to Analyze Highly Radioactive Samples in the Onsite Count Room Cornerstone Significance Cross-Cutting Aspect Report Section Public Radiation Safety

Green NCV 05000327,05000328/2021003-03 Open/Closed

[H.3] - Change Management 71124.06 The inspectors identified a Green finding and associated NCV of Sequoyah Technical Specification 5.4.1.c, Procedures, when the licensee failed to implement a quality assurance procedure related to the analysis of high activity effluent samples.

Description:

During the review of a 10 CFR 61 quality assurance report for resin liner PO690656-21, the inspectors noted that the licensee's gamma analysis results were not in agreement with the offsite vendor laboratory, Teledyne Brown Engineering (TBE). The report determined the error was due to the radioactivity of the resin sample being too high (30 mrem/hr on contact) and contains this conclusion: "TBE has a defined geometry for counting samples with high dose rates. The onsite lab does not have this capability." Discussions with Chemistry staff revealed that the licensee had previously maintained a geometry for highly radioactive samples, but that this detector geometry (Shelf 4) had been abandoned during an equipment upgrade in 2016 and the onsite count room was currently not prepared to analyze hot samples. The inspectors noted however, that Updated Final Safety Analysis Report (UFSAR) Section 11.4.2.2.4 describes maintaining the ability to collect and analyze normal and post-accident particulate and iodine effluent samples in the onsite count room. Also, licensee procedure 0-TI-CEM-016-001.4, "Shield Building Radiation Monitor Sampling Methods", revision 3 states that, "Counting room must be prepared to analyze samples having dose rates of ~ 500 mrem/hr". In order to ensure accurate gamma analysis results, licensee procedure CHDP-109, "Chemistry QA/QC", revision. 1, requires annual verification of detector efficiencies for each geometry and that each geometry be evaluated by periodic interlaboratory cross checks supplied by a National Institute of Standards and Technology (NIST)-traceable vendor. Although Shelf 4 was abandoned in 2016, and no quality assurance checks had been performed on it since that time, it still existed as a selectable geometry in the analysis software. At the inspector's request, the licensee performed a calibration verification per CHDP-109 and determined that Shelf 4 was substantially out of calibration and that the results were consistently low. The licensee also performed an interlaboratory cross-check and Shelf 4 did not meet the acceptance criteria.

Corrective Actions: The licensee plans to recalibrate the Shelf 4 geometry.

Corrective Action References: CR 1707802

Performance Assessment:

Performance Deficiency: The licensees failure to perform routine quality assurance activities on Shelf 4, as required by licensee procedures, was a performance deficiency.

Screening: The inspectors determined the performance deficiency was more than minor because if left uncorrected, it would have the potential to lead to a more significant safety concern. Specifically, the failure to perform quality assurance testing on count room equipment relied upon to analyze highly radioactive particulate and iodine samples could result in inaccurate estimates of effluents released to the environment during off-normal or accident conditions.

Significance: The inspectors assessed the significance of the finding using Appendix D, Public Radiation Safety SDP. Although the finding involved a performance deficiency in the licensee's effluent release program, it did not involve a substantial failure to implement the effluent release program and it did not involve an actual release exceeding 10 CFR 50 Appendix I or 10 CFR 20.1301 dose limits, therefore the finding was determined to have very low safety significance (Green).

Cross-Cutting Aspect: H.3 - Change Management: Leaders use a systematic process for evaluating and implementing change so that nuclear safety remains the overriding priority.

Leaders failed to use a systematic process for evaluating and implementing the last count room equipment upgrade such that nuclear safety remained the overriding priority.

Enforcement:

Violation: Sequoyah Technical Specification 5.4.1.c states that written procedures shall be established, implemented, and maintained for a quality assurance program for effluent and environmental monitoring. Specifically, licensee procedure CHDP-109, "Chemistry QA/QC",

revision. 1, section 3.2.14 requires annual verification of detector efficiencies for each geometry and that each geometry be evaluated by periodic interlaboratory cross-checks. Contrary to this, from 2016 to 2021, detector efficiencies for the Shelf 4 geometry were not verified annually and Shelf 4 was omitted from the periodic interlaboratory cross-check program.

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

Enforcement Discretion Enforcement Action EA-21-106: Failure to Comply with 10 CFR 37 for the Protection of Disused Steam Generators Stored in a Concrete Storage Module 71124.08

Description:

During the 1R12 (spring 2003) and 2R18 (fall 2012) refueling outages, the licensee removed old steam generator units from the Unit 1 and Unit 2 containment buildings and transferred them to a large concrete storage module. Although this waste material exceeded the threshold for a Category 2 quantity of radioactivity, it did not contain discrete radioactive sources, ion-exchange resins, or activated material that weighed less than 2,000 kg. Therefore, the steam generators are considered waste material that is exempt from 10 CFR 37 Subparts B, C, and D, but must comply with the requirements of 10 CFR 37.11. The inspectors observed that some of these requirements were not met.

Corrective Actions: The licensee entered the issue into their corrective action program.

Corrective Action References: CR 1707916

Enforcement:

Violation: 10 CFR 37.11 specifies certain minimal security requirements for a Category 2 quantity of radioactive waste that is exempt from 10 CFR 37 Subparts B, C, and D. Contrary to this, from March 19, 2014 (initial compliance date with 10 CFR 37) to the present, the licensee has stored a Category 2 quantity of exempt waste in a large concrete storage module without meeting all of the security requirements of 10 CFR 37.11.

Basis for Discretion: This violation met the criteria for Enforcement Discretion as described in Enforcement Guidance Memorandum (EGM) 14-001, "Interim Guidance for Dispositioning 10 CFR Part 37 Violations with Respect to Large Components or Robust Structures Containing Category 1 or Category 2 Quantities of Material at Power Reactor Facilities Licensed Under 10 CFR Parts 50 and 52."

EXIT MEETINGS AND DEBRIEFS

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

• On October 27, 2021, the inspectors presented the integrated inspection results to Mr.

Tom Marshall and other members of the licensee staff.

• On July 20, 2021, the inspectors presented the Radiation Protection Exit Meeting inspection results to Mr. T. Marshall and other members of the licensee staff.

• On August 5, 2021, the inspectors presented the Triennial Heat Sink Exit Meeting inspection results to Tom Marshall, Site Vice President and other members of the licensee staff.

• On September 10, 2021, the inspectors presented the Emergency Preparedness Exercise Preliminary Exit Meeting inspection results to Mr. T. Marshall and other members of the licensee staff.

• On November 4, 2021, the inspectors presented the Emergency Preparedness Exercise Inspection Exit Meeting inspection results to Mr. T. Marshall and other members of the licensee staff.

THIRD PARTY REVIEWS

Inspectors reviewed Institute on Nuclear Power Operations reports that were issued during the inspection period.

DOCUMENTS REVIEWED

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

71111.01

Miscellaneous

SQN-DC-V-12.1

Flood Protection Provisions

Revision 18

Procedures

0-TI-SXX-000-017.0

Hazard Barriers

Revision 4

AOP-N.03 Part 1

External Flooding

Revision 61

71111.04

Miscellaneous

0-GO-16 Attachment 15

System Operability Checklists - MCR HVAC

Revision 28

Procedures

0-SO-74-1

Residual Heat Removal System

Revision 110

GO-16 Attachment 18

Checklists for Protected Equipment - U2 ECCS/ESF

Revision 29

71111.05

Corrective Action

Documents

Resulting from

Inspection

20795

A202 fire door found with excessive play when closed

09/13/2021

21445

NRC inspector noted that door A57 has a broken

automatic closing mechanism

09/15/2021

Fire Plans

0-AUX-734-03

Pre-Fire Plan Auxiliary Building, Elevation 734 (U-X)

Revision 8

AUX-0-669-01

Pre-Fire Plan Auxiliary Building, Elevation 669 Unit 1

Side

Revision 8

AUX-0-669-02

Pre-Fire Plan Auxiliary Building, Elevation 669 Unit 2

Side

Revision 12

AUX-0-669-03

Pre-Fire Plan Auxiliary Building, Elevation 669 Common

Area

Revision 3

AUX-0-690-01

Pre-Fire Plan Auxiliary Building, Elevation 690 Unit 1

Side

Revision 9

AUX-0-690-02

Pre-Fire Plan Auxiliary Building, Elevation 690 Unit 2

Side

Revision 9

AUX-0-749-01

Pre-Fire Plan Auxiliary Building, Elevation 749 Unit 1

Side

Revision 7

AUX-0-749-02

Pre-Fire Plan Auxiliary Building, Elevation 749 Unit 2

Side

Revision 8

AUX-0-759-01

Pre-Fire Plan Auxiliary Building, Elevation 759 Unit 1

Side

Revision 5

AUX-0-759-02

Pre-Fire Plan Auxiliary Building, Elevation 759 Unit 2

Side

Revision 5

71111.06

Calculations

MDN-000-000-2010-

203

SQN Probabilistic Risk Assessment - Internal Flooding

Analysis

Revision 6

Procedures

AOP-M.08

Internal Flooding

Revision 6

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

71111.07T

Calculations

MDQ0000742017000040 RHR Heat Exchanger Tube Plugging Limit Analysis

Revision 0

SQN-63-D0530-HCG-

KBO-051383

SQN Safety Injection System Pump Oil Heat Exchanger

Revision 1

Corrective Action

Documents

CRs by Number

1436447, 1437004, 1439556, 1528237, 1551560,

1565716, 1578600

Miscellaneous

0-TI-CEM-000-001.4

Auxiliary System and Common System Chemistry

Specifications

Revision

0049

0-TI-DXX-000-915.0

Underground Piping and Tanks Integrity Program

Revision

0007

CHEM-004

Sequoyah Nuclear - Raw Water Chemistry Strategic

Plan

Revision 003

SQN-DC-V-7.4

Design Criteria Document for the Essential Raw Cooling

Water System

Revision 34

Procedures

0-PI-SFT-067-001.A

ERCW Train A Flow Monitoring

Revision 005

AOP-M.01

Loss of Essential Raw Cooling Water

Revision

0036

Work Orders

Work Orders by Number

114073526, 117838594, 118652831, 118913750,

119876527, 120561705, 121497641

71111.11Q Miscellaneous

SEG SX-402

Tcold, Thermal Barrier Booster Pump Trip, RCP trip and

LBLOCA

Revision 0

71111.12

Miscellaneous

Maintenance Rule Fifteenth Periodic Assessment

Report Units 1, 2, and Common - 10CFR50.65

Paragraph (a)(3)

Revision 0

71111.13

Corrective Action

Documents

Resulting from

Inspection

CR 1708706

Herculite on top of 2A-A DG Battery

07/20/2021

Procedures

0-GO-16

System Operability Checks

Revision 28

71111.15

Miscellaneous

Past Operability Evaluation for CR 1709839

08/10/2021

ACMP CR#1713390

Adverse Condition Monitoring Plan for C-B ERCW Pump

Failed Section XI Test

08/10/2021

SQN-DC-V-7.4

Design Criteria - Essential Raw Cooling Water System

Revision 34

VTD-C173-0310

C&D Technologies Standby Battery Vented Cell

Installation and Operating Instructions

Revision 2

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

Operability

Evaluations

Past Operability Evaluation for CR 1715829 - ABSCE

door A118 found open

09/23/2021

Prompt Determination of Operability for CR 1710144

Procedures

0-TI-DXX-000-923.0

Battery Monitoring and Maintenance Program

Revision 1

NPG-SPP-07.8.1

Surveillance Frequency Control Program

Revision 1

71111.18

Calculations

SCG4M00750

Seismic Qualification of Anchor Darling 4" 1500 lb

Double Disc Gate Valve with Motor Operator

Revision 12

Operability

Evaluations

Prompt Determination of Operability for CR 1170545 -

Operability of EDGs during tornado event

05/16/2016

71111.19

Procedures

0-SI-SXV-067-237.1

Inspection of Diesel Generator 1A-A Essential Raw

Cooling Water Supply Check Valves

Revision 3

71111.22

Corrective Action

Documents

CR 1714139

Flex diesel bogged down when generator was loaded

08/13/2021

Work Orders

21504440

0-SI-EBT-250-100.3 Vital Battery II and Charger Annual

Inspection

07/14/2021

71114.04

Corrective Action

Documents

CR 1673364

Latent calculational error for J.01 & K.02 setpoints

2/22/2021

CR 1676064

Missed impacted organization (EP) for ECP SQN-20-

219

03/03/2021

Corrective Action

Documents

Resulting from

Inspection

CR 1720740

NRC proposed AV on RVLIS and REP

09/13/2021

Miscellaneous

CECC 2020-066

Screening Evaluation Form for EPIP-1, Rev. 56

09/28/2020

CECC 2020-066

Effectiveness Evaluation Form for EPIP-1, Rev. 56

09/28/2020

CECC 2020-069

Screening Evaluation Form for Radiological Emergency

Plan, Appendix B, Rev. 108

2/02/2020

CECC 2021-015

Screening Evaluation Form for EPIP-1, Rev. 57

03/05/2021

CECC 2021-015

Effectiveness Evaluation Form for EPIP-1, Rev. 57

03/05/2021

Procedures

EPIP-01

Emergency Plan Classification Matrix

Rev. 55, 56,

& 57

NP-REP

Radiological Emergency Plan Appendix B, Sequoyah

Nuclear Plant

Rev. 107 &

108

71124.06

Corrective Action

Documents

Condition Report

1692579

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

Procedures

0-TI-CEM-016-001.4

Shield Building Radiation Monitor Sampling Methods

Revision

0003

0-TI-CEM-260-012.11

Radiological Analytical Methods

Revision

0007

CHDP-109

Chemistry QA/QC

Revision 1

SQN - ODCM

Sequoyah Nuclear Plant Offsite Dose Calculation

Manual

Revision 63

71124.08

Corrective Action

Documents

CR 1138010

Corrective Action

Documents

Resulting from

Inspection

CR 1707916

Engineering

Evaluations

Radiation Protection Assessment to Support 10 CFR 37

Physical Protection of Category 1 and Category 2

Quantities of Radioactive Materials

2/28/14

Procedures

RHSI-13

Administration and Control of Onsite Storage of Low

Level Radioactive Waste

Rev. 4

Radiation

Surveys

SQN-O-20191107-6

Pre-shipping survey Box# DEI-8870-1

11/7/19

71151

Miscellaneous

Unit 1 and Unit 2 PI Summary Reports - Safety System

Functional Failures (July 1, 2021 - June 30, 2021)

MSPI Derivation Reports (UAI, URI, PLE) - Unit 1 and

Unit 2 High Pressure Injection System (July 1. 2020 -

June 30, 2021)

MSPI Derivation Reports (UAI, URI, PLE) - Unit 1 and

Unit 2 Emergency AC System (July 1. 2020 - June 30,

21)

MSPI Derivation Reports (UAI, URI, PLE) - Unit 1 and

Unit 2 Heat Removal System (July 1. 2020 - June 30,

21)

MSPI Derivation Reports (UAI, URI, PLE) - Unit 1 and

Unit 2 Cooling Water System (July 1. 2020 - June 30,

21)

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

71152

Calculations

SCG1S596

Maintenance Rule for Structures and License Renewal

Structures Monitoring Program Inspections

Revision 14

Corrective Action

Documents

CR 1685874

Defect identified in concrete slab underneath Unit 1

reactor cavity/equipment pit area

4/13/2021

71153

Corrective Action

Documents

CR 1696187

Unit 1 Reactor Trip - Level 2 Evaluation Report

Revision 1

Miscellaneous

CR 1696187

U1F25 Forced Outage Trip Report

5/27/2021