IR 05000352/2020003

Integrated Inspection Report 05000352/2020003 and 05000353/2020003

ML20309A884
Person / Time
Site:	Limerick
Issue date:	11/04/2020
From:	Jon Greives Reactor Projects Region 1 Branch 4
To:	Bryan Hanson Exelon Generation Co, Exelon Nuclear
Greives J
References
IR 2020003
Download: ML20309A884 (18)

Text

November 4, 2020

SUBJECT:

LIMERICK GENERATING STATION, UNITS 1 AND 2 - INTEGRATED INSPECTION REPORT 05000352/2020003 AND 05000353/2020003

Dear Mr. Hanson:

On September 30, 2020, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Limerick Generating Station, Units 1 and 2. On October 15, 2020, the NRC inspectors discussed the results of this inspection with Mr. Martin Bonifanti, Plant Manager, and other members of your staff. The results of this inspection are documented in the enclosed report.

No findings or violations of more than minor significance were identified during this inspection.

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

Sincerely, X /RA/

Signed by: Jonathan E. Greives Jonathan E. Greives, Chief Reactor Projects Branch 4 Division of Reactor Projects Docket Nos. 05000352 and 05000353 License Nos. NPF-39 and NPF-85

Enclosure:

As stated

Inspection Report

Docket Numbers: 05000352 and 05000353 License Numbers: NPF-39 and NPF-85 Report Numbers: 05000352/2020003 and 05000353/2020003 Enterprise Identifier: I-2020-003-0036 Licensee: Exelon Nuclear Facility: Limerick Generating Station, Units 1 and 2 Location: Sanatoga, PA 19464 Inspection Dates: July 1, 2020 to September 30, 2020 Inspectors: A. Ziedonis, Senior Resident Inspector S. Haney, Resident Inspector J. Ambrosini, Senior Emergency Preparedness Inspector E. Dipaolo, Senior Reactor Inspector L. Cline, Senior Project Engineer N. Warnek, Senior Allegations Coordinator J. Rady, Emergency Preparedness Inspector A. Turilin, Reactor Inspector Approved By: Jonathan E. Greives, Chief Reactor Projects Branch 4 Division of Reactor Projects Enclosure

SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Limerick Generating Station, 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

No findings or violations of more than minor significance were identified.

Additional Tracking Items

None.

PLANT STATUS

Unit 1 began the inspection period at rated thermal power. On September 26, 2020, operators reduced power to approximately 40 percent to remove the B recirculation pump from service to repair a coolant leak on the motor adjustable speed drive unit. Following repairs, the unit was returned to rated thermal power on September 28, 2020, and remained at or near rated thermal power for the remainder of the inspection period.

Unit 2 operated at or near rated thermal power for the entire 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 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, and procedures are consistent with Exelons design requirements and risk analysis assumptions for coping with external flooding

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) Unit 2 'D21' emergency diesel generator air start sub-system with one of two compressors failed on July 30, 2020

(2) Unit 2 reactor core isolation cooling following restoration from planned maintenance on August 13, 2020

(3) Unit 1 hardened vent purge and manual pneumatic alignment on September 8, 2020

71111.05 - Fire Protection

Fire Area Walkdown and Inspection Sample (IP Section 03.01) (5 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 area 57, Unit 2 high pressure coolant injection pump room on July 13, 2020

(2) Fire area 353, Unit 2 turbine building feedwater pump area motor control centers and distribution panels on July 16, 2020

(3) Fire area F-P-001, Unit common diesel driven fire pump room on August 11, 2020

(4) Fire area 1, Unit common control room chiller rooms on August 24, 2020

(5) Fire area 78, Unit common refueling floor on August 27, 2020

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 residual heat removal pump and heat exchanger rooms on September 21, 2020

Cable Degradation (IP Section 03.02) (1 Sample)

The inspectors evaluated cable submergence protection in:

(1) Manhole 106E cable vault on July 15, 2020, and manhole 106W cable vault on July 20, 2020

71111.11Q - Licensed Operator Requalification Program and Licensed Operator Performance

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

(2 Samples)

(1) The inspectors observed and evaluated licensed operator performance in the Control Room during a Unit 1 planned power reduction and rod pattern adjustment on September 13, 2020

(2) The inspectors observed and evaluated licensed operator performance in the Control Room during Unit 1 'B' adjustable speed drive restoration, reactor recirculation pump start and power ascension activities on September 28, 2020

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

(1) The inspectors observed and evaluated licensed operator requalification training on August 19, 2020

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 remain capable of performing their intended function:

(1) Unit 2 D21 emergency diesel generator failure to control voltage from the main control room during slow start surveillance on June 29, 2020

(2) Unit common high pressure coolant injection oil pressure control valve maintenance and inventory controls following notification of 10 CFR Part 21 reportable condition (ML101820160) on July 10, 2020

(3) Unit common Maintenance Rule 10 CFR 50.65 (a)(3) Periodic Assessment on August 5, 2020

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 1 B residual heat removal heat exchanger outlet bypass valve internal inspection and planned maintenance on August 4, 2020

(2) Unit common yellow risk condition during severe weather on August 4, 2020

(3) Unit common emergent work in response to the B flexible mitigating strategies diesel generator failure to start on August 11, 2020

(4) Unit 2 emergent scram discharge volume vent and drain valves air supply solenoid valve replacement on August 21, 2020

(5) Unit 2 emergent work in response to 'D21' emergency diesel generator motor operated potentiometer erratic performance on August 27, 2020

(6) Unit 1 emergent work in response to D traversing in-core probe detector stuck while fully inserted on September 2, 2020

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 common D emergency service water in-service test data engineering evaluation on July 24, 2020

(2) Unit 2 D21' emergency diesel generator speed load changes during surveillance testing on July 27, 2020

(3) Unit common B residual heat removal service water spray network nozzle clogging on August 19, 2020

(4) Unit 2 B residual heat removal heat exchanger outlet bypass valve plug baffle plate bolts lost parts evaluation on August 31, 2020

(5) Unit 1 channel distortion testing to verify control rod operability on September 8, 2020

71111.17T - Evaluations of Changes, Tests, and Experiments Sample Selection (IP Section 02.01)

The inspectors reviewed the following evaluations, screenings, and/or applicability determinations for 10 CFR 50.59 from July 20 to 24, 2020:

Safety Evaluations

(1) LG2020E001, Item Equivalency Evaluation of AZZ Nuclear Inverter Model NLI-

===072034-CSI-K-5-A, Firmware Vr. 56FBSD02 (EC 627860), Revision 0

(2) LG2019E001, Bypass FT-087-120A Signal To Return Drywell Cooler Drain Flow Monitoring System to Operable (E5C629175), Revision 0

(3) LG2018E001, Reactor Pressure Vessel Lost Part Retrieved In 2R15. Imposed minimum critical power ratio Penalties Not Required (EC623456), Revision 1

(4) LG2018E002, Replace current analog Love Corporation model 54 controllers PIC-011-053A/B with new, digital standard technical specification model 535 controllers (EC621885), Revision 0

(5) LG2017E001, Open Phase Modification Auto Trip No Longer Needed. Manual Only Option Being Implemented Per Revised Nuclear Energy Institute Guidance (EC618105), Revision 1

(6) LG2017E002, Technical Requirements Manual (TRM) Revision 59 Shutdown Removal, Revision 0

(7) LG2017E003, TRM Revision 59 Turbine Missile, Revision 0

(8) LG2017E004, TRM Revision 59 Chem, Revision 0 Screens (CFR 50.59 Screened-out Evaluations)

(9) LG2017S051, Limerick Generating Station (LGS) SLC System Pump Flow Rate, Revision 0

(10) LG2018S022, LGS Unit 1 Temporary Leak Mitigation Clamp for emergency service water (ESW), Revision 0

(11) LG2018S026, Scram Recovery, Revision 0

(12) LG2018S028, 50.69 Implementation for Core Spray, Revision 0

(13) LG2019S026, Convert motor-operated valve (MOV) HV-011-015B to Manual Valve 011-0124B and Convert Manual Valve 011-0124B to MOV HV-011-015B and Shift ESW residual heat removal service water (RHRSW) System Boundaries to Valve HV-011-015A/B, Revision 0

(14) LG2019S030, 50.69 Components for diesel generators, residual heat removal (RHR),

RHRSW, Reactor Enclosure Heating Ventilation and Air Conditioning (HVAC) and Drywell HVAC, Revision 0

(15) LG2019S032, Replace 'B' ESW Return to 'B' RHRSW Return Piping -1R18 (Downstream of HV-011-015B), Revision 0

(16) LG2019S033, Replace 'A' ESW Return to 'B' RHRSW Return Piping -Online Work (Downstream of HV-011-015A), Revision 0

(17) LG2019S045, 'A' Spray Pond Spray Network Piping Replacement Flange Addition &

Strut Modification, Revision 0

(18) LG2019S038, Unit 1 adjustable speed drive Runback Transfer Switch Installation, Revision 0

(19) LG2017S033, Unit 2 average power range monitor & rod-block monitor Trip Setpoint Change, Revision 0

(20) LG2018S012, Installation of Blanks on Unit Cooler 1D-V113, Revision 0

(21) LG2018S015, Procedurally Controlled Temporary Configuration Change for Changing the Drywell Chiller Low Oil Temperature Start Inhibit Setpoint, Revision 0

(22) LG2019S008, Seismic and Flooding Mitigation Strategies Assessments, Revision 0

(23) LG2019S010, Unit 2 ASD Runback Transfer Switch Installation, Revision 0

(24) LG2019S023, Gag Open Valve HV-C-007-201A (2A SJAE Supply Valve), Revision 0

(25) LG2019S025, Combine Obsolete Analog TIC-010-201, TT-010-201, & TSHL-010-201 into Digital TICSHL-010-201, Revision 0

(26) LG2019S034, Replace 'A' ESW Return to 'A' RHRSW Return Piping -2R16 (Downstream of HV-011-011A), Revision 0

(27) LG2017S049, Unit 1 reactor recirculation pump (RRP) Motor Oil Level Indication, Revision 1

(28) LG2018S017, Inservice Testing Safety Classification Correction for HV-051-

• F014A(B) and HV-051-*F068A(B), Revision 0

(29) LG2018S020, Temporary Pressure Instruments Installed at 069-1183A for Troubleshooting, Revision 0

(30) LG2019S001, Installation of Anti-Vibration System On Unit 1 and Unit 2 Jet Pumps, Revision 0

(31) LG2019S020, Metal Ring Discovered and Not Recovered in Limerick Unit 2 Bottom Head Drain, Revision 0

(32) LG2019S018, American Society of Mechanical Engineers/American National Standards Institute Code Reconciliation for Revised Material Allowables, Revision 0

71111.18 - Plant Modifications

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

=

The inspectors evaluated the following temporary or permanent modifications:

(1) Unit common emergency service water and residual heat removal service water system boundaries shift on August 26, 2020

71111.19 - Post-Maintenance Testing

Post-Maintenance Test Sample (IP Section 03.01) (6 Samples)

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

(1) Unit 1 B residual heat removal heat exchanger outlet bypass valve following inspection and internals replacement on August 5, 2020

(2) Unit 2 reactor core isolation cooling injection valve following hand switch replacement on August 12, 2020

(3) Unit common C residual heat removal service water spray network pipe header draining following dynamic flush corrective maintenance on August 20, 2020

(4) Unit common B flexible mitigating strategies diesel generator testing following corrective maintenance on August 24, 2020

(5) Unit 2 A residual heat removal heat exchanger outlet bypass valve following inspection and internals replacement on August 26, 2020

(6) Unit 1 'D14' emergency diesel generator following planned maintenance on September 17, 2020

71111.22 - Surveillance Testing

The inspectors evaluated the following surveillance tests:

Surveillance Tests (other) (IP Section 03.01)

(1) ST-6-092-314-2, Unit 2 'D24' emergency diesel generator slow start operability test run on July 24, 2020

(2) ST-4-012-961-0, Unit common in-service inspection pressure test of residual heat removal service water B spray network on August 18, 2020

(3) ST-2-051-416-2, Unit 2 residual heat removal low pressure coolant injection pump high discharge pressure division 1 calibration / functional test on August 26, 2020

(4) ST-6-043-391-1, Unit 1 reactor recirculation single loop operation temperature and flow check on September 27, 2020

Inservice Testing (IP Section 03.01) (1 Sample)

(1) ST-6-049-230-2, Unit 2 reactor core isolation cooling in-service testing on August 12, 2020

71114.02 - Alert and Notification System Testing

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

(1) The inspectors evaluated Exelon's maintenance and testing of the Limerick alert and notification system on September 8 through September 11, 2020, for the period of December 2018 through August 2020.

71114.03 - Emergency Response Organization Staffing and Augmentation System

Inspection Review (IP Section 02.01-02.02) (1 Sample)

(1) The inspectors evaluated the readiness of Exelon's Emergency Preparedness Organization on September 8 through September 11, 2020.

71114.04 - Emergency Action Level and Emergency Plan Changes

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

(1) The inspectors evaluated the following submitted Emergency Action Level and Emergency Plan changes onsite on September 8 through September 11, 2020.

• Evaluation No.: 20-11, EP-AA-1008, Addendum 3, Exelon Nuclear Emergency Action Levels for Limerick Generating Station, Revision 4

• Evaluation No.: 20-26, EP-AA-1008, Addendum 3, Exelon Nuclear Emergency Action Levels for Limerick Generating Station, Revision 5

• Evaluation No.: 20-79, Emergency Offsite Notification System (EONS), dated August 31, 2020 This evaluation does not constitute NRC approval.

71114.05 - Maintenance of Emergency Preparedness

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

(1) The inspectors evaluated the maintenance of the emergency preparedness program on September 8 through September 11, 2020, for the period of December 2018 through August 2020.

71114.06 - Drill Evaluation

Select Emergency Preparedness Drills and/or Training for Observation (IP Section 03.01)

(1 Sample)

(1) The inspectors evaluated the conduct of a routine emergency planning drill on September 15,

OTHER ACTIVITIES - BASELINE

===71151 - Performance Indicator Verification The inspectors verified licensee performance indicators submittals listed below:

EP01: Drill/Exercise Performance (IP Section 02.12) ===

(1) Unit common for the period of October 1, 2019 through June 30, 2020

IE01: Unplanned Scrams per 7000 Critical Hours Sample (IP Section 02.01) (2 Samples)

(1) Unit 1 for the period of July 1, 2019, through June 30, 2020

(2) Unit 2 for the period of July 1, 2019, through June 30, 2020

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

(1) Unit common for the period of October 1, 2019 through June 30, 2020

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

(1) Unit common for the period of October 1, 2019 through June 30, 2020

IE04: Unplanned Scrams with Complications (USwC) Sample (IP Section 02.03) (2 Samples)

(1) Unit 1 for the period of July 1, 2019, through June 30, 2020

(2) Unit 2 for the period of July 1, 2019, through June 30, 2020

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

(1) Unit 1 for the period of July 1, 2019, through June 30, 2020

(2) Unit 2 for the period of July 1, 2019, through June 30, 2020

71152 - Problem Identification and Resolution

Annual Follow-up of Selected Issues (IP Section 02.03) (2 Samples)

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

(1) Review actions to address NRC-identified inadequate functionality determinations for the Diesel-Driven Fire Pump (DDFP) and several overheating events on the DDFP and Backup DDFP

(2) Unit 1 residual heat removal valve inoperable due to foreign material

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

(1) Unit 1 single loop operation due to B adjustable speed drive coolant leak and removal from service on September 27,

INSPECTION RESULTS

Observation: Review actions to address NRC-identified inadequate functionality 71152 determinations for the Diesel-Driven Fire Pump (DDFP) and several overheating events on the DDFP and Backup DDFP During the 2019 NRC triennial fire protection inspection, the team identified a Green FIN (05000352, 05000353/2019-011-01) for failure to perform adequate functionality assessments of the DDFP in accordance with Exelon procedure OP-AA-108-115, Operability Determinations, associated with raw cooling water strainer fouling. Exelon addressed the technical issues regarding raw cooling water strainer fouling and the human performance issues regarding functionality determinations. However, a series of cooling water challenges were identified with continued overheating of the DDFP and the Backup DDFP. The inspectors reviewed the corrective actions taken for the finding, the actions taken to resolve the cooling water issues, and the actions to improve reliability of the fire water system. The inspectors reviewed several engine overheating events and actions taken dating back to 2014 and assessed Exelons problem identification threshold, prioritization of the issues, causal analysis or troubleshooting, use of operating experience, and timeliness of corrective actions.

Exelon performed a work group evaluation for the failure to perform adequate functionality assessments (IR 4220058). The cause was determined to be failure to properly use the technical human performance tool of Questioning Attitude during the performance of the operability determination. Exelons corrective actions were to revise the alarm response card to provide better guidance for DDFP overheating events and to apply Performance Management to the senior reactor operator who performed the operability determination.

The extent of condition identified several other similar inadequate functionality determinations associated with DDFP overheating involving other senior reactor operators. To address this, Exelon planned corrective action to revise the licensed operator lesson plan associated with Technical Specifications to reinforce requirements for operability/functionality determinations.

The inspectors identified that the corrective action to revise the lesson plan was canceled and changed to an action item inappropriately. Exelon entered this issue into the corrective action program as IR 4358791 and planned to change the action item back to a corrective action.

The inspector determined that inappropriately changing the corrective action to an action item was a minor issue because the revision to the lesson plan was completed in a timely manner and other actions (e.g., issue a Shift Training Notebook item) reinforced operability/functionality determination requirements to all senior reactor operators. Besides this deficiency, the inspectors concluded that Exelon appropriately evaluated the issue, performed a thorough extent of condition review, and completed timely corrective actions.

The inspectors reviewed the most recent overheating event of the DDFP which occurred on August 13, 2019 (IR 4271519). The cause was determined to be inadequate raw cooling water flow and not due to raw cooling water strainer fouling as previously experienced. The DDFP uses cooling tower water as its suction and cooling water source which is silted.

Apparently, silt and calcium built up in raw cooling water piping over the years (decades) of operation. Exelon found a section of the discharge piping that was 90% fouled. Exelon replaced the majority of the raw cooling water piping, instituted a preventive maintenance item to inspect the piping every ten years, and initiated additional monitoring of DDFP operating parameters that would detect raw cooling water pipe fouling. The inspectors observed that Exelon appropriately evaluated the issue and completed timely corrective actions.

The inspectors reviewed the most recent Backup DDFP overheating events and actions taken to resolve them. One event was due to cooling water discharge line freezing (IR 4090918) during cold weather and the other was attributed to an undersized cooling water pressure control valve. The inspectors noted that the pressure control valve was undersized for high pump discharge flows only experienced during testing and not for flows expected during normal operation. To address discharge line freezing, Exelon reconfigured the cooling lines and system drain lines to prevent buildup of water in the discharge line which exits the heated enclosure and is susceptible to freezing. Additional pipe configuration changes are planned to be completed prior to the next winter freezing season. Exelon replaced the cooling water pressure control valve with a higher flow capacity valve. The inspectors observed that Exelon appropriately evaluated the issue and completed or planned timely corrective actions.

Observation: Exelon Root Cause Report (RCR) Did Not Take Action to Address 71152 Vendor Performance Gaps The inspectors reviewed Exelon RCR 4337051 ,Unit 1 A Train of Residual Heat Removal (RHR) Inoperable Due to Foreign Material, and corrective actions associated with the discovery of foreign material in the Unit 1 A RHR full flow test valve when it would not throttle closed during a surveillance test on April 20, 2020. The foreign material resulted in valve inoperability, requiring unplanned entry into a technical specification limiting condition for operation, and emergent repairs to the valve internals.

Exelon determined the root cause and source of the foreign material was an inadequate design of a heat exchanger outlet bypass valve, a Masoneilan model series 40400 control valve. Specifically, a baffle plate separated from the valve plug and became foreign material in the downstream RHR full flow test valve. In the original valve design, the baffle plate was bolted to the plug. The valve was later modified such that the plug was re-designed to an all-in-one cast baffle that is integral to the valve plug. Exelons corrective actions included replacing the Unit 1 A RHR heat exchanger outlet bypass valve internals with the modified valve plug. Exelon also performed extent of condition inspections and plug replacements of the three other RHR heat exchanger outlet bypass valves across both units. During those extent of condition inspections, it was confirmed that the Unit 2 B RHR heat exchanger outlet bypass valve was the source of previously unidentified foreign material that was recovered from jet pump number 9 in October 2017 (see NRC Inspection Report 05000352/3/2020001, Section 71153 [ML20126G342]). The inspectors conducted personnel interviews and reviewed associated issue reports, procedures, preventive maintenance templates, and procurement documentation, and determined that the foreign material issues, both in 2017 and 2020, were not reasonably within Exelons ability to foresee and correct, and therefore did not constitute a performance deficiency.

Exelon also identified a contributing cause that the vendor did not communicate the original design issue to the industry via Title 10 of the Code of Federal Regulations (CFR) Part 21 reporting, nor any other means of industry notification. Exelon subsequently performed a technical evaluation and determined the inadequate design of the Masoneilan model series 40400 control valves required a communication under 10 CFR Part 21. Baker Hughes (formerly Masoneilan) subsequently reported the condition as a transfer of information under 10 CFR Part 21 on June 3, 2020 (ADAMS Accession No. ML20164A085).

The inspectors noted that Exelon missed an opportunity to pursue a vendor performance issue that was identified in the RCR. Exelon captured this observation in IR 4377240, and added assignment 35 to the RCR IR 4337051. Specifically, Exelons RCR identified that a purchase order for a new heat exchanger outlet bypass valve was completed with the vendor in 2012, which included the upgraded valve plug design. While the new valve was not installed until after the learnings from the RCR, Exelon also identified that the vendor misclassified the plug design change as an administrative change in the purchase order, with the same form, fit and function. The inspectors questioned Exelon as to whether further actions were warranted to verify adequacy of the vendors processes for design changes and subsequent customer notifications pertaining to components under the scope of 10 CFR Part 50, Appendix B. In response, Exelon engaged directly with the vendor, and captured the specific vendor performance gap in Exelons vendor performance management database.

The inspectors determined that these missed opportunities by Exelon did not represent any actual performance deficiencies.

EXIT MEETINGS AND DEBRIEFS

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

• On October 15, 2020, the inspectors presented the integrated inspection results to Mr. Martin Bonifanti, Plant Manager, and other members of the licensee staff.

• On September 11, 2020, the inspectors presented the Emergency Preparedness Program inspection results to Mr. Frank Sturniolo, Site Vice President and other members of the licensee staff.

• On July 24, 2020, the inspectors presented the Evaluation of Changes, Tests and Experiments inspection results to Mr. Frank Sturniolo, Site Vice President and other members of the licensee staff.

DOCUMENTS REVIEWED

Inspection Type Designation Description or Title Revision or

Procedure Date

71111.04 Corrective Action IR 4361117

Documents

71111.05 Procedures F-R-700 Unit 1 Refueling Area Revision 12

F-R-708 Unit 2 Refueling Area Revision 8

F-T-353 Unit 2 Reactor Feedpump Compartments Auxiliary Revision 11

Equipment, Piping, and Control Panels

OP-LG-201-008 Limerick Generating Station Fire Protection Pre-Fire Plan Revision 5

Strategies

71111.06 Corrective Action IR 4262796

Documents

71111.12 Corrective Action CAPE 4334315- 23PCV-12 Oil Leak 06/24/2020

Documents 05

IR 1086768

IR 4348906

IR 4353576

Corrective Action IR 4361653

Documents IR 4367206

Resulting from

Inspection

Miscellaneous General Electric- Part 21 Reportable Condition Notification: Failure of HPCI

Hitachi issued Turbine Overspeed Reset Control Valve Diaphragm

MFN 10-192

(ML101820160)

71111.13 Corrective Action IR 4358228

Documents IR 4361152

71111.15 Corrective Action IR 4358671

Documents IR 4363877

IR 4364116

71111.19 Corrective Action IR 4361996

Documents IR 4367705

Work Orders WO 1472555

WO 1472632

Inspection Type Designation Description or Title Revision or

Procedure Date

71111.22 Work Orders WO 4329667

71114.02 Miscellaneous Design Report Limerick Generating Station Public Alert and Notification Revision 3

System Design Report

71114.03 Corrective Action IR 4227035

Documents

Corrective Action IR 4368791

Documents

Resulting from

Inspection

Miscellaneous EP-AA-1000 Exelon Nuclear Standardized Radiological Emergency Plan Revision 33

EP-AA-1008 Exelon Nuclear Radiological Emergency Plan Annex for Revision 32

Limerick Generating Station

EP-AA-1008, Limerick Generating Station On-Shift Staffing Technical Revision 2

Addendum 1 Basis

71114.04 Procedures EP-AA-120-1001 10 CFR 50.54(q) Change Evaluation Revision 11

71114.05 Corrective Action IR 4278484

Documents

Miscellaneous EP-AA-121-F-08 Limerick Equipment Matrix Revision 3

71152 Corrective Action IR 2386692

Documents IR 2386937

IR 2522850

IR 4090918

IR 4219061

IR 4220058

IR 4230400

IR 4232170

IR 4271519

IR 4275115

IR 4337051

Corrective Action IR 4344408

Documents IR 4358791

Resulting from IR 4367240

Inspection

Miscellaneous M-19-82 Fire Pump Drive Engines Operations and Maintenance Revision 2

Inspection Type Designation Description or Title Revision or

Procedure Date

Manual

Procedures ARC-MCR-005 B- Diesel Fire Pump Raw Water Hi Temperature Revision 2

ST-6-022-252-0 Diesel Driven Fire Pump Flow Test Revision 40

Work Orders WO 4754179

WO 4878165

WO 4926351

WO 4950702

71153 Corrective Action IR 4372277

Documents IR 4372283

IR 4372296

IR 4372305

IR 4372308

IR 4373761

IR 4374532

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