IR 05000352/2022011

Triennial Fire Protection Inspection Report 05000352/2022011 and 05000353/2022011

ML22181B069
Person / Time
Site:	Limerick
Issue date:	06/30/2022
From:	Glenn Dentel Division of Operating Reactors
To:	Rhoades D Constellation Energy Generation, Constellation Nuclear
Dentel G
References
IR 2022011
Download: ML22181B069 (12)

Text

June 30, 2022

SUBJECT:

LIMERICK GENERATING STATION, UNITS 1 AND 2 - TRIENNIAL FIRE PROTECTION INSPECTION REPORT 05000352/2022011 AND 05000353/2022011

Dear Mr. Rhoades:

On June 23, 2022, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Limerick Generating Station, Units 1 and 2 and discussed the results of this inspection with Mr. Frank Sturniolo, Site Vice President and other members of your staff. The results of this inspection are documented in the enclosed report.

One finding of very low safety significance (Green) is documented in this report. This finding did not involve a violation of NRC requirements.

If you disagree with a finding not associated with a regulatory requirement 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 I; and the NRC Resident Inspector at Limerick Generating Station, 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, Glenn T. Dentel, Chief Engineering Branch 2 Division of Operating Reactor Safety

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:

05000352/2022011 and 05000353/2022011

Licensee:

Constellation Energy Generation, LLC

Facility:

Limerick Generating Station, Units 1 and 2

Location:

Sanatoga, PA 19464

Inspection Dates:

June 6, 2022 to June 23, 2022

Inspectors:

C. Bickett, Senior Reactor Inspector

E. Miller, Reactor Inspector

A. Patel, Senior Reactor Inspector

Approved By:

Glenn T. Dentel, Chief

Engineering Branch 2

Division of Operating Reactor Safety

SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting a triennial fire protection 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

Failure to Validate Time Critical Action per Operator Response Time Program Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green FIN 05000352,05000353/2022011-01 Open/Closed None (NPP)71111.21N.

The inspectors identified a Green finding because Constellation did not validate a 20-minute time critical action to manually initiate low pressure coolant injection (LPCI) for a fire in Fire Area 68W in accordance with Section 4.2 of procedure OP-AA-102-106, Operator Time Response Program.

Additional Tracking Items

None.

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.

REACTOR SAFETY

===71111.21N.05 - Fire Protection Team Inspection (FPTI)

Structures, Systems, and Components (SSCs) Credited for Fire Prevention, Detection, Suppression, or Post-Fire Safe Shutdown Review (IP Section 03.01)===

The inspectors verified that components and/or systems would function as required to support the credited functions stated for each sample. Additional inspection considerations were located in the fire hazards analysis (FHA) or safe shutdown analysis (SSA).

(1) Residual Heat Removal System

(2) Class 1E DC Power

(3) Halon Suppression System

(4) Fire Barriers

Fire Protection Program Administrative Controls (IP Section 03.02) (1 Sample)

The inspectors verified that the selected control or process was implemented in accordance with the licensees current licensing basis. The inspectors ensured that the licensees fire protection program contained adequate procedures to implement the selected administrative control and verified that the selected administrative control met the requirements of all committed industry standards.

(1) Combustible Control Program

Fire Protection Program Changes/Modifications (IP Section 03.03) (2 Samples)

The inspectors verified the following:

a. Changes to the approved fire protection program did not constitute an adverse effect on the ability to safely shutdown.

b. The adequacy of the design modification, if applicable.

c. Assumptions and performance capability stated in the SSA had not been degraded through changes or modifications.

d. The fire protection program documents, such as the Updated Final Safety Analysis Report, fire protection report, FHA, and SSA were updated consistent with the fire protection program or design change.

e. Post-fire safe shutdown operating procedures, such as abnormal operating procedures, affected by the modification were updated.

(1) EC 625788, 201 Safeguard 0BX103 Transformer Replacement

(2) EC 632790, Combustible Free Zone/Transient Combustible Free Zone Reduction

INSPECTION RESULTS

Failure to Validate Time Critical Action per Operator Response Time Program Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems

Green FIN 05000352,05000353/2022011-01 Open/Closed

None (NPP)71111.21N.05 The inspectors identified a Green finding because Constellation did not validate a 20-minute time critical action to manually initiate low pressure coolant injection (LPCI) for a fire in Fire Area 68W in accordance with Section 4.2 of procedure OP-AA-102-106, Operator Time Response Program.

Description:

Constellation procedure OP-AA-102-106, Operator Time Response Program, provides corporate governance regarding identification, control, validation, and documentation requirements for time critical actions (TCAs). TCAs include manual operator actions required to support a credited strategy in the safety analysis. This includes actions in the fire hazards and fire safe shutdown analyses.

This procedure states, in part, that each plant has actions that are to be accomplished in a specified time, and completion of these actions ensures the plant complies with the assumptions made during the analysis of plant events. Per Section 4.2.2, the master list of TCAs shall include the available time in minutes, performance time in minutes, and the ratio of available time to performance time, which determines whether periodic time validation is required. Available time is defined as the time interval from the cue to perform the manual action to the time the analysis credits completion of the manual action and still meet the requirements of the plants design basis or other documented evaluations. Additionally, Section 4.2.7 states that issues that need to be considered include the sequence of TCAs.

Procedure OP-LG-102-106, Operator Time Response Program at Limerick Station, provides the master list of TCAs at Limerick. Included in this list are TCAs 9, 10, and 11, which describe the actions credited to manually initiate LPCI, a mode of the residual heat removal system, in the event of a major fire in Fire Area 68W. Specifically:

• TCA 9 - operator starts the residual heat removal pump from the respective switchgear

• TCA 10 - operator positions residual heat removal valves 2F015B, 2F027B, and 2F048B from panel 20-C601X1 on 217 elevation

• TCA 11 - operator positions residual heat removal valve 2F017B from panel 20-C601X2 on 283 elevation

These TCAs are analogous to Steps 3.2.1, 3.3.1, and 3.3.2 in the associated fire safe shutdown guide, 2FSSG-3068W. Operators use 2FSSG-3068W in conjunction with other operating procedures to safely shutdown the plant following a fire in Fire Area 68W. In this scenario, LPCI is the credited source for reactor vessel inventory control. Per 2FSSG-3068W, Steps 3.3.1 and 3.3.2 (TCA 10 and TCA 11), which encompass the valve lineup, are performed by one operator in sequence, and Step 3.2.1 (TCA 9) is performed by another operator after the valve lineup is complete. Additionally, 2FSSG-3068W and the supporting fire safe shutdown calculation, LF-0016-0068W, state that manual initiation of LPCI is a prompt action that may be required for safe shutdown and is required to be completed within 20 minutes.

To determine whether operators could manually initiate LPCI within 20 minutes, the inspectors reviewed the most recent time validations of TCAs 9, 10, and 11. The inspectors noted that the station time-validated these TCAs independently of each other and assigned each individual TCA an available time of 20 minutes. The inspectors also noted that Constellation exempted TCA 9 from the six-year periodic validation since the ratio of available time (20 minutes) to expected performance time (four minutes) was greater than three (i.e., low risk of failure).

Constellations last time validation of TCA 10, completed in October 2021, demonstrated that operators took an average of 11.75 minutes to complete the action, with the fastest being eight minutes and the slowest being 13 minutes. The last validation of TCA 11, completed in October 2016, demonstrated that most of the operators took less than six minutes to complete the action, with the fastest being just over three minutes and the slowest being over nine minutes. Constellation also noted in both time validations that ratio of the average performance time to available time (20 minutes) was less than 0.8, so no issue reports or margin improvement actions were required.

The inspectors determined that assigning an available time of 20 minutes to each individual action did not meet the OP-AA-102-106 definition of available time since all three actions are required to manually initiate LPCI within a total of 20 minutes for a fire in Fire Area 68W. The inspectors also noted that Constellation did not holistically review individual TCAs completed in a certain sequence to meet a comprehensive objective, like manual initiation of LPCI, to ensure that the periodic validations demonstrated operators could meet the times assumed in station analyses. Additionally, the inspectors determined that calculated margins for the TCAs needed to manually initiate LPCI were incorrect when using an available time of 20 minutes for each separate action. Based on information available in the existing validations, the inspectors concluded it is likely that the time required to manually initiate LPCI per 2FSSG-3068W would exceed a margin threshold and require an issue report and/or margin improvement actions. Based on an inspector field walkdown completed with an operator on June 10, 2022, and consideration of the individual time validations discussed above, the inspectors concluded there was reasonable assurance that the operators could manually initiate LPCI within 20 minutes for a fire in Fire Area 68W. Of note, portions of TCA 9 could be performed concurrently with TCA 10 and 11.

Corrective Actions: Constellation entered this issue into their corrective action program for further evaluation.

Corrective Action References: IR 04507318

Performance Assessment:

Performance Deficiency: The inspectors determined that Constellations failure to validate a 20-minute time critical action to manually initiate LPCI for a fire in Fire Area 68W in accordance with Section 4.2 of procedure OP-AA-102-106, Operator Time Response Program was a performance deficiency that was reasonably within Constellations ability to foresee and correct. Constellation did not ensure that the three TCAs that were credited to manually initiate LPCI could all be performed together within 20 minutes to satisfy the assumptions in the associated fire safe shutdown guide and calculation.

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. Because Constellations time validation structure did not account for the sequence of actions required to manually initiate LPCI, and the individual TCAs were each assigned an available time of 20 minutes, the station could unknowingly exceed the overall 20-minute requirement documented in 2FSSG-3068W and fire safe shutdown calculation LF-0016-0068W. Additionally, the inspectors noted that there were other examples of TCAs in OP-LG-102-106 that were sequenced together to accomplish an overall objective but were not validated as such (e.g., TCAs 2 and 3 for the reactor core isolation cooling system for a fire in Fire Area 7).

Significance: The inspectors assessed the significance of the finding using Appendix F, Fire Protection and Post - Fire Safe Shutdown SDP. Appendix F was applicable in this case because the finding was associated with post-fire safe shutdown. This issue screened as Green in Step 1.4.7-C because the fire finding did not adversely affect the ability to reach and maintain hot shutdown/hot standby using the credited safe shutdown path. Based on field walkdowns and consideration of individual time validations, the inspectors determined there was reasonable assurance that the operators could manually initiate the LPCI system in 20 minutes for a fire in Fire Area 68W.

Cross-Cutting Aspect: Not Present Performance. No cross-cutting aspect was assigned to this finding because the inspectors determined the finding did not reflect present licensee performance.

Enforcement:

Inspectors did not identify a violation of regulatory requirements associated with this finding.

EXIT MEETINGS AND DEBRIEFS

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

• On June 23, 2022, the inspectors presented the triennial fire protection inspection results to Mr. Frank Sturniolo, Site Vice President and other members of the licensee staff.

DOCUMENTS REVIEWED

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

71111.21N.05 Calculations

LE-130

Class 1E 125/250V DC System Analysis

LEAM-0001

HPCI and RCIC Loads During FSSD

0A

LF-0016-007

Fire Area 007 Fire Safe Shutdown Analysis

LF-0016-068W

Fire Area 068W Fire Safe Shutdown Analysis

LF-0016-068W

Fire Area 068W Fire Safe Shutdown Analysis

1A

LF-0016-068W

Fire Area 068W Fire Safe Shutdown Analysis

1B

LG-PRA-021.11

Limerick Generating Station Fire Probabilistic Risk

Assessment Summary and Quantification Notebook

Corrective Action

Documents

04156586

233701

278009

284972

04312374

04337862

04400188

Corrective Action

Documents

Resulting from

Inspection

04504421

04504447

04504646

04504667

04504704

04504767

04504891

04505317

04505478

04505495

04506733

04506974

04506981

04507012

04507054

04507056

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

04507318

Engineering

Changes

28970

201 Safeguard Transformer Fire System Design

2790

Combustible Fire Zone Evaluation

Engineering

Evaluations

IR 01382361-41

Performance Based Evaluation of Selected Fire Protection

Testing to Extend the Testing Interval

LEAF-0088

Limerick Generating Station Combustible Free Zone

Evaluation

Fire Plans

F-R-500

Limerick Generating Station Pre-Fire Plan

F-R-574

Limerick Generating Station Pre-Fire Plan

Miscellaneous

1P-13.5

Unit 1 Halon Pre-Op Test

04/10/1989

2P-13.5

Halon Pre-Op Test

04/10/1989

LGSOPS2008

LGS Operations Initial Training - Fire Safe Shutdown

Guides (FSSG)

NE-294

Post-Fire Safe Shutdown Program Requirements

NFPA 12A-1977

Standard for Halon 1301

OP-AA-102-106

TCA 11 Operator Response Time Validation Sheet

10/11/2016

OP-AA-102-106

TCA 10 Operator Response Time Validation Sheet

10/14/2021

TCP 754

Fire Zone Permit 754

2/23/2022

Procedures

1/2 FSSG-3007

Fire Area 007 Fire Guide

2FSSG-3068W

Fire Area 068W Fire Guide

CC-AA-211

Fire Protection Program

MA-AA-716-026

Station Housekeeping/Material Condition Program

MA-AA-716-026-

1001

Additional Guidance for In-Plant/Yard Storage and

Housekeeping at Limerick

OP-AA-102-106

Operator Time Response Program

OP-AA-201-009

Control of Transient Combustible Material

OP-LG-102-106

Operator Time Response Program at Limerick Station

SE-1

Remote Shutdown

ST-4-022-930-0

Unit Common TRM Fire Door Inspection

Work Orders

280402

04643397

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

04736727

05044327