ML20293A171

Information Request to Support Triennial Baseline Design Bases Assurance Inspection (Team); Inspection Report 05000352/2021010 and 05000353/2021010

ML20293A171
Person / Time
Site:	Limerick
Issue date:	10/19/2020
From:	Mel Gray Engineering Region 1 Branch 1
To:	Bryan Hanson Exelon Generation Co, Exelon Nuclear
Gray M
References
IR 2021010
Download: ML20293A171 (8)

See also: IR 05000352/2021010

Text

October 19, 2020

Mr. Bryan C. Hanson

Senior Vice President

Exelon Generation Company, LLC

President and Chief Nuclear Officer

Exelon Nuclear

4300 Winfield Road

Warrenville, IL 60555

SUBJECT: LIMERICK GENERATING STATION, UNITS 1 AND 2 - INFORMATION

REQUEST TO SUPPORT TRIENNIAL BASELINE DESIGN BASES

ASSURANCE INSPECTION (TEAM); INSPECTION REPORT

05000352/2021010 AND 05000353/2021010

Dear Mr. Hanson:

The purpose of this letter is to notify you that the U.S. Nuclear Regulatory Commission (NRC)

Region I staff will conduct a Design Bases Assurance Inspection (DBAI) at your Limerick

Generating Station, Units 1 and 2. Elise Burket, a Senior Reactor Inspector from the NRCs

Region I office, will lead the inspection team. The inspection will be conducted in accordance

with Inspection Procedure 71111.21M, Design Bases Assurance Inspection (Team), dated

December 8, 2016 (ADAMS Accession No. ML16340B000).

The inspection will evaluate the capability of risk-significant/low-margin components to function

as designed to support proper system operation. The inspection will also include a review of

selected modifications, operating experience, and as applicable, operator actions.

During an electronic mail exchange on October 8, 2020, with Mr. C. R. Wheeler, Limerick

Generating Station Regulatory Assurance, we confirmed arrangements for an information-

gathering visit and the two-week onsite inspection. The schedule is as follows:

• Information-gathering activities (remote): Week of November 9, 2020

• Onsite weeks*: Weeks of January 25, 2021 and February 8, 2021.

• Due to the current COVID PHE, some inspection activities may occur remotely.

The purpose of the information-gathering visit is to meet with members of your staff to identify

risk-significant components, modifications, operator actions, and operating experience items.

Information and documentation needed to support the inspection will also be identified. Dave

Werkheiser, a Region I Senior Risk Analyst, will support Elise Burket during the information-

gathering visit to review probabilistic risk assessment data and identify components to be

examined during the inspection.

B. Hanson 2

Experience with previous baseline design/modification inspections of similar depth and length

has shown this type of inspection is resource intensive, both for the NRC inspectors and the

licensee staff. In order to minimize the inspection impact on the site and to ensure a productive

inspection for both parties, we have enclosed a request for information needed for the

inspection.

It is important that all of these documents are up-to-date and complete in order to minimize the

number of additional documents requested during the preparation and/or the onsite portions of

the inspection. Insofar as possible, this information should be provided electronically to the lead

inspector. The information request has been divided into two groups:

• The first group lists information necessary for our initial inspection scoping activities.

This information should be provided to the lead inspector by November 9, 2020. By

December 11, 2020, the lead inspector will communicate the initial selected set of

components and modifications.

• The second group of documents requested are those items needed to support our in-

office preparation activities. This set of documents, specific to the selected components

and modifications, should be provided to the lead inspector at the Regional Office no

later than January 13, 2021. During the in-office preparation activities, the team may

identify additional information needed to support the inspection, and those items will be

communicated directly to Mr. C.R. Wheeler.

If there are any questions about the inspection or the material requested in the enclosure,

please contact the lead inspector at 610-337-5266 or via e-mail at elise.burket@nrc.gov.

This letter does not contain new or amended information collection requirements subject to the

Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.). Existing information collection

requirements were approved by the Office of Management and Budget, Control Number 3150-

0011. The NRC may not conduct or sponsor, and a person is not required to respond to, a

request for information or an information collection requirement unless the requesting document

displays a currently valid Office of Management and Budget Control Number.

B. Hanson 3

This letter and its enclosure 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, Part 2.390, Public Inspections,

Exemptions, Requests for Withholding.

Sincerely,

X /RA/

Signed by: Melvin K. Gray

Mel Gray, Chief

Engineering Branch 1

Division of Reactor Safety

Docket Nos. 05000352 and 05000353

License Nos. NPF-39 and NPF-85

Enclosure:

Document Request for Design Bases

Assurance Inspection

cc: Distribution via ListServ

ML20293A171

Non-Sensitive Publicly Available

SUNSI Review

Sensitive Non-Publicly Available

OFFICE RI/DRS RI/DRS RI/DRS

NAME EBurket DWerkheiser MGray

DATE 10/12/20 10/19/20 10/19/20

DOCUMENT REQUEST FOR DESIGN BASES ASSURANCE INSPECTION

Inspection Report: 05000352/2021010 and 05000353/2021010

Onsite Inspection Dates*: January 25, 2021 through January 29, 2021; and

February 8, 2021 through February 12, 2021

• Onsite inspection is pending status of COVID PHE

Inspection Procedure: Inspection Procedure 71111.21M, Design Bases Assurance

Inspection (Team)

Lead Inspector: Elise Burket, Senior Reactor Inspector

610-337-5266

elise.burket@nrc.gov

I. Information Requested for Selection of Components and Modifications

The following information is requested by November 9, 2020, to facilitate inspection

preparation. Feel free to contact the lead inspector as soon as possible if you have any

questions regarding this information request. Please provide the information electronically

in pdf files, Excel, or other searchable formats, preferably on some portable electronic

media (e.g., Certrec/Sharefile, CD-ROM, DVD). The files should contain descriptive names,

and be indexed and hyperlinked to facilitate ease of use. Information in lists should contain

enough information to be easily understood by someone who has knowledge of light water

reactor technology.

1. The site probabilistic risk analysis (PRA) System Notebook and latest PRA Summary

Document.

2. Risk ranking of top 250 basic events sorted by Risk Achievement Worth (>/= 1.3).

Include values for Risk Reduction Worth, Birnbaum Importance, and Fussell-Vesely (as

applicable). Please provide in an excel spreadsheet or other sortable format, and

include an understandable definition of the coded basic events.

3. Risk-ranking of top 100 components from site specific PRA sorted by Large Early

Release Frequency. Provide any basic event mapping used to develop the ranking of

components.

4. List of the top 200 cut-sets from your PRA. Provide the descriptions of the basic events

in the list of cut-sets.

5. List of the top 200 cut-sets for each initiator modeled in the PRA that contributes more

than 5 percent to the baseline plant core damage frequency.

6. If you have an External Events or Fire PRA Model, provide the information requested in

Items 1 and 2 for external events and fire. Provide narrative description of each coded

event, including fire and flood zone description.

7. List of time-critical and/or risk significant operator actions.

Enclosure

DOCUMENT REQUEST FOR DESIGN BASES ASSURANCE INSPECTION

8. List of emergency and abnormal operating procedures.

9. If available, any pre-existing evaluation or list of components and associated

calculations with low design margins (e.g., pumps closest to the design limit for flow or

pressure, diesel generator close to design required output, heat exchangers close to

rated design heat removal).

10. If applicable, copy of any self-assessments and/or Quality Assurance assessments of

low margin structures, systems and components (SSC), completed in the last 3 years.

11. List of available design margins in both the open and closed direction for valves in the

motor-operated valve and air-operated valve programs. Identify the safety-related

direction and the basis for how the margin was determined.

12. The age and capacity of the safety-related DC batteries.

13. The In-Service Testing Program (IST) Basis document identifying the in-scope valves

and pumps, and the associated IST Program requirements for each component (e.g.,

IST valve table identifying category, active/passive function).

14. SSCs in the Maintenance Rule (a)(1) category in the last 3 years.

15. List of Root Cause Evaluations associated with SSCs failures or design issues

initiated/completed in the last 4 years.

16. List of formal operability evaluations in the last 4 years.

17. List of current operator work arounds/burdens.

18. List of permanent plant modifications to SSCs that are field work complete in the last 3

years. For the purpose of this inspection, permanent plant modifications include

permanent: plant changes, design changes, set point changes, equivalency

evaluations, suitability analyses, and commercial grade dedications. The list should

contain the number of each document, title (sufficient to understand the purpose of the

modification), revision/date, and the affected system.

19. List of calculation changes that have been issued for use in the last 3 years.

20. Corrective Action Program Procedure.

21. Procedures addressing the following: modifications, design changes, set point changes,

equivalency evaluations or suitability analyses, commercial grade dedications, and

post-modification testing.

22. List of corrective action documents (open and closed) in the last 3 years that address

permanent plant modifications issues, concerns, or processes.

23. Any internal/external self-assessments and associated corrective action documents

generated in preparation for this inspection.

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DOCUMENT REQUEST FOR DESIGN BASES ASSURANCE INSPECTION

24. Corrective Action Program documents (e.g., condition reports) associated with

inspection findings from the previous NRC Inspection Procedure 71111.21 (or 71111.21

Attachment M inspection).

25. Updated Final Safety Analysis Report, Technical Specifications, Technical

Specifications Bases, and Technical Requirements Manual.

26. Major one line safety-related electrical drawings (AC and DC), and Piping and

Instrumentation Drawings of emergency core cooling systems, ultimate heat sink, and

[for PWRs - emergency feedwater system].

II. Information Requested to Be Available by January 13, 2021

This information should be separated for each selected component and modification,

especially if provided electronically (e.g., a folder for each component and modification

named after the component or modification that includes the information requested below).

Items 1 through 11 are associated with the selected components and Item 12 is for the

selected modifications.

1. List of corrective action documents associated with each selected component for the

last 4 years.

2. Maintenance history (e.g., corrective, preventive, and elective) associated with each

selected component for the last 6 years. Identify frequency of preventive maintenance

activities.

3. Aging Management Program documents applicable to each selected component.

4. List of calculations associated with each selected component, excluding data files. Pipe

stress calculations are excluded from this request.

5. System Health Report (last completed) and Design Basis Document associated with

each selected component.

6. Access to or copy of vendor manual(s) for each selected component.

7. List of open temporary modifications associated with each selected component, if

applicable.

8. Trend data/graphs on the selected components performance for the last 3 years (e.g.,

pump performance including IST, other vibration monitoring, oil sample results).

9. List of normal operating and alarm response procedures associated with each selected

component.

10. Last completed tests and surveillances for each selected component performed during

the last 3 years. For those tests and surveillances performed at a periodicity of greater

than three years, provide the latest test performed.

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DOCUMENT REQUEST FOR DESIGN BASES ASSURANCE INSPECTION

11. Schedule of surveillance testing of selected components that occur during the onsite

inspection weeks.

12. For each selected modification, copies of associated documents such as modification

package, engineering changes, 50.59 screening or evaluation, relevant calculations,

post-modification test packages, associated corrective action documents, design

drawings, and new/revised preventive maintenance requirements.

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