ML20090F585
| ML20090F585 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 03/30/2020 |
| From: | Bhalchandra Vaidya NRC/NRR/DORL/LPL3 |
| To: | Kusumawatimurray P, Taken J Exelon Generation Co |
| References | |
| L-2020-LLA-0018 | |
| Download: ML20090F585 (6) | |
Text
From: Vaidya, Bhalchandra Sent: Monday, March 30, 2020 2:39 PM To: Kusumawatimurray, Putri:(GenCo-Nuc); Taken, Jason C.:(Exelon Nuclear)
Cc: Salgado, Nancy
Subject:
LaSalle Units 1 and 2, EPID-L-2020-LLA-0018 License Amendment Request re:
TSTF-505 , Audit Plan
Subject:
LASALLE COUNTY STATION, Units 1 and 2 - AUDIT PLAN REGARDING LICENSE AMENDMENT REQUEST TO IMPLEMENT RISK-INFORMED EXTENDED COMPLETION TIMES, DOCKET NOS. 50-373 and 50-374 (L-2020-LLA-0018)
Dwi and Jason, The U.S. Nuclear Regulatory Commission (NRC) staff has started the review of the risk informed completion time license amendment request (LAR) and determined that a regulatory audit of the technical acceptability of the probabilistic risk assessments (PRAs) used to develop insights to support the licensees proposed approach would assist in the timely completion of the LAR review. A regulatory audit is a planned activity that includes the examination and evaluation of primarily non-docketed information. The audit will be conducted to increase the NRC staffs understanding of the LAR and identify information that will require docketing to support the NRC staffs regulatory finding. The NRC staff will conduct a regulatory audit to support its review of the LAR in accordance with the following audit plan.
I. BACKGROUND By letter dated January 31, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20035E577), Exelon Generation Company, LLC (Exelon, the licensee) requested that the NRC amend the Technical Specifications, Appendix A of Renewed Facility Operating License Nos. NPF-11 and NPF-18 for LaSalle County Station, Units 1 and 2 (LaSalle). Exelons proposed license amendment request would revise technical specification requirements to permit the use of risk informed completion times for actions to be taken when limiting conditions for operation are not met. The proposed changes are based on Technical Specifications Task Force Traveler (TSTF) 505, Revision 2, Provide Risk Informed Extended Completion Times - RITSTF Initiative 4b, dated July 2, 2018 (ADAMS Accession No. ML18183A493).
II. REGULATORY AUDIT BASES The basis of this audit is the licensees LAR for LaSalle, and the Standard Review Plan Section 19.2, Review of Risk Information Used to Support Permanent Plant-Specific Changes to the Licensing Basis: General Guidance (ADAMS Accession No. ML071700658).
The audit will be performed consistent with NRC Office of Nuclear Reactor Regulation Office Instruction LIC-111, Revision 1, Regulatory Audits, dated October 31, 2019 (ADAMS Accession No. ML19226A274). An audit was determined to be the most efficient approach toward a timely resolution of issues associated with this LAR review, since the staff will have an opportunity to minimize the potential for multiple rounds of requests for additional information (RAIs) and ensure no unnecessary burden will be imposed by requiring the licensee to address issues that are no longer necessary to make a safety determination.
III. PURPOSE AND SCOPE The purpose of the audit is to gain a more detailed understanding of licensees Risk Informed Completion Time (RICT) program and its application to the technical specifications (TS) completion times as proposed in the LAR. The NRC staff will review the licensees application including the internal events, internal flooding, and fire PRAs, consideration of seismic and non-seismic external hazards, and fire PRAs and the risk informed approach for establishing extended completion times.
The areas of focus for the regulatory audit are the information contained in the licensees submittal, the enclosed audit information needs, and all associated and relevant supporting documentations (e.g., methodology, process information, calculations, etc.). The relevant supporting documents are identified below.
IV. INFORMATION AND OTHER MATERIAL NECESSARY FOR THE REGULATORY AUDIT The following documentation should be available to the audit team:
- 1. Reports of peer reviews (full-scope and focused-scope), self-assessments, and facts and observations (F&Os) closure reviews for the internal events, internal flooding, and fire PRAs cited in LaSalles LAR dated January 31, 2020;
- 2. Uncertainty notebooks for the LaSalle internal events, internal flooding, and fire PRAs related to PRA model assumptions and sources of uncertainty;
- 3. Documentation on evaluation of the generic and plant specific uncertainties with respect to the Lasalle LAR dated January 31, 2020;
- 4. Documentation supporting the example RICT calculations presented in LAR Enclosure 1 Table E1-2, including determination of corresponding risk management actions;
- 5. PRA notebooks for the modeling of FLEX equipment and FLEX human error probabilities, if credited in the PRA;
- 6. Results of the fire PRA and resolution of F&Os;
- 7. Draft or final RICT program procedures (e.g., procedures related to risk management actions, PRA functionality determination, and recording limiting conditions for operation);
- 8. LOF analysis and the licensee models for I&C in PRA. Also, any documents that support the defense-in-depth justification; and
- 9. We need to understand the interactions between the electrical divisions AC and DC that that require an opposite unit division system to be operable. If there are shared support systems (essential cooling water, HVAC etc.), we would like to understand the systems involved. For the DGs, what are the worst case scenarios for the loss of multiple DGs from different divisions for a potential accident on one unit. Under what scenarios, are the HPCS Division 3 DGs for each unit required? Are the five DGs for both units considered a system where only one failure may be assumed?
Applicable documents:
Single line diagrams of the electrical systems, with description of a) normal alignment, b) any LCO related configuration if one or more power source(s) is/are inoperable including interconnection of DGs which may require DC power for associated breakers.
c) any unique accident mitigation alignment credited in the failure mode analyses for calculating RICT d) Station Blackout considerations e) Indicate where loss of function occurs for loss of multiple power sources, System descriptions if available for DGs and DC system
- 10. For loss of offsite power (both circuits) a 30 day RICT is proposed.
- a. We need to understand the design of the cooling water system or ultimate heat sink (UHS) so that the DGs, RHRSW etc. can run for 30 days with cooling available. The licensing basis for UHS is 30 day inventory. A preliminary review of the UHS description in UFSAR seems to indicate that non-safety related systems are not required to maintain cooling for ECCS and DGs.
- b. Some plants need station air or instrument air for cycling valves. We need to understand if air systems for critical valves (containment isolation, residual heat removal etc.) need non-safety related power sources to maintain systems in operable condition over a 30 day period.
Applicable documents:
System description and flow diagrams associated with UHS and DG cooling systems and if applicable station air/instrument air systems.
- 11. TS 3.3.8.1 Loss-of-Power (LOP) Instrumentation: we need to understand the success criterion and what systems (DG and offsite power) are assumed to fail when this LCO is extended. Enclosure 1, Page E1-7 assumes only the DG fails to start. LCO 3.3.8.1 A is related to One or more channels inoperable. We need to understand the interpretation of or more as related to a single division and as related to redundant divisions, as there are several channels associated with LOP instrumentation Applicable Documents:
Description of LOP Instrumentation and applicable failure modes considered in the RICT
- 12. Any other supporting documentation that the licensee may determine is responsive to the staffs above information requests.
The NRC staff may request additional documents that would be needed on the portal as the audit progresses.
V. AUDIT TEAM The members of the audit team are:
Name Organization Email Adrienne Brown NRC Adrienne.Driver@nrc.gov Todd Hilsmeier NRC Todd.Hilsmeier@nrc.gov Shilp Vasavada NRC Shilp.Vasavada@nrc.gov
Mehdi Reisi Fard NRC Mehdi.Reisifard@nrc.gov PNNL Garill Coles Garill.Coles@pnnl.gov (Contractor)
PNNL Mark Wilk Mark.Wilk@pnnl.gov (Contractor)
Bob Vettori NRC/training Robert.Vettori@nrc.gov Carte Norbert NRC Norbert.Carte@nrc.gov Stacey NRC Stacey.Rosenberg@nrc.gov Rosenberg Andrea Russell NRC Andrea.Russell@nrc.gov Victor Cusumano NRC Victor.Cusumano@nrc.gov Joseph Ashcraft NRC Joseph.Ashcraft@nrc.gov Matharu NRC Gurcharan.Matharu@nrc.gov Gurcharan Ed Kleeh NRC Edmund.Kleeh@nrc.gov John Honcharik NRC John.Honcharik@nrc.gov G. Bedi NRC Gurjendra.Bedi@nrc.gov Bhalchandra NRC Bhalchandra.Vaidya@nrc.gov Vaidya The NRC staff may request access for additional staff as the audit progresses.
VI. LOGISTICS The audit will be conducted in two parts: In-Office which will commence when an online portal (i.e., electronic portal, ePortal, electronic reading room) containing the documents requested in Section IV of this audit plan is established by Exelon, and Site from June 15, 2020 to June 19, 2020. The NRC staff requests dedicating 2 - 2.5 days for the audit of the proposed alternate seismic approach, including a potential plant walkdown for that audit (i.e., the audit for the proposed alternate seismic approach is not conducted in parallel with other audit(s)). NRC staff and contractors access to the online portal should be terminated when the Audit Report is issued.
The NRC project manager will coordinate any changes to the audit schedule and location with the licensee.
VII. SPECIAL REQUESTS The NRC staff would like access to the documents listed above in Section IV through an online portal that allows the NRC staff and contractors to access documents via the internet. The following conditions associated with the online portal must be maintained throughout the duration that the NRC staff and contractors have access to the online portal:
- The online portal will be password-protected, and separate passwords will be assigned to the NRC staff and contractors who are participating in the audit.
- The online portal will be sufficiently secure to prevent the NRC staff and contractors from printing, saving, downloading, or collecting any information on the online portal.
- Conditions of use of the online portal will be displayed on the login screen and will require acknowledgement by each user.
- User name and password information should be provided directly to the NRC staff and contractors. The NRC project manager will provide Exelon the names and contact information of the NRC staff and contractors who will be participating in the audit. All other communications should be coordinated through the NRC project manager.
VIII. DELIVERABLES An audit summary, which may be public, will be prepared within 90 days of the completion of the audit. If the NRC staff identifies information during the audit that is needed to support its regulatory decision, the staff will issue RAIs to the licensee.
Please contact me, if you have any questions.
Sincerely, Bhalchandra K. Vaidya., Licensing Project Manager Plant Licensing Branch 3 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-373 and 50-374 bhalchandra.vaidya@nrc.gov 301-415-3308
Hearing Identifier: NRR_DRMA Email Number: 501 Mail Envelope Properties (MN2PR09MB40780E0824F5FDFA70D58D748DCB0)
Subject:
LaSalle Units 1 and 2, EPID-L-2020-LLA-0018 License Amendment Request re:
TSTF-505 , Audit Plan Sent Date: 3/30/2020 2:38:38 PM Received Date: 3/30/2020 2:38:00 PM From: Vaidya, Bhalchandra Created By: Bhalchandra.Vaidya@nrc.gov Recipients:
"Salgado, Nancy" <Nancy.Salgado@nrc.gov>
Tracking Status: None "Kusumawatimurray, Putri:(GenCo-Nuc)" <Putri.Kusumawatimurray@exeloncorp.com>
Tracking Status: None "Taken, Jason C.:(Exelon Nuclear)" <Jason.Taken@exeloncorp.com>
Tracking Status: None Post Office: MN2PR09MB4078.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 11757 3/30/2020 2:38:00 PM Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: