ML20352A275

Request for Additional Information Regarding FitzPatrick Primary Containment Isolation Valve Amendment Request

ML20352A275
Person / Time
Site:	FitzPatrick
Issue date:	12/17/2020
From:	Justin Poole Plant Licensing Branch 1
To:	Bryan Hanson, Reggie Sullivan, Enrique Villar Exelon Generation Co
Poole J
References
EPID: L-2020-LLA-0145
Download: ML20352A275 (3)

Text

From: Poole, Justin To: Villar, Enrique:(Exelon Nuclear); Sullivan, Richard M:(Exelon Nuclear)

Cc: Danna, James

Subject:

Request for Additional Information Regarding FitzPatrick Primary Containment Isolation Valve Amendment Request (L-2020-LLA-0145)

Date: Thursday, December 17, 2020 10:18:00 AM Attachments: L-2020-LLA-0145 RAI SCPB.pdf

Rick, By letter dated June 30, 2020, as supplemented by letter dated November 10, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession Nos.

ML20182A198 and ML20315A245), Exelon Generation Company, LLC (Exelon, the licensee) submitted a license amendment request (LAR) to revise the TS 3.6.1.3, Primary Containment Isolation Valves, for James A. FitzPatrick Nuclear Power Plant. Specifically, the LAR would modify the containment venting flow path in Surveillance Requirement 3.6.1.3.1 of TS 3.6.1.3. In reviewing the submitted information, the U.S. Nuclear Regulatory Commission (NRC) staff has determined that additional information is necessary to complete its review.

On December 8, 2020, the NRC staff sent Exelon the DRAFT RAI to ensure that the question is understandable, the regulatory basis is clear, there is no proprietary information contained in the RAI, and to determine if the information was previously docketed. On December 17, 2020, the NRC and Exelon held a clarifying call. During the call, Exelon requested a response date of January 31, 2021. The NRC staff informed Exelon that this timeframe is acceptable. The attached is the final version of the RAIs. These RAIs will be put in ADAMS as a publicly available document.

Justin C. Poole Project Manager NRR/DORL/LPL I U.S. Nuclear Regulatory Commission (301)415-2048

REQUEST FOR ADDITIONAL INFORMATION REGARDING TECHNICAL SPECIFICATION 3.6.1.3 PRIMARY CONTAINMENT ISOLATION VALVES EXELON GENERATION COMPANY, LLC JAMES A. FITZPATRICK NUCLEAR POWER PLANT DOCKET NO. 50-333 Title 10 of the Code of Federal Regulations (10 CFR) Section 50.36(c)(3) states that, Surveillance requirements are requirements relating to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the limiting conditions for operation will be met.

Current TS Surveillance Requirement (SR) 3.6.1.3.1 contains valve configuration restrictions to prevent potential overpressurization (displacement) of the demister loop seals within the Standby Gas Treatment System (SGTS) should a Loss of Coolant Accident (LOCA) occur during containment venting.

By letter dated June 30, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No.ML20182A198), Exelon Generation Company, LLC (Exelon or the licensee) submitted a license amendment request to modify Technical Specifications 3.6.1.3, Primary Containment Isolation Valves, for James A. FitzPatrick Nuclear Power Plant (FitzPatrick). As defined in the application, the function of SGTS is accomplished with two 100 percent redundant SGT air filtration trains. Each filter train is physically and electrically independent. As described in Updated Final Safety Analysis Report (UFSAR) Section 5.3.3.4, upon receipt of an initiation signal at least one filter train fan will start up, and all valves in that train will open to draw air from the isolated Reactor Building at 6,000 cubic feet per minute (cfm). Based on this design, each SGTS train should be capable of withstanding applicable flow and pressures.

In the application, the Exelon Generation Company, LLC (the licensee) described new assumptions that were incorporated into previous analysis to reevaluate the potential for overpressure of demister loop seal and verify that the SGTS can withstand the LOCA-induced loads during the brief periods of containment venting. The licensee indicated the previous model maintained a fixed flow (equal to the fan flow) through the operating train of SGTS. One of the updated model assumptions is to allow free flow through both trains when evaluating overpressurization. It's described that the overpressure condition is driven by the pressure surge generated in the system by the drywell pressure change being higher than previously modeled. The Licensee described how the modeling of constant flow equal to that prior to the accident artificially increases the flow through the filter on the parallel train, which is noted as unrealistic representation of the scenario. Since the reanalyzed model assumes flow through both trains and higher surge pressure, it is not clear how worst case overpressure conditions for filter train and demister loop seal were defined and considered in the analysis.

Request In order for the NRC staff to have a clearer understanding of the analysis, please provide the following additional details:

• In the revised configuration, please describe what impact, if any, the accident environment (e.g. temperature, wet steam) will have on the SGT filter trains.

• Provide a discussion related to worst case conditions of: 1) only one of the SGTS trains operating, or 2) both SGTS trains operating during LOCA from the perspective of pressure surge and flow, and how they were evaluated.