ML21189A161

NRR E-mail Capture - Second Round Request for Additional Information - Byron Permanently Defueled Technical Specification Amendment

ML21189A161
Person / Time
Site:	Byron
Issue date:	07/08/2021
From:	Joel Wiebe NRC/NRR/DORL/LPL3
To:	Simpson L Exelon Generation Co
References
Download: ML21189A161 (4)

Text

From: Wiebe, Joel Sent: Thursday, July 8, 2021 9:55 AM To: Lisa Simpson (Lisa.Simpson@exeloncorp.com)

Subject:

Second Round Request for Additional Information - Byron Permanently Defueled Technical Specification Amendment Attachments: 2021-07-07 Byron Permanently Defueled Draft RAI 2.docx Hi Lisa, We would like to hold a clarification call regarding this second round RAI. Let me know when you are available.

Joel

Hearing Identifier: NRR_DRMA Email Number: 1263 Mail Envelope Properties (MN2PR09MB4971CC4FB848A071CEA261468B199)

Subject:

Second Round Request for Additional Information - Byron Permanently Defueled Technical Specification Amendment Sent Date: 7/8/2021 9:55:06 AM Received Date: 7/8/2021 9:55:07 AM From: Wiebe, Joel Created By: Joel.Wiebe@nrc.gov Recipients:

"Lisa Simpson (Lisa.Simpson@exeloncorp.com)" <Lisa.Simpson@exeloncorp.com>

Tracking Status: None Post Office: MN2PR09MB4971.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 133 7/8/2021 9:55:07 AM 2021-07-07 Byron Permanently Defueled Draft RAI 2.docx 32374 Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

REQUEST FOR ADDITIONAL INFORMATION RELATED TO LICENSE AMENDMENT REQUEST FOR CHANGES TO THE BYRON NUCLEAR GENERATING STATION PERMANENTLY DEFUELED TECHNICAL SPECIFICATIONS EXELON GENERATION COMPANY, LLC BYRON NUCLEAR GENERATING STATION UNITS 1 AND 2 DOCKET NO. 50-454 AND 50-455 By letter dated September 2, 2020, (Agencywide Documents Access and Management System Accession Number (ADAMS) ML20246G613) Exelon Generation Company, LLC. (Exelon),

provided formal notification to the U.S. Nuclear Regulatory Commission (NRC) of its plans to permanently cease power operations to Renewed Facility Operating License (RFOL) Nos. NPF-37 and NPF-66 for Byron Nuclear Power Station (Byron), Units 1 and 2 by September 30, 2021.

By application dated October 29, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20304A147), Exelon Generation Company, LLC (Exelon or the licensee), requested changes to Renewed Facility Operating Licenses (RFOLs) Nos. NPF-37 and NPF-66 and technical specifications (TSs) for the Byron Nuclear Generating Station (OCNGS). Exelon requested an amendment to revise the OCNGS RFOL and the associated TS to Permanently Defueled Technical Specifications (PDTS) consistent with the permanent cessation of reactor operation and permanent defueling of the reactor.

Previously approved License Amendment Nos. 147 to NPF-37 and 147 to NPF-66, Byron Station, Unit Nos. 1 and 2, and Braidwood Station, Unit Nos. 1 and 2 - Issuance of Amendments RE: Alternative Source Term (TAC NOS. MC6221, MC6222, MC6223, AND MC6224) dated September 8, 2006 (ADAMS Accession No. ML062340420), to adopt full implementation of the Alternative Source Term (AST) methodology.

By letter date March 16, 2021 (ADAMS Accession No. ML21075A308) the licensee responded to the staffs requests for additional information. The staff reviewed the responses and on June 29, 2021 held a clarification call with the licensee to discuss the submittal.

The U.S. Nuclear Regulatory Commission (NRC) staff has determined that additional information is required to enable the NRC staff to make an independent assessment regarding its technical review.

Regulatory Basis/Issue: New Fuel Handling Accident Analysis Regulatory Guide 1.183, Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors, Rev. 0, July 2000 provides a methodology for analyzing the radiological consequences of several design-basis accidents (DBAs) to show compliance with 10 CFR 50.67. Regulatory Guide 1.183 provides guidance to licensees on acceptable application of alternate source term (AST) submittals, including acceptable radiological analysis assumptions for use in conjunction with the accepted AST.

NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR [Light-Water Reactor] Edition, (SRP) Section 15.0.1, Radiological Consequence Analyses Using Alternative Source Terms, Rev. 0, July 2000 provides review guidance to the staff for the review of alternative source term amendment requests. Section 15.0.1 states that the NRC reviewer should evaluate the proposed change against the guidance in RG 1.183. The dose acceptance criteria for the fuel handling accident (FHA) are a Total Effective Dose Equivalent (TEDE) of 6.3 rem at the exclusion area boundary (EAB) for the worst 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, 6.3 rem at the outer boundary of the low population zone (LPZ), and 5 rem in the control room for the duration of the accident.

Staff Requests The response to RAI 2 provided information on the new FHA analysis for the permanently defueled condition. The staff has the following requests for information based on the information provided in that response.

1. The licensee indicates in the response that they used RADTRAD to calculate the FHA dose analysis. The text above Table 1 and the title of Table 1 indicate that Table 1 provides inputs to the FHA calculation. The input to RADTRAD is normally the core or assembly source term. Yet in the clarification call the licensee indicated that Table 2 provided the source term for the quantity of radioactive material that escapes the spent fuel pool following a fuel handling accident. Furthermore, the RAI response inaccurately describes the Table 2 source term. Specifically, Table 1 of the RAI response states that Table 2 provides the Isotopic Core Inventory (Ci/MWt). In addition, the paragraph directly above Table 2 indicates that it is a fuel source term (instead of the quantity of radioactive material that escapes the pool following an accident), and doesnt state that the source term in Table 2 credits the decontamination from the spent fuel pool water.

UFSAR section 15.7-6 discusses the Byron Fuel Handling Accident. Table 15.7-6 provides the bounding isotopic core inventory for the fuel handling accident. Please provide an updated Table 15.7-6 source term used to support the new fuel handling accident radiological consequence analysis and correct the information provided in the response, as appropriate, to adequately describe the information that is provided.

2. Using the information provided in the response, with the clarifications provided in the clarification call, the staff performed a confirmatory calculation and the results showed that EAB, LPZ, and control room doses are all much higher than the values provided in the RAI response for all three locations. Please review the calculation supporting the RAI response and the information provided (i.e. the calculation inputs and results provided) and ensure that there are no errors.