NMP2L2729, Supplemental Information No.1 for Nine Mile Point Nuclear Station, Unit 2, to Adopt 10 CFR 50.69, Risk-Informed Categorization and Treatment of Structures, Systems and Components for Nuclear Power Reactors

Supplemental Information No.1 for Nine Mile Point Nuclear Station, Unit 2, to Adopt 10 CFR 50.69, Risk-Informed Categorization and Treatment of Structures, Systems and Components for Nuclear Power Reactors

ML20121A005
Person / Time
Site:	Nine Mile Point
Issue date:	04/30/2020
From:	David Gudger Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NMP2L2729
Download: ML20121A005 (5)

Text

200 Exelon Way Kennett Square, PA 19348 www.exeloncorp.com 10 CFR 50.90 NMP2L2729 April 30, 2020 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Nine Mile Point Nuclear Station, Unit 2 Renewed Facility Operating License No. NPF-69 NRC Docket No. 50-410

Subject:

Supplemental Information No.1 for Nine Mile Point Nuclear Station, Unit 2, to Adopt 10 CFR 50.69, "Risk-Informed Categorization and Treatment of Structures, Systems and Components for Nuclear Power Reactors"

Reference:

Letter from S. Rafferty-Czincila (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "Application to Adopt 10 CFR 50.69, 'Risk-Informed Categorization and Treatment of Structures, Systems and Components for Nuclear Power Reactors'," dated December 26, 2019 By letter dated December 26, 2019 (Reference), Exelon Generation Company, LLC (Exelon) requested to change the Nine Mile Point Nuclear Station, Unit 2 (NMP2) license. The proposed amendment would modify the NMP2 licensing basis, by the addition of a License Condition, to allow for the implementation of the provisions of Title 10 of the Code of Federal Regulations (10 CFR), Part 50.69, "Risk-Informed Categorization and Treatment of Structures, Systems and Components for Nuclear Power Reactors." to this letter provides supplemental information to the referenced letter for Section 3.2.3, "Seismic Hazards" and Section 6.0, "References." In addition, the proposed license condition presented in Section 2.3, "Description of the Proposed Change," and in , "Proposed Facility Operating License Condition Markup," of the referenced letter is clarified to identify that Section 2.3 contains the correct wording.

Exelon has reviewed the information supporting a finding of no significant hazards consideration and the environmental consideration provided to the NRC in the Referenced document. The supplemental information provided in this letter does not affect the bases for concluding that the proposed license amendment does not involve a significant hazards

U.S. Nuclear Regulatory Commission Supplemental Information to Adopt 10 CFR 50.69 Docket No. 50-41 O April 30, 2020 Page2 consideration. Furthermore, the supplemental information provided in this letter does not affect the bases for concluding that neither an environmental impact statement nor an environmental assessment needs to be prepared in connection with the proposed amendment.

There are no commitments contained in this response.

If you should have any questions regarding this submittal, please contact Ron Reynolds at 610-765-5247. ,

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 301h day of April 2020.

Respectfully,

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David T. Gudger Senior Manager - Licensing Exelon Generation Company, LLC : Supplemental Information cc: USNRC Region I Regional Administrator w/attachments II USN RC Senior Resident Inspector - NMP II USNRC Project Manager, NRR - NMP II A. L. Peterson, NYSERDA

ATTACHMENT 1 Nine Mile Point Nuclear Station, Unit 2 Renewed Facility Operating License NPF-69 Docket No. 50-410 SUPPLEMENTAL INFORMATION

Attachment 1 Supplemental Information to Adopt 10 CFR 50.69 Page 1 of 2 SUPPLEMENTAL INFORMATION A. Seismic Hazards The following supplemental information provides a correction in the Enclosure to the referenced letter. On page 7 of the Enclosure, in Table 3-1, in the "Element" column for Risk (PRA Modeled), the word "Seismic " is deleted. This correction aligns Table 3-1 with the NEI template as "Seismic" is correctly identified in the next Element-Risk (Non-modeled).

Excerpt of Table 3-1 with correction shown:

Drives Categorization Step - IDP Change Element Evaluation Level Associated NEI 00-04 Section HSS to LSS Functions Internal Events Base Not Allowed Yes Case - Section 5.1 Fire, Seismic and Other External Events Allowable No Risk (PRA Base Case Component Modeled) PRA Sensitivity Allowable No Studies Integral PRA Assessment - Not Allowed Yes Section 5.6 Fire, seismic and Other External Component Not Allowed No Hazards -

Risk (Non-modeled) Seismic Function/Component Allowed 2 No Shutdown - Section Function/Component Not Allowed No 5.5 2

IDP consideration of seismic insights can also result in an LSS to HSS determination.

The following supplemental information provides clarification to Section 3.2.3, Seismic Hazards, at the end of the first paragraph of page 14 of the enclosure to the reference letter:

NMP2 follows the same categorization approach for seismic risk as approved for Calvert Cliffs Nuclear Power Plant as identified in Reference 49 with no deviations.

In the second paragraph on page 16 to the reference letter, the last sentence states, in part,

" are shown in Figure 1 of Attachment 4." Figure 1 is the incorrect figure number. identifies the figure as A4-1. Figure A4-1 is the correct figure number.

The following supplemental information is added to Section 6.0, References, for clarification:

49 Calvert Cliffs Nuclear Power Plant, Units 1 and 2- Issuance of Amendment Nos. 332 and 310 RE: Risk-Informed Categorization and Treatment of Structures, Systems, And Components for Nuclear Power Reactors (EPID L-2018-LLA-0482), dated February 28, 2020 (ML19330D909).

Attachment 1 Supplemental Information to Adopt 10 CFR 50.69 Page 2 of 2 50 Calvert Cliffs Nuclear Power Plant, Units 1 and 2, "Response to Request for Additional Information Regarding the Application to Adopt 10 CFR 50.69, 'Risk-informed categorization and treatment of structures, systems, and components for nuclear power reactors,' " dated July 1, 2019 (ML19183A012).

51 Calvert Cliffs Nuclear Power Plant, Units 1 and 2, "Response to Request for Additional Information Regarding the Application to Adopt 10 CFR 50.69, 'Risk-informed categorization and treatment of structures, systems, and components for nuclear power reactors,' " dated July 19, 2019 (ML19200A216).

52 Calvert Cliffs Nuclear Power Plant, Units 1 and 2, "Revised Response to Request for Additional Information Regarding the Application to Adopt 10 CFR 50.69, 'Risk-Informed Categorization and Treatment of Structures, Systems, and Components for Nuclear Power Reactors,' letter dated July 19, 2019," dated August 5, 2019 (ML19217A143).

B. License Condition Clarification In addition, the referenced letter describes the proposed license condition in Section 2.3 differently from the description in Attachment 8. For clarification, the wording presented in Section 2.3 is the correct description of the proposed license condition and replaces the wording in Attachment 8 in its entirety.

The proposed license condition from Section 2.3 is replicated below:

Exelon is approved to implement 10 CFR 50.69 using the processes for categorization of Risk-Informed Safety Class (RISC)-1, RISC-2, RISC-3, and RISC-4 Structures, Systems, and Components (SSCs) using: Probabilistic Risk Assessment (PRA) models to evaluate risk associated with internal events, including internal flooding, and internal fire; the shutdown safety assessment process to assess shutdown risk; the Arkansas Nuclear One, Unit 2 (ANO-2) passive categorization method to assess passive component risk for Class 2 and Class 3 and non-Class SSCs and their associated supports; the results of the non-PRA evaluations that are based on the IPEEE Screening Assessment for External Hazards updated using the external hazard screening significance process identified in ASME/ANS PRA Standard RA-Sa-2009 for other external hazards except seismic; and the alternative seismic approach as described in Exelon's submittal letter dated [DATE], and all its subsequent associated supplements as specified in License Amendment No. [XXX] dated [DATE].

Exelon will complete the items listed in Attachment 7 of Exelon letter to NRC dated

[DATE] prior to implementation of 10 CFR 50.69. All issues identified in the attachment will be addressed and any associated changes will be made, focused-scope peer reviews will be performed on changes that are PRA upgrades as defined in the PRA standard (ASME/ANS RA-Sa-2009, as endorsed by RG 1.200, Revision 2), and any findings will be resolved and reflected in the PRA of record prior to implementation of the 10 CFR 50.69 categorization process.

Prior NRC approval, under 10 CFR 50.90, is required for a change to the categorization process specified above (e.g., change from a seismic margins approach to a seismic probabilistic risk assessment approach).