NMP2L2586, Request for Exemption from 10 CFR Part 50, Appendix a, GDC-56

Request for Exemption from 10 CFR Part 50, Appendix a, GDC-56

ML15176A008
Person / Time
Site:	Nine Mile Point
Issue date:	06/24/2015
From:	Jim Barstow Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-13-109, NMP2L2586
Download: ML15176A008 (2)

Text

200 Exelon Way Exelon Generation Kennett Square. PA 19348 www.exeloncorp.com NMP2L2586 June 24, 2015 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:

Request for Exemption from 10 CFR Part 50, Appendix A, GDC-56

References:

1) NRC Order Number EA-13-109, "Issuance of Order to Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," dated June 6, 2013 (ML13143A321)

2) Letter from M. Korsnick (Constellation Energy Nuclear Group, LLC) to U.S. Nuclear Regulatory Commission, "Request for Exemption from 10 CFR 50, Appendix A, GDC 56," dated June 27, 2014

3) Letter from M. Korsnick (Constellation Energy Nuclear Group, LLC) to U.S. Nuclear Regulatory Commission, "Partial Withdrawal of Request for Exemption from 10 CFR 50, Appendix A, GDC Penetration Z-48 (Drywell)," dated March 30, 2015 On June 6, 2013, the Nuclear Regulatory Commission (NRC) issued Order EA-13-109 (Reference 1) to all licensees that operate Boiling Water Reactors (BWRs) with Mark I and Mark II containments to take certain actions to ensure the functionality of reliable hardened containment vent systems (HCVS) to remove decay heat and maintain control of containment pressure following events that result in loss of active containment heat removal capability or Extended Loss of AC Power (ELAP), and ensure that containment venting functions are also available during severe accident conditions.

In References 2 and 3, Exelon Generation Company, LLC (Exelon) submitted information regarding a request for exemption from the requirements of 10 CFR 50, Appendix A, General Design Criterion (GDC) 56, "Primary containment isolation," to permit an alternative containment isolation valve configuration for Nine Mile Point Nuclear Station, Unit 2 (NMP2).

The HCVS system will share components including the containment penetration and isolation valves with the containment vent and purge system. The existing configuration is one automatic isolation valve inside and one automatic isolation valve outside of the primary

U.S. Nuclear Regulatory Commission Request for Exemption from 10 CFR Part 50, Appendix A, GDC-56 June 24, 2015 Page 2 containment. As part of the HCVS modification, the automatic isolation valve function located inside containment will be relocated to the outside of the containment resulting in both inboard and outboard containment automatic isolation functions being located outside of the containment. The new configuration is consistent with that described in the NMP2 Safety Evaluation Report (NUREG-1047, "Safety Evaluation Report related to the operation of Nine Mile Point Nuclear Station, Unit No. 2," Supplement No. 3, dated July 1986).

Based on the below discussion with the NRC Staff on Thursday June 11, 2015, Exelon is withdrawing this exemption.

As discussed in the call, NMP2's proposed arrangement satisfies the requirements of GDC-56 and is consistent with the previous licensing decisions for the plant and the current Standard Review Plan (SRP) for "Containment Isolation System" (SRP 6.2.4). In the 1986 Safety Evaluation Report for NMP2 (NUREG-1047, Supplement 3), the staff authorized both the inboard and outboard containment isolation valves to be located outside of containment for more than one set of penetrations. The stated reason for this arrangement was The location of a valve inside containment would subject it to more severe environmental conditions (including suppression pool dynamic loads), and it would not be easily accessible for inspection. An example of this is the purge lines in the drywell and suppression chamber."

Accordingly, the NRC Staff determined that the proposed arrangement of both valves located outside of containment is an acceptable method for meeting the GDC-56 requirements; thus, no exemption is required.

There are no commitments contained in this submittal.

Respectfully, tJ~ U-James Barstow Director - Licensing and Regulatory Affairs Exelon Generation Company, LLC cc: Regional Administrator - NRC Region I NRC Senior Resident Inspector - Nine Mile Point Nuclear Station NRC Project Manager - Nine Mile Point Nuclear Station Mr. Charles H. Norton - NRR/JLD/JOMB, NRC A. L. Peterson - NYSERDA