ML12048A069

NRR E-mail Capture - FW: Draft Balance of Plant RAIs Related to MUR Dated June 23, 2011

ML12048A069
Person / Time
Site:	Byron, Braidwood
Issue date:	02/08/2012
From:	Mozafari B Division of Operating Reactor Licensing
To:	Byam T, Holden L Exelon Corp
References
Download: ML12048A069 (3)

Text

1 NRR-PMDAPEm Resource From:

Mozafari, Brenda Sent:

Wednesday, February 08, 2012 5:28 PM To:

'Leslie.Holden@exeloncorp.com'; 'timothy.byam@exeloncorp.com' Cc:

'Lisa.Schofield@exeloncorp.com'

Subject:

FW: Draft Balance of Plant RAIs related to MUR dated June 23, 2011

Leslie, Pursuant to 10 CFR 50.90, by letter to the Nuclear Regulatory Commission (NRC) dated June 23, 2011, the Exelon Generation Company, LLC (the licensee), submitted a license amendment request (LAR) for the Byron Station Units 1 and 2 and Braidwood Station Units 1 and 2. The proposed measurement uncertainty recapture power uprate would increase the current licensed thermal power at Byron Station Units 1 and 2 and Braidwood Station Units 1 and 2, by approximately 1.63 percent. The NRC staff has provided a clarification of the first Question of the questions previously sent with other Balance of Plant RAI questions in an email (Wed 1/18/2012 7:36 PM). The response to this RAI is needed to complete the technical review in this area.

After you have had time to consider your response, we can schedule a call to provide any clarifications and discuss your planned response. I will provide the questions formally after our discussion, however we would expect the this RAI question to be responded to by letter 2 weeks after the initial set of questions scheduled for February 20, 2012. I appreciate your cooperation by responding in such a timely fashion.

The formal letter will be provided as soon as possible. Please let me know if you need a telecom for clarification and discussion of the path forward.

Thanks, Brenda L. Mozafari Senior Project Manager, NRR/DORL U.S. Nuclear Regulatory Commission 301-415-2020 email: brenda.mozafari@nrc.gov

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REQUEST FOR ADDITIONAL INFORMATION BYRON STATION, UNITS 1 AND 2 AND BRAIDWOOD STATION, UNITS 1 AND 2 LICENSE AMENDMENT REQUEST MEASUREMENT UNCERTAINTY RECAPTURE POWER UPRATE (TAC NOS. ME6587, ME6588, ME6589 AND ME6590)

BRAIDWOOD STATION, UNIT NOS. 1 & 2, AND BYRON STATION, UNIT NOS 1 & 2 REQUEST FOR FOLLOW-UP ADDITIONAL INFORMATION REGARDING MEASUREMENT UNCERTAINTY RECAPTURE (MUR) POWER UPRATE TAC NOS. ME6587, ME6588, ME6589, ME6590 Balance of Plant - RAI - 1 The licensee provides a new steam generator tube rupture (SGTR) analysis, taking credit for plant modifications in order to ascertain an adequate margin to overfill. The new analysis for a SGTR credits the use

2 of two steam generator (SG) power operated relief valves (PORVs) to cooldown the reactor coolant system (RCS) rapidly to achieve a subcooling margin in order to depressurize the RCS to stop the break flow prior to overfilling the SGs. The analysis identifies the most limiting single failure is a failure of a SG PORV on an intact steam generator. Thus, the licensee credits the SG PORVs with a high significance for successfully mitigating a SGTR.

Technical Specification (TS) 3.7.4 for the SG PORVs currently allows 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> completion time to restore all but one of the four SG PORVs when two or more are inoperable. Hence, the TS action statement allows all four SG PORVs to be inoperable for up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Westinghouse Standard TS does provide some guidance on multiple SG PORVs inoperable based upon availability of the steam bypass system and main steam safety valves. However, for Bryon/Braidwood these components may not be available in a loss of off-site power or may not provide the same cool down function. Hence, the licensee may have to provide alternate (safety-related or available during a LOOP) components that can perform the same function to justify continued operations with no operable SG PORVs to provide the safety function.

The staff requests the licensee to provide confirmation that the current TS action statement allowing all four SG PORVs to be inoperable (loss of function) remains valid based on the new SGTR analysis.

Hearing Identifier:

NRR_PMDA Email Number:

271 Mail Envelope Properties (9C2386A0C0BC584684916F7A0482B6CA58745E38FD)

Subject:

FW: Draft Balance of Plant RAIs related to MUR dated June 23, 2011 Sent Date:

2/8/2012 5:27:57 PM Received Date:

2/8/2012 5:27:00 PM From:

Mozafari, Brenda Created By:

Brenda.Mozafari@nrc.gov Recipients:

"'Lisa.Schofield@exeloncorp.com'" <Lisa.Schofield@exeloncorp.com>

Tracking Status: None

"'Leslie.Holden@exeloncorp.com'" <Leslie.Holden@exeloncorp.com>

Tracking Status: None

"'timothy.byam@exeloncorp.com'" <timothy.byam@exeloncorp.com>

Tracking Status: None Post Office:

HQCLSTR02.nrc.gov Files Size Date & Time MESSAGE 3914 2/8/2012 5:27:00 PM Options Priority:

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