[Federal Register Volume 80, Number 8 (Tuesday, January 13, 2015)]
[Notices]
[Pages 1678-1679]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-00369]


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NUCLEAR REGULATORY COMMISSION

[Docket Nos. STN 50-456, STN 50-457, STN 50-454 and STN 50-455; NRC-
2012-0203]


Issuance; Exelon Generation Company, LLC

AGENCY: Nuclear Regulatory Commission.

ACTION: Director's decision under 10 CFR 2.206; issuance.

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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) has issued a 
director's decision with regard to a petition dated April 29, 2012, 
filed by Mr. Barry Quigley (the petitioner), requesting that the NRC 
take action with regard to Braidwood Station, Units 1 and 2, and Byron 
Station, Units 1 and 2. The petitioner's requests and the director's 
decision are included in the SUPPLEMENTARY INFORMATION section of this 
document.

ADDRESSES: Please refer to Docket ID NRC-2012-0203 when contacting the 
NRC about the availability of information regarding this document. You 
may obtain publicly-available information related to this document 
using any of the following methods:
     Federal Rulemaking Web site: Go to http://www.regulations.gov and search for Docket ID NRC-2012-0203. Address 
questions about NRC dockets to Carol Gallagher; telephone: 301-287-
3422; email: [email protected].
     NRC's Agencywide Documents Access and Management System 
(ADAMS): You may obtain publicly available documents online in the 
ADAMS Public Documents collection at http://www.nrc.gov/reading-rm/adams.html. To begin the search, select ``ADAMS Public Documents'' and 
then select ``Begin Web-based ADAMS Search.'' For problems with ADAMS, 
please contact the NRC's Public Document Room (PDR) reference staff at 
1-800-397-4209, 301-415-4737, or by email to [email protected]. The 
ADAMS accession number for each document referenced in this document 
(if that document is available in ADAMS) is provided the first time 
that a document is referenced.
     NRC's PDR: You may examine and purchase copies of public 
documents at the NRC's PDR, Room O1-F21, One White Flint North, 11555 
Rockville Pike, Rockville, Maryland 20852.

SUPPLEMENTARY INFORMATION: Notice is hereby given that the Director, 
Office of Nuclear Reactor Regulation, has issued a director's decision 
(ADAMS Accession No. ML14239A313), on a petition filed by the 
petitioner on April 20, 2012 (ADAMS Accession No. ML12130A318).
    The petitioner requested that the NRC immediately shutdown 
Braidwood Station, Units 1 and 2, and Byron Station, Units 1 and 2, 
until all turbine building (TB) high-energy line break (HELB) concerns 
were identified and those important to safety were corrected.
    As the basis of the request, the petitioner asserted:

     An adequate supply of combustion air for the emergency 
diesel generators (EDGs) is threatened because the combustion air 
can be diluted with steam. Although the combustion air is drawn from 
an air shaft (not the TB), it is also the same air shaft that 
supplies ventilation for the EDG room. Under certain conditions, the 
ventilation damper alignment is such that steam that enters the EDG 
room from the ventilation exhaust can back flow into the inlet air 
shaft. From there it can be drawn into the engine, potentially 
starving the engine of air.
     The effects of high temperature in the engineered 
safeguards features (ESF) switchgear (SWGR) rooms on the protective 
relaying setpoints have not been evaluated. The concern is that high 
temperatures could alter the setpoints such that protective actions 
occur under normal loading conditions.
     The current method of analysis for TB HELB uses a 
``lumped volume'' approach wherein the mass and energy (M&E) of the 
ruptured line mixes instantly with the entire volume before flowing 
into the areas of concern. Because this substantially reduces the 
energy flow, it does not always give conservative results. For 
example, the petitioner's preliminary assessment using the

[[Page 1679]]

subdivided volume feature in GOTHIC showed that the structural 
limits on the block wall between the ESF SWGR rooms would be 
substantially exceeded.
     There has been no structured and detailed review of the 
licensing requirements for HELB.

    On May 14, 2012, the petitioner and the licensee met with the NRC's 
Petition Review Board. The meeting provided the petitioner and the 
licensee an opportunity to provide additional information and to 
clarify issues cited in the petition. On November 15, 2012, the 
petitioner and the licensee again met with the NRC's Petition Review 
Board at the request of the Petition Review Board. The transcripts of 
these meetings were treated as supplements to the petition and are 
available in the ADAMS (Accession Nos. ML 12145A633 and ML 12347A354, 
respectively).
    The NRC sent a copy of the proposed director's decision to the 
petitioner and the licensee for comment on June 18, 2014. The 
petitioner and the licensee were asked to provide comments within 30 
days on any part of the proposed director's decision that was 
considered to be erroneous or any issues in the petition that were not 
addressed. The staff did not receive any comments on the proposed 
director's decision.
    The Director of Nuclear Reactor Regulation has determined that the 
request, to require immediate shutdown of Braidwood Station, Units 1 
and 2, and Byron Station, Units 1 and 2, until all turbine building 
(TB) high-energy line break (HELB) concerns were identified and those 
important to safety were corrected be denied. The Director of Nuclear 
Reactor Regulation has determined to partially grant the petition in 
that the licensing basis requirements for high energy line break were 
reviewed during the review of the application for the Braidwood/Byron 
measurement uncertainty recapture uprate, which was completed in the 
February 7, 2014 (ADAMS accession No. ML13281A000). The reasons for 
this decision are explained in the director's decision NRC-2012-0203 
pursuant to Section 2.206 of Title 10 of the Code of Federal 
Regulations (10 CFR) of the Commission's regulations.
    The NRC will file a copy of the director's decision with the 
Secretary of the Commission for the Commission's review in accordance 
with 10 CFR 2.206. As provided by this regulation, the director's 
decision will constitute the final action of the Commission 25 days 
after the date of the decision unless the Commission, on its own 
motion, institutes a review of the director's decision in that time.

    Dated at Rockville, Maryland, this 22nd day of December, 2014.

    For the Nuclear Regulatory Commission.
William Dean,
 Director, Office of Nuclear Reactor Regulation.
[FR Doc. 2015-00369 Filed 1-12-15; 8:45 am]
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