[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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