[Federal Register: October 14, 2009 (Volume 74, Number 197)]
[Notices]
[Page 52822-52823]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr14oc09-91]
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NUCLEAR REGULATORY COMMISSION
[NRC-2009-0453]
Draft Regulatory Guide: Issuance, Availability
AGENCY: Nuclear Regulatory Commission.
ACTION: Notice of Issuance and Availability of Draft Regulatory Guide,
DG-1199, ``Alternative Radiological Source Terms for Evaluating Design
Basis Accidents at Nuclear Power Reactors.''
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FOR FURTHER INFORMATION CONTACT: Mark Blumberg, U. S. Nuclear
Regulatory Commission, Washington, DC 20555-0001, telephone: (301) 415-
1083 or e-mail Mark.Blumberg@nrc.gov.
SUPPLEMENTARY INFORMATION:
I. Introduction
The U.S. Nuclear Regulatory Commission (NRC) is issuing for public
comment a draft regulatory guide in the agency's ``Regulatory Guide''
series. This series was developed to describe and make available to the
public such information as methods that are acceptable to the NRC staff
for implementing specific parts of the NRC's regulations, techniques
that the staff uses in evaluating specific problems or postulated
accidents, and data that the staff needs in its review of applications
for permits and licenses.
The draft regulatory guide (DG), titled, ``Alternative Radiological
Source Terms for Evaluating Design Basis Accidents at Nuclear Power
Reactors,'' is temporarily identified by its task number, DG-1199,
which should be mentioned in all related correspondence. DG-1199 is
proposed Revision 1 of Regulatory Guide 1.183, dated July 2000. This
regulatory guide describes a method that the staff of the NRC considers
acceptable in complying with alternative source term (AST) regulations
for design basis accident dose consequence analysis. This guidance for
light-water reactor designs includes the scope, nature, and
documentation of associated analyses, evaluations; consideration of
impacts on analyzed risk; and content of submittals. This guide
establishes the AST based on NUREG-1465, ``Accident Source Terms for
Light-Water Nuclear Power Plants,'' and identifies significant
attributes of other accident source terms that may be acceptable. This
guide also identifies acceptable radiological analysis assumptions for
use in conjunction with the AST. In some cases, unusual site
characteristics, plant design features, or other factors may require
different assumptions, which will be considered on an individual case
basis.
The draft guide references Regulatory Guide 1.89, ``Environmental
Qualification of Certain Electric Equipment Important to Safety for
Nuclear Power Plants,'' regarding environmental qualification analyses
that may be affected by implementing alternate source terms. This
guidance will be available in the forthcoming revision of Regulatory
Guide 1.89 and is currently available in Appendix I of Regulatory Guide
1.183, Revision 0.
II. Further Information
The Commission invites advice and recommendations on the content of
DG-1199. Specifically, comments are solicited for the following
questions. Each comment should include supporting basis or rationale to
enable the staff to fully understand the point of view being provided.
1. The alternative source term methodology described in the draft
regulatory guide permits the assumption that the release of radioactive
effluent to the environment occurs at some time period following the
onset of the accident within the plant facility. Section 5.3,
Meteorology Assumptions, provides guidance on pairing atmospheric
dispersion factors ([chi]/Q values) with the periods of maximum
postulated release of radioactive effluent to the environment.
a. Is it equally or more appropriate to include consideration of
engineering factors such as time of control room isolation and
initiation of filtration, in addition to the time sequence release of
radiological effluent to the environment, when assessing the limiting
dose to control room operators?
2. Table 3 of DG-1199 provides revised non-loss of coolant accident
fission product gap inventories applicable to all current fuel designs.
The purpose of revising Table 3 was to expand its applicability by
replacing the prior footnote 11 limitation (i.e., 6.3 kw/ft beyond 54
GWd/MTU) with bounding fuel rod power envelopes.
a. Does the bounding fuel rod power envelopes depicted in Figure 1
of DG-1199 provide sufficient fuel management flexibility such that
current and anticipated fuel loading patterns will be able to utilize
the Table 3 fission product gap fractions?
b. Fission gas release and the resulting fission product gap
inventory are sensitive to fuel rod design and rod power history. To
maintain consistency with current regulatory guidance, the revised
Table 3 remains applicable to all current pressurized water reactor
(PWR) and boiling water reactor (BWR) fuel rod designs (limited only by
the bounding power envelope). Significant reductions in fission product
gap inventories are achievable with specific fuel rod design
calculations (e.g., PWR 17x17 versus PWR 14x14) and/or less bounding
rod power histories. Should RG 1.183 provide alternate versions of
Table 3, each with its own set of applicability criteria?
3. Reference 18 of DG-1199 documents the expanded fission gas
release empirical database and methods used to calculate the revised
Table 3 and Table 4 fission product gap inventories. Are any further
fission gas measurements available which would help enhance the gap
inventories listed in Table 3 and 4?
Comments should mention DG-1199 in the subject line. Comments
submitted in writing or in electronic form will be made available to
the public in their entirety through the NRC's Agencywide Documents
Access and Management System (ADAMS).
Personal information will not be removed from the comments.
Comments may be submitted by any of the following methods:
1. Mail comments to: Rulemaking and Directives Branch, Division of
Administrative Services, Mail Stop: TWB-05-B01M, Office of
Administration, U.S. Nuclear Regulatory
[[Page 52823]]
Commission, Washington, DC 20555-0001.
2. Federal e-Rulemaking Portal: Go to http://www.regulations.gov
and search for documents filed under Docket ID [NRC-2009-0453]. Address
questions about NRC dockets to Carol Gallagher, 301-492-3668; e-mail
Carol.Gallagher@nrc.gov.
3. Fax comments to: Rulemaking and Directives Branch, Division of
Administrative Services, Office of Administration, U.S. Nuclear
Regulatory Commission at (301) 492-3446.
Requests for technical information about DG-1199 may be directed to
Mark Blumberg at (301) 415-1083 or e-mail to Mark.Blumberg@nrc.gov.
Comments would be most helpful if received by December 11, 2009.
Comments received after that date will be considered if it is practical
to do so, but the NRC is able to ensure consideration only for comments
received on or before this date. Although a time limit is given,
comments and suggestions in connection with items for inclusion in
guides currently being developed or improvements in all published
guides are encouraged at any time.
Electronic copies of DG-1199 are available through the NRC's public
Web site under Draft Regulatory Guides in the ``Regulatory Guides''
collection of the NRC's Electronic Reading
Room at http://www.nrc.gov/reading-rm/doc-collections/. Electronic
copies are also available in ADAMS (http://www.nrc.gov/reading-rm/
adams.html), under Accession No. ML090960464. In addition, regulatory
guides are available for inspection at the NRC's Public Document Room
(PDR) located at 11555 Rockville Pike, Rockville, Maryland. The PDR's
mailing address is USNRC PDR, Washington, DC 20555-0001. The PDR can
also be reached by telephone at (301) 415-4737 or (800) 397-4205, by
fax at (301) 415-3548, and by e-mail to pdr.resource@nrc.gov.
Regulatory guides are not copyrighted, and Commission approval is
not required to reproduce them.
Dated at Rockville, Maryland, this 6th day of October 2009.
For the Nuclear Regulatory Commission.
Andrea D. Valentin,
Chief, Regulatory Guide Development Branch, Division of Engineering,
Office of Nuclear Regulatory Research.
[FR Doc. E9-24719 Filed 10-13-09; 8:45 am]
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