[Federal Register Volume 69, Number 147 (Monday, August 2, 2004)]
[Proposed Rules]
[Pages 46110-46111]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-17477]
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Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
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Federal Register / Vol. 69, No. 147 / Monday, August 2, 2004 /
Proposed Rules
[[Page 46110]]
NUCLEAR REGULATORY COMMISSION
10 CFR Part 50
RIN 3150-AH29
Risk-Informed Changes to Loss-of-Coolant Accident Technical
Requirements
AGENCY: U.S. Nuclear Regulatory Commission.
ACTION: Availability of draft rule conceptual basis, draft rule
language and notice of public meeting.
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SUMMARY: The Nuclear Regulatory Commission (NRC) is making available
the draft rule conceptual basis and the draft rule language for a new
Sec. 50.46a, and conforming changes to Sec. Sec. 50.34, 50.46, 50.46a
(to be redesignated as Sec. 50.46b), 50.109, and 10 CFR part 50,
Appendix A, General Design Criterion 35, concerning emergency core
cooling systems (ECCS) for light-water nuclear power reactors. The
amended regulations would permit power reactor licensees to implement a
voluntary risk-informed alternative to the current requirements for
analysis of loss-of-coolant accidents and for ECCS in 10 CFR 50.46. The
availability of the draft rule conceptual basis and draft rule language
is intended to inform stakeholders of the current status of the NRC's
activities to risk-inform 10 CFR 50.46, but the NRC is not soliciting
formal public comments on the information at this time. The NRC has
scheduled a public meeting for August 17, 2004, at which stakeholders
are invited to inform the NRC of possible nuclear power plant
modifications that might be sought under such a rule and their
associated costs and benefits. The NRC plans to use this information in
preparing the regulatory analysis for the rule.
DATES: A public meeting is scheduled on August 17, 2004, at 9 a.m. in
the Auditorium of the NRC's offices located at Two White Flint North,
11545 Rockville Pike, Rockville, Maryland. Should it become necessary
to change the date or time of this meeting, the NRC will provide the
revised information in a meeting notice posted on the NRC's public Web
site at http://www.nrc.gov/public-involve/public-meetings/meeting-schedule.html#NRR.
ADDRESSES: The public meeting will be held in the Auditorium of the
NRC's offices located at Two White Flint North, 11545 Rockville Pike,
Rockville, Maryland. The draft rule conceptual basis and draft rule
language can be viewed and downloaded electronically via the NRC's
rulemaking Web site at http://ruleforum.llnl.gov. Along with other
publicly available documents related to this rulemaking, the draft
information may be viewed electronically on public computers in the NRC
Public Document Room (PDR), located at One White Flint North, 11555
Rockville Pike, Rockville, MD 20852, Room O-1 F21, and open to the
public on Federal workdays from 7:45 a.m. until 4:15 p.m. The PDR
reproduction contractor will make copies of documents for a fee.
Publicly available NRC documents created or received in connection
with this rulemaking are also available electronically via the NRC's
Electronic Reading Room at http://www.nrc.gov/reading-rm/adams.html.
From this site, the public can gain entry into the NRC's Agencywide
Document Access and Management System (ADAMS), which provides text and
image files of NRC's public documents. The draft rule conceptual basis
and draft rule language are available under ADAMS accession number
ML042080299. If you do not have access to ADAMS, or if there are
problems in accessing the documents located in ADAMS, contact the NRC
PDR Reference staff at (800) 397-4209, (301) 415-4737 or by e-mail at
[email protected].
FOR FURTHER INFORMATION CONTACT: Richard Dudley, Policy and Rulemaking
Program, Division of Regulatory Improvement Programs, Office of Nuclear
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC
20555-0001; telephone: (301) 415-1116; Internet: [email protected].
SUPPLEMENTARY INFORMATION:
In a staff requirements memorandum dated July 1, 2004, the
Commission directed the staff to propose a risk-informed alternative
rule to the current requirements in 10 CFR 50.46. The NRC is making
preliminary versions of the draft rule conceptual basis and draft rule
language available to inform stakeholders of the current status of the
NRC's activities to risk-inform 10 CFR 50.46. This draft rule
conceptual basis may be subject to significant revisions during the
rulemaking process. To meet the Commission's schedule, the NRC is not
soliciting early public comments on this draft rule conceptual basis
and draft rule language. No stakeholder requests for a comment period
will be granted at this stage in the rulemaking process. Stakeholders
will have an opportunity to comment on the rule conceptual basis and
rule language when it is published as a proposed rule.
Under this risk-informed alternative, the NRC would establish
requirements, in a new Sec. 50.46a, which would divide the existing
spectrum of LOCA pipe break sizes up to the double-ended rupture of the
largest reactor coolant system pipe into two regions. Each region will
be subject to different ECCS analysis requirements, commensurate with
likelihood of the break. Loss-of-coolant accidents in the smaller break
size region (up to and including a ``transition break size'') will be
analyzed by the methods, assumptions and criteria currently used for
LOCA analysis; accidents in the larger break size region (from the
transition break size up to the double-ended rupture of the largest
reactor coolant system pipe) may be analyzed by less stringent methods
based on their lower likelihood. Although loss-of-coolant accidents for
breaks larger than the transition break size will become beyond design-
basis accidents, the NRC will promulgate regulations ensuring that
licensees maintain the ability to mitigate pipe breaks up to the
double-ended rupture of the largest reactor coolant system pipe. Since
LOCAs in the larger break size region would be required to be
mitigated, such accidents would remain separate from severe accidents,
which are addressed by voluntary industry guidelines.
Licensees who perform new LOCA analyses using the new risk-informed
alternative requirements may find that their plant designs are no
longer limited by certain parameters associated with previous analyses.
Changing these limitations could enable licensees to
[[Page 46111]]
propose a wide scope of design or operational changes up to the point
of being limited by some other parameter on any of the required
analyses. Potential changes might include increasing power, modifying
core peaking factors, removing some accumulators from service,
eliminating fast starting of one or more emergency diesel generators,
etc. Some of these design and operational changes could increase plant
safety. In order to ensure that any design and operational changes do
not unacceptably reduce plant safety margins or unacceptably increase
risk, the rule will require that any potential increase in risk
associated with plant modifications is small and consistent with the
Commission's Safety Goal Policy Statement (60 FR 42622, August 15,
1995). The risk-informed 10 CFR 50.46 option will also establish a
design change evaluation process. The evaluation process will generally
involve the criteria for risk-informed license amendments similar to
those in Regulatory Guide 1.174 (ADAMS Accession No. ML023240437). The
rule would require monitoring of plant risk to ensure that the bases
for any facility changes made under this rule are maintained. The rule
would require that proposed facility changes be reviewed and approved
by the NRC via the routine license amendment process,\1\ including any
needed changes to the facility's technical specifications. Potential
impacts of the plant changes on facility security will be evaluated
during the process for license amendment reviews.
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\1\ Requirements for this process are specified in 10 CFR 50.90.
They include public notice of all amendment requests in the Federal
Register, an opportunity for affected persons to request a public
hearing, preparation of an environmental analysis, and a detailed
NRC technical evaluation to ensure that the facility will continue
to provide adequate protection of public health and safety after the
amendment is implemented.
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The NRC intends to periodically evaluate LOCA frequency
information. If estimated LOCA frequencies significantly change, the
NRC may revise the transition break size. In such a case, the backfit
rule (10 CFR 50.109) would not apply. Similarly, if future evaluations
of LOCA frequency invalidate the bases for a design change made by a
licensee, that licensee would be required to change the facility and/or
procedures or make other compensatory changes elsewhere to reduce
facility risk to acceptable levels. In such cases, the backfit rule (10
CFR 50.109) also would not apply.
The NRC's current concept regarding the rule framework, the
associated technical bases, and early draft rule language will be
posted on the NRC's rulemaking Web site at http://ruleforum.llnl.gov.
This draft rule conceptual basis and draft rule language are
preliminary and may be incomplete in one or more respects. This early
draft information is being released to inform stakeholders of the
current status of the 10 CFR 50.46 rulemaking. Periodically, the NRC
may post updates to the draft rule conceptual basis or draft rule
language on the rulemaking Web site.
At the public meeting on August 17, 2004, the NRC would like to
obtain information about the potential costs and benefits of the above
rule changes in order to complete the regulatory analysis for the
proposed rule. After licensees and other stakeholders review the draft
rule conceptual basis and draft rule language posted on the NRC Web
site (http://ruleforum.llnl.gov), the NRC would like to obtain
information as described below.
1. Estimate the number and type of plants that might pursue this
voluntary option. Estimate the costs of performing the ECCS reanalyses
at these plants.
2. Provide the estimated number and types of plant design changes
that would be permitted by the ECCS reanalyses at these plants (on a
per unit basis) and the estimated costs of any decision analyses
associated with such design changes.
3. Estimate the costs of additional analyses (apart from the ECCS
reanalyses) required by the proposed rule to determine the
acceptability of the above design changes. These costs could include
but may not be limited to (1) updating probabilistic risk assessments
(PRAs) to reflect the new design and to meet the PRA quality and scope
requirements and (2) analyses to determine compliance with the risk
acceptance criteria and the defense-in-depth criteria.
4. Estimate the number and types of plant design changes (on a per
unit basis) that would meet the acceptance criteria for the additional
analyses.
5. Estimate the costs of implementing the plant design changes that
meet the acceptance criteria for the additional analyses.
6. Estimate any operational costs and/or savings resulting from
implementing the above design changes.
7. Estimate any anticipated changes in licensee information
collection, reporting, and retention burden that could result if this
rulemaking is implemented.
Dated in Rockville, Maryland, this 26th day of July, 2004.
For the Nuclear Regulatory Commission.
Catherine Haney,
Program Director, Policy and Rulemaking Program, Division of Regulatory
Improvement Programs, Office of Nuclear Reactor Regulation.
[FR Doc. 04-17477 Filed 7-30-04; 8:45 am]
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