Federal Register: February 27, 2003 (Volume 68, Number 39)
DOCID: FR Doc 03-4624
NUCLEAR REGULATORY COMMISSION
Nuclear Regulatory Commission
ACTION: Reports and guidance documents; availability, etc.:
DOCUMENT ACTION: Announcement of issuance for public comment, availability, and public meeting.
Handbook of Parameter Estimation for Probabilistic Risk Assessment (PRA)
DATES: Please submit comments by May 23, 2003. Comments received after this date will be considered if is practical to do so, but the NRC Staff is able to ensure consideration only for comments received on or before this date.
A public meeting will be held on April 2, 2003, from 8:30 a.m. until 4:30 p.m. The purpose of this meeting is to discuss the document and give guidance for its review and to address external stakeholder comments received before the public meeting. The primary authors will be available at the public meeting to answer questions and discuss items of interest to the public.
The NRC is interested in receiving comments on specific topics
reviewers wish to discuss at the public meeting. Reviewers are
requested to contact Mr. Arthur Salomon at 3014156552 or email
firstname.lastname@example.org by March 21, 2003, with comments or issues they wish to have addressed at the public meeting.
The U.S. Nuclear Regulatory Commission (NRC) has issued for
public comment a document entitled ``Handbook of Parameter Estimation
for Probabilistic Risk Assessment.'' This handbook provides guidance on
sources of information and methods of estimating distributions of
parameters used in probabilistic risk assessment. This includes
determination of both plantspecific and generic estimates for initiating event frequencies, component failure rates and
unavailability, and equipment nonrecovery probabilities. Interested individuals may obtain a copy of this document from the person identified under the caption FOR FURTHER INFORMATION CONTACT.
Parameter Estimation for Probabilistic Risk Assessment Handbook,
During the last several years the NRC and
the nuclear industry have recognized that PRA has evolved to the point
where it can be used as a tool in the regulatory decisionmaking
process. The increased use of PRA has led to the conclusion that the
PRA scope and model must be commensurate with the applications. Several
procedural guides and standards (such as the ``Standard For
Probabilistic Risk Assessment For Nuclear Power Plant Applications''
published by The American Society of Mechanical Engineers in 2002) have
been and are being developed that identify requirements for the PRA
models. This handbook was prepared to supplement these documents. It
provides a compendium of good practices that a PRA analyst can use to
develop parameter distributions required for quantifying PRA models. It
complements the ASME PRA Standard by providing guidance for estimation
of parameters related to initiating events; by describing statistical techniques for estimating parameters used in analysis
of basic events such as equipment failures; and by addressing methods for estimating equipment unavailability. Furthermore, the handbook includes appendices describing the basics of probability and statistics used in performing the more detailed analyses discussed in the main portion of the document.
The handbook provides the basic information needed to generate estimates of the parameters commonly used in PRA analysis. It begins by describing the probability models and plant data used to evaluate each of the parameters. Possible sources for the plant data are identified and guidance on the collection, screening, and interpretation is provided. The statistical techniques (both Bayesian and classical methods) required to analyze the collected data and test the validity of statistical models are described. Examples are provided to help the PRA analyst utilize the different techniques. The handbook also provides advanced techniques that address modeling of time trends. Methods for combining data from a number of similar, but not identical sources are also provided. This includes empirical and hierarchical Bayesian approaches. Examples are provided to guide the analyst. The handbook does not provide guidance on parameter estimation for all of the events included in a PRA. Specifically, common cause failure and human error probabilities are not addressed. In addition, guidance is not provided regarding the use of expert elicitation. However, suggested references regarding these technical areas are provided in the handbook introduction.
Dated at Rockville, Maryland, this 21st day of February, 2003.
For the Nuclear Regulatory Commission.
Scott F. Newberry,
Director, Division of Risk Analysis and Applications, Office of Nuclear Regulatory Research.
[FR Doc. 034624 Filed 22603; 8:45 am]
BILLING CODE 759001P
FOR FURTHER INFORMATION CONTACT
Arthur D. Salomon, Division of Risk Analysis and Applications, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC 205550001. Telephone: 3014156552, email: email@example.com.