E6-1775. Regulatory Guide: Issuance, Availability

The U.S. Nuclear Regulatory Commission (NRC) has issued a new guide in the agency's Regulatory Guide Series. This series has been 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.

Regulatory Guide 1.201, “Guidelines for Categorizing Structures, Systems, and Components in Nuclear Power Plants According to Their Safety Significance,” which is being issued for trial use, provides guidance for use in developing and assessing evaluation models for accident and transient analyses. An additional benefit is that evaluation models that are developed using these guidelines will provide a more reliable framework for risk-informed regulation and a basis for estimating the uncertainty in understanding transient and accident behavior.

The NRC has promulgated regulations to permit power reactor licensees and license applicants to implement an alternative regulatory framework with respect to “special treatment,” where special treatment refers to those requirements that provide increased assurance beyond normal industrial practices that structures, systems, and components (SSCs) perform their design-basis functions. Under this framework, licensees using a risk-informed process for categorizing SSCs according to their safety significance can remove SSCs of low safety significance from the scope of certain identified special treatment requirements.

The genesis of this framework stems from Option 2 of SECY-98-300, “Options for Risk-Informed Revisions to 10 CFR part 50, ‘Domestic Licensing of Production and Utilization Facilities',” dated December 23, 1998.^[1] In that Commission paper, the NRC staff recommended developing risk-informed approaches to the application of special treatment requirements to reduce unnecessary regulatory burden related to SSCs of low safety significance by removing such SSCs from the scope of special treatment requirements. The Commission subsequently approved the NRC staff's rulemaking plan and issuance of an Advanced Notice of Proposed Rulemaking (ANPR) as outlined in SECY-99-256, “Rulemaking Plan for Risk-Informing Special Treatment Requirements,” dated October 29, 1999.

The Commission published the ANPR in the Federal Register (65 FR 11488) on March 3, 2000, and subsequently published a proposed rule for public comment (68 FR 26511) on May 16, 2003. Then, on November 22, 2004, the Commission adopted a new section, referred to as § 50.69, within Title 10, part 50, of the Code of Federal Regulations, on risk-informed categorization and treatment of SSCs for nuclear power plants (69 FR 68008).

This trial regulatory guide describes a method that the NRC staff considers acceptable for use in complying with the Commission's requirements in § 50.69 with respect to the categorization of SSCs that are considered in risk-informing special treatment requirements. This categorization method uses the process that the Nuclear Energy Institute (NEI) described in Revision 0 of its guidance document NEI 00-04, “10 CFR 50.69 SSC Categorization Guideline,” dated July 2005.^[2] Specifically, this process determines the safety significance of SSCs and categorizes them into one of four risk-informed safety class (RISC) categories.

The NRC issued a draft of this guide, Draft Regulatory Guide DG-1121, as part of the § 50.69 rulemaking package in May 2003, and solicited public comments specifically concerning the draft guide by publishing related Federal Register notices (68 FR 34012 and 68 FR 41408) on June 6 and July 11, 2003. Following the closure of the public comment period on August 1, 2003, the staff considered all stakeholder comments in the course of preparing the new Regulatory Guide 1.201. However, a few issues of technical interpretation and implementation still remain, with respect to specific aspects of the guidance. Because the staff believes these issues will be best resolved by testing the guide against actual applications, the NRC decided to issue this guide for trial use. This trial regulatory guide does not establish any final staff positions, and may be revised in response to experience with its use. As such, this trial guide does not establish a staff position for purposes of the Backfit Rule, 10 CFR 50.109, and any changes to this trial guide prior to staff adoption in final form will not be considered to be backfits as defined in 10 CFR 50.109(a)(1). This will ensure that the lessons learned from regulatory review of pilot and follow-on applications are adequately addressed in the final regulatory guide, and that the guidance is sufficient to enhance regulatory stability in the review, approval, and implementation of probabilistic risk assessments (PRAs) and their results in the risk-informed categorization process required by § 50.69.

The NRC staff encourages and welcomes comments and suggestions in connection with improvements to published regulatory guides, as well as items for inclusion in regulatory guides that are currently being developed. You may submit comments by any of the following methods.

Mail comments to: Rules and Directives Branch, Office of Administration, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.

Hand-deliver comments to: Rules and Directives Branch, Office of Administration, U.S. Nuclear Regulatory Commission, 11555 Rockville Pike, Rockville, Maryland 20852, between 7:30 a.m. and 4:15 p.m. on Federal workdays.

Fax comments to: Rules and Directives Branch, Office of Administration, U.S. Nuclear Regulatory Commission, at [phone].

Requests for technical information about Regulatory Guide 1.201 may be directed to Donald G. Harrison at [phone] or via e-mail to [e-mail].

Regulatory guides are available for inspection or downloading through the NRC's public Web site in the Regulatory Guides document collection of the NRC's Electronic Reading Room at http://www.nrc.gov/​reading-rm/​doc-collections. Electronic copies of Regulatory Guide 1.201 are also available in the NRC's Agencywide Documents Access and Management System (ADAMS) at http://www.nrc.gov/​reading-rm/​adams.html,, under Accession No. ML060260164.

In addition, regulatory guides are available for inspection at the NRC's Public Document Room (PDR), which is 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 [phone] or [phone], by fax at [phone], and by e-mail to [e-mail]. Requests for single copies of draft or final guides (which may be reproduced) or for placement on an automatic distribution list for single copies of future draft guides in specific divisions should be made in writing to the U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, Attention: Reproduction and Distribution Services Section; by e-mail to [e-mail]; or by fax to [phone]. Telephone requests cannot be accommodated.

Regulatory guides are not copyrighted, and Commission approval is not required to reproduce them.

(5 U.S.C. 552(a))

Dated at Rockville, Maryland, this 27th day of January, 2006.

For the U.S. Nuclear Regulatory Commission.

Carl J. Paperiello,

Director, Office of Nuclear Regulatory Research.

Footnotes

1.  Commission papers cited in this notice are available through the NRC's public Web site at http://www.nrc.gov/​reading-rm/​doc-collections/​commission/​secys/​, and the related Federal Register notices are available through the Federal Register Web site sponsored by the Government Printing Office (GPO) at http://www.gpoaccess.gov/​fr/​index.html.

2.  NEI 00-04, “10 CFR 50.69 SSC Categorization Guideline,” is available through the NRC's public Web site at http://adamswebsearch2.nrc.gov/​idmws/​doccontent.dll?​ID=​052910091:&LogonId=​2b2cbc48fd7897510347535dd7c30495,, and through the NRC's Agencywide Documents Access and Management System (ADAMS), http://www.nrc.gov/​reading-rm/​adams/​web-based.html,, under Accession #ML052910035.