# Supplemental Guidance for Radiological Consequence Analyses Using Alternative Source Terms
**AGENCY:**
Nuclear Regulatory Commission.
**ACTION:**
Draft interim staff guidance; request for comment.
**SUMMARY:**
The U.S. Nuclear Regulatory Commission (NRC) is soliciting public comment on its draft Interim Staff Guidance (ISG) Supplemental Guidance for Radiological Consequence Analyses Using Alternative Source Terms. This draft ISG proposes changes to the NRC's license amendment request (LAR) review guidance document. This ISG is not intended as standalone guidance but instead supplements NUREG-0800, “Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR [Light-Water Reactor] Edition” Section 15.0.1, “Radiological Consequence Analyses Using Alternative Source Terms.” NUREG-0800, Section 15.0.1 was published in July 2000 and is not scheduled to be updated for several years. This ISG provides additional guidance for the NRC staff reviewing LARs that request to increase the main steam isolation valve (MSIV) leakage allowed by technical specifications (TS) for boiling water reactors (BWRs).
**DATES:**
Submit comments by June 21, 2021. Comments received after this date will be considered if it is practical to do so, but the Commission is able to ensure consideration only for comments received before this date.
**ADDRESSES:**
You may submit comments by any of the following methods; however, the NRC encourages electronic comment submission through the Federal Rulemaking website:
• *Federal Rulemaking Website:* Go to *https://www.regulations.gov* and search for Docket ID NRC-2021-0106. Address questions about Docket IDs in *Regulations.gov* to Stacy Schumann; telephone: 301-415-0624; email: *[email protected].* For technical questions, contact the individuals listed in the *FOR FURTHER INFORMATION CONTACT* section of this document.
• *Mail comments to:* Office of Administration, Mail Stop: TWFN-7-A60M, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, ATTN: Program Management, Announcements and Editing Staff.
For additional direction on obtaining information and submitting comments, see “Obtaining Information and Submitting Comments” in the *SUPPLEMENTARY INFORMATION* section of this document.
**FOR FURTHER INFORMATION CONTACT:**
Jerry Dozier, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001; telephone: 301-415-3925, email: *[email protected].*
**SUPPLEMENTARY INFORMATION:**
**I. Obtaining Information and Submitting Comments**
**A. Obtaining Information**
Please refer to Docket ID NRC-2021-0106 when contacting the NRC about the availability of information for this action. You may obtain publicly available information related to this action by any of the following methods:
• *Federal Rulemaking Website:* Go to *https://www.regulations.gov* and search for Docket ID NRC-2021-0106.
• *NRC's Agencywide Documents Access and Management System (ADAMS):* You may obtain publicly available documents online in the ADAMS Public Documents collection at *https://www.nrc.gov/reading-rm/adams.html.* To begin the search, 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 proposed ISG, “Supplemental Guidance for Radiological Consequence Analyses Using Alternative Source Terms” is available in ADAMS under Accession No. ML21078A051.
• Attention: The PDR, where you may examine and order copies of public documents, is currently closed. You may submit your request to the PDR via email at *[email protected]* or call 1-800-397-4209 or 301-415-4737, between 8:00 a.m. and 4:00 p.m. (EST), Monday through Friday, except Federal holidays.
**B. Submitting Comments**
The NRC encourages electronic comment submission through the Federal Rulemaking website ( *https://www.regulations.gov* ). Please include Docket ID NRC-2021-0106 in your comment submission.
The NRC cautions you not to include identifying or contact information that you do not want to be publicly disclosed in your comment submission. The NRC will post all comment submissions at *https://www.regulations.gov* as well as enter the comment submissions into ADAMS. The NRC does not routinely edit comment submissions to remove identifying or contact information.
If you are requesting or aggregating comments from other persons for submission to the NRC, then you should inform those persons not to include identifying or contact information that they do not want to be publicly disclosed in their comment submission. Your request should state that the NRC does not routinely edit comment submissions to remove such information before making the comment submissions available to the public or entering the comment into ADAMS.
**II. Background**
This ISG is intended to provide guidance for the NRC staff reviewing LARs that request to increase the MSIV leakage allowed by TS for BWRs. This ISG is not intended as standalone guidance but instead supplements NUREG-0800, “Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR [Light-Water Reactor] Edition” Section 15.0.1, “Radiological Consequence Analyses Using Alternative Source Terms” (ADAMS Accession No. ML003734190).
As noted in an NRC memorandum, “Implementing Commission Direction on Applying Risk-informed Principles in Regulatory Decision making,” dated November 19, 2019 (ADAMS Accession No. ML19319C832), the staff's application of risk-informed decision making continues to evolve as improved realism, evaluation techniques, and additional information are applied to improve regulatory decision making. The development of this ISG serves as an example of NRC's continuous efforts in working toward being a more modern and risk-informed regulator.
For the Nuclear Regulatory Commission.
Dated: May 17, 2021.
Michael X. Franovich,
Director, Division of Risk Assessment, Office of Nuclear Reactor Regulation.