Document: NRC Regulatory Guide
Document ID: b3da4d67-03d8-4f52-b04b-8e76d142c857
Document Type: regulatory_guide
Title: Guidance for a Technology-Inclusive, Risk-Informed, and Performance-Based Methodology to Inform the Licensing Basis and Content of Applications for Licenses, Certifications, and Approvals for Non-Light Water Reactors + HISTORY - HISTORY 05/2019 – Issued DG-1353 , Proposed Revision 0
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1831/ML18312A242.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.233
CFR Part: 
CFR Title: 

Content:
he spectrum of events for evaluating the need for emergency planning zones is expected to be the LBEs as described in NEI 18-04, adjusted as necessary to reflect the specific criteria in the emergency planning decision-making process (e.g., dose calculations over a period of 96 hours from the release of radioactive materials in DG-1350 versus the 30-day period in NEI 18-04 for plotting on the F-C target). Mechanistic Source Term An evaluation of events, plant features and programs, and related uncertainties must address the state of knowledge related to the behavior of reactor systems, fuel, and the way in which radionuclides may move within and be released from a facility. The established methods for addressing radiological source terms for LWRs have limited applicability to non-LWR designs, and more mechanistic approaches have been proposed. The NRC will validate analytical tools and computer codes by comparing results to information available from operating experience and experiments. In SRM-SECY-93-092, the Commission approved the NRC staff’s recommendation that source terms for non-LWRs be based upon a mechanistic analysis and that the acceptability of the applicant’s analysis will rely on the staff’s assurance that the following conditions are met: DG-1353, Page 22 • The performance of the reactor and fuel under normal and off-normal conditions is sufficiently well understood to permit a mechanistic analysis. Sufficient data should exist on the reactor and fuel performance through the research, development, and testing programs to provide adequate confidence in the mechanistic approach. • The transport of fission products can be adequately modeled for all barriers and pathways to the environs, including the specific consideration of containment design. The calculations should be as realistic as possible so that the values and limitations of any mechanism or barrier are not obscured. • The events considered in the analyses to develop the set of