Document: NRC Regulatory Guide
Document ID: 4d46a966-d280-43da-9b03-8b0abe7b29ce
Document Type: regulatory_guide
Title: Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2120/ML21204A065.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.183
CFR Part: 
CFR Title: 

Content:
duction or mitigation. H-7.4 The transport model described in Regulatory Positions E-6.5 and E-6.6 of Appendix E to this guide should be used for iodine and particulates. DG-1389, Appendix I, Page I-1 APPENDIX I ANALYSIS DECISION FLOWCHART Identify Proposed Changes Identify Impacts of Proposed Changes Plant Mod Invalidates Current Analysis Assumption/ Input EAB, LPZ or CR Analysis is Affected Scoping/Sensitivity Analysis is Appropriate Scoping analysis indicates TID 14844 result is bounding Do Scoping Analysis No No No No Yes Yes Yes Yes Leave current analysis in place. Change design basis to reflect the scoping analysis and that AST is now the licensing basis. Describe analyses, significant inputs, and conclusions in submittal package. Recalculate affected analysis; use AST in dose portions. Change design basis to reflect the reanalysis and that the AST is now the licensing basis. NOTE 2: Sensitivity/Scoping analyses should not comprise a significant part of the exclusion area boundary (EAB), low population zone (LPZ), and control room (CR) analyses. NOTE 3: Scoping analyses may be used where a number of similar analyses are involved and generic conclusions can be drawn. However, scoping analyses should not be used for EAB/LPZ/CR doses. NOTE 6 NOTE 4: If any dose analysis is to be recalculated, the upgrade should address the selected (or all) characteristics of the source term and, as applicable, total effective dose equivalent (TEDE). NOTE 5: Once the design basis source term is changed from the current design basis source term to a new alternative source term (AST), the selected AST becomes the design basis source term for all future radiological analyses, including revisions to those analyses that were shown to be bounding with the previous source term. There is no requirement to update these later analyses unless future plant modifications invalidate one or more assumptions, making such re-analysis necessary. NOTE 1: All impacts, radiological and