Document: NUREG-0800
Document ID: 49aefb86-1adb-4b3c-826f-480e32947595
Document Type: srp
Title: Radiological Consequence Analyses Using Alternative Source Terms
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0037/ML003734190.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.0.1
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CFR Title: 

Content:
e have the scope and depth to adequately evaluate the impacts of the change. All affected design basis analyses should be updated. An analysis is considered to be affected if the proposed modification changes one or more assumptions or inputs used in that analysis such that the results, or the conclusions drawn on those results, are no longer valid. Because of the wide scope of possible AST implementations, both full and selective, specific review guidance cannot be provided. However, the following aspects should be considered in performing these reviews: a. A complete recalculation of all design basis radiological analyses may not be required. However, all significant radiological and nonradiological impacts of the proposed plant modifications are to be evaluated in the context of the proposed AST. b. The NRC staff performed a rebaselining study (Ref. 4) of the implementation of an AST at operating reactors. This study may be referenced by a licensee to disposition the impacts of differences between source terms as they apply to radiation doses caused by fission product releases. The reviewer should ensure that all remaining radiological and nonradiological impacts of proposed plant modifications in the context of the proposed AST, including the impact on equipment environmental qualification, are evaluated. For example -- (1) A licensee has proposed removing analysis credit for the standby gas treatment system (SGTS) on the basis of a full implementation of an AST. The licensee has reanalyzed the offsite and control room doses for all accidents that credited the SGTS filtration. Does the licensee need to reanalyze the environmental qualification (EQ) doses for components exposed to the containment airborne activity? Answer: In this case, the plant modification has no impact on the EQ doses. The licensee can reference the rebaselining study to disposition the airborne activity EQ doses. (2) As part of a larger AST implementation, a licensee proposed removing