Document: NUREG-1555
Document ID: 07028c9f-5219-46b4-8c75-bb8fea4e2d2a
Document Type: esrp
Title: DESIGN BASIS ACCIDENTS
Source: NUREG-1555
Source URL: https://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1555/initial/
Revision Date: 2007-10
Chapter: 7
Section ID: 7.1
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Content:
logy for reviewing the models, assumptions, and parameter values used to determine the offsite releases from DBAs. However, the conservative assumptions and calculations used in NRC safety evaluations substantially overestimate the environmental risk. Among the conservative assumptions used pursuant to the Chapter 15 analyses is the use of adverse meteorological dispersion conditions (i.e., 95th percentile χ/Q). Actual consequences will likely be far less severe than those given for the same events in SARs where more conservative evaluations are used. For this reason, DBAs (up through Class 8) are evaluated using more realistic meteorological conditions. Consequences predicted in NUREG-1555 7.1-4 October 1999 this way will be far less severe than those given for the same events in SARs where more conservative estimates of meteorology are used. III. REVIEW PROCEDURES Accidents are categorized as “design basis” or “severe.” The DBAs are accidents that the plant is designed specifically to accommodate. The evaluation of DBAs is performed for the NRCGs SER using conservative assumptions. This ESRP section is designed to evaluate the applicant’s assessment of the environmental consequences of DBAs. The analysis procedures are given for DBAs only. Design-Basis Accidents When analyzing doses calculated to result from DBAs, the reviewer should do the following: (1) Examine the applicant’s descriptions of accidents considered (as given in the ER) and compare them with the descriptions of accidents given in Appendix A of this ESRP (as taken from Chapter 15 of the SRP) to ensure that all accidents with anticipated offsite-dose consequences have been considered. (a) Coordinate with the reviewer of SRP Chapter 15 to ensure that all appropriate accidents have been identified. (b) Verify that the applicant provides a justification (included in the EIS) for not estimating the consequences of any accident given in Appendix A to this ESRP. (2) Examine the applicant’s