Document: NRC Regulatory Guide
Document ID: 7e57474b-e9b7-4add-afd3-4b3269b1a0cb
Document Type: regulatory_guide
Title: Assumptions Used for Evaluating the Potential Radiological Consequences of a Radioactive Offgas System Failure in a Boiling Water Reactor
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1605/ML16053A354.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.98
CFR Part: 
CFR Title: 

Content:
n RG 1.145, Rev. 1, “Atmospheric Dispersion Models for Potential Accident Consequence Assessments at Nuclear Power Plants,” for example, the consideration of a meandering plume at, or, near ground levels, is not described or referenced in RG 1.98, Rev. 0. (Note: The NRC reviewed RG 1.145, Rev. 1, in 2014 and identified issues for future consideration; however, RG 1.145, Rev. 1 was not updated. The reader is directed to consider the review memoranda at Agencywide Documents Access and Management System (ADAMS) Accession Nos. ML14114A735 and ML14114A736 before applying the guidance in RG 1.145, Rev. 1). BTP 11-5 provides acceptance criteria for doses at the exclusion area boundary (EAB) that result from radioactive offgas system failures. While not specifically an assumption in the analysis of these types of events, the applicable acceptance criteria is information that should be provided in future versions of RG 1.98. For plants that have radioactive offgas systems that are designed in accordance with the guidance of RG 1.143, “Design Guidance for Radioactive Waste Management Systems, Structures, and Components Installed in Light-Water-Cooled-Nuclear Power Plants,” to withstand the effects of a hydrogen explosion and earthquakes, the resulting dose to the whole body to an individual at the EAB shall not exceed 2.5 roentgen equivalent man (rem) (25 millisievert (mSv)). For plants with offgas systems that are not hardened, as prescribed in RG 1.143, the resulting dose to the whole body to an individual at the EAB shall not exceed 0.1 rem (1 mSv). While the staff has identified these issues with RG 1.98, Rev. 0, this review did not identify any safety concerns or an immediate need to revise this RG. 2. What is the impact on internal and external stakeholders of not updating the RG for the known issues, in terms of anticipated numbers of licensing and inspection activities over the next several years? For operating reactors, the staff anticipates few licensing