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:
Baxter for) UShoop KHsueh JGiitter DATE 03/14/2016 03/08/2016 03/21/2016 03/25/2016 04/05/2016 OFFICIAL RECORD COPY Enclosure Regulatory Guide Periodic Review Regulatory Guide Number: 1.98, Revision 0 Title: Assumptions Used for Evaluating the Potential Radiological Consequences of a Radioactive Offgas System Failure in a Boiling Water Reactor Office/Division/Branch: NRR/DRA/ARCB Technical Lead: David Garmon Staff Action Decided: Reviewed with issues identified for future consideration 1. What are the known technical or regulatory issues with the current version of the Regulatory Guide (RG)? Regulatory Guide (RG) 1.98, Revision (Rev.) 0, was published in 1976 to provide boiling-water reactor licensees guidance in selecting appropriate assumptions for the analysis of radioactive offgas system failures. While the guidance in the current version of RG 1.98 remains adequate, there are several technical and regulatory issues that should be considered and addressed during future revisions of this RG. These issues are primarily the result of the Nuclear Regulatory Commission (NRC) publishing updated guidance that is applicable to this area in other documents (i.e., other RGs and NUREGs), as described below. The updated guidance provides additional flexibility and more accurate assumptions for use in analyzing radioactive offgas system failure events, and thus should be included in future revisions to RG 1.98. RG 1.98, Rev. 0, Section B states that the staff assumes 100 percent release of noble gas inventory in the offgas system and a fractional release of the particulate matter on high-efficiency particulate air filters in the system. The RG does not provide guidance on what constitutes an adequate assumption for a fractional release of particulate matter, and instead directs licensees to select and justify their own levels. The RG states that specific release fractions are to be provided at a later date; however, this additional information was never published. Section C