Document: NRC Regulatory Guide
Document ID: c406a126-ec51-4b8a-aafa-6fd4c7a7e7b9
Document Type: regulatory_guide
Title: Methods for Estimating Atmospheric Transport and Dispersion of Gaseous Effluents in Routine Releases from Light-Water-Cooled Reactors (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1411/ML14114A674.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.111
CFR Part: 
CFR Title: 

Content:
itions; and determining whether deposition over large bodies of water represents a potentially significant dose pathway and, if so, methodologies and data needs for handling such scenarios. Issues and items for discussion with and feedback from the contractor tasked to update the XOQDOQ model include, but are not limited to: considering whether a straight-line model should be used for site boundary and maximum exposed individual receptors within 5 miles (unless complex topography is present) and a variable trajectory model between 5 and 50 miles downwind; evaluating potential discontinuities in calculations near that transition distance; and reconciling potential differences between the plume depletion and deposition curves in Revision 0 of RG 1.111 and the curves presented in the Errata Notice included in the “for comment” version of Revision 1. 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? There are no large power reactor license applications anticipated in the near future (next 3 to 5 years). Thus, there is no immediate need for revising RG 1.111 at this time to address their licensing. For small modular reactors, as of March, 2014, four applications are anticipated in the next two years. Two will be design certification applications, one a construction permit application, and one a combined operating license application. Due to the small size and design of the small modular reactors atmospheric dispersion is not expected to be a significant licensing issue. Therefore, the existing version of RG 1.111 (and the XOQDOQ dispersion model which implements a number of its regulatory positions) will continue to be useful. 3. What is an estimate of the level of effort needed to address identified issues in terms of full-time equivalent (FTE) and contractor resources? Estimates from DSEA technical staff are for