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:
Enclosure Regulatory Guide Periodic Review Regulatory Guide Number: 1.111 Title: Methods for Estimating Atmospheric Transport and Dispersion of Gaseous Effluents in Routine Releases from Light-Water-Cooled Reactors Office/division/branch: NRO/DSEA/RHMB Technical Lead: Michael Mazaika Recommended Staff Action: 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)? RG 1.111 provides guidance for two general purposes: • Establishing site atmospheric dispersion characteristics and parameters as part of the Early Site Permit (ESP), Combined License (COL), and Design Certification (DC) application processes pursuant to 10 CFR 100.21(c)(1) requirements that airborne radiological effluent release limits associated with normal operation can be met for any individual located offsite. • Determining X/Q and D/Q values for use in an operating plant’s Offsite Dose Calculation Manual (ODCM). The ODCM establishes a facility’s methodology for estimating the maximum potential annual radiation doses to the public from radioactive releases in compliance with the requirements in 10 CFR 50.36a “Technical specifications on effluents from nuclear power reactors.” RG 1.111 was first issued in March 1976. A January 1977 Errata Notice identified an error in the plume depletion and deposition curves provided with that guidance. That notice, including guidance to utilize the corrected curves in future assessments of potential annual radiation doses to the public resulting from routine releases of radioactive materials in gaseous effluents, was made part of Revision 1 when issued for comment in July 1977. The “for comment” version of Revision 1 remains the de facto current guidance. Many licensees from among the existing fleet and applicants for new reactors base their annual average (or long-term) X/Q and D/Q analyses of routine releases following the constant mean wind