NRC-2021-0133
Regulatory Guide: Use of ARCON Methodology for Calculation of Accident-Related Offsite Atmospheric Dispersion Factors
Summary
The U.S. Nuclear Regulatory Commission (NRC) is issuing a new Regulatory Guide (RG) 1.249 (Revision 0), "Use of ARCON Methodology for Calculation of Accident-Related Offsite Atmospheric Dispersion Factors." This new RG describes an approach for reactor applicants and licensees for determining atmospheric relative concentration ([chi]/Q) values in support of modeling onsite releases to offsite boundaries from a design-basis accident. Also, this RG implements the methodology in RG 1.194, "Atmospheric Relative Concentrations for Control Room Radiological Habitability Assessments at Nuclear Power Plants," for offsite dose locations at boundaries.