# Regulatory Guide: Use of ARCON Methodology for Calculation of Accident-Related Offsite Atmospheric Dispersion Factors
> **Nuclear Regulatory Commission** · Final guide; issuance. · Published 2023-08-21 · 88 FR 56750
## Document
- **Document number:** 2023-17908
- **Category:** other
- **Sub-agency:** Nuclear Regulatory Commission
- **Federal Register citation:** 88 FR 56750
- **CFR reference:** 10 CFR 50
- **Publication date:** 2023-08-21
- **Energy docket:** NRC-2021-0133
## Abstract

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.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2023/08/21/2023-17908/regulatory-guide-use-of-arcon-methodology-for-calculation-of-accident-related-offsite-atmospheric)
---
*AI Analytics · CC0 1.0*