F * U.S. NUCLEAR REGULATORY COMMISSION STANDARD REVIEW PLAN OFFICE OF NUCLEAR REACTOR REGULATION 2.3.4 SHORT-TERM DISPERSION ESTIMATES FOR ACCIDENTAL ATMOSPHERIC RELEASES REVIEW RESPONSIBILITIES Primary- Accident Evaluation Branch (AEB) Secondary- None

Information is presented by the applicant and reviewed by the staff concerning atmospheric dispersion estimates for postulated accidental releases of effluents to the atmosphere. The review covers the following specific areas: 1. Atmospheric transport and diffusion models to calculate relative concen-trations for postulated accidental radioactive and hazardous airborne releases. 2. Meteorological data summaries used as input to diffusion models. 3. Derivation of diffusion parameters. 4. Probability distributions of relative concentrations. 5. Determination of relative concentrations used for assessment of conse-quences of postulated radioactive atmospheric releases for design basis accidents and for other accidents, and of onsite and offsite hazardous airborne releases. II. ACCEPTANCE CRITERIA The applicant should provide conservative estimates of atmospheric transport and diffusion conditions at appropriate distances from the source for postulated accidental releases of radioactive and hazardous materials to the atmosphere. The plant should be considered as both a source and a receptor. The information is necessary to demonstrate compliance with the following regulations