0 U.S. NUCLEAR REGULATORY COMMISSION' STANDARD REVIEW PLAN OFFICE OF NUCLEAR REACTOR REGULATION 2.3.5 LONG-TERM DIFFUSION ESTIMATES REVIEW RESPONSIBILITIES Primary- Accident Evaluation Branch (AEB)

Information is presented by the applicant and reviewed by the staff concerning atmo-spheric diffusion estimates for routine releases of effluents to the atmosphere. The review covers the following specific areas: 1. Atmospheric dispersion models to calculate concentrations in air and amount of material deposited as a result of routine releases of radioactive material to the atmosphere. 2. Meteorological data used as input to diffusion models. 3. Derivation of diffusion parameters. 4. Relative concentration (X/Q) and relative deposition (D/Q) values used for assessment of consequences of routine airborne radioactive releases. A secondary review is performed by ETSB and RAB and the results are used by AEB in the overall evaluation of the long-term diffusion estimates. The ETSB reviews the points of routine release of radioactive material to the atmosphere and the characteristics of each release mode. The RAB reviews the locations of potential receptors for dose computations. The results of their analyses are transmitted to AEB for use in its independent review. II. ACCEPTANCE CRITERIA Characterization of atmospheric transport and diffusion conditions is necessary for estimating the radiological consequences of routine releases of radioactive