Document: NUREG-0800
Document ID: 4e1c316a-99c2-4fd3-9d9b-323791bd85f8
Document Type: srp
Title: SHORT-TERM ATMOSPHERIC DISPERSION ESTIMATES FOR ACCIDENT
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0707/ML070730398.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.3.4
CFR Part: 
CFR Title: 

Content:
the staff can evaluate their appropriateness of use with regards to release characteristics, plant configuration, plume density, meteorological conditions, and site topography. 2. Meteorological data used for the evaluation (as input to the dispersion models) which represent annual cycles of hourly values of wind direction, wind speed, and atmospheric stability for each mode of accidental release. Any dispersion estimates should be calculated from the most representative meteorological data available for the site. Guidance on appropriate onsite meteorological data is provided in Regulatory Guide 1.23. This information is also reviewed in SRP Section 2.3.3. 3. A discussion of atmospheric diffusion parameters, such as lateral and vertical plume spread (σy and σz) as a function of distance, topography, and atmospheric conditions, should be related to measured meteorological data. The methodology for establishing these relationships should be appropriate for estimating the consequences of accidents within the range of distances which are of interest with respect to site characteristics and established regulatory criteria. 4. Hourly cumulative frequency distributions of χ/Q values from the effluent release point(s) to the EAB and LPZ should be constructed to describe the probabilities of these χ/Q values being exceeded. All cumulative frequency distributions of χ/Q values should be presented for appropriate distances (e.g., the EAB distance and the outer boundary of the LPZ) and time periods as specified in Section 2.3.4.2 of Regulatory Guide 1.70, "Standard Format and Content of Safety Analysis Reports for Nuclear Power Plants" and Section 2.3.4.2 of RG 1.206, “Combined License Applications for Nuclear Power Plants ( LWR Edition)”. The methods for generating these distributions should be adequately described. Guidance for calculating EAB and LPZ atmospheric dispersion factors is provided in Regulatory Guide 1.145. 5. Atmospheric dispersion factors used for the