Document: NUREG-0800
Document ID: 7bbfa5be-36ba-4273-8f24-038130581ae5
Document Type: srp
Title: SHORT-TERM DISPERSION ESTIMATES FOR ACCIDENTAL ATMOSPHERIC RELEASES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340583.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.3.4
CFR Part: 
CFR Title: 

Content:
red for elevated releases. In the absence of site-specific information concerning the frequency, duration, and directional prefer- ence of fumigation conditions, deterministic approaches such as those described in Regulatory Guides 1.5, 1.24, 1.25, and 1.145 may be used. 2. Meteorological Data The meteorological data used in atmospheric dispersion analyses are reviewed for compatibility with the models, representativeness with respect to airflow characteristics of the site and vicinity, and representation of normal annual distribution of meteorological condi- tions. If adequate onsite meteorological data are not available, the reviewer must ensure that adequate conservatism is applied. General criteria for onsite data are stated in Regulatory Guide 1.23 and in subsection III.2 of SRP Section 2.3.3. Additional sources of meteoro- logical data for consideration in the description of airflow trajectories from the site may include National Weather Service stations or other meteorological programs that are well maintained and well exposed (e.g., other nuclear facilities, university and private meteorological programs). 2.3.4-3 Rev. 1 - July 1981 3. Atmospheric Diffusion Parameters To define atmospheric stability, measurement of vertical temperature gradient (Ref. 4) should be used, particularly during stable conditions accompanied by low wind speeds (i.e., less than 1.5 m/s). Other classi- fication schemes (Refs. 14 and 15) may be used to estimate atmospheric stability class or to determine plume spread parameters directly for unstable and neutral conditions, or for wind speeds greater than 1.5 m/s. Methods for the classification of atmospheric stability, or for direct determination of plume spread parameters, should be adequately described and substantiated for applicability to the site. Lateral and vertical plume spread parameters, a and oz, as functions of meteorological conditions and topography, are reviewed with respect to the characteristics of the accidental