Document: NUREG-0800
Document ID: 112961d5-bbf7-4ebc-8a51-ee8e2292ddbc
Document Type: srp
Title: LONG-TERM DIFFUSION ESTIMATES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340585.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.3.5
CFR Part: 
CFR Title: 

Content:
should be sufficiently documented and substantiated to allow a review of their appropriateness to site, plant, and release characteristics. 2. A discussion of atmospheric diffusion parameters, such as vertical plume spread (az) as a function of distance and wind speed, related to measured meteorological parameters. Use of these parameters should be substan- tiated as to their appropriateness for use in estimating the consequences of routine releases from the site boundary to a radius of 50 miles from the plant. 3. Meteorological data used as input to-the dispersion models. Data used for this evaluation should represent hourly average values of wind speed, wind direction, and atmospheric stability which are appropriate for each mode of release and which are characteristic of annual average atmospheric transport and diffusion conditions in the vicinity of the plant. (See SRP Section 2.3.3 for data acceptability criteria, and see Regulatory Guide 1.23 (Ref. 6) for data formats.) 4. Relative concentration (X/Q) and relative deposition (D/Q) values used for assessment of consequences of routine radioactive gas releases as described in Section 2.3.5.2 of Regulatory Guide 1.70 (Ref. 7). III. REVIEW PROCEDURES 1. Atmospheric Dispersion Models The applicant's models are compared to the general modeling criteria presented in Regulatory Guide 1.1U1. The models should be suitable to 2.3.5-2 Rev. 2 - July 1981 topography of the site and vicinity, plant configuration, and release characteristics. Additional information for determining model suit- ability may be found in standard references such as "Meteorology and Atomic Energy - 1968" (Ref. 8). The staff performs an independent evaluation of long-term dispersion characteristics. Identification of release points and release character- istics is provided by ETSB. RAB provides the locations of receptors of interest. Each release should be characterized as continuous or inter- mittent. Using the criteria presented in Regulatory