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:
of the model so that the staff can evaluate their appropriateness to site, plant, and release characteristics. 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. 3. A discussion of atmospheric diffusion parameters, such as lateral and vertical plume spread (ay and az) as a function of distance, topography, and atmospheric conditions should be related to measured meteorological parameters. 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. Cumulative probability distributions of relative concentrations (XIQ) should be constructed to describe the probabilities of these X/Q values being exceeded. All cumulative probability distributions of X/Q should be presented for appropriate distances (e.g., the exclusion area boundary distance and the outer boundary of the low population zone) and time periods as specified in Section 2.3.4.2 of Regulatory Guide 1.70, "Standard Format and Contents of Safety Analysis Reports for Nuclear Power Plants," (Ref. 11). The methods of generating these distributions should be adequately described. 5. Relative concentrations used for assessment of consequences of atmospheric radioactive releases for design basis and other acci- dents, and for onsite and offsite releases of hazardous airborne materials. 2.3.4-2 Rev. 1 - July 1981 III. REVIEW PROCEDURES 1. Atmospheric Dispersion Models The applicant's dispersion models are compared to the general Gaussian models which are contained in Regulatory Guide 1.145 for design basis accidental releases. The models are reviewed for suitability to release characteristics, plant configuration, and site topography. The accidents and release