Effects of wind shift and cross-plume concentration models on calculated accident consequences. [Effects on calculation of early and late cancer fatalities]

Conference · Mon Jan 01 04:00:00 EST 1979

OSTI ID:6254677

Schueckler, M; Aldrich, D; Bayer, A

The dispersion of released atmospheric contaminants is normally treated using a Gaussian plume model. To simplify this treatment, the U.S. Reactor Safety Study (RSS) replaced the Gaussian cross-plume shape with a uniform, or top-hat, distribution. This simplification has two effects on the calculation of accident consequences. First, consequences calculated using the top-hat are limited to the assumed width of the distribution, whereas in actuality they might occur over either wider, or narrower, areas. Second, all persons affected by the plume at a given distance are exposed to the same average radionuclide concentrations, rather than the distribution from 0 to some peak value. To improve upon the top-hat treatment, a cross-plume concentration distribution with four distinct concentration steps was used in phase A of the German RSS. Using the phase A German RSS consequence model, a series of reactor accident consequence calculations was performed using eight different cross-plume concentration models. The results of these calculations are compared and discussed. To account for hourly wind direction changes a wind shift model has been proposed for use in the German RSS. The effects of this model on calculated accident consequences are also discussed. From the discussions, the following conclusions can be drawn: (1) the U.S. top-hat distribution overestimates early fatalities andslightly underestimates latent cancer fatalities; (2) for the calculation of latent cancer fatalities, a top-hat distribution with outer distances y/delta/sub y/ = 2 (width = 4delta/sub y/) is adequate; (3) for the calculation of early fatalities, a 2-step distribution with outer distances y/delta/sub y/ = (1.0, 2.0) might be adequate; and (4) use of the proposed wind shift model results in a moderate reduction in calculated early fatalities for releases of long duration. (ERB)

• Research Organization: Kernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.); Sandia Labs., Albuquerque, NM (USA)
• DOE Contract Number: EY-76-C-04-0789
• OSTI ID: 6254677
• Report Number(s): SAND-78-2075C; CONF-790519-2
• Country of Publication: United States
• Language: English

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ACCIDENTS
AEROSOLS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
CARCINOGENESIS
COLLOIDS
DELAYED RADIATION EFFECTS
DIFFUSION
DISPERSIONS
DOSIMETRY
EARLY RADIATION EFFECTS
EARTH ATMOSPHERE
ENVIRONMENTAL TRANSPORT
FISSION PRODUCT RELEASE
FORECASTING
HUMAN POPULATIONS
MASS TRANSFER
MATHEMATICAL MODELS
PATHOGENESIS
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RADIATION EFFECTS
RADIOACTIVE AEROSOLS
REACTOR ACCIDENTS
RISK ASSESSMENT
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WIND