Radioactive Material Offsite Exposure Determination.

DOE-STD-3014-96

Radioactive Material Offsite Exposure Determination. The exposure to

7.2.3.2

the maximally exposed individual at or beyond the site boundary will be

estimated in terms consistent with the screening guidelines presented in

Section 4.1. For radioactive material releases, Reference 3 contains a

series of nomographs for common radioactive materials that provide dose

estimates under various conditions relevant to aircraft crash scenarios.

These nomographs may be used to provide a screening value for the site

boundary dose for the materials and conditions specified. Using the

nomographs to calculate doses should account for the additive property

of dose over all isotopes of concern, so that isotopes are evaluated

cumulatively, as opposed to individually, against guidelines. If a particular

facility has materials or conditions not covered by the nomographs

provided, the simple Gaussian dispersion equation that was used to

develop the nomographs will be used to estimate the dose at the site

boundary, using the shortest distance to the site boundary as the

evaluation point and an atmospheric stability of F, with a wind speed of

2 m/s, as explained in Reference 8. For releases that are potentially

buoyant, the buoyancy will be ignored for the purposes of screening

calculations. The centerline dose can be estimated using the following

equation:

SAi

CEDEi

Dose

(7-1)

i 1

where:

Dose

dose (sievert [rem]) - CEDE;

material released and respirable (i.e., source term) (g);

specific activity (Curies/gram [Ci/g], [Bq/g] );

CEDE =

committed effective dose equivalent (rem/Ci [Sv/Bq]

inhaled assuming a 1-m activity median aerodynamic

diameter particle size);

breathing rate (3E-4 m3/s);

BR =