Radiological (No Ingestion)

DOE-STD-6003-96

2.5.1 Radiological (No Ingestion)

Guidance for sheltering, evacuation, and food interdiction is given in the EPA "Manual of

Protective Action Guides and Protective Actions for Nuclear Incidents" (EPA 1991). A nuclear

incident is divided into three phases: early, intermediate, and late. During the early phases shel-

tering or evacuation is the appropriate measure to consider. The PAGs are criteria based upon

the potentially avoided dose, which determine whether action must be taken.

a. Evacuation (or, for some situations, sheltering) should normally be initiated to avoid a

10-mSv (1-rem) dose to a standard man for "early" pathways inhalation (CED) and

external gamma ED (cloudshine/immersion and ground surface).

b. For radionuclides with long effective half-times in the body, use 50-mSv (5-rem)

CED + ED as the action criterion. For committed effective dose equivalent to the skin,

use 500 mSv (50 rem) for the action criterion.

2.5.2 Radiological (Ingestion)

During the intermediate and late phases of the incident, controls on the ingestion of con-

taminated food and water are appropriate (FDA 1982). The avoided doses at which such inter-

diction is appropriate are shown below:

a. "Preventative PAG"--5 mSv (0.5 rem) to "whole body, bone marrow, or any other

organ." This is the level at which protective actions having minimal impact should be

taken.

b. "Emergency PAG"--50 mSv (5 rem) to "whole body, bone marrow, or any other

organ." This is the level at which food should be isolated for condemnation or other

disposition.

2.6 Models Used in Relating Exposures to Estimated Consequences

The following code systems are examples of tools that have been accepted for use in a

regulatory context for relating releases, exposures, and estimated consequences. This list is not

all inclusive, and other codes of greater capability might be developed in the future.

GENII (Napier 1988) is a coupled system of computer codes used to estimate potential

radiation doses to individuals or populations from both routine and accidental releases of

radionuclides to air or water and residual contamination from spills or decontamination

operations.

The MACCS (MELCOR Accident Consequence Code System) (Chanin 1990) code sys-

tem calculates impacts of severe accidents at nuclear reactors on the surrounding environment.

Principle phenomena considered include atmospheric transport dose mitigation actions, dose

accumulation, and health effects. The MACCS code has been expanded to include isotopes of

interest in fusion facilities.