Estimating Potential Event Consequences

DOE-STD-1136-2004

Guide of Good Practices for Occupational Radiation Protection in Uranium Facilities

9.2.1.5 Estimating Potential Event Consequences

For the scenarios developed in the previous step, this step determines the area potentially

affected, the need for protective actions, and the time available to take those actions. The way these

consequences are determined will depend on properties of the hazardous material. For uranium and its

compounds, the following possibilities should be considered.

Model types. Depending on the relative significance of radiological and chemical toxicity,

the analyst may need to calculate either radiation dose, air concentration, or both for the

postulated releases. For a specific scenario, different models may be needed to analyze

different consequences to determine which effect is limiting (for example, radiation dose,

soluble uranium intake, or HF concentration).

Model features. For reactive species, the ability to model the transformation and

depletion of material during transport is important to a sound analysis. Because the

hydrated uranyl fluoride formed by hydrolysis of UF6 is a solid, some will be lost due to

gravitational settling as a plume moves away from the release point. When analyzing

consequences of a postulated accidental criticality, correcting for the decay during

transport of the short-lived fission product gases will produce a more accurate assessment

of consequences.

9.2.2 Program Elements

Properties and characteristics of uranium and its compounds will also need to be considered in

formulating the emergency management program elements. Following are specific program element

considerations related to the hazardous properties of uranium.

9.2.2.1 Emergency Response Organization

The primary influence of uranium's hazardous properties on the Emergency Response

Organization (ERO) is in the staffing of the consequence assessment component. As will be discussed

below in Consequence Assessment, staff assigned to the ERO should be knowledgeable of, and able to

quantitatively evaluate, both the health physics (radiological) and industrial hygiene (non-radiological)

aspects of the hazard.

9.2.2.2 Offsite Response Interfaces

The specific properties of the hazardous material do not significantly affect the content of this

program element.

9.2.2.3 Operational Emergency Event Classes

As with all hazardous materials, classification of emergencies for uranium facilities should be

based on the predic ted consequences at specific receptor locations, as compared with numerical criteria for

taking protective action (dose, exposure, air concentration). If a material has two or more recognized modes

of effect and associated protective action criteria, classification decisions should be based on the more

limiting one.

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