Basic procedure

Basic procedure

Casus is very versatile. To use it, it is not necessary to observe a rigorous procedure. The user may flexibly use Casus according to the nature of the task. Nevertheless, most tasks include a basic procedure, which consists of the following steps:

• input of the source term (the activity of the released radioactive substances)
• if necessary, adaptation of the calculation parameters
• calculation of the atmospheric dispersion and deposition of the released radioactive substances
• dose assessment for all selected age groups and exposure pathways at any given downwind distance

In order to follow this basic procedure, the user has to do the following steps. All involved calculations are automatically and immediately performed by Casus.

Step 1: Enter the source term, i.e. the activity (in Bq) of the released radioactive substances.

The source term is given in the Source Term form:

The source term may be divided into four release periods:

• From 0 h to 8 h
• From 8 h to 24 h
• From 1 d to 3 d
• From 3 d to 7 d

Furthermore, one additional release period is considered for very short releases with duration of less than one hour.

Step 2: Adapt the calculation parameters for the atmospheric dispersion calculation and the dose assessment.

All parameter values are specified in the Parameters form.

The Parameters form consists of several tabs: Release, Chemistry, Dispersion, Deposition, Terrain, Exposure, Age Groups, and Compatibility.

The user may change all parameter values or use default values in accordance with regulatory guides.

Step 3: View the dose results

The Dose Results form shows the current results of the dose assessment (equivalent doses and effective dose in mSv for all age groups) for a given downwind distance.

When the user changes the source term or the calculation parameters, the new dose results are shown immediately.