Monitoring Strategy in Support of Radiological Emergency Management

Monitoring radioactive contamination after a radiological accident provides decision-makers with information on whether or not to take protective action. The monitoring strategy discussed concerns the response phase of the accident, which is subdivided into two stages. In the first, early monitoring stage, given the very short time span available for protective action, data have to be available within several hours after the radioactive release. The main purpose of measurements in this stage is to test and adjust model predictions. This implies measuring activity concentration in air, ambient dose rate and surface contamination. In the second, extensive monitoring stage, emphasis is on monitoring foodstuffs (milk, vegetables and meat) and drinking water. Depending on the expected gradient in the contamination and the purpose of the measurements a basic monitoring density of about 50 km x 50 km is observed. Within a radius of 10 km from nuclear facilities extra monitoring stations will be necessary.