Development of operational intervention levels for events with release of radionuclides

An essential part of a protection strategy for radiological emergencies is the development of national dose criteria and of operational intervention levels to decide about protective measures for all 10 scenarios Germany is preparing for. For the process of planning and implementing such protection strategies as required by the German Radiation Protection Law the Federal Ministry BMU has commissioned the German Radiation Protection Commission (SSK) to recommend dose criteria and operational intervention levels (OILs) for emergency response measures. Operational intervention levels link a chosen dose criterion for a protective action with a suitable measurement of the contamination situation such as ambient dose rate (Sv h-1), contamination level on surfaces (Bq cm-2) or activity content (Bq g-1, Bq cm-3). This link should adequately model the exposure of persons during a defined exposure period (e.g. 7 days, one year) caused by the measured contamination. Dose calculations to quantify OILs should apply assumptions and parameter values that are in tendency realistic and not unduly conservative. Operational interventions levels have been developed for the following emergency response actions based on radiation measurements: • Sheltering on the basis of dose rate (Sv h-1) and contamination level (Bq cm-2) • Evacuation on the basis of dose rate (Sv h-1) and contamination level (Bq cm-2) • Establishing a radiological hazard area to implement access and contamination control on the basis of dose rate (Sv h-1) and contamination level (Bq cm-2) • Contamination control and possibly decontamination of persons and objects (items, goods, vehicles, etc.) based on contamination level (Bq cm-2) • A set of precautionary early actions: warning of population to consume freshly contaminated food and agricultural measures to reduce food contamination based on dose rate (Sv h-1) • Application of maximum permitted levels of radioactive contamination of food and feed (Bq kg-1) according to Euratom Regulation.