From 10 to 21 June 2002, over 100 researchers from 30 countries participated in an exercise to compare physical and biological dosimetry techniques which they would apply in case of nuclear accidents.

The exercise was organised and planned jointly by IRSN and NEA, with financial support of the European Commission and the collaboration of the Valduc site of the CEA. The exercise was a test of the respective countries’ dosimetric techniques under experimental conditions simulating an irradiation accident.

The programme consisted of four irradiation scenarios. Three were carried out at the Valduc site using the unique SILENE, a liquid-fuel irradiation test reactor equipped with various shields.

These scenarios simulated three different aspects of criticality accidents which typically involve simultaneous high levels of neutron and gamma-ray emission. The fourth experiment involved exposure to high doses of gamma-rays; it was carried out at the IRSN laboratories.

Participants allowed their dosimeters to be irradiated by exposure in the test facilities, following which they determined their best measure of the dose received.

Preliminary results were delivered in 48 hours, to simulate the urgency of an accident situation; refined values would become available a few weeks later, after laboratory analyses. Such measurements are intended to characterise the physical and radiobiological consequences of an accident; a thorough understanding of the types of radiation and precise estimates of the doses are needed for the timely design of appropriate medical treatment.