Aerial platform equipped for nuclear emergency measurements

Aerial Radiological Measuring Systems (ARMS) developed in the late 1950s for uranium ore prospecting have also provide an invaluable tool in environmental surveillance of nuclear power plants and nuclear processing facilities as well as in emergency response for large-scale radiological accidents. Historically the international concern of the potentialities of such systems was triggered in 1978 by the search and partial recovery of radioactive debris scattered over an estimated area of about 100,000 km2 as a consequence of the impact in the Northwest Territories of Canada of the nuclear powered Soviet 'COSMOS-954' satellite. Less than 10 years after, in occasion of the Chernobyl accident, many countries had developed such systems and maps of surface contamination have been collected over several European countries showing a large diffusion of the radioactive fallout originated by the release from Chernobyl nuclear plant. Also in Italy an ARMS mounted on Agusta-Bell 412 helicopter having as detector large NaI(Tl) counters was used by the group of Physics Laboratory of Istituto Superiore di Sanita' to map the ground surface contamination over the central-southern part of the country. From that experience it was deduced that aerial platforms without air sampling and air radioactive contaminants measurement capability can only give quantitative information on ground contamination when the air contamination is negligible and then, in the more critical period when the radioactive plume is passing over the country, it can only be used for qualitative assessments. (author)