2014 CALIBAN AND PROSPERO EXPERIMENTS FOR THE CRITICALITY ACCIDENT DOSIMETRY INTERCOMPARISON

摘要

Nuclear criticality accident dosimetry is very specific, due to the mixed fields and to energy and dose ranges which could be out of the range of classical individual dosimetry. The maximal neutron and gamma dose must be determined as well as other information such as the orientation of the victim in the radiation field. It is exceptionally challenging to establish doses in the event of partial body exposures. Therefore, frequent exercises are organized to maintain competences and to train staff to perform such dosimetry. Experiments using the CALIBAN and PROSPERO reactors were performed in June and September 2014 in order to test various criticality accident dosimeters (CAD). These two metallic reactors are located at the CEA research center at Valduc (Cote-d'Or, France). They are composed of a metallic alloy of uranium with a high enrichment in the isotope ~(235)U. These reactors are used for the production of mixed radiation fields primarily comprised of fission neutrons and gammas. CADs from three different laboratories (AWE, UK ; IRSN, FR ; LLNL, USA) were irradiated on water phantoms with three different orientations (0° and 45°, front and rear faces) and free in air at both CALIBAN and PROSPERO reactors, in pulse and steady state modes. This paper will present the comparison of some results. These experiments will be useful preparation for other exercises planned in 2016 at the GODIVA-IV and FLATTOP reactors located at the Nevada National Security Site, USA.