Year
2006
Abstract
Calorimetry has been used for many years in the nuclear field (civil and military) but the knowledge of the applications remains very confidential. However the thermal characterization of the nuclear materials is a critical problem that has to be solved. One problem is the management of the nuclear wastes coming from different sources. It is needed to accurately know their thermal activity in order to find the adequate storage mode and define the safety parameters of this storage. Another problem that is easily solved with calorimetry is the quantification of radioactive elements, especially tritium in the military nuclear activities. As it is very important to trace these elements, calorimetry by measuring the activity of the elements is used to give very precisely the amount of the element in a container. In order to fit with the requirements of the nuclear research sector, SETARAM Instrumentation develops large volume calorimeters more particularly for the analysis of radioactive wastes and for the quantification of radioactive elements (e.g. curium, plutonium, tritium). In fact, the calorimetric detector has to be adapted to the size of the vessels containing the radioactive substances. These instruments are also used to measure the energy of hard gamma and neutron emitting sources in shielded containers. The large-volume calorimeters are able to accommodate 60- and 90-liter containers . Thanks to their excellent sensitivity, the large volume calorimeters can accurately measure very low thermal effects (less than 10µW/litre, that is to say 10 nW/ml), which makes them powerful working tools for nuclear applications. The calorimeters, which conform to EC standards, are placed in glove boxes under controlled atmosphere. The construction materials are chosen for their good fire resistance and the fact that they can be easily decontaminated. All the electronic unit ensuring temperature control, heating power and data acquisition, can be remotely positioned outside the \"contaminating zone\".