Different detection techniques for tritium inventory
Résumé
Tritium is a radionuclide very difficult to analyze mainly because of its energy, type of emission (-) and its chemical and physical behavior. In all kinds of developments concerning the tritium (dismantling processes, fusion development, environmental control…), it is essential to characterize the radionuclide with high accuracy and a minimum of uncertainty. Elevated concentrations of tritium in the environment associated with producing, handling and managing the radioactive form of hydrogen at nuclear facilities are of great public concern. At present time in France, wastes containing tritium come mainly from defense, research activities and nuclear power plants. Concerning NPP internationally, PWR produces less tritium than other reactors such as CANDU. This production of tritium in the nuclear industry is currently an important subject and tritium inventory must be deeply investigated. In the very near future with the development of fusion machines such as ITER, that will use Deuterium and Tritium as fuel, production of tritiated wastes and needs to assess the exact inventory of tritium will be crucial. The presentation will focus on the different chemical forms of tritium, which induce very different ways for the development of analytical techniques to provide the tritium inventory. Different analytical techniques already exist commercially but mainly consider some applications to control tritiated wastes in particular chemical form and for particular activities. Some international regulations already exist and will be described to assess the different ways of tritium investigations for public acceptance.
However with new fusion technologies such as ITER, tritium inventory inside the machine still remain a high challenge, and the investigation of tritiated wastes will require of course standard techniques but also new technological breakthrough.
A nearly complete panel of standard techniques and of new technologies will be described during the talk. The autoradiography technique, a technique commercially developed for researches in biology is currently developed in CEA France because of its high potentialities to investigate tritium in situ. New developments of this technology will be presented and particularly the technique using phosphor screen and another one providing results in real time with new SiPM detectors