The Double definition of the Transport Index (T.I) : A wrong good idea ?

The transport index (T.I) was set up at the beginning of the sixties in order to facilitate and make safer the gathering in the same conveyance of a certain number of packages of radioactive and fissile materials. T.l allows on the one hand to limit the radiation dose rate around the packages to an acceptable value, on the other hand to avoid any possible risk of criticality, both possible consequences of the accumulation of several packages on a conveyance. In order to simplify the loading and control of its safety a single T.l which covered at the same time the radioactive and fissile aspects without making any difference between the packages was set up.