In the first part, this paper reviews several ways to derive kinetical results from Controlled transformation Rate Thermal Analysis (CRTA) experiments: applying the rate-jump method to measure the activation energy, determining the reaction mechanism simply from the shape of the curve and finally deriving both the activation energy and the reaction mechanism from a single CRTA experiment. Application to the 5 steps of the thermal analysis of UO2(NO3)2(H20)2.4H20 shows that the layered structure of the hydrate leads to 4 dehydration steps essentially following a mechanism of nucleation and 2-dimensional growth whereas the denitration step seems to be controlled by a double mechanism of diffusion and desorption. The first 4 water molecules to leave are in the same starting state but evolve in 2 steps, well separated by CRTA and involving 3 and I molecule, respectively, which is understood by structural considerations.Previous work [1,2] has demonstrated the efficiency of Controlled transformation Rate Thermal Analysis (CRTA) [3] for separating the successive steps of the dehydration and denitration of hexahydrated uranyl nitrate UO2(NO3)2(H20)2.4H20. The "separating power" or "resolution" of CRTA first results from the possibility of controlling the rate of transformation at such a low rate -if needed -that the remaining temperature and pressure gradients through the sample are themselves low enough to avoid any overlapping of the successive steps. We have shown that in the case of hexahydrated uranyl nitrate, the separation of 5 successive steps also needs a control of the gas pressure over the sample at a relatively low value, which is also possible with CRTA: the recording given in Fig.

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