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Several irradiation experiments have confirmed the positive effect of adding Si to the matrix of an U(Mo) dispersion fuel plate on its in-pile irradiation behavior. E-FUTURE, the first experiment of the LEONIDAS program, was performed to select an optimum Si concentration and fuel plate heat treatment parameters for further qualification. It consisted of the irradiation of 4 distinct (regarding Si content and heat treatments), full size flat fuel plates in the BR2 reactor under bounding conditions (470 W/cm 2 peak BOL power, ∼70% peak burn-up). After the irradiation, the E-FUTURE plates were examined non-destructively and found to have pillowed in the highest burn-up positions. The destructive post-irradiation examination confirmed that the fuel evolves in a stable way up to a burn-up of 60% 235 U. Even in the deformed area (pillow) the U(Mo) fuel itself shows stable behavior and remaining matrix material was present. From the calculation of the volume fractions, the positive effect of a higher Si amount added to the matrix and the higher annealing temperature can be derived.

We developed a new apparatus dedicated to Supercritical Water Oxidation in order to overcome the two well-known problems of this process, which are corrosion and salt plugging. This reactor has both a double shell in titanium, which prevents corrosion, and a stirrer creating a turbulent flow, which prevents the sedimentation of inorganic compounds and enables better heat transfers. We first tested our reactor with easily oxidized effluents, i.e. pure organic compounds like PEG and dodecane. Then we oxidized two different kinds of effluent: one forming a corrosive phosphoric acid, and another one containing an inorganic salt in significant amount. We get conversion yields over 99.8% with organic and salt concentrations up to 6 and 4%, respectively, without production of chars or undesired gases like CO and CH4. © 2003 Elsevier B.V. All rights reserved.

Nuclear fuel plates based on a γU-Mo/Al mixture are proposed for research reactors. In this work their thermal behavior in the [425; 550°C] temperature range has been studied mainly by neutron and high energy X-ray diffraction. Even if complementary studies will be necessary, the kinetics of first the growth of the interaction layer between γU-Mo and Al and second of the γU-Mo destabilization have been accurately measured. This basic work should be helpful for defining manufacturing conditions for fuel plates with optimized composition.

The 'service of research on neutronics and criticality' of Valduc CEA research center, proposes several experimental facilities for neutron and gamma irradiation: two metallic reactors, a solution reactor, two accelerators.