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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.

In this paper, we present the critical experiment performed in March 2008 in the high-flux reactor (HFR) to reproduce physical conditions similar to the core light water introduction accident. We present the HFR, the context of the study and two Monte Carlo models: TRIPOLI4 – JEFF3.1 and MCNP – ENDF/BVII. All comparisons between calculations and experimental results show, within both models, that the safety rods efficiencies, in AIC alloy, are always underestimated in normal as well as in accidental configuration of the reactor.

Converting biomass into hydrogen can be accomplished in supercritical water. State of the art experiments are thoroughly presented. Chars and tars formation may be the most significant technological problem. However, catalysis should be the solution to obtain higher yields of hydrogen and to decrease the amounts of chars and tars. As conversion yield reaches 98% with a proportion of hydrogen higher than 50% in the gaseous phase, the next step to consider in a successful transfer to the industrial scale is to evaluate the energy cost of the process. We made an evaluation of the energy efficiency of biomass gasification, basing our work on data of the literature. Our results show that the energy efficiency from thermodynamic calculation reaches 60% when considering hydrogen, carbon monoxide and methane as valuable species in the ideal case. Including energy recovery from the water at 280 bar and 740 °C, the overall energy yield reaches 90%. These calculations are overestimated because no heat losses are taken into account. However, this study shows that the key point of the process is energy recovery as the chemical reaction is endothermic and needs high temperature and a rather large ratio of water/biomass.

International audience; The aim of this work is to validate experimentally the results of the Monte Carlo Recoil Energy Determination (MC-RED) nuclear physics code used to determine the deposited energy in a silicon volume taking into account the probabilistic approach of the physical phenomenon. A silicon sensor has been used to measure the deposited energy spectrum after an irradiation with a 14 MeV neutron source. Neutrons of 14 MeV were produced by the SAMES accelerator of the Valduc CEA research center. The experimental results were compared with the one obtained by the MC-RED code in the same silicon volume. To compare experiment and simulations, it requires that the complete neutron field be specified. We have to take into account the facility cell environment. Nuclear simulations were performed with the MCNP code to determine with accuracy the energy spectra of neutrons and gamma rays produced by this facility on the sensor. It is shown that the contribution of secondary neutrons is not negligible