Cesar: a simplified evolution code for reprocessing applications

In the framework of a collaboration between CEA and COGEMA, CESAR has been developed to provide the required characterization data for burn up fuels from PWRs. BWRs and FRs. It can quickly calculate the evolution, in and out of pile, of material balances, and the activity, decay heat and neutron source emitted by the irradiated fuel, taking into account 104 actinides, 208 fission products and 125 activation products. CESAR can also make flux depletion calculations of radioactive sources, up to geological times (106 years). The neutronics data libraries (cross sections sets) are supplied by the CEA reference calculation codes for neutron physics: APOLLO for thermal spectrum systems and ERANOS for fast spectrum systems. In the near future, they will be supplied by the DARWIN package. For the principal nuclides, the code has been validated using two types of experimental results: isotopic analysis from burn up fuel rod samples and also from full assemblies dissolutions from the reprocessing plants. (author)