New CEA handbooks for criticality safety assessment demonstrations

Overview & Synopsis

Criticality safety assessment demonstrations may be supported by basic 1D calculations performed by neutron transport deterministic codes (standard calculations). In the case of the French CRISTAL V2.0 package, critical and permissible values for simple geometries like spheres, infinite height cylinders or infinite section slabs are determined with the APOLLO2 cell code and its discrete ordinates SN module (standard route). The most pertinent values (e.g. values at optimal moderation) are aggregated in documents called handbooks. 45 years after the first and up to now unique French handbook, nicknamed “Maubert” from his author, this paper presents new handbooks, prepared by CEA. They compile latest CRISTAL V2.0 standard route results from more than 250 standard calculation reports. Two handbooks have currently been produced: one with critical values, the other with permissible values with a neutron effective multiplication factor, keff, criterion equal to 0.95. They both present results for uranium, plutonium, mixed media, and pure actinides fissile material with various physico-chemical, densities and isotopic compositions. The influence of various reflecting and moderating materials has been investigated. Moreover, criticality parameters for several fissile media containing homogeneous neutron absorbers (boron, gadolinium, cadmium) have been determined. These handbooks are available to everyone on request. Additionally, this paper discusses some singular and unexpected results observed while producing those handbooks.