Development of the core-bowing reactivity analysis code system ATLAS and its application to a large FBR core Original Research Article

A new code system called ATLAS has been developed to calculate core-bowing reactivity feedback behavior in fast breeder reactor cores. Based on the structural mechanics of a core (core mechanics), the code also incorporates neutron physics and thermo-hydraulic calculations. Using this new code system, the core barrel restraint system of a typical large fast breeder reactor was investigated in detail and core-bowing reactivity coefficients were determined to assess their sensitivity to several design parameters.