APOLLO1 / MORETIII - A VERSATILE CRITICALITY CALCULATION TOOL TO MASTER THE DRY STORAGE OF VVER 440 FUEL ASSEMBLIES

摘要

The calculation tool used in France for the assessment of criticality safety has been developed and validated for more than two decades. The Institute for Nuclear Protection and Safety (IPSN) together with the French industrialists (including fuel fabrication and reprocessing plants) have supported extensive experimental programs for the qualification of the calculation scheme in different configurations encountered in the nuclear fuel cycle where criticality safety is of concern. A computer codes package based on APOLLO1 - MORETIII modules performs criticality safety studies for any kind of fissile materials, shapes and configurations. An exhaustive experimental database was used to validate and qualify the above computer codes containing a wide range of benchmarks coming from national and foreign criticality experimental facilities. Among these experiments, a set of configurations including UO2 rods with a triangular pitch in a hexagonal assembly, low moderated systems and poisoned water are used to demonstrate the capability to deal with VVER type assemblies from wet storage in a borated water pool through fuel transportation and finally to the dry storage units. After a short description of the calculation method and its qualification, this paper will deal with a current project based on the dry storage of VVER type assemblies.