The Development of fuel pins and material specimens mixed loading irradiation test rig in the experimental fast reactor Joyo; The Development of the fuel-material hybrid rig

Oyamatsu, Yasuko*; Someya, Hiroyuki

In the experimental fast reactor Joyo, there were many tests using the irradiation rigs that it was possible to be set irradiation conditions for each compartment independently. In case of no alternative fuel element to irradiate after unloading the irradiated compartments, the irradiation test was restarted with the dummy compartment which the fuel elements was not mounted. If the material specimens are mounted in this space, it is possible to realize effective utilization of the irradiation space. For these reasons, the irradiation rig (hybrid rig) consolidated with fuel elements and material specimens are developed. Fuel elements and material specimens differ greatly with heat generation, so that the point for developing of hybrid rig is being able to distribute appropriately the coolant flow which satisfies irradiation conditions. The following is described by this report. (1) It was confirmed that the flow distribution of loading the same irradiation rig with the compartment from which a flow demand differs could be satisfied. (2) It was confirmed that temperature setting capability equivalent to the former was securable. (3) By standardizing the coolant entrance structure of the compartment lower part, the prospect which can perform easily recombination of the compartment from which a kind differs between irradiation rigs was acquired.