Development status of Au-In-Cd alloy decoupler for spare reflector and moderators in J-PARC

Oi, Motoki ; Teshigawara, Makoto   ; Harada, Masahide   ; Takada, Hiroshi  

In the spallation neutron source of the Japan Proton Accelerator Complex (J-PARC), generated neutrons are moderate in liquid hydrogen moderators and supplied to neutron instruments. The design life of the reflector and the moderator is 30,000 MWh (6 years at 1 MW), and we are preparing spare reflector and moderators. In the first ones, Ag-In-Cd alloy decoupler is used, but in order to reduce the residual radioactivity, Au-In-Cd alloy decoupler was developed and adapted to the spare reflector and moderators. It performed R&D about HIP bonding with aluminum alloy, manufacturing and processing method of the Au-In-Cd alloy. In HIP bonding, the optimal conditions were determined by the bonding test using temperature, time, surface condition, etc. as parameters, and these were applied to the spare reflector and moderators. The spare reflector was delivered at the end of FY2015, and now we are preparing decoupled moderators and poisoned moderators with Au-In-Cd alloys.