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Teshigawara, Makoto; Ikeda, Yujiro; Oi, Motoki; Harada, Masahide; Takada, Hiroshi; Kakishiro, Masanori*; Noguchi, Gaku*; Shimada, Tsubasa*; Seita, Kyoichi*; Murashima, Daisuke*; et al.
Nuclear Materials and Energy (Internet), 14, p.14 - 21, 2018/01
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)We developed an Au-In-Cd (AuIC) decoupler material to reduce induced radioactivity instead of Ag-In-Cd one, which has a cut off energy of 1eV. In order to implement it into an actual moderator-reflector assembly, a number of critical engineering issues need to be resolved with regard to large-sized bonding between AuIC and A5083 alloys by the hot isostatic pressing process. We investigated this process in terms of the surface conditions, sizes, and heat capacities of large AuIC alloys. We also show a successful implementation of an AuIC decoupler into a reflector assembly, resulting in a remarkable reduction of radioactivity by AuIC compared to AIC without sacrificing neutronic performance.
Oi, Motoki; Teshigawara, Makoto; Harada, Masahide; Takada, Hiroshi
no journal, ,
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.
Oi, Motoki; Harada, Masahide; Teshigawara, Makoto
no journal, ,
J-PARC neutron source facility is 1MW pulsed spallation neutron source in Japan. There are three liquid hydrogen moderators, one is for high intensity, the others are for short pulse neutron beam. In order to make short pulsed neutron beam, neutron absorber called decoupler is attached around the moderators. Characteristics of the decoupler is described by the neutron cut-off energy (Ed). In J-PARC, Ed of 1eV is realized by the Ag-In-Cd decoupler at the 1MW spallation neutron source. Due to the radiation damage and burn-up of the decoupler material, we have to replace these moderator and reflector assembly in near future. For the second moderator and reflector assembly, we developed a Au-In-Cd alloy as a low activation material. Ed of Au-In-Cd alloy is 1eV. Activation of the Au-In-Cd is much lower than that of Ag alloy. We manufactured the Au-In-Cd alloy and processed the alloy by ourselves. Finally, it was installed into the moderator and reflector assembly.
