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Tsujimoto, Kazufumi; Nishihara, Kenji; Takei, Hayanori; Sugawara, Takanori; Iwamoto, Hiroki; Oizumi, Akito; Sasa, Toshinobu
no journal, ,
To continue the utilization of the nuclear fission energy, the management of the high-level radioactive waste (HLW) is one of the most important issues to be solved. Partitioning and Transmutation (P&T) technology of HLW is expected to be effective to mitigate the burden of the HLW disposal by reducing the radiological toxicity and heat generation. The research and development on P&T in Japan are basing on two kinds of concepts: one is the homogeneous recycling of minor actinide (MA) in commercial fast breeder reactors and the other is the dedicated MA transmutation, so-called "double-strata" strategy, using an accelerator-driven system (ADS). The objective of this research program is to enhance the technology revel from basic research phase to semi-engineering research phase for the main component of the double-strata P&T concept, MA partitioning process and the ADS technologies. For the ADS, the simulation experiments in the critical assembly connecting with the proton accelerator will be carried out to accumulate the reactor experimental results to solve R&D issues in the reactor physics aspect of the ADS. The results of this R&D program will be reflected on the assessment of the technically feasibility for each technology.
Takei, Hayanori
no journal, ,
Frequent beam trips as experienced in existing high power proton accelerators may cause thermal fatigue problems in Accelerator-Driven System (ADS) components which may lead to degradation of their structural integrity and reduction of their lifetime. The comparison showed that for beam trips with durations exceeding 10 s, beam-trip frequencies were about 6 to 35 times larger than acceptable values. One of the methods to improve the reliability is redundancy which the duplication of critical components or functions of a system. In this study, technical feasibility and possibility for parallelization of the beam line were investigated for the enhanced redundancy of the ADS accelerator.
Okubo, Nariaki; Fujimura, Yuki
no journal, ,
The accelerator driven system (ADS) adopts a liquid metal of lead-bismuth eutectic (LBE) as a coolant and also spallation target to produce high energy neutrons. In this study, irradiation effect on the corrosion behavior was evaluated for the compativility of 316L stainless steel, which is candidate material of ADS target window, through the immersion test under LBE with saturated and low oxygen concentration followed by ion irradiation experiment. In the case of soaking in LBE with saturated oxygen concentration for SS316L steels at 450
C, 330 hrs, non-irradiated region did not show clear oxide layer, however, irradiated region showed bi-layers of magnetite and spinel type oxides. The formation rate of oxide layer for irradiated region was about twice faster than that of non-irradiated region. This result suggests that diffusion behavior after irradiation and mass transfer in the interface between LBE and steel surface is important for understanding of irradiation effect on liquid metal corrosion.