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Oi, Motoki; Teshigawara, Makoto; Wakui, Takashi; Nishi, Tsuyoshi; Harada, Masahide; Maekawa, Fujio; Futakawa, Masatoshi
Journal of Nuclear Materials, 431(1-3), p.218 - 223, 2012/12
Times Cited Count：7 Percentile：43.75(Materials Science, Multidisciplinary)The Japan Spallation Neutron Source (JSNS) at the Japan Proton Accelerator Research Complex (J-PARC) is developed as a 1 MW spallation neutron source. The Ag-In-Cd (AIC) alloy was adopted as a decoupler material for two decoupled moderators. A high decoupling energy at 1 eV was for the first time achieved in MW class spallation neutron source due to the adoption of the AIC alloy. Although the AIC decoupler is superior in the neutronic performance, it has a demerit in high residual radioactivity due to production of Ag-110m and Ag-108m. To overcome this demerit, Au-In-Cd alloy was proposed. We studied to make ternary Au-In-Cd alloy and successfully done it at the maximum temperature of 1123 K with diffusion of the cadmium into the gold. Uniformity of the alloy was confirmed with EDX analysis. Thermal conductivity of Au-In-Cd alloy was 87.7 W/m/K. These results show enough performance as a decoupler.
Kikuchi, Kenji*; Rivai, A. K.*; Saito, Shigeru; Bolind, A. M.*; Kogure, Akinori*
Journal of Nuclear Materials, 431(1-3), p.120 - 124, 2012/12
Times Cited Count：7 Percentile：43.75(Materials Science, Multidisciplinary)The oxide layer on the 12Cr steel, HCM12A, is investigated using a scanning probe microscope (SPM), which was formed in lead bismuth eutectic (LBE) at 450
500
C, during 5500 hrs. Hitherto oxide formation mechanisms were studied from viewpoints of the location of original base metal surface, the pass for oxygen travel and Fe diffusion to understand the stability of oxide layer. The new findings in this research are that surface potential measurement detected the boundary between (FeCr)
O
and FeO, which is not found at the topographic mode measurement. The spinel layer can be distinguished from the bulk area with lower surface potential profile, but near the boundary between the spinel and magnetite layers the surface potential profile seems to be continuous except for the narrow path corresponding to the boundary line. The band structure penetrating magnetite and spinel layer was found, which was not found at the topography.
Naoe, Takashi; Yamaguchi, Yoshihito; Futakawa, Masatoshi
Journal of Nuclear Materials, 431(1-3), p.133 - 139, 2012/12
Times Cited Count：10 Percentile：55.63(Materials Science, Multidisciplinary)Liquid metals are expected to be used as the nuclear materials because of its good thermal conductivity. However, in specific combinations of the liquid and solid metals, liquid metals have possibility to decrease lifetime of the structural material due to the LME. In this study, the LME in combination between the mercury and an austenitic stainless steel as a target and structural material for the pulsed spallation neutron source was investigated through the fatigue tests with the notched specimen under mercury immersion. The FRASTA method combined with the measurement of the notch opening distance was performed to estimate the fatigue crack growth rate in mercury. The results showed that the fatigue crack growth rate in mercury was slightly higher than that of in air at low cycle fatigue region. It was suggested that the crack propagation accelerated by the mercury immersion.
Saito, Shigeru; Kikuchi, Kenji*; Hamaguchi, Dai; Tezuka, Masao*; Miyagi, Masanori*; Kokawa, Hiroyuki*; Watanabe, Seiichi*
Journal of Nuclear Materials, 431(1-3), p.91 - 96, 2012/12
Times Cited Count：19 Percentile：76.01(Materials Science, Multidisciplinary)To evaluate lifetime of structural materials for ADS, corrosion tests in LBE have been done at JAEA. The corrosion test was performed by using JAEA lead-bismuth flowing loop (JLBL-1). Experimental condition was as follows; The temperature of high and low temperature parts of the loop were 450C and 350C, respectively. Flowing velocity at the test specimens was about 1m/s. Plate type SS316L-BM and SS316L-GBEM were used as a specimens. After the 3,000 hours operation, the test specimens were cut and macroscopic observation was carried out. The result showed that both materials were intensively eroded. Corrosion depth and LBE penetration through grain boundaries of GBEM were smaller than these of 316SS-BM.
Futakawa, Masatoshi
no journal, ,
The current status on research and development in J-PARC/MLF in terms of mercury cavitation damage which is a crucial issue for the high power pulsed spallation neutron source JSNS will be reported. In particular, developments on bubbling techniques, micro-bubble distribution in target vessel, pressure wave mitigation and reduction of negative pressure will be introduced.
CRivai, A. K.; Saito, Shigeru; Obayashi, Hironari; Tezuka, Masao*; Kato, Chiaki; Kikuchi, Kenji*
no journal, ,
Saito, Shigeru; Hamaguchi, Dai; Kikuchi, Kenji*; Usami, Koji; Endo, Shinya; Ono, Katsuto; Matsui, Hiroki; Kawai, Masayoshi*; Yong, D.*
no journal, ,
In several institutes, the research and development for an accelerator-driven transmutation system (ADS) to transmute minor actinide (MA) have been progressed. To evaluate lifetime of the beam window, post irradiation examination (PIE) of the STIP (SINQ target irradiation program, SINQ; Swiss spallation neutron source) specimens was carried out at JAEA. The specimens were austenitic steels JPCA and Alloy800H. The irradiation conditions of the specimens irradiated at SINQ target 4 (STIP-II) were as follows: proton energy was 580 MeV, irradiation temperatures were ranged from 100 to 450C, and dpa were ranged from 6.5 to 19.5 dpa. All PIE works has been carried out at WASTEF and RFEF in Tokai Research and Development Center, JAEA. Tensile tests were performed in air at R.T., 250C and 350C. Fracture surface observation after the tests was done by SEM. Results of the tensile tests performed at R.T. indicate that irradiation hardening occurred with increasing displacement damage level up to 10 dpa. At higher doses, irradiation hardening seemed to tend to saturate. Degradation of ductility was bottomed around 10 dpa and specimens kept its ductility until 19.5 dpa. The most of specimens fractured in ductile manner, however, the specimens irradiated at the higher dose (
19 dpa) and higher temperature ( 400C) showed partially intergranular morphology.
