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Hirata, Sakiko*; Kusaka, Ryoji; Meiji, Shogo*; Tamekuni, Seita*; Okudera, Kosuke*; Hamada, Shoken*; Sakamoto, Chihiro*; Honda, Takumi*; Matsushita, Kosuke*; Muramatsu, Satoru*; et al.
Inorganic Chemistry, 62(1), p.474 - 486, 2023/01
Times Cited Count:0 Percentile:0.01(Chemistry, Inorganic & Nuclear)Teshigawara, Makoto; Ikeda, Yujiro*; Yan, M.*; Muramatsu, Kazuo*; Sutani, Koichi*; Fukuzumi, Masafumi*; Noda, Yohei*; Koizumi, Satoshi*; Saruta, Koichi; Otake, Yoshie*
Nanomaterials (Internet), 13(1), p.76_1 - 76_9, 2023/01
Times Cited Count:0 Percentile:59.51(Chemistry, Multidisciplinary)To enhance neutron intensity below cold neutrons, it is proposed that nanosized graphene aggregation could facilitate neutron coherent scattering under particle size conditions similar to nanodiamond. It might also be possible to use it in high neutron radiation conditions due to graphene's strong sp2 bonds. Using the RIKEN accelerator-driven compact neutron source and iMATERIA at J-PARC, we performed neutron measurement experiments, total neutron cross-section, and small-angle neutron scattering on nanosized graphene aggregation. The measured data revealed, for the first time, that nanosized graphene aggregation increased the total cross-sections and small-angle scattering in the cold neutron energy region, most likely due to coherent scattering, resulting in higher neutron intensities, similar to nanodiamond.
Naoe, Takashi; Teshigawara, Makoto; Futakawa, Masatoshi; Mizutani, Haruki; Muramatsu, Toshiharu; Yamada, Tomonori; Ushitsuka, Yuji*; Tanaka, Nobuatsu*; Yamasaki, Kazuhiko*
Proceedings of 8th International Congress on Laser Advanced Materials Processing (LAMP 2019) (Internet), 5 Pages, 2019/05
Laser cutting is one of the options in the disposal of radio-active waste, such as spallation neutron target vessel in J-PARC, etc. Due to unique characteristic of laser, such as non-contact system, it is more easily to provide remote-controlled system in comparison with conventional one, such as mechanical cutting machine, etc. However, a demerit of laser cutting is the sputter and fume caused by laser cutting, resulting in contamination with radio-active materials its surroundings. Recently it was developed that the spatter suppression technique by controlling laser beam profile in laser welding process. In order to apply this suppression technique to laser cutting, first of all, we attempted to observe the phenomenon at melting area during laser cutting using a high-speed video camera in order to make the physical model. The result showed that the appearance of fume and sputter were independently confirmed in the time evolution.
Muramatsu, Toshiharu; Sano, Kazuya; Terauchi, Makoto
Dekomisshoningu Giho, (57), p.65 - 74, 2018/03
The Decommissioning Technology Demonstration Test Center (tentative name) is established as a central facility of "Fukui Smart Decommissioning Technology Demonstration Base" which was adopted by the support policy "Regional Science and Technology Demonstration Base Establishment Project" of the Ministry of Education, Culture, Sports, Science and Technology in FY 2016 supplementary budget. This facility is a base to train local companies about technology concerning the decommissioning of nuclear power plants and for the industry, academia and government to contribute to the development of the regional economy and solving the problem of decommissioning under one roof, and consists of decommissioning dismantling technology verification field, laser processing advanced field and decommissioning mock-up test field. The papers introduce the outline of the facilities in each of these fields.
Togo, Yoko*; Takahashi, Yoshio*; Amano, Yuki; Matsuzaki, Hiroyuki*; Suzuki, Yohei*; Terada, Yasuko*; Muramatsu, Yasuyuki*; Ito, Kazumasa*; Iwatsuki, Teruki
Geochimica et Cosmochimica Acta, 191, p.165 - 186, 2016/10
Times Cited Count:25 Percentile:73.46(Geochemistry & Geophysics)Iodine distribution, speciation, and isotope ratio (I/I) in both rock and groundwater phases were determined to investigate long-term migration of iodine in diatomaceous and siliceous shale. It was suggested that I is released to the ground water during the progress of the maturation of organic matter. Dissociated I could move toward the surface because of the upward water flow driven by the compaction during burial diagenetic process. Thus, iodine rich brine is created by integration of iodine released from underlying formations. Because of low affinity of I to solid phase, released I remains in solution phase, and the concentration of the iodine in the solution has been possibly increasing during sedimentation history.
Seki, Miharu*; Oikawa, Junichi*; Taguchi, Taro*; Onuki, Toshihiko; Muramatsu, Yasuyuki*; Sakamoto, Kazunori*; Amachi, Seigo*
Environmental Science & Technology, 47(1), p.390 - 397, 2013/01
Times Cited Count:43 Percentile:75.55(Engineering, Environmental)The laccase released by microorganisms oxidizes iodide to molecular iodine or hypoiodous acid, both of which are easily incorporated into natural soil organic matter.
Moriyama, Kiyofumi; Takagi, Seiji*; Muramatsu, Ken; Nakamura, Hideo; Maruyama, Yu
JAEA-Research 2007-072, 54 Pages, 2007/11
The containment failure probability due to ex-vessel steam explosions was evaluated for BWR and PWR model plants. A stratified Monte Carlo technique (Latin Hypercube Sampling (LHS)) was applied for the evaluation of steam explosion loads, in which a steam explosion simulation code JASMINE was used as a physics model. The evaluation was made for three scenarios: a steam explosion in the pedestal area or in the suppression pool of a BWR model plant with Mark-II containment, and in the reactor cavity of a PWR model plant. The scenario connecting the generation of steam explosion loads and the containment failure was assumed to be displacement of the reactor vessel and pipings, and failure at the penetration in the containment boundary. We evaluated the conditional containment failure probability (CCFP) based on the preconditions of failure of molten core retention within the reactor vessel, relocation of the core melt into the water pool without significant interference, and a strong triggering at the time of maximum premixed mass. The obtained mean and median values of the CCPF were 6.4E-2 (mean) and 3.9E-2 (median) for the BWR suppression pool case, 2.2E-3 (mean) and 2.8E-10 (median) for the BWR pedestal case, and 6.8E-2 (mean) and 1.4E-2 (median) for the PWR cavity case. The evaluation of CCFPs on the basis of core damage needs consideration of probabilities for the above-mentioned preconditions. Thus, the CCFPs per core damage should be lower than the values given above. The specific values of the probability were most dependent on the assumed range of melt flow rate and fragility curve that involved conservatism and uncertainty due to simplified scenarios and limited information. Additionally, the source term significance of the fine particles generated by steam explosions was discussed.
Komuro, Yo; Hirade, Tetsuya; Suzuki, Ryoichi*; Odaira, Toshiyuki*; Muramatsu, Makoto*
Radiation Physics and Chemistry, 76(2), p.330 - 332, 2007/02
Times Cited Count:3 Percentile:25.53(Chemistry, Physical)Recently, positronium (Ps) formation mechanism in the spur is becoming clarified. Blob model, the modified Spur model, proposed by Stepanov can give information of Ps formation time. Dauwe et al. showed that S(t) curve of PMMA observed by AMOC measurement could be fitted by the blob model. The young-age broadening was found and explained with the delayed slowing down of Ps by Stuttgart group. The delayed Ps formation was shown by Suzuki et al. especially at low temperatures, because positrons can diffuse long distance to find trapped electrons. According to the blob model, Ps formation even after long diffusion of positrons might be possible even at the room temperature. Now we are trying to obtain the experimental evidence of delayed Ps formation in spur process.
Moriyama, Kiyofumi; Takagi, Seiji*; Muramatsu, Ken; Nakamura, Hideo; Maruyama, Yu*
Journal of Nuclear Science and Technology, 43(7), p.774 - 784, 2006/07
Times Cited Count:16 Percentile:74.73(Nuclear Science & Technology)The containment failure probability due to ex-vessel steam explosions was evaluated for Japanese BWR and PWR model plants. A stratified Monte Carlo technique (Latin Hypercube Sampling (LHS)) was applied for the evaluation of steam explosion loads, in which a steam explosion simulation code JASMINE was used as a physics model. The evaluation was made for three scenarios: a steam explosion in the pedestal area or in the suppression pool of a BWR model plant with a Mark-II containment, and in the reactor cavity of a PWR model plant. The scenario connecting the generation of steam explosion loads and the containment failure was assumed to be displacement of the reactor vessel and pipings, and failure at the penetration in the containment boundary. The mean conditional containment failure probabilities (CCFPs) were (mean) and (median) for the BWR suppression pool case, (mean) and (median) for the BWR pedestal case, and (mean) and (median) for the PWR cavity case. Note that the specific values of the probability are most dependent on assumed range of melt flow rates and on fragility curves that involve conservatism and uncertainty due to simplified scenarios and limited information. Also, note that these CCFPs were based on the preconditions of failure of accident termination within the reactor vessel, relocation of the core melt into the water pool at the place in question without significant interference, and a strong triggering ofa steam explosion with maximized premixed mass for the given premixing condition. The evaluation of CCFPs on the basis of core damage needs consideration of probabilities for these preconditions. Thus, the CCFPs per core damage should be lower than the values given above.
Moriyama, Kiyofumi; Takagi, Seiji; Muramatsu, Ken; Nakamura, Hideo; Maruyama, Yu
Proceedings of 2005 International Congress on Advances in Nuclear Power Plants (ICAPP '05) (CD-ROM), 9 Pages, 2005/05
The containment failure probability due to ex-vessel steam explosions were evaluated for a BWR Mk-II model plant. The evaluation was made for two scenarios: a steam explosion in the pedestal area, or in the suppression pool. A probabilistic approach, Latin Hypercube Sampling (LHS), was applied for the evaluation of steam explosion loads, in which a steam explosion simulation code JASMINE was used as a physics model. The fragility curves connecting the steam explosion loads and containment failure were developed based on simplified assumptions on the containment failure scenarios. The mean conditional probabilities of containment failure per occurrence of a steam explosion were for suppression pool and for pedestal area. Note that the results depend on the assumed range of input parameters and fragility curves that involve conservatism and simplification.
Zegers, R. G. T.*; Sumihama, Mizuki*; Ahn, D. S.*; Ahn, J. K.*; Akimune, Hidetoshi*; Asano, Yoshihiro; Chang, W. C.*; Dat, S.*; Ejiri, Hiroyasu*; Fujimura, Hisako*; et al.
Physical Review Letters, 91(9), p.092001_1 - 092001_4, 2003/08
Times Cited Count:128 Percentile:94.91(Physics, Multidisciplinary)no abstracts in English
Nakano, Takashi*; Ahn, D. S.*; Ahn, J. K.*; Akimune, Hidetoshi*; Asano, Yoshihiro; Chang, W. C.*; Date, S.*; Ejiri, Hiroyasu*; Fujimura, Hisako*; Fujiwara, Mamoru; et al.
Physical Review Letters, 91(1), p.012002_1 - 012002_4, 2003/07
Times Cited Count:1003 Percentile:99.86(Physics, Multidisciplinary)no abstracts in English
Ishikawa, Jun; Shintani, Kiyonori; Takagi, Seiji; Muramatsu, Ken
Nihon Kikai Gakkai Dai-8-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.203 - 208, 2002/00
no abstracts in English
Hirose, Jiro*; Muramatsu, Ken; Kanda, S.*; Tomishima, S.*; Takeda, Masatoshi*
Transactions of 16th International Conference on Structural Mechanics in Reactor Technology (SMiRT-16) (CD-ROM), 8 Pages, 2001/08
no abstracts in English
Oikawa, Tetsukuni; Fukushima, Seiichiro*; Takase, Hidekazu*; Uchiyama, Tomoaki*; Muramatsu, Ken
Transactions of 16th International Conference on Structural Mechanics in Reactor Technology (SMiRT-16) (CD-ROM), 8 Pages, 2001/08
no abstracts in English
*; *; *; *; *; *; Muto, Suguru*; Koizumi, Mitsuo; Osa, Akihiko; Sekine, Toshiaki; et al.
Journal of Radioanalytical and Nuclear Chemistry, 239(2), p.251 - 255, 1999/00
Times Cited Count:0 Percentile:0.01(Chemistry, Analytical)no abstracts in English
*; *; *; *; *; *; *; *; Muto, Suguru*; Koizumi, Mitsuo; et al.
Physical Review B, 58(17), p.11313 - 11321, 1998/11
Times Cited Count:5 Percentile:32.48(Materials Science, Multidisciplinary)no abstracts in English
*; *; *; *; *; *; Koizumi, Mitsuo; Osa, Akihiko; Sekine, Toshiaki; *; et al.
KURRI-TR, 0, p.102 - 106, 1996/02
no abstracts in English
*; *; *; Miura, Taichi*; Koizumi, Mitsuo; Osa, Akihiko; Sekine, Toshiaki; *; *; *; et al.
Hyperfine Interactions (C), p.396 - 399, 1996/01
no abstracts in English
Muramatsu, Toshiharu; *; Tamura, Seiji*; *; *
PNC TN941 83-06, 70 Pages, 1983/02
Flowrate seasurement of subassemblies of the reactor core was conducted under zero power and 250C conditions for the final core configuration of MK-I operation (79 fuel core S/A). The purpose of the mesurement is to comfime the change of flow distribution in reactor core due to core volume enlargement, As consequences, (1)Flowlate measurement of Subassemblies under the high flowrate condition of the main loops brought up followings: (i)Flowrates for core fuel assemblies decreased about 6.3% than the 70 fuel S/A core measurement. (ii)Flowrates of inner blanket fuel assemblies increased about 4.0% than the 70 fuel S/A core. (iii)Flowrates of all outer blanket fuel assemblies decreased about 2.5% than the 70 fuel S/A core. (2)All subassemblies flowrate under the low flowrate condition of the main loops was measured lower than the estimated values. (3)The flowrate indication at the center channed increased about 3.0% after 115 hours after steeped in sodium. This change was compasated to evaluate the subassembly flowrate as flowmeter drift.