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Tamakuma, Yuki*; Yamada, Ryohei; Iwaoka, Kazuki*; Hosoda, Masahiro*; Kuroki, Tomohiro*; Mizuno, Hiroyuki*; Yamada, Koji*; Furukawa, Masahide*; Tokonami, Shinji*
Perspectives in Science (Internet), 12, p.100414_1 - 100414_4, 2019/09
In this study, a portable radioactive plume monitor using a silicon photodiode was developed for the detection of a radioactive plume (e.g. 
I, 
Cs and 
Cs) in an emergency situation. It was found that the background count rate was proportional to ambient dose equivalent rate and the detection limit for the monitor at 20 
Sv h
as an ambient dose equivalent rate was evaluated to be 187 Bq m
using the ISO11929 method. These results suggest that the detection limit for the system can be decreased effectively by lead shielding with optimized thickness.
Wang, H.*; Miyatake, Hiroari*; Oba, Hironori; Saeki, Morihisa; Miyabe, Masabumi; Shibata, Takemasa; Iimura, Hideki
Review of Scientific Instruments, 75(10), p.3775 - 3776, 2004/10
Times Cited Count：1 Percentile：10.27(Instruments & Instrumentation)Laser-induced fluorescence spectroscopy has been employed to characterize a plume produced in nanosecond laser ablation of metallic neodymium. Kinetic energy distributions of ions and neutrals in the plume were investigated as functions of processing parameters such as laser fluence and ambient gas pressure. Population distributions of metastable levels in the ablated atoms were also measured. These investigations provide useful data for the design of a new types of resonance photo-ionization ion source and also for high-resolution laser spectroscopy.
Hayashi, Takashi; Chino, Masamichi; Yamazawa, Hiromi; Nagai, Haruyasu; Moriuchi, Shigeru*; Ishikawa, Hirohiko*; Adachi, Takashi*; Kojima, Hiromi*; Okano, Hiroshi*; Odagawa, Fumiaki*; et al.
JAERI-Tech 2001-034, 137 Pages, 2001/06
no abstracts in English
Owada, Hitoshi*; Mihara, Morihiro; *; *
JNC TN8400 2000-027, 19 Pages, 2000/08
Bactch leaching experiments of granite with the artifitial cement leachate and the leachate of low-alkalinity-cement (LW) were carried out to evaluate the effect of the hiperalkaline plume on the environment of the high-level and TRU radioactive waste repository. Dissolution of Si and Al from feldspar included in the granite and precipitation of C-S-H were confirmed from the results of the leaching experiments with artifitial cement leachate. From this result it was found that the composition of sorrounding rock changed. It also suggested that the retardation factor of migration of radionuclides would change. On the contrary, only decrease of concentrations in Si, Al and Ca in the leachate was observed in the experiment with LW. This result might indicate that C-S-H and/or C-A-S-H precipitated as secondary minerals in the LW case. From these results, it was considered that the hiperalkaline plume from the cementitious leachate might caused the change of disposal conditions such as the change in distribution coefficients of rock by precipitation of the secondary mineral and the increase in hydraulic conductivity by the dissolution of rock. On the other hand, the influences of the LW would be comparatively small, because LW and granite might equilibrate in short time.
Kato, Hiroshige*; Sato, Mitsuyoshi*; Owada, Hitoshi*; Mihara, Morihiro;
JNC TN8430 2000-008, 53 Pages, 2000/05
Cementitious materials will be used in TRU waste disposal repository. In such cases, it is considered that the migration of alkaline leachates from cementitious materials, so called high pH plume, will cause dissolution of rock and precipitation of secondary minerals. In addition, the high pH plume will move along the flow of groundwater, so it is predicted that rock formation and components of high pH groundwater vary with time and space. However, time and spatial dependence of the variations of secondary minerals and groundwater components has not been clarified. In order to acquire the data of variations of secondary minerals and groundwater components, we carried out the rock alteration experiments with column method. The crushed granodiorite was filled into 4 meters length column (
3.7 cm) and artificial cement leachate (pH=13.3; Na=0,1 mol/l, K=0.1 mol/l, Ca=0.002 mol/l) was streamed at flow rates of 0.1 ml/min for 7 months at 80
C. As the result, secondary minerals confirmed on the rock were calcite and C-S-H at upstream of column and C-S-H at mid-downstream. The pH value of the fluid dominated by Na and K did not be decreased by reaction with the rock. In this study, the data relating to the effect of high pH plume on rock over the long term was acquired.
*; *; *; Fumizawa, Motoo
5th Triennial Int. Symp. on Fluid Control,Measurement and Visualization, 2, p.887 - 892, 1997/00
no abstracts in English
*; *; Fumizawa, Motoo
Dai-9-Kai Suchi Ryutai Rikigaku Shimpojiumu Koen Rombunshu, 0, p.469 - 470, 1995/00
no abstracts in English
*; *; *; Fumizawa, Motoo
Kashika Joho Gakkai-Shi, 13(SUPPL.1), p.261 - 264, 1993/07
no abstracts in English
Fumizawa, Motoo
Kashika Joho Gakkai-Shi, 13(SUPPL.1), p.253 - 256, 1993/07
no abstracts in English
*; *; *; Iida, Takao*; *; *
PNC TJ1545 93-005, 36 Pages, 1993/03
no abstracts in English
Kitahara, Yoshihisa*; Narita, Osamu; Asano, Tomohiro; *
PNC TN841 81-01, 97 Pages, 1981/01
no abstracts in English
Miyabe, Masabumi; Oba, Masaki; Akaoka, Katsuaki; Kato, Masaaki; Wakaida, Ikuo
no journal, ,
no abstracts in English
Oba, Masaki; Miyabe, Masabumi; Akaoka, Katsuaki; Wakaida, Ikuo
no journal, ,
We used laser-induced fluorescence imaging with a varying beam focal point to observe ablation plumes from metal and oxide samples of gadolinium. The plumes expand vertically when the focal point is far from the sample surface. In contrast, the plume becomes hemispherical when the focal point is on the sample surface. In addition, the internal plume structure and the composition of the ablated atomic and ionic particles also vary significantly. The fluorescence intensity of a plume from a metal sample is greater than that from an oxide sample, which suggests that the number of monatomic species produced in each plume differs. For both the metal and oxide samples, the most intense fluorescence from atomic (ionic) species is observed with the beam focal point at 3-4 mm (2 mm) from the sample surface.
Osada, Naoyuki*; Ishizaki, Azusa; Nishizawa, Yukiyasu*; Yuki, Yoichi*; Sanada, Yukihisa
no journal, ,
no abstracts in English
Nagai, Haruyasu
no journal, ,
no abstracts in English
