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Miura, Akihiko
International Symposium NUCEF2005, 0 Pages, 2005/02
Based on some lessons learned from the accidents in the reprocessing plant all over the world, Japan Nuclear Cycle Development Institute (JNC) has researched and developed the safety technologies for the reprocessing plants and its related facilities. This paper describes some accidental information around the reprocessing plants and its related research activities in JNC.
Kurosawa, Susumi; Yui, Mikazu; Yoshikawa, Hideki
International Symposium NUCEF2005, 0 Pages, 2005/02
It is reported that the nuclide migration in groundwater is enhanced according to transport behavior of colloids compared with the migration behavior as the ion when the nuclide generates colloids. For example, in the colloids and radionuclide retardation experiment (CRR experiment) in the Grimusel test site in Switzerland had been performed as collaboration of JNC and NAGRA (Switzerland), the possibility that the nuclide migration was enhanced by the influence of the colloids in the groundwater was indicated. We will present on the simulations of the analysis by numerical code COLFRAC which describes colloid-facilitated solute transport in fractured media. Moreover, in order to evaluate the impact of microorganism on the performance assessment for geological disposal of HLW, we simulated effects of microorganism on radionuclide migration by using the COLFRAC code.
Kurosawa, Susumi; Yui, Mikazu; Yoshikawa, Hideki
International Symposium NUCEF2005, 0 Pages, 2005/02
On the geological disposal of high-level radioactive waste (HLW), it is known that the actinide ion which is released from the HLW generates true-colloids with hydrolysis reaction, and forms pseudo- colloids by sorption reaction onto the colloids in the groundwater. Recently, it is reported that the radionuclide migration in groundwater is enhanced by transport behavior of colloids compared with the migration behavior of the solute. For example, the in-situ experiment on the colloids and radionuclide retardation (CRR experiment) in the Grimsel test site in Switzerland had been performed by the collaboration among NAGRA (Switzerland), ENRESA (Spain), ANDRA (France), FZK-INE (Germany), USDoE/SNL (U.S.A) and JNC (Japan), the possibility of the radionuclide migration enhancement by the influence of the colloids was indicated. We will present the modeling results by numerical code COLFRAC which describes colloid-facilitated solute transport in fractured media. Moreover, in order to evaluate the impact of microorganisms on the performance assessment for geological disposal of HLW, we simulated effects of microorganism as a colloid on radionuclide migration by using the COLFRAC code.
Mikami, Satoshi; Yoshida,Tadayoshi; Takada, Chie; Tsujimura, Norio
Program and Abstract, p.78, P. 78, 2005/02
Authors began feasibility study of a hard rubber named ebonite as an activation detector for fast neutron, because it contains about 30 wt% of sulphur and of its easy handling. Characteristics of ebonite, a feasibility of it as an neutron dosemeter are investigated. According to our results, The neutron dose assessment method using an ebonite can be applied to dose reconstruction in the fields such as fuel fabrication plant and reprocessing plant etc., and to personal working there too. For easy dose assessment, the conversion factors to neutron tissue kerma from spectra were tabulated as a function of thickness of shielding of steel and concrete. The disc-shaped ebonite is one of the most useful tools to evaluate the dose induced by fast neutrons in case of criticality accident. It has the advantage of simple handling, measurements and rapid dose assessment.
Koyama, Tomozo; Sano, Yuichi; Kamiya, Masayoshi; Shibata, Atsuhiro
Program and Abstracts, p.50, P. 50, 2005/02
Small scale hot tests have been conducted with irradiated fuel pins of the experimental Fat Reactor
Hara, Akio; Tsuji, Takashi*; Hoshi, Kazuyoshi*; Yagi, Masahiko*; Nishimura, Mizue*; Kawada, Koji*; Hou, J.-Y.*
Program and Abstracts, p.65, P. 65, 2005/02
To evaluate heterogeneity of diatomaceous mudstone in Horonobe area, physical properties and lithofacies of sedimentary rocks have been estimated from natural 
ray log data and electrical micro imaging (EMI) log data. Spatial distribution of heterogeneity of sedimentary rocks has been discussed by comparison of log data acquired from several boreholes. Five sedimentary facies, A to E, have been established. Sedimentary facies A and B, which can decipher bedding planes clearly in EMI image, have been developed horizontally with low ray and high SiO
contents while sedimentary facies D, bedding planes are not clear to decipher, have been developed horizontally with high ray and low SiOcontents. The results of this study support the estimation of Hara (2004) namely the strata which characterized with high ray have been high AlO
contents and rich in terrigenous sediments such as clay minerals, on the other hand, the strata characterized with low ray have high SiOcontents and rich in diatomaceous fossils. Layered sedimentary facies can correlate between boreholes based on natural ray log and EMI log analysis. Sedimentary system and spatial distribution of strata of Horonobe area can estimate from the results of the facies correlation.
Sanada, Yukihisa; Mikami, Satoshi; Kobayashi, Hirohide; Kurimata, Tomoyuki*; Fukazawa, Satoshi*
Program and abstracts, p.77, P. 77, 2005/02
It researched concerning the method of evaluating the radionuclide discharged by using the gas monitor at a criticality accident. The measurement condition was set from the evaluation result of the -ray spectrum at a criticality accident of the use of the calculation code. The measurement system was developed in consideration of those conditions. The evaluation after three hours is possible at a criticality accident according to this system. The evaluation before three hours was examined about the method of doing the detector pulse by high-speed processing by digital oscilloscope.