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Koizumi, Satoshi; Monkenbusch, M.*; Richter, D.*; Schwahn, D.*; Farago, B.*
Journal of Chemical Physics, 121(24), p.12721 - 12731, 2004/12
Times Cited Count：57 Percentile：85.88(Chemistry, Physical)no abstracts in English
Nakashio, Nobuyuki; Nakashima, Mikio; Hirabayashi, Takakuni*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(3), p.279 - 287, 2004/09
Large-scale melting tests of simulated miscellaneous solid wastes were conducted to characterize solidified products (50L-drum size). Two heating modes were adopted in the tests: hybrid heating and induction heating modes. In the former, wastes were heated with both an induction furnace and a plasma torch, and in the latter, an electrically-conductive crucible was used with the induction furnace. Visual observation, chemical analysis and radioactivity measurements were conducted to the solidified products. It was found that the radioisotope distribution of solidified products was almost homogeneous. There was no remarkable deterioration in the solidified products subsequent to the leaching test.
Oshima, Takeshi; Lee, K. K.; Onoda, Shinobu*; Kamiya, Tomihiro; Oikawa, Masakazu*; Laird, J. S.; Hirao, Toshio; Ito, Hisayoshi
Nuclear Instruments and Methods in Physics Research B, 210, p.201 - 205, 2003/09
Times Cited Count：4 Percentile：33.7(Instruments & Instrumentation)Electrodes on SiC pn diode were studied uising Transient Ion Beam Induced Current system (TIBIC). pn junction of SiC diode was formed by phosphorus ion implantation at 800 
C and subsequent annealing at 1800 C for 1 min in Ar. Electrodes of diode were fabricated (1) Al evaporation and sintering at 850 C or (2) one more Al evaporation after the process mentioned above. TIBIC measurement using 15 MeV-O and 12 MeV-Ni ion micro beam. As the result, non-uniformity for transient current from the electrodes of diode (1)was observed. As for diode (2), such non-uniformity was not observed. On the other hand, the value of collected charges was the same for both diodes. This indicates that the quality of pn junction is the almost same for both diodes. For current-voltage characteristics, both diodes showed a order of pA at reverse bias of 30 V and turn-on at forward bias of 2V which are ideal for SiC diode. Thus, we can conclude that we obtain the information on electrical characteristics of electrodes which is not obtained from normal current-voltage measurement.
Nakashio, Nobuyuki; Nakashima, Mikio
Dekomisshoningu Giho, (26), p.45 - 55, 2002/11
Melting treatment of low-level radioactive wastes (LLW) is considered to be a promising technology for the preparation of a stable solid that will be disposed of in near surface repositories. This is because of large reduction of waste volume and production of a stable homogeneous solidified product. In the Japan Atomic Energy Research Institute (JAERI), the construction of the Waste Volume Reduction Facilities (WVRF) has been in progress since 1999. In advance of operation of the WVRF, we have been conducting melting tests of non-metallic solid wastes with the aim of establishing the optimum melting condition for preparation of a stable solid that is suitable for disposal. We have reviewed a part of the melting test conducted in our program.
*;
JNC TN8400 2001-027, 131 Pages, 2001/11
In order to document a basic manual about input data, output data, execution of computer code on groundwater flow and radionuclide transport calculation in heterogeneous porous rock, we investigated the theoretical background about geostastical computer codes and the user's manual for the computer code on groundwater flow and radionuclide transport which calculates water flow in three dimension, the path of moving radionuclide, and one dimensional radionuclide migration. In this report, based on above investigation we describe the geostastical background about simulating heterogeneous permeability field. And we describe construction of files, input and output data, a example of calculating of the programs which simulates heterogeneous permeability field, and calculates groundwater flow and radionuclide transport. Therefore, we can document a manual by investigating the theoretical background about geostastical computer codes and the user's manual for the computer code on groundwater flow and radionuclide transport calculation. And we can model heterogeneous porous rock and analyze groundwater flow and radionuclide transport by utilizing the information from this report.
; *
JNC TN8400 2001-010, 25 Pages, 2001/03
Performance assessment in geosphere for the JNC's 2nd progress report was based on nuclide migration calculation results by discrete fracture network model. The channel network model approximated from fracture network model with considering fracture connectivity was applied for nuclide migration analysis, since fracture network model had too large data to calculate nuclide migration. However, there are many options in the process of approximation from fracture network model to channel network model. In case of analyzing nuclide migration for above report, so-called "base case", one option was chosen from many options, arbitrarily. In this report, the sensitivity of these options to nuclide migration calculation results was studied. As a result, there was no significant impact to nuclide migration although connectivity of channel and flow characteristics of the model slightly changed among different options. Based on above studies, we concluded that an option used for the base case was appropriate.
*; *; *; *
JNC TJ8400 2000-006, 232 Pages, 2000/05
JNC-TJ8400-2000-006.pdf:7.75MB
In this research, simulations with some parameters which characterize ground water flow and the reliability evaluation for the expansion of the calculation method of groundwater flow were carried out by using the radionuclide transport computations in nearfield heterogeneous porous media. Concretely contents are follows: (1)With the series of calculation method for three-dimensional saturated/unsaturated groundwater flow and one-dimensional radionuclide transport. the computational analyses with the parameters used in JNC report in 2000 was carried out and the influence of the different input flux was evaluated. (2)The examination of the application for the different ways of inverse laplace transformation which is used in one-dimensional radionuclide tansport analysis code "MATRICS" was carried out. (3)The examination of the application of multi-element "MATRICS" (m-MATRICS) for radionuclide transport computations in nearfield heterogeneous porous media was carried out. (4)The series of calculation methods from three-dimensional saturated/unsaturated ground water flow simulation code to one-dimensional radionuclide transport simulation code was integrated.
*; *
JNC TJ7440 2000-004, 52 Pages, 2000/03
JNC-TJ7440-2000-004.pdf:12.62MB
no abstracts in English
*
JNC TJ7420 2000-007, 28 Pages, 2000/03
JNC-TJ7420-2000-007.pdf:11.92MB
no abstracts in English
Nagasaki, Shinya*
JNC TJ8400 2000-004, 32 Pages, 2000/02
JNC-TJ8400-2000-004.pdf:0.69MB
Equilibrium and kinetics of sorption of NpO
on illite were investigated at pH = 6 by using the differential pulse anodic stripping voltammetry method and the spectroscopic method, respectively. It was found that the sorption isotherm obtained was fitted better by the Langmuir-Freundlich type equation than by the Langmuir equation. The heterogeneity coefficient was 0.89 
0.05 and the half width at half maximum (HWHM) of affinity spectrum was 0.19 log unit, indicating that the surfacc of illite used has a low degree of heterogeneity. The kinetic spectra indicated that the sorption of NpO occurs only at the outer surfacc. The mean HWHM of the kinetic spectra was 0.18 log unit. This also proves that the sorption kinetics of NpO on the illite used is controlled by the same heterogeneity of the sorption sites. From the dependence of mean rate constants on temperature, a mean apparent activation enthalpy and a mean apparent activation entropy were evaluated at 373 kJ/mol and - 69 7 J/K
mol, respectively. This value of enthalpy suggests that the sorption is not controlled by diffusion through the hydrodynamic film around the illite. Equilibrium and kinetics of sorption of NpO and Np(V) carbonate complexes (mainly NpO
CO
) on Na-montmorillonite were also examined by using same technique.
Toida, Masaru*; Shiogama, Yukihiro*; Atsumi, Hiroyuki; Masumoto, Kazuhiko*; Yasui, Shingo*; Abe, Yasunori*; Furuichi, Mitsuaki*
JNC TJ7440 2000-006, 137 Pages, 2000/02
JNC-TJ7440-2000-006.pdf:3.55MB
no abstracts in English
Sawada, Atsushi; Ijiri, Yuji; *; Watari, Shingo
JNC TN8400 99-093, 58 Pages, 1999/11
This paper decribes the results of PA studies considering heterogeneous fracture characteristics, for the purpose of contributing for the performance assessment of the natural barrier system PA in H12 report (The second progress report on research and development for the Geological Disposal of HLW in Japan). In this study, 3-D discrete fracture network mode1 (DFN) and 1-D multiple pathways model is applied for 100m scale of rock block. Although nuclide release rate calculated by DFN are widely distributed among the realizations, it is shown that several tens realizations are enough number to understand the stochastic characteristics of the nuclide release. From the data uncertainty analysis, there are no significant effects for the nuclide retardation in fracture geometry parameters such as fracture radius, density and etc. 1-D multiple pathways model is developed with focusing on the heterogeneity of the transmissivity, which has a large effect to the nuclide retardation effects. The nuclide release rate calculated by using 1-D multiple pathways model approximates to the results of DFN. This result also shows that the relatively large fractures/faults that connects disposal tunnel and downstream faults have an important role for performance assessment in natural barrier system.
Jinno, Kenji*; Nakagawa, Kei*; *; *; Ijiri, Yuji*; *; Watari, Shingo
PNC TY1606 98-001, 54 Pages, 1998/03
no abstracts in English
Jinno, Kenji*; Nakagawa, Kei*; *; ; Ijiri, Yuji*; Watari, Shingo; Webb, E. K.*; Kanazawa, Yasuo*; Uchida, Masahiro
PNC TY1606 97-001, 44 Pages, 1997/03
no abstracts in English
