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Hosoda, Atsushi*; Sato, Seiji*; Yamamoto, Ryuichi*; Yamamoto, Asao*; Yatake, Yoichi*
JNC TJ8400 2005-007, 145 Pages, 2005/01
We have conducted the flow and transport simulations using the 3D fracture models with large contact area of fracture faces varying the standard deviation of apertures, and studied the results. Then we have simulated the hydraulic tests for the 10 cm - square natural granite rock samples with a single fracture and compared the results with the measured transmissivity. Finally, we have analyzed the relationship of microscopic and macroscopic fluid property.
Muraoka, Tamotsu*; Sato, Seiji*; Yamamoto, Asao*; Yatake, Yoichi*; Asano, Rinichi*; Yamamoto, Ryuichi*
JNC TJ8400 2003-074, 160 Pages, 2004/01
The heterogeneity of the transmissivity and aperture in a single fracture, so called "in-plane heterogeneity", is considered to have an effect on the migration of radionuclides in a host rock of geological disposal of nuclear wastes. Aiming at better understanding of this effect for the safety assessment of geological disposal, we have improved the computer simulation code for the 3D flow and transport analysis in a single fracture developed in 2002 using the lattice Gas Automaton (LGA) method, and we have conducted the various flow and transport simulations using the 3D fracture models. Upon the improvement of the LGA code, we have investigated the macroscopic averaging method for the pseudo-4D face-centered-hypercubic (FCHC) model of 3D LGA simulation to come up with relation to map the numerical results of the LGA code onto real physical quantities such as pressure and velocity. Furthermore, we have improved the usability of the LGA code and its computational efficiency by algorithm tuning and parallel processing. We have also surveyed the results of the previous research on the in-plane heterogeneity of single fractures, examined the parameters to describe the heterogeneity, and obtained the 3D mathmatical model by S.R. Brown and P.W.J. Glover to create fractally rough synthetic fractures with these parameters reproduced well. Based on the above results, we have conducted the 3D simulations of fluid flow and mass transport in various numerically synthesized fractures. Finally, we have evaluated the effects of the parameters describing the in-plane heterogeneity on the property of fluid flow and mass transport through single fractures.
Hisada, Tsukasa*
JNC TJ7440 2002-005, 126 Pages, 2002/03
no abstracts in English
Imai, Hiroshi*; Miwa, Yuko*
JNC TJ7440 2000-003, 650 Pages, 2000/02
no abstracts in English
*; Yumoto, Ryozo; *; *; *
JNC TJ9440 99-019, 106 Pages, 1999/03
Problems were picked up by investigating how to strengthen JNC's competitive position of the fuel cycle technologies (reprocessing and MOX fabrication) in world markets. Market needs in mainly Asian countries were also investigated about plutonium utilization in light water reactors (LWRs). Legal regulations were surveyed on import, export and transport of nuclear fuels. Foreign enterprises involved in fuel reprocessing and MOX fabrication businesses were surveyed on their activities and company histories. Fundamental conditions required to a company which is going to commence and run a fuel reprocessing and MOX fuel fabrication were discussed. Technical problems were picked up concerning strengthening JNC's competitive position of reprocessing technologies by making an image of 400tons / year model plant. Cost reduction and improvement of safety are two basic indexes for pick up technical problems other indexes are simplification of process, cutting down of radioactive waste generation and so on. Accumulated amount and generation rate of spent fuels discharged from LWRs in some Asian countries were analyzed from the date of electric power consumption and share of nuclear power plant generation. Latent reprocessing demand which is caused by the pressure of big accumulations of spent fuel storage were also estimated. Then timing of commencing fuel reprocessing and MOX fuel utilizing were forecasted for Korea, Taiwan and China based on the above results.
Imai, Hiroshi*
JNC TJ7420 99-001, 619 Pages, 1999/03
no abstracts in English