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Aoyagi, Takayoshi*; *; Mihara, Morihiro; Okutsu, Kazuo*; Maeda, Munehiro*
JNC TN8400 2001-024, 103 Pages, 2001/06
JNC-TN8400-2001-024.pdf:8.84MB
In the disposal concept of TRU waste, concentrated disposal of wastes forms in large cross-section underground cavities is envisaged, because most of TRU waste is no-heat producing in spite of large generated volume as compared with HLW. In the design of engineered barrier system based on large cross-section cavities, it is necessary to consider the long-term mechanical process such as creep displacement of the host rock from the viewpoint of the stability of engineered barrier system. In this study, the long-term creep displacement of the host rock was calculated using the non-linear viscoelasticity model and the effects on the stability of engineered barrier system was evaluated. As a result, in the disposal concept of crystalline rock, no creep displacement occurred at the time after 1 milion year. On the other hand, in the disposal concept of sedimentary rock, creep displacement of 80
90mm occurred at the time after 1 milion year. Also, in this calculation, a maximum reduction of 45mm concerned with the thickness of buffer material was estimated. But these values resulted within allowance of design values. Therefore, these results show that the effects of the creep displacement on the stability of engieered barrier system would not be significant.
Koshizuka, Seiichi*; *; Okano, Yasushi; *; Yamaguchi, Akira
JNC TY9400 2000-012, 91 Pages, 2000/03
JNC-TY9400-2000-012.pdf:2.82MB
no abstracts in English
Okoshi, Minoru; Sakai, Akihiro; Yoshimori, Michiro; Yamamoto, Hideaki; Takahashi, Tomoyuki; Kimura, Hideo
Proc. of 7th Int. Conf. on Radioactive Waste Management and Environmental Remediation (ICEM'99)(CD-ROM), 8 Pages, 1999/09
no abstracts in English
; Yamaguchi, Akira
PNC TN9410 98-028, 33 Pages, 1997/12
The safety analysis of FBR plant system for sodium leak phenomena needs to evaluate the deposition of the aerosol particle to the components in the plant, the chemical reaction of aerosol to humidity in the air and the effect of the combustion heat through aerosol to the structural component. For this purpose, ABC-INTG (Aerosol Behavior in Containment-INTeGrated Version) code has been developed and used until now. This code calculates aerosol behavior in the gas area of uniform temperature and pressure by 1 cell-model. Later, however, more detailed calculation of aerosol behavior requires the installation of aerosol model into multi-cell thermal hydraulic analysis code AQUA. AQUA can calculate the carrier gas flow, temperature and the distribution of the aerosol spatial concentration. On the other hand, ABC-INTG can calculate the generation, deposition to the wall and flower, agglomeration of aerosol particle and figure out the distribution of the aerosol particle size. Thus, the combination of these two codes enables to deal with aerosol model coupling the distribution of the aerosol spatial concentration and that of the aerosol particle size. AQUA and ABC-INTG were developed separately, therefore, several subroutine were modified and composed. Especially, the interface program which exchanges data between these two codes is important to execute transient calculation. This report describes aerosol behavior model, how to install the aerosol model to AQUA and new subroutine equipped to the code. Furthermore, the test calculations of the simple structural model were executed by this code, appropriate results were obtained. Thus, this code has prospect to predict aerosol behavior by the introduction of coupling analysis with multi-dimensional gas thermo-dynamics for sodium combustion evaluation.
PNC TN9410 94-233, 264 Pages, 1994/08
A numerical method, which is represented by both time- and volume-averaged transport analysis and direct numerical simulation of turbulence, was developed for thermal striping phenomena. The phenomena are characterized by a stationary random temperature fluctuation occurring in the region immediately above the fast breeder reactor (FBR) core due to a temperature difference of the core outlet coolant between subassemblies. The thermal striping phenomena are recognized as one of the key problems from the standpoint of high-cycle thermal fatigue of the in-vessel components such as the upper core structure, flow guide tube, etc.. Fundamental experiments using water and sodium to simulate these thermal striping phenomena were calculated using the method developed in this study. Calculated results by the method were compared with the data under wide experimental conditions on the amplitude and frequency of the temperature fluctuations. Furthermore, the thermal striping phenomena in a 1:1 scale mock-up model sodium experiment simulating the outlet region of the FBR core were calculated by the method, and were compared with the calculational data. From these comparisons with the experimental data, it was confirmed that the numerical method has a sufficiently high potential in accuracy and efficiency to predict the amplitude and frequency of the temperature fluctuations related to the thermal striping phenomena. Consequently, it is concluded that the numerical prediction by the method developed in the present study can replace conventional experimental approaches using 1:1 or other scale model aiming at the simulation of the thermal striping phenomena in actual FBR plants. Furthermore, economical improvements in the FBR plants can be carried out based on the discussions of optimization and rationalization of the structural design using the numerical method.
Mukai, Masayuki; Takebe, Shinichi; Komiya, Tomokazu; Kamiyama, Hideo
JAERI-M 91-100, 17 Pages, 1991/07
no abstracts in English
JAERI-M 83-106, 55 Pages, 1983/07
no abstracts in English