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Igarashi, Hiroshi
JAEA-Review 2020-006, 261 Pages, 2020/09
JAEA-Review-2020-006.pdf:4.42MB
A literature review was conducted on the increase in surface area of vitrified products of HLW due to the fracturing caused by cooling during glass pouring process and by mechanical impact, from the perspective of a parameter of the radionuclide release model in the performance assessment of geological disposal system studied overseas. The review was focused on the value of surface area increase factor set as a parameter in the model, the experimental work to evaluate an increase in surface area, and how the parameters on surface area were determined based on the experimental results. The surface area obtained from the experiments executed in Japan was also discussed in comparison with the overseas studies. On the basis of the investigation, the effects of various conditions on the surface area were studied, such as a diameter of vitrified product, cooling condition during and after the glass pouring, impact on vitrified products during their handling, environment after the closure of disposal facility, and others. The causes of fracturing are associated with the phenomena or events in the waste management process such as production, transport, storage, and disposal. The surface area increase factors set in the nuclide release model of the glass and their bases were reviewed. In addition, the measured values and the experimental methods for surface increase factors published so far were compared. Accordingly, the methods for measuring surface area as the bases were identified for these factors set in the models. The causes of fracturing and features of these factors were studied with respect to the relation with the waste management process. The results from the review and assessment can contribute to the expanding the knowledge for the conservative and realistic application of these factors to performance assessment, and to the developing and upgrading of safety case as a consequence.
C from irradiated graphite materials, 1; Oxidation behaviors and the changes in pore structure of Q1 and IG-110 graphite due to the air reaction (Joint research)Fujii, Kimio
JAERI-Tech 2005-048, 108 Pages, 2005/09
JAERI-Tech-2005-048.pdf:25.05MB
The graphite-moderated power reactor was shut down in 1998 and its decommissioning program is being planned. Various graphites are used in the core of magnox-type reactors and HTTR as core-support structural materials and moderating materials of fast neutrons. For the nuclear graphite disposal, it is necessary to determine especially the treatment of long-lived nuclides, such as C which are generated in the graphite components during reactor operation. As a research, which solves the problem of the C concentration, the cooperative research is concluded between JAERI and Japan Nuclear Power Corp. in 1999, and the research for the basic data acquisition has been advanced up to the present. To find the optimum conditions for C reduction, basic data on oxidation reaction and the structure of graphite materials are indispensable. In the present experiment, we measure the air oxidation characteristics in the temperature range 450
800
C in Quality1 graphite and IG-110 graphite. Changes in pore diameter and pore size distribution due to air oxidation are discussed.
; Fujine, Sachio; Maeda, Mitsuru; Adachi, Takeo; Sakurai, Tsutomu;
Proc. of the 3rd Int. Conf. on Nuclear Fuel Reprocessing and Waste Management,Vol. 2, p.682 - 686, 1991/00
no abstracts in English
Matsui, Hiroshi; Ikezawa, Yoshio
Firumu Bajji Nyusu, 0(161), p.7 - 10, 1990/05
no abstracts in English
powdersShiba, Koreyuki; ; Ugajin, Mitsuhiro
J. Nucl. Mater., 96(3), p.255 - 260, 1981/00
Times Cited Count：6 Percentile：62.50(Materials Science, Multidisciplinary)no abstracts in English
