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Ishiguro, Katsuhiko*; Ueda, Hiroyoshi*; Wakasugi, Keiichiro*; Sakabe, Yasushi*; Kitayama, Kazumi*; Umeki, Hiroyuki; Takase, Hiroyasu*
Engineered Barrier Systems (EBS) in the Safety Case; The Role of Modelling, p.167 - 180, 2007/02
Japanese siting approach calls for volunteer host municipalities for an HLW repository and places particular emphasis on design flexibility. The repository concept should be developed to be tailored to the given siting environments. Starting from the H12 repository concept, NUMO has been examining a range of possible repository design options including EBS. The requirements and strategy of model development for performance assessment and process understanding have been discussed taking into account the step-wise, iterative process of development of repository concepts. The areas further to develop the models and databases in the long-term R&D programme have been identified as a wish list in order to evaluate a range of potential repository concepts, focusing on the near-field for the early stages of development process. Among the issues in the list, NUMO has started the development of a flexible computer code for three-dimensional mass transport model to evaluate various design options and components of the EBS. This tool has been applied for the analysis of the barrier effects of the tunnel plugs placed in fractured rock media.
-process branching at 
W revisedMohr, P.*; Shizuma, Toshiyuki; Ueda, Hiroyasu*; Goko, Shinji*; Makinaga, Ayano*; Hara, Kaoru*; Hayakawa, Takehito; Lui, Y.-W.*; Ogaki, Hideaki*; Utsunomiya, Hiroaki*
Physical Review C, 69(3), p.032801_1 - 032801_4, 2004/03
Times Cited Count：35 Percentile：84.6(Physics, Nuclear)The neutron capture cross section of the unstable s-process branching nucleus W has been derived from experimental data of the inverse 
W(
,n)W photodisintegration taken with monochromatic photon beams from laser Compton scattering. The result of 
mb at 
keV leads to a relatively high effective neutron density in the classical s process of 
. A realistic model for the s process in thermally pulsing AGB stars overestimates the abundance of Os significantly because of the relatively small neutron capture cross section of W.
Asakura, Nobuyuki; Hoshino, Kazuo; Uto, Hiroyasu; Someya, Yoji; Tokunaga, Shinsuke; Shimizu, Katsuhiro; Suzuki, Satoshi; Tobita, Kenji; Ono, Noriyasu*; Ueda, Yoshio*; et al.
no journal, ,
Radiative cooling scenario by impurity seeding has been developed and the divertor geometry, and the plasma operation have been investigated for Demo with the fusion power of 1.5 GW, using SONIC simulation. Results showed the total peak heat load is reduced to less than 10 MWm
for the total radiation power fraction of 0.7-0.8. The heat load can be handled by the water-cooling and tungsten (W) monoblock target design, provided that Cu-alloy cooling pipe is applied. The design is applied only in the divertor target. F82H cooling pipe design will be applied for the divertor baffle and dome under higher neutron flux and lower heat load condition. Heat transport analysis of the target design and cooling-water pipes showed that the divertor design can handle the heat load distribution. The conceptual design study of the Demo divertor and power exhaust is presented. Development issues of physics, engineering and plasma material interaction from ITER technology will be also discussed.
