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Kudo, Tamotsu
Proceedings of 3rd Korea-Japan Joint Summer School (JSS-3) for Students and Young Researchers, p.203 - 210, 2007/08
After the TMI-2 accident, a number of experimental data on radionuclide release from fuel have been obtained in the world. However, these data were obtained under only conditions with atmospheric pressure, fuel temperature below 2900 K. And data for radionuclide release from MOX, and interactive effect of fuel oxidation and dissolution were limited. Then, the VEGA program was conducted at JAEA at pressure of 0.1 and 1.0 MPa, temperature to about 3130 K, using UO
and MOX fuels, under inert and oxidized atmosphere. The VEGA program showed that the Cs release at 1.0 MPa was smaller by about 30 % than that at atmospheric pressure, and acceleration of Cs release rate was observed above 2800 K due to foaming and melting of fuel. This article mainly describes the radionuclide release from UO and MOX fuels, and effects of fuel oxidation and dissolution.
Sawa, Kazuhiro
Proceedings of 3rd Korea-Japan Joint Summer School (JSS-3) for Students and Young Researchers, p.147 - 153, 2007/08
The high-temperature gas-cooled reactor (HTGR), which is graphite-moderated and helium-cooled, is attractive due to its unique capability of producing high temperature helium gas and its fully inherent reactor safety. In particular, hydrogen production using the nuclear heat from HTGR offers one of the most promising technological solutions to curb the rising level of CO emission. In the field of fuels and materials for HTGR, the JAEA precedes the several important research and developments. For upgrading of HTGR technologies, the JAEA has developed an extended burnup TRISO-coated fuel particle and ZrC coated particles. The JAEA also proceeds development of new graphite, C/C composite material. In parallel, in order to extend in-core life of the core components, the JAEA started to develop non-destructive evaluation method of irradiation damage by ultrasonic wave propagation and micro-indentation. This test introduces the present status of research and development for HTGR fuels and materials.