著者

大橋 弘史 佐藤 博之 國富 一彦 小川 益郎

出版者

一般社団法人 日本原子力学会

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.13, no.1, pp.17-26, 2014 (Released:2014-02-15)

参考文献数

19

被引用文献数

1 5

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A new safety concept in a high-temperature gas-cooled reactor (HTGR) was proposed to provide the most advanced nuclear reactor that exerts no harmful consequences on the people and the environment even if multiple failures in all safety systems occur. The proposed safety concept is that the consequence of the accidents is mitigated by the confinement of fission products employing not multiple physical barriers as in light water reactors, but only the cladding of fuel (i.e., the coating layers of the coated fuel particle). The progression of the events that lead to the loss or degradation of the confinement function of the coating layers (i.e., core heat up, oxidation of the coating layers, and explosion of carbon monoxide) is suppressed by only physical phenomena (i.e., the Doppler effect, thermal radiation and natural convection, formation of a protective oxide layer for coating layers of fuel, oxidation of carbon monoxide) that emerge deterministically as a cause of the events. The feasibility studies for severe events and related information revealed that the HTGR design based on this safety concept is technically feasible. This concept indicates the direction in which nuclear reactor research should be headed in terms of safety after the accident at the Fukushima Daiichi Nuclear Power Plant.

著者

深谷 裕司 國富 一彦 小川 益郎

出版者

一般社団法人 日本原子力学会

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.14, no.3, pp.189-201, 2015 (Released:2015-08-15)

参考文献数

25

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A study on reduction of potential radiotoxicity for spent fuel by using high-temperature gas-cooled reactors (HTGRs) has been performed. Unlike partitioning and transmutation (P&T), the reactor concept is investigated from the viewpoint of reduction of radiotoxicity generation itself. To reduce radiotoxicity, 238U, which generates Pu, Am and Cm, should be excluded. Therefore, we proposed HTGR fueled by new-concept fuels with alternative fuel matrixes instead of 238U. Those are yttria-stabilized zirconia (YSZ) and thorium, and the fissile material is highly enriched uranium (HEU) with an enrichment of 93%. With HEU, the radiotoxicity can be significantly reduced, and the cooling time to decay to a natural uranium level can be shortened to approximately 800 years. Fuel integrity and proliferation resistance can be maintained by dilution using YSZ, and the neutronic characteristics of self-regulation are maintained by the loading of erbium. The fuel can generate the same amount of heat as ordinary uranium fuel. The electricity generation cost is as cheap as GTHTR300. It is concluded that the proposed reactor concept can reduce the cooling time by less than 1% from 100 thousand years to 800 years without additional development of innovative technology.