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

坂場 成昭 大橋 弘史 佐藤 博之 原 輝夫 加藤 竜馬 國富 一彦

出版者

Atomic Energy Society of Japan

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.7, no.3, pp.242-256, 2008 (Released:2012-03-02)

参考文献数

30

被引用文献数

6 6

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Nuclear hydrogen production is necessary in an anticipated hydrogen society that demands a massive quantity of hydrogen without economic disadvantage. Japan Atomic Energy Agency (JAEA) has launched the conceptual design study of a hydrogen production system with a near-term plan to connect it to Japan's first high-temperature gas-cooled reactor HTTR. The candidate hydrogen production system is based on the thermochemical water-splitting iodine sulphur (IS) process. The heat of 10 MWth at approximately 900°C, which can be provided by the secondary helium from the intermediate heat exchanger of the HTTR, is the energy input to the hydrogen production system. In this paper, we describe the recent progresses made in the conceptual design of advanced process heat exchangers of the HTTR-IS hydrogen production system. A new concept of sulphuric acid decomposer is proposed. This involves the integration of three separate functions of sulphuric acid decomposer, sulphur trioxide decomposer, and process heat exchanger. A new mixer-settler type of Bunsen reactor is also designed. This integrates three separate functions of Bunsen reactor, phase separator, and pump. The new concepts are expected to result in improved economics through construction and operation cost reductions because the number of process equipment and complicated connections between the equipment has been substantially reduced.

著者

深谷 裕司 大橋 弘史 佐藤 博之 後藤 実 國富 一彦

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

pp.J21.005, (Released:2022-03-30)

参考文献数

33

被引用文献数

1

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An improvement of the electricity generation cost evaluation method for High Temperature Gas-cooled Reactors (HTGRs) has been performed. Japan Atomic Energy Agency (JAEA) had completed the commercial HTGR concept named Gas Turbine High Temperature Reactor (GTHTR300) and the electricity generation cost evaluation method approximately a decade ago. The cost evaluation was developed on the basis of the method of Federation of Electric Power Companies (FEPC). The FEPC method was markedly revised after the Fukushima Daiichi nuclear disaster. Moreover, the escalation of material and labor costs for the decade should be considered to evaluate the latest cost. Therefore, we revised the cost evaluation method for GTHTR300 and the determined cost was compared with that of the Light Water Reactor (LWR). As a result, it was found that the electricity generation cost of HTGR of 7.9 yen/kWh is cheaper than that of LWR of 11.7 yen/kWh by approximately 30% at the capacity factor of 70%.

著者

大橋 弘史 Steven R. SHERMAN

出版者

Atomic Energy Society of Japan

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.7, no.4, pp.439-451, 2008 (Released:2012-03-02)

参考文献数

21

被引用文献数

2

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Tritium migration behavior in the next-generation nuclear plant (NGNP) employing a high-temperature electrolysis (HTE) process to produce hydrogen is estimated by numerical analysis. Estimated tritium concentrations in the hydrogen product and tertiary heat transport fluid in heat exchangers in the HTE process are higher than the limit in drinking water defined by the U.S. Environmental Protection Agency (EPA) and in the effluent at the boundary of an unrestricted area defined by the U.S. Nuclear Regulatory Commission (NRC), respectively. The effects of some countermeasures (i.e., reducing tritium release rate, increasing purification system capacity, removing tritium at high-temperature positions in the heat transport fluids, reducing the permeability of heat exchangers, and hydrogen or water injection in the heat transport fluids) to reduce tritium concentrations in the hydrogen product and tertiary heat transport fluid are proposed and evaluated. The alternative countermeasure proposed in this study to decrease the tritium permeation rate by water injection, which produces HTO from HT according to an isotope exchange reaction (HT+H2O=H2+HTO) in the heat transport fluids, is effective for decreasing the tritium concentrations.

著者

坂場 成昭 佐藤 博之 大橋 弘史 西原 哲夫 國富 一彦

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 年会・大会予稿集

巻号頁・発行日

vol.2007, pp.262, 2007

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原子力機構では、HTTRに接続させる熱化学水素製造法ISプロセスの設計研究を進めている。商用段階における経済性向上のためには、HTTRに接続するISプロセスを一般化学プラントの規格基準を用いて非原子力級にて設計、製作、管理することが重要である。本報では、非原子力級化に必要となるR&D項目について述べる。