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Sakaba, Nariaki; Ohashi, Hirofumi; Sato, Hiroyuki; Hara, Teruo; Kato, Ryoma; Kunitomi, Kazuhiko
Nihon Genshiryoku Gakkai Wabun Rombunshi, 7(3), p.242 - 256, 2008/09
Nuclear hydrogen production is necessary in an anticipated hydrogen society that demands 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 MW that 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. The paper describes 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 that integrates three separate functions of sulphuric acid decomposer, sulphur trioxide decomposer and process heat exchanger in the previous design. A new mixer-settler type of Bunsen reactor is also designed that integrates three separate functions of Bunsen reactor, phase separator, and pump in the previous design. 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.
Hara, Teruo; Sakaba, Nariaki; Sato, Hiroyuki; Ohashi, Hirofumi; Tachibana, Yukio; Kunitomi, Kazuhiko
JAEA-Technology 2008-020, 28 Pages, 2008/03
JAEA-Technology-2008-020.pdf:5.69MB
Since nuclear hydrogen production system should be economically competitive compared with other hydrogen production methods, it is important to reduce the construction cost of the IS process hydrogen production plant. Japan Atomic Energy Agency (JAEA) has started the conceptual design study of components in the IS process hydrogen production system to be connected with the HTTR (HTTR-IS system). This paper describes the additional proposal for the mixer-Settler type Bunsen reactor and combined sulphuric acid decomposer of the HTTR-IS system which enhances their performance and enables reduction of fabrication cost. The enhancements of the mixing and separating performance in the Bunsen reactor using static mixers with microbubble and dams, and minimizing the size of the combined sulphuric acid decomposer by optimizing its flow path remarkably contribute to the size reduction of components.
Sakaba, Nariaki; Sato, Hiroyuki; Hara, Teruo; Kato, Ryoma; Ohashi, Kazutaka; Nishihara, Tetsuo; Kunitomi, Kazuhiko
JAEA-Research 2007-058, 31 Pages, 2007/08
JAEA-Research-2007-058.pdf:16.44MB
Since hydrogen produced by nuclear should be competitiveness economically compared by other method in a hydrogen society, it is important to built hydrogen production system to be coupled with the reactor as a conventional chemical plant. Japan Atomic Energy Agency started the safety study to establish a new safety philosophy with safety requirements and with considering non-nuclear grade hydrogen production system for the nuclear coupling system. Also, structural concepts with integrating functions for the Bunsen reactor and sulphuric acid decomposer were proposed to reduce construction cost of the IS process hydrogen production system. In addition, HI decomposer which enabled the process condition to be eased and could adopt conventional materials and technologies was studied. Moreover, basic approval of the HTTR-IS system in which the hydrogen production rate of 1,000 Nm
/h by using the supplied heat of 10 MW from the intermediate heat exchanger of the HTTR was confirmed. This paper describes the conceptual design of the HTTR-IS hydrogen production system.
Homma, Hiroyuki; Sato, Hiroyuki; Kasahara, Seiji; Ohashi, Hirofumi; Hara, Teruo; Kato, Ryoma; Sakaba, Nariaki
JAEA-Technology 2007-006, 60 Pages, 2007/02
JAEA-Technology-2007-006.pdf:15.91MB
At the present time, we are alarmed by depletion of fossil energy and adverse effect of rapid increase in fossil fuel burning on environment such as climate changes and acid rain, because our lives depend still heavily upon fossil energy. It is thus widely recognized that hydrogen is one of important future energy carriers in which it is used without emission of carbon dioxide greenhouse gas and atmospheric pollutants and that hydrogen demand will increase greatly as fuel cells are developed and applied widely in the near future. To meet massive demand of hydrogen, hydrogen production from water utilizing nuclear, especially by thermochemical water-splitting Iodine-Sulphur (IS) process utilizing heat from High-Temperature Gas-cooled Reactors (HTGRs), offers one of the most attractive zero-emission energy strategies and the only one practical on a substantial scale. However, to establish a technology based for the HTGR hydrogen production by the IS process, we should close several technology gaps through R&D with the High-Temperature Engineering Test Reactor (HTTR), which is the only Japanese HTGR built and operated at the Oarai Research & Development Centre of Japan Atomic Energy Agency (JAEA). We have launched design studies of the IS process hydrogen production system coupled with the HTTR (HTTR-IS system) to demonstrate HTGR hydrogen production. In designing the HTTR-IS system, it is necessary to consider preventive and breakdown maintenance against accidents occurred in the IS process as a chemical plant. This report describes case study on chemical plant accidents relating to the IS process plant and shows a proposal of accident protection measures based on above case study, which is necessary for flow-sheet design of the HTTR-IS System.
Kunitomi, Kazuhiko; Takeda, Takeshi; ; Okubo, Minoru; ; ;
Nihon Genshiryoku Gakkai-Shi, 38(8), p.665 - 672, 1996/00
Times Cited Count：1 Percentile：14.12(Nuclear Science & Technology)no abstracts in English
Yamamoto, Yoichi; Mukaiyama, Takehiko; ; ;
Dai-14-Kai Kaku Busshitsu Kanri Gakkai (INMN) Nihon Shibu Nenji Taikai Rombunshu, p.131 - 137, 1993/11
no abstracts in English
Sakaba, Nariaki; Hara, Teruo; Sato, Hiroyuki; Nishihara, Tetsuo; Kunitomi, Kazuhiko
no journal, ,
no abstracts in English
Sakaba, Nariaki; Kato, Ryoma; Hara, Teruo; Sato, Hiroyuki; Nishihara, Tetsuo; Kunitomi, Kazuhiko
no journal, ,
This paper describes the conceptual design of the HTTR-IS hydrogen production system.
