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Dipu, A. L.; Ohashi, Hirofumi; Hamamoto, Shimpei; Sato, Hiroyuki; Nishihara, Tetsuo
Annals of Nuclear Energy, 88, p.126 - 134, 2016/02
Times Cited Count：5 Percentile：43.12(Nuclear Science & Technology)The tritium concentration in the high temperature engineering test reactor (HTTR) was measured during the high temperature continuous operation for 50 days. The tritium concentration in the primary helium gas increased after startup and reached a maximum value. It then decreased slightly over the course during the normal operation phase. Decrease of concentration of tritium in primary helium gas during the normal operation phase could be attributed to the effect of tritium chemisorption on graphite. The tritium concentration in the secondary helium gas showed a peak value during the power ramp up phase. Afterwards, it decreased gradually at the end of normal power operation. It was assessed that the concentration and total quantity of tritium in the secondary helium cooling system for the HTTR-Iodine Sulfur (IS) system can be maintained below the regulatory limits, which means the hydrogen production plant can be exempt from the safety function of the nuclear facility.
Shiozawa, Shusaku; Ogawa, Masuro; Hino, Ryutaro; Onuki, Kaoru; Sakaba, Nariaki
Karyoku Genshiryoku Hatsuden, 57(1), p.7 - 12, 2006/01
no abstracts in English
Iyoku, Tatsuo; Sakaba, Nariaki; Nakagawa, Shigeaki; Tachibana, Yukio; Kasahara, Seiji; Kawasaki, Kozo
Nuclear Production of Hydrogen, p.167 - 176, 2006/00
no abstracts in English
Sakaba, Nariaki; Hirayama, Yoshiaki*
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 6 Pages, 2005/10
The high-temperature gas-cooled reactor (HTGR) is capable of producing a massive quantity of hydrogen with no carbon dioxide emission during its production by a thermo chemical IS (Iodine-Sulphur) process. The HTTR (High Temperature Engineering Test Reactor), which is the first high-temperature gas-cooled reactor in Japan, will be connected to some heat utilization system in the near future. The thermo chemical IS process is one of the progressive candidates. The metallic material of the heat transfer tube of the intermediate heat exchanger (IHX) and liner in the concentric hot gas duct in the HTTR-IS system, which allows usage in high-temperature conditions, is the nickel-based high-temperature alloy Hastelloy XR. Since the coolant helium contains small amounts of impurities, it is necessary to control the chemical composition in order to minimize corrosion of the Hastelloy XR. Major corrosion phenomena of the Hastelloy XR are carburization, decarburization, oxidation, and carbon deposition depending upon the particular gas composition and its temperature. The carburization and decarburization phenomena can be restricted by controlling the carbon activity and oxygen partial pressure. This paper describes the effect of each coolant impurity for the carburization and decarburization. Also a chemical composition limit was evaluated to avoid the Hastelloy XR corrosion.
