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Nemoto, Takahiro; Arakawa, Ryoki; Kawakami, Satoru; Nagasumi, Satoru; Yokoyama, Keisuke; Watanabe, Masashi; Onishi, Takashi; Kawamoto, Taiki; Furusawa, Takayuki; Inoi, Hiroyuki; et al.
JAEA-Technology 2023-005, 33 Pages, 2023/05
JAEA-Technology-2023-005.pdf:5.25MB
During shut down of the HTTR (High Temperature engineering Test Reactor) RS-14 cycle, an increasing trend of filter differential pressure for the helium gas circulator was observed. In order to investigate this phenomenon, the blower of the primary helium purification system was disassembled and inspected. As a result, it is clear that the silicon oil mist entered into the primary coolant due to the deterioration of the charcoal filter performance. The replacement and further investigation of the filter are planning to prevent the reoccurrence of the same phenomenon in the future.
Takeda, Tetsuaki*; Inagaki, Yoshiyuki; Aihara, Jun; Aoki, Takeshi; Fujiwara, Yusuke; Fukaya, Yuji; Goto, Minoru; Ho, H. Q.; Iigaki, Kazuhiko; Imai, Yoshiyuki; et al.
High Temperature Gas-Cooled Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.5, 464 Pages, 2021/02
As a general overview of the research and development of a High Temperature Gas-cooled Reactor (HTGR) in JAEA, this book describes the achievements by the High Temperature Engineering Test Reactor (HTTR) on the designs, key component technologies such as fuel, reactor internals, high temperature components, etc., and operational experience such as rise-to-power tests, high temperature operation at 950
C, safety demonstration tests, etc. In addition, based on the knowledge of the HTTR, the development of designs and component technologies such as high performance fuel, helium gas turbine and hydrogen production by IS process for commercial HTGRs are described. These results are very useful for the future development of HTGRs. This book is published as one of a series of technical books on fossil fuel and nuclear energy systems by the Power Energy Systems Division of the Japan Society of Mechanical Engineers.
adsorption 
lattice defect sites of Prussian blue filled with coordination and crystallization water moleculesIshizaki, Manabu*; Akiba, Sae*; Otani, Asako*; Hoshi, Yuji*; Ono, Kenta*; Matsuba, Mayu*; Togashi, Takanari*; Kanaizuka, Katsuhiko*; Sakamoto, Masatomi*; Takahashi, Akira*; et al.
Dalton Transactions, 42(45), p.16049 - 16055, 2013/12
Times Cited Count：178 Percentile：99.58(Chemistry, Inorganic & Nuclear)We have revealed the fundamental mechanism of specific Cs adsorption into Prussian blue (PB) in order to develop high-performance PB-based Cs adsorbents in the wake of the Fukushima nuclear accident. We compared two types of PB nanoparticles with formulae of Fe
[Fe
(CN)
]3
xH
O (x = 10-15) (PB-1) and (NH)0.70Fe1.10[Fe(CN)]1.7HO (PB-2) with respect to the Cs adsorption ability. The synthesised PB-1, by a common stoichiometric aqueous reaction between 4Fe
and 3[Fe(CN)]
, showed much more efficient Cs adsorption ability than did the commercially available PB-2.
Chen, R.*; Tanaka, Hisashi*; Kawamoto, Toru*; Asai, Miyuki*; Fukushima, Chikako*; Na, H.*; Kurihara, Masato*; Watanabe, Masayuki; Arisaka, Makoto; Nankawa, Takuya
Electrochimica Acta, 87, p.119 - 125, 2013/01
Times Cited Count：108 Percentile：94.92(Electrochemistry)A novel electrochemical adsorption system using a nanoparticle film of copper (II) hexacyanoferrate (III) was proposed for selectively removing cesium from wastewater. This system can be used for cesium separation without extra chemical reagents or any filtration treatment. Cesium uptake and elution can be simply controlled by switching the applied potentials between anodes and cathodes. Data from batch kinetic studies well fitted the intraparticle diffusion equation, reflecting a two-step process: a steepest ascent portion followed by a plateau extending to the equilibrium. The effective cesium removal with a high distribution coefficient (
5
10
mL/g) can be adopted in a large pH range from 0.3 to 9.2, and in the presence of several diverse coexisting alkaline cations, suggesting it can be taken as a promising technology for actual nuclear wastewater treatment.
Chen, R.*; Tanaka, Hisashi*; Kawamoto, Toru*; Asai, Miyuki*; Fukushima, Chikako*; Kurihara, Masato*; Watanabe, Masayuki; Arisaka, Makoto; Nankawa, Takuya
Electrochemistry Communications, 25, p.23 - 25, 2012/11
Times Cited Count：50 Percentile：79.8(Electrochemistry)We first synthesized water-dispersed nanoparticle copper hexacyanoferrate (CuHCF) ink and then coated its nanoparticles on electrodes to electrochemically remove cesium from wastewater. Cesium uptake and elution can be controlled by switching the potentials between anodes and cathodes. Effective cesium removal can be adopted in a large pH range from 0.2 to 8.9, and in the presence of several diverse coexisting alkaline cations, suggesting that it can be taken as a promising technology for actual radioactive wastewater treatment. The prepared CuHCF nanoparticles can be simply and uniformly coated on electrodes by wet process like conventional printing methods, so any sizes or patterns are feasible at low cost, which indicated the potential as a promising sorption electrode of large size in the columns for sequential removal and recycle of Cs from wastewater.
Hamamoto, Shimpei; Iigaki, Kazuhiko; Shimizu, Atsushi; Sawahata, Hiroaki; Kondo, Makoto; Oyama, Sunao; Kawano, Shuichi; Kobayashi, Shoichi; Kawamoto, Taiki; Suzuki, Hisashi; et al.
JAEA-Technology 2006-030, 58 Pages, 2006/03
JAEA-Technology-2006-030.pdf:10.69MB
During normal operation of High Temperature engineering Test Reactor (HTTR) in Japan Atomic Energy Agency (JAEA), the reactivity is controlled by the Control Rods (CRs) system which consists of 32 CRs (16 pairs) and 16 Control Rod Drive Mechanisms (CRDMs). The CR system is located in stand-pipes accompanied by the Reserved Shutdown System (RSS). In the unlikely event that the CRs fail to be inserted, the RSS is provided to insert BC/C pellets into the core. The RSS shall be designed so that the reactor should be held subcriticality from any operation condition by dropping in the pellets. The RSS consists of BC/C pellets, hoppers which contain the pellets, electric plug, driving mechanisms, guide tubes and so on. In accidents when the CRs cannot be inserted, an electric plug is pulled out by a motor and the absorber pellets fall into the core by gravity. A trouble, malfunction of one RSS out of sixteen, occurred during a series of the pre-start up checks of HTTR on February 21, 2005. We investigated the cause of the RSS trouble and took countermeasures to prevent the issue. As the result of investigation, the cause of the trouble was attributed to the following reason: In the motor inside, The Oil of grease of the multiplying gear flowed down from a gap of the oil seal which has been deformed and was mixed with abrasion powder of brake disk. Therefore the adhesive mixture prevented a motor from rotating.
Tanaka, Hisashi*; Kawamoto, Toru*; Asai, Miyuki*; Fukushima, Chikako*; Kurihara, Masato*; Arisaka, Makoto; Nankawa, Takuya; Watanabe, Masayuki
no journal, ,
The adsorption/desorption of cesium, which was included in the radioactive liquid waste was controlled by electrodes which were made by nanoparticle ink of hexacyano ferrous salts. As a result, we will report the development on the recovery method which was reusable.
Tanaka, Hisashi*; Asai, Miyuki*; Fukushima, Chikako*; Kawamoto, Toru*; Kurihara, Masato*; Arisaka, Makoto; Nankawa, Takuya; Watanabe, Masayuki
no journal, ,
Copper hexacyanoferrate complex could be repetitively adsorb cesium cation in terms of electrochemical reduction and oxidation. We demonstrated the adsorption performance of the thin membrane electrode which copper hexacyanoferrate complex was formed on a metal electrode and also attempted thickening of the copper hexacyanoferrate complex layer on the electrode. The copper hexacyanoferrate complex electrochemically adsorbed about 90% of Cs from the solution by 4 times repetition of the adsorption cycle. The electrochemical efficiency of the adsorption increased 50 times by thickening of the copper hexacyanoferrate complex layer on the electrode.
Takahashi, Akira*; Kawamoto, Toru*; Tanaka, Hisashi*; Sugiyama, Yutaka*; Esaka, Fumitaka; Watanabe, Masayuki; Arisaka, Makoto; Nankawa, Takuya
no journal, ,
Inorganic composite is generally durable to radiation compared to organic materials. This type of materials would be useful for the development of adsorbents to radioactive elements from the view of the functionalization by the inorganic component. We developed adsorbents for radio-cesium by using the composites which consists of adsorbents of cesium cation and inorganic materials. As the result of the development, we successfully synthesized inorganic magnetic composites which maintain the absorbability of Cs.
Tanaka, Hisashi*; Chen, R.*; Fukushima, Chikako*; Na, H.*; Asai, Miyuki*; Kawamoto, Toru*; Kurihara, Masato*; Arisaka, Makoto; Nankawa, Takuya; Watanabe, Masayuki
no journal, ,
Hexacyanoferrate complex could repeatedly adsorb and desorb cesium by electrochemical reduction and oxidation. We have recently developed to form a film on a metal electrode in terms of nano particle of the hexacyano ferrate complex "ink". The optimum condition of the electrochemical adsorption and desorption under the acidic condition would be reported in the present study.
Tanaka, Hisashi*; Chen, R.*; Asai, Miyuki*; Fukushima, Chikako*; Kawamoto, Toru*; Ishizaki, Manabu*; Kurihara, Masato*; Arisaka, Makoto; Nankawa, Takuya; Watanabe, Masayuki
no journal, ,
Hexacyanoferrate metal Complex (MHCF) is well-known as adsorption materials for Cesium ion. We have developed the effective processing method by making MHCF of nano particle ink. In this paper, we investigated the effect of the presence of other metal cations on electrochemical adsorption and desorption of cesium.
Chen, R.*; Tanaka, Hisashi*; Fukushima, Chikako*; Asai, Miyuki*; Kawamoto, Toru*; Kurihara, Masato*; Ishizaki, Manabu*; Arisaka, Makoto; Nankawa, Takuya; Watanabe, Masayuki
no journal, ,
Transition metal hexacyanoferrates (MHCFs) are preferred to be competitive ion exchangers over other materials due to their selectivity and high capacity. CuHCF has been much used as precipitants for alkali metal cations, especially cesium, to remove them from aqueous radioactive wastes. Instated of the conventional adsorption by using copper hexacyanoferrate powder, we developed and coated the CuHCF nanoparticles on the electrode substance, and then performed Cs removal in an electrochemical column System. The objective of this study was to develop a nanoparticle film of CuHCF for Cs removal and to suggest a promising column technology for sequential removal of actual radiocesium wastewater.
Nakaya, Hiroyuki*; Matsuura, Hideaki*; Kawamoto, Yasuko*; Nagasumi, Satoru*; Katayama, Kazunari*; Goto, Minoru; Nakagawa, Shigeaki
no journal, ,
We proposed the used of High Temperature Gas-cooled Reactors (HTGR) as a tritium production device, which produces tritium by 
Li(n,
)T reaction, for initial fusion reactors. Concentrating of Li suppresses undesirable leakage of produced tritium into reactor coolant. In this study, the effect of Li concentration difference on the amount of the tritium leakage and the tritium production efficiency was investigated.
