Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 116

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Numerical reproduction of dissolved U concentrations in a PO$$_{4}$$-treated column study of Hanford 300 area sediment using a simple ion exchange and immobile domain model

Saito, Tatsuo; Sato, Kazuhiko; Yamazawa, Hiromi*

Journal of Environmental Radioactivity, 237, p.106708_1 - 106708_9, 2021/10

 Times Cited Count:0 Percentile:0(Environmental Sciences)

We succeeded at numerical reproduction of dissolved U concentrations from column experiments with PO$$_{4}$$-treated Hanford 300 Area sediment. The time-series curves of dissolved U concentrations under various Darcy flow rate conditions were reproduced by the numerical model in the present study through optimization of the following parameters:(i) the mass of U in mobile domain (on surface soil connected to the stream) and the rest of the total U left as precipitation in immobile domain (isolated in deep soil);(ii) the mixing ratio between immobile and mobile domains, to fit the final recovering curve of concentration; and (iii) the cation exchange capacity (CEC$$_{Zp}$$) and equilibrium constant (k$$_{Zp}$$) of the exchange reaction of UO$$_{2}$$$$^{2+}$$ and H$$^{+}$$ on simulated soil surface ($$Zp$$), to fit the transient equilibrium concentration, forming the bed of the bathtub curve.

Journal Articles

Hydrogen production using thermochemical water-splitting iodine-sulfur process test facility made of industrial structural materials; Engineering solutions to prevent iodine precipitation

Noguchi, Hiroki; Kamiji, Yu; Tanaka, Nobuyuki; Takegami, Hiroaki; Iwatsuki, Jin; Kasahara, Seiji; Myagmarjav, O.; Imai, Yoshiyuki; Kubo, Shinji

International Journal of Hydrogen Energy, 46(43), p.22328 - 22343, 2021/06

An iodine-sulfur process offers the potential for mass producing hydrogen with high-efficiency, and it uses high-temperature heat sources, including HTGR, solar heat, and waste heat of industries. R&D tasks are essential to confirm the integrity of the components that are made of industrial materials and the stability of hydrogen production in harsh working conditions. A test facility for producing hydrogen was constructed from corrosion-resistant components made of industrial materials. For stable hydrogen production, technical issues for instrumental improvements (i.e., stable pumping of the HIx solution, improving the quality control of glass-lined steel, prevention of I$$_{2}$$ precipitation using a water removal technique in a Bunsen reactor) were solved. The entire process was successfully operated for 150 h at the rate of 30 L/h. The integrity of components and the operational stability of the hydrogen production facility in harsh working conditions were demonstrated.

Journal Articles

R&D status of hydrogen production test using IS process test facility made of industrial structural material in JAEA

Noguchi, Hiroki; Takegami, Hiroaki; Kamiji, Yu; Tanaka, Nobuyuki; Iwatsuki, Jin; Kasahara, Seiji; Kubo, Shinji

International Journal of Hydrogen Energy, 44(25), p.12583 - 12592, 2019/05

 Times Cited Count:8 Percentile:46.26(Chemistry, Physical)

JAEA has been conducting R&D on thermochemical water-splitting hydrogen production IS process to develop one of heat applications of high-temperature gas-cooled reactor. A test facility was constructed using corrosion-resistant industrial materials to verify integrity of the IS process components and to demonstrate continuous and stable hydrogen production. The performance of components installed in each section was confirmed. Subsequently, a trial operation of integration of the processing sections was successfully carried out for 8 hours with hydrogen production rate of approximately 10 NL/h. After that, hydrogen production operation was extended to 31 hours (approximately hydrogen production rate of 20 NL/h) by introducing a corrosion-resistance pump system with a developed shaft seal technology.

JAEA Reports

Applied research for the establishment of radiation monitoring and evaluation of exposure dose of residence at the zone designated for reconstruction and recovery

Funaki, Hironori; Takahara, Shogo; Sasaki, Miyuki; Yoshimura, Kazuya; Nakama, Shigeo; Sanada, Yukihisa

JAEA-Research 2018-016, 48 Pages, 2019/03

JAEA-Research-2018-016.pdf:29.73MB

Cabinet Office Nuclear Emergency Response Headquarters starts to consider radiation protection in the "specific reconstruction reproduction base area" of which evacuation order will be lifted by 2023. It is essential to grab the present situations of radiation contamination and evaluate exposure dose in the area to realize the plan. Many surveys have evaluated the distributions of air dose rate and exposure dose has been estimated based on the results since the Fukushima Daiichi Nuclear Power Plant accident. Nevertheless, more detailed information on exposure is needed for the areas because its radiation level is relatively high. That is also to help make prudent evaluation plan. This study aimed to evaluate the detailed contamination situation there and estimate exposure dose with considering areal circumstances. Investigations were carried out for (1) airborne survey of air dose rate using an unmanned helicopter (2) evaluation of airborne radiocesium and (3) estimation of external/internal effective doses for typical activity patterns assumed. Additionally, we applied new methods for the airborne survey to evaluate exposure dose. Our study showed a detailed three-dimensional map of air dose rate and clarified the distribution pattern in the areas. Results of effective dose estimation suggested that the internal effective dose due to inhalation accounts for less than 1% of the external effective dose.

Journal Articles

IS process hydrogen production test for components and system made of industrial structural material, 2; H$$_{2}$$SO$$_{4}$$ decomposition, HI distillation, and HI decomposition section

Noguchi, Hiroki; Takegami, Hiroaki; Kamiji, Yu; Tanaka, Nobuyuki; Iwatsuki, Jin; Kasahara, Seiji; Kubo, Shinji

Proceedings of 8th International Topical Meeting on High Temperature Reactor Technology (HTR 2016) (CD-ROM), p.1029 - 1038, 2016/11

JAEA has been conducting R&D on the IS process for nuclear-powered hydrogen production. We have constructed a 100 NL/h-H$$_2$$-scale test apparatus made of industrial materials. At first, we investigated performance of components in this apparatus. In this paper, the test results of H$$_2$$SO$$_4$$ decomposition, HI distillation, and HI decomposition were shown. In the H$$_2$$SO$$_4$$ section, O$$_2$$ production rate is proportional to H$$_2$$SO$$_4$$ feed rate and SO$$_3$$ decomposition ratio was estimated about 80%. In HI distillation section, we confirmed to acquire a concentrated HI solution over azeotropic HI composition in the condenser. In HI decomposition section, H$$_2$$ could be produced stably by HI decomposer and decomposition ratio was about 18%. The H$$_2$$SO$$_4$$ decomposer, the HI distillation column, and the HI decomposer were workable. Based on the results added to that shown in Series I, we conducted a trial continuous operation and succeeded it for 8 hours.

Journal Articles

Assessment of amount and concentration of tritium in HTTR-IS system based on tritium behavior during high-temperature continuous operation of HTTR

Dipu, A. L.; Ohashi, Hirofumi; Hamamoto, Shimpei; Sato, Hiroyuki; Nishihara, Tetsuo

Annals of Nuclear Energy, 88, p.126 - 134, 2016/02

 Times Cited Count:4 Percentile:45.9(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.

Journal Articles

Study on operation scenario of tritium production for a fusion reactor using a high temperature gas-cooled reactor

Kawamoto, Yasuko*; Nakaya, Hiroyuki*; Matsuura, Hideaki*; Katayama, Kazunari*; Goto, Minoru; Nakagawa, Shigeaki

Fusion Science and Technology, 68(2), p.397 - 401, 2015/09

 Times Cited Count:1 Percentile:12.03(Nuclear Science & Technology)

To start up a fusion reactor, it is necessary to provide a sufficient amount of tritium from an external device. Herein, methods for supplying a fusion reactor with tritium are discussed. Use of a high temperature gas cooled reactor (HTGR) as a tritium production device has been proposed. So far, the analyses have been focused only on the operation in which fuel is periodically exchanged (batch) using the block type HTGR. In the pebble bed type HTGR, it is possible to design an operation that has no time loss for refueling. The pebble bed type HTGR (PBMR) and the block type HTGR (GTHTR300) are assumed as the calculation and comparison targets. Simulation is made using the continuous-energy Monte Carlo transport code MVPBURN. It is shown that the continuous operation using the pebble bed type HTGR has almost the same tritium productivity compared with the batch operation using the block type HGTR. The issues for pebble bed type HTGR as a tritium production device are discussed.

Journal Articles

High thermo-separation efficiency of $$^{99m}$$Tc from molten $$^{100}$$MoO$$_{3}$$ samples by repeated milking tests

Nagai, Yasuki; Kawabata, Masako; Sato, Nozomi; Hashimoto, Kazuyuki; Saeki, Hideya; Motoishi, Shoji*

Journal of the Physical Society of Japan, 83(8), p.083201_1 - 083201_4, 2014/07

 Times Cited Count:10 Percentile:62.33(Physics, Multidisciplinary)

Journal Articles

The Integral experiment on beryllium with D-T neutrons for verification of tritium breeding

Verzilov, Y. M.; Sato, Satoshi; Ochiai, Kentaro; Wada, Masayuki*; Klix, A.*; Nishitani, Takeo

Fusion Engineering and Design, 82(1), p.1 - 9, 2007/01

 Times Cited Count:8 Percentile:53.84(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Hydrogen permeation through heat transfer pipes made of Hastelloy XR during the initial 950$$^{circ}$$C operation of the HTTR

Sakaba, Nariaki; Ohashi, Hirofumi; Takeda, Tetsuaki

Journal of Nuclear Materials, 353(1-2), p.42 - 51, 2006/07

 Times Cited Count:6 Percentile:43.58(Materials Science, Multidisciplinary)

The permeation of hydrogen isotopes through the Hastelloy XR high-temperature alloy adopted for the heat transfer pipes of the intermediate heat exchanger in the HTTR, is one of the concerns in the hydrogen production system, which will be connected to the HTTR in the near future. The hydrogen permeation between the primary and secondary coolant through the Hastelloy XR was evaluated using the actual hydrogen concentration observed during the initial 950$$^{circ}$$C operation of the HTTR. The hydrogen permeability of the Hastelloy XR was estimated conservatively high as follows. The activation energy E$$_{0}$$ and pre-exponential factor F$$_{0}$$ of the permeability of hydrogen were E$$_{0}$$ = 65.8 kJ/mol and F$$_{0}$$ = 7.8$$times$$10$$^{-9}$$m$$^{3}$$(STP)/(m$$ast$$s$$ast$$Pa$$^{0.5}$$), respectively, in the temperature range from 707K to 900K.

Journal Articles

Development of control technology for the HTTR hydrogen production system

Nishihara, Tetsuo; Inagaki, Yoshiyuki

Nuclear Technology, 153(1), p.100 - 106, 2006/01

 Times Cited Count:8 Percentile:52.29(Nuclear Science & Technology)

Japan Atomic Energy Research Institute (JAERI) has performed the research and development of hydrogen production using the high temperature engineering test reactor (HTTR). One of the key issues for the HTTR hydrogen production system is the development of control technology for stable operation. A thermal load absorber concept using a steam generator installed downstream of a reformer is proposed to mitigate a variation of helium temperature. Thermal hydraulic analyses for the start up operation and the suspension of feed gas supply to the reformer are carried out. These results show that a large variation of the reformer outlet helium temperature takes place due to a change of the feed gas flow rate. However the steam generator can mitigate the variation of helium temperature. It is clarified that the HTTR can continue normal operation independently of the feed gas flow rate.

JAEA Reports

Journal Articles

Methods for tritium production rate measurement in design-oriented blanket experiments

Verzilov, Y. M.; Ochiai, Kentaro; Nishitani, Takeo

Fusion Science and Technology, 48(1), p.650 - 653, 2005/07

 Times Cited Count:7 Percentile:47.08(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Annual report on experimental operation of mock-up model test facility with a full-scale reaction tube for HTTR hydrogen production system in 2001 fiscal year (Contract research)

Hayashi, Koji; Inagaki, Yoshiyuki; Kato, Michio; Fujisaki, Katsuo*; Aita, Hideki; Takeda, Tetsuaki; Nishihara, Tetsuo; Inaba, Yoshitomo; Ohashi, Hirofumi; Katanishi, Shoji; et al.

JAERI-Tech 2005-032, 46 Pages, 2005/06

JAERI-Tech-2005-032.pdf:4.79MB

This is annual report on the experimental operation of the mock-up test facility with a full-scale reaction tube for the HTTR hydrogen production system in 2001 fiscal year. The first experimental operation was performed during two weeks from March 1, 2002 to March 13, 2002 to test on the thermal hydraulic performance of the steam reformer and also to train the operators. The thermal hydraulic performance test of the steam reformer was performed to evaluate the heat transfer characteristics between helium gas and process gas in the steam reformer. This report is summarized with an overview of the test, the results and its operation records.

Journal Articles

Evaluation of permeated hydrogen through heat transfer pipes of the intermediate heat exchanger during the initial 950$$^{circ}$$C operation of the HTTR

Sakaba, Nariaki; Matsuzawa, Takaharu*; Hirayama, Yoshiaki*; Nakagawa, Shigeaki; Nishihara, Tetsuo; Takeda, Tetsuaki

Proceedings of 2005 International Congress on Advances in Nuclear Power Plants (ICAPP '05) (CD-ROM), 8 Pages, 2005/05

The permeation of hydrogen isotopes through the Hastelloy XR high-temperature alloy adopted for the heat exchanger pipes of the intermediate heat exchanger in the HTTR (High Temperature Engineering Test Reactor) is one of the concerns in the hydrogen production system, which will be connected to the HTTR in the near future. An evaluation of the hydrogen permeation between the primary and secondary coolant through the Hastelloy XR was performed using the hydrogen concentration data observed during the initial 950$$^{circ}$$C operation of the HTTR. The hydrogen permeability of the Hastelloy XR was estimated conservatively high as follows. The activation energy E$$_{0}$$ and pre-exponential factor F$$_{0}$$ of the permeability of hydrogen were E$$_{0}$$ = 62 kJ/mol and F$$_{0}$$ = 3.6$$times$$10$$^{-5}$$ cm$$^{3}$$(NTP)/(cm s Pa$$^{0.5}$$), respectively, in the temperature range from 735K to 940K. The results implied that some oxidized film had been formed on the surface of the heat exchanger pipes of the intermediate heat exchanger.

JAEA Reports

Verification of HTTR hydrogen production system analysis code using experimental data of mock-up model test facility with a full-scale reaction tube; Cooling system of the secondary helium gas using steam generator and radiator (Contract research)

Sato, Hiroyuki; Ohashi, Hirofumi; Inaba, Yoshitomo; Maeda, Yukimasa; Takeda, Tetsuaki; Nishihara, Tetsuo; Inagaki, Yoshiyuki

JAERI-Tech 2005-014, 89 Pages, 2005/03

JAERI-Tech-2005-014.pdf:7.25MB

In a hydrogen production system using HTTR, it is required to control a secondary helium gas temperature within an allowable value at an intermediate heat exchanger (IHX) inlet to prevent a reactor scram. To mitigate thermal disturbance of the secondary helium gas caused by the hydrogen production system, a cooling system of the secondary helium gas using a steam generator(SG) and a radiator will be installed at the downstream of the chemical reactor. In order to verify a numerical analysis code of the cooling system, numerical analysis has been conducted. The pressure controllability in SG is highly affected by the heat transfer characteristics of air which flows outside of the heat exchanger tube of the radiator. In order to verify a numerical analysis code of the cooling system, the heat transfer characteristics of air has been investigated with experimental results of a mock-up model test. It was confirmed that numerical analysis results were agreed well with experimental results, and the analysis code was successfully verified.

Journal Articles

High temperature gas-cooled reactor

Tachibana, Yukio

Genshiryoku Nenkan 2005-Nen Ban, p.279 - 287, 2005/00

no abstracts in English

Journal Articles

Achievement of reactor-outlet coolant temperature of 950$$^{circ}$$C in HTTR

Fujikawa, Seigo; Hayashi, Hideyuki; Nakazawa, Toshio; Kawasaki, Kozo; Iyoku, Tatsuo; Nakagawa, Shigeaki; Sakaba, Nariaki

Journal of Nuclear Science and Technology, 41(12), p.1245 - 1254, 2004/12

 Times Cited Count:75 Percentile:97.45(Nuclear Science & Technology)

A High Temperature Gas-cooled Reactor (HTGR) is particularly attractive due to its capability of producing high-temperature helium gas and to its inherent safety characteristics. The High Temperature Engineering Test Reactor (HTTR), which is the first HTGR in Japan, achieved its rated thermal power of 30MW and reactor-outlet coolant temperature of 950$$^{circ}$$C on 19 April 2004. During the high-temperature test operation which is the final phase of the rise-to-power tests, reactor characteristics and reactor performance were confirmed, and reactor operations were monitored to demonstrate the safety and stability of operation. The reactor-outlet coolant temperature of 950$$^{circ}$$C makes it possible to extend high-temperature gas-cooled reactor use beyond the field of electric power. Also, highly effective power generation with a high-temperature gas turbine becomes possible, as does hydrogen production from water. The achievement of 950$$^{circ}$$C will be a major contribution to the actualization of producing hydrogen from water using the high-temperature gas-cooled reactors. This report describes the results of the high-temperature test operation of the HTTR.

JAEA Reports

Integral experiments for verification of tritium production on the beryllium/lithium titanate blanket mock-up with a one-breeder layer

Verzilov, Y. M.; Sato, Satoshi; Nakao, Makoto*; Ochiai, Kentaro; Wada, Masayuki*; Nishitani, Takeo

JAERI-Research 2004-015, 55 Pages, 2004/10

JAERI-Research-2004-015.pdf:3.29MB

no abstracts in English

Journal Articles

Present status of energy in Japan and HTTR project

Ogawa, Masuro; Nishihara, Tetsuo

Nuclear Engineering and Design, 233(1-3), p.5 - 10, 2004/10

 Times Cited Count:25 Percentile:83.83(Nuclear Science & Technology)

An amount of primary energy supply in Japan is increasing year by year. Much energy such as oil, coal and natural gas is imported so that the self-sufficiency ratio in Japan is only 20 % even if including nuclear energy. An amount of energy consumption is also increasing especially in commercial and resident sector and transport sector. As a result, a large amount of greenhouse gas was emitted into the environment. Nuclear energy plays the important role in energy supply in Japan. Japan Atomic Energy Research Institute (JAERI) has been carried out research and development of a hydrogen production system using a high temperature gas cooled reactor (HTGR). The HTTR project aims at the establishment of the HTGR hydrogen production system. Reactor technology of the HTGR, hydrogen production technology with thermochemical water splitting process and system integration technology between the HTGR and a hydrogen production plant are developed in the HTTR project.

116 (Records 1-20 displayed on this page)