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JAEA Reports

Risk communication activity which used "YUME Chisoukan" in the Horonobe Underground Research Center (FY 2018)

Nogami, Toshinobu; Hoshino, Masato; Tokunaga, Hiroaki*; Horikoshi, Hidehiko*

JAEA-Review 2020-005, 120 Pages, 2020/07

JAEA-Review-2020-005.pdf:4.31MB

Horonobe Underground Research Center managed by Japan Atomic Energy Agency (JAEA) is the Japan's best environment to understand the project of geological disposal of high-level radioactive waste, because there is an Underground Research Laboratory (URL) in the center besides an exhibition facility which explains the content of research conducted in the URL. In the area of the center, there is also an exhibition facility for the full-scale model of engineered barrier system of geological disposal. JAEA takes advantage of this opportunity to conduct public hearing including questionnaire research regarding the questions, anxieties and comments by the visitors for geological disposal project. This report summarizes the result of statistical analysis of 3,349 visitors from April 2018 to January 2019.

JAEA Reports

Risk communication activity which used "YUME Chisoukan" in the Horonobe Underground Research Center; FY2017

Nogami, Toshinobu; Hoshino, Masato; Tokunaga, Hiroaki*; Horikoshi, Hidehiko*

JAEA-Review 2019-004, 116 Pages, 2019/08

JAEA-Review-2019-004.pdf:6.89MB

Horonobe Underground Research Center managed by Japan Atomic Energy Agency (JAEA) is the Japan's best environment to understand the project of geological disposal of high-level radioactive waste, because there is an Underground Research Laboratory (URL) in the center besides an exhibition facility which explains the content of research conducted in the URL. In the area of the center, there is also an exhibition facility for the full-scale model of engineered barrier system of geological disposal. JAEA takes advantage of this opportunity to conduct public hearing including questionnaire research regarding the questions, anxieties and comments by the visitors for geological disposal project. This report summarizes the result of statistical analysis of 3,842 visitors from April 2017 to January 2018.

Journal Articles

Risk communication at Horonobe Underground Research Center, using the Public Information House and Underground Research Laboratory

Osawa, Hideaki; Nogami, Toshinobu; Hoshino, Masato; Tokunaga, Hiroaki*; Horikoshi, Hidehiko*

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 26(1), p.45 - 55, 2019/06

Japan Atomic Energy Agency has performed risk communication at Horonobe Underground Research Center, using the Public Information House and Underground Research Laboratory (URL), to promote understanding R&D of geological disposal technology and waste disposal against public. In this paper, we conducted the analysis of questionnaire investigation performing after visiting those facilities from FY2013 to FY2017. The results show that long-term safety would gain prominent attention as agita factor by growing understanding. The results also shows that visiting to those facility would become valuable experience to understand geological disposal because, for example, respondents with visiting to URL positively evaluated necessity, appropriates and safety of geological disposal, compared with those without visiting URL.

JAEA Reports

Risk communication activity which used "YUME Chisoukan" in the Horonobe Underground Research Center; 2016

Nogami, Toshinobu; Hoshino, Masato; Tokunaga, Hiroaki*; Horikoshi, Hidehiko*; Kawabata, Kazuki*

JAEA-Review 2018-003, 151 Pages, 2018/03

JAEA-Review-2018-003.pdf:3.94MB

Horonobe Underground Research Center managed by Japan Atomic Energy Agency (JAEA) is the Japan's best environment to understand the project of geological disposal of high-level radioactive waste, because there is an Underground Research Laboratory (URL) in the center besides an exhibition facility which explains the content of research conducted in the URL. In the area of the center, there is also an exhibition facility for the full-scale model of engineered barrier system of geological disposal. JAEA takes advantage of this opportunity to conduct public hearing including questionnaire research regarding the questions, anxieties and comments by the visitors for geological disposal project. This report summarizes the result of statistical analysis of 2,795 visitors from April to November in 2016.

JAEA Reports

Risk communication activity which used "YUME Chisoukan" in the Horonobe Underground Research Center; 2015

Fujiwara, Toshiyuki; Hoshino, Masato; Tokunaga, Hiroaki*; Horikoshi, Hidehiko*

JAEA-Review 2017-008, 128 Pages, 2017/07

JAEA-Review-2017-008.pdf:8.28MB

Horonobe Underground Research Center managed by Japan Atomic Energy Agency (JAEA) is the Japan's best environment to understand the project of geological disposal of high-level radioactive waste, because there is an Underground Research Laboratory (URL) in the center besides an exhibition facility which explains the content of research conducted in the URL. In the area of the center, there is also an exhibition facility for the full-scale model of engineered barrier system of geological disposal. JAEA takes advantage of this opportunity to conduct public hearing including questionnaire research regarding the questions, anxieties and comments by the visitors for geological disposal project. This report summarizes the result of statistical analysis of 2,674 visitors from April to November in 2015.

JAEA Reports

Risk communication activity which used "YUME Chisoukan" in the Horonobe Underground Research Center; FY2014

Fujiwara, Toshiyuki; Katada, Inao; Hoshino, Masato; Tokunaga, Hiroaki*; Horikoshi, Hidehiko*

JAEA-Review 2015-035, 103 Pages, 2016/03

JAEA-Review-2015-035.pdf:5.65MB

Horonobe Underground Research Center managed by Japan Atomic Energy Agency (JAEA) is the Japan's best environment to understand the project of geological disposal of high-level radioactive waste of Japan because there is an underground research laboratory (URL) in the center besides an exhibition facility which explains the content of research conducted in the URL. In the area of the center, there is also an exhibition facility for the full-scale model of engineered barrier system of geological disposal. JAEA takes advantage of this opportunity to conduct public hearing including questionnaire research regarding the questions, anxieties and comments by the visitors for geological disposal project. This report summarizes the result of statistical analysis of 2457 comments by the visitors from April to November in 2014.

Journal Articles

Progress report of Japanese simulation research projects using the high-performance computer system Helios in the International Fusion Energy Research Centre

Ishizawa, Akihiro*; Idomura, Yasuhiro; Imadera, Kenji*; Kasuya, Naohiro*; Kanno, Ryutaro*; Satake, Shinsuke*; Tatsuno, Tomoya*; Nakata, Motoki*; Nunami, Masanori*; Maeyama, Shinya*; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 92(3), p.157 - 210, 2016/03

The high-performance computer system Helios which is located at The Computational Simulation Centre (CSC) in The International Fusion Energy Research Centre (IFERC) started its operation in January 2012 under the Broader Approach (BA) agreement between Japan and the EU. The Helios system has been used for magnetised fusion related simulation studies in the EU and Japan and has kept high average usage rate. As a result, the Helios system has contributed to many research products in a wide range of research areas from core plasma physics to reactor material and reactor engineering. This project review gives a short catalogue of domestic simulation research projects. First, we outline the IFERC-CSC project. After that, shown are objectives of the research projects, numerical schemes used in simulation codes, obtained results and necessary computations in future.

JAEA Reports

Risk communication activity which used "YUME Chisoukan" in the Horonobe Underground Research Center

Abe, Shinya; Katada, Inao; Hoshino, Masato; Tokunaga, Hiroaki*; Horikoshi, Hidehiko*

JAEA-Review 2014-034, 81 Pages, 2014/11

JAEA-Review-2014-034.pdf:8.76MB

The Horonobe Underground Research Center conducts research and development to enhance the reliability of geological disposal technology, indicate the margin of technical safety for legally decided depth of repository, improve understanding of the deep geological environment, and promote greater public understanding for geological disposal technology. "YUME chisoukan" ceased its role as an exhibition facility as of end August 2012 as part of an administrative reform under the then Democratic Party rule, and came to be focused on disclosing the underground drifts to ascertain that JAEA is true to its tripartite agreement signed between the Hokkaido Prefecture, Town of Horonobe and JAEA (i.e., no nuclear materials will be used, etc.). It is also used as the facility to provide information on the research results of the Center. This report presents the statistical results of a questionnaire (2,566 responses) conducted from April to October 2013.

Journal Articles

Waste management scenario in the hot cell and waste storage for DEMO

Someya, Yoji; Tobita, Kenji; Yanagihara, Satoshi*; Kondo, Masatoshi*; Uto, Hiroyasu; Asakura, Nobuyuki; Hoshino, Kazuo; Nakamura, Makoto; Sakamoto, Yoshiteru

Fusion Engineering and Design, 89(9-10), p.2033 - 2037, 2014/10

 Times Cited Count:6 Percentile:50.1(Nuclear Science & Technology)

In the replacement period of a fusion power reactor, the assembly of blanket or divertor modules need to be removed from the reactor in order to minimize remote maintenance in the vacuum vessel and to attain a reasonable plant availability. In the hot cell, the modules will be removed from the backplate of the assembly. Here, note that the active cooling must be done by a way that does not cause contamination of the hot cell environment due to dispersion of tritium and tungsten dust. In this sense, the cooling scenario is adopted that the existing pipe of cooling water in the assembly is connected to a different cooling water system in the hot cell. In this scenario, the temperature of the assembly is maintained about 40-100$$^{circ}$$C. On the other hand, the structural material (RAFM) of the blanket and divertor is not recycled due to its high contact dose rate. It should be crushed into small pieces to reduce volume of the waste and required storage space. Here, the decay heat must be removed by natural convection to keep the temperature below 65$$^{circ}$$C for preventing water evaporation from the mortar. The RAFM is kept in the interim storage during 12 years until the required temperature conditions for mortar are ensured and then is disposed of.

Journal Articles

Development of the water cooled ceramic breeder test blanket module in Japan

Enoeda, Mikio; Tanigawa, Hisashi; Hirose, Takanori; Suzuki, Satoshi; Ochiai, Kentaro; Konno, Chikara; Kawamura, Yoshinori; Yamanishi, Toshihiko; Hoshino, Tsuyoshi; Nakamichi, Masaru; et al.

Fusion Engineering and Design, 87(7-8), p.1363 - 1369, 2012/08

 Times Cited Count:33 Percentile:93.74(Nuclear Science & Technology)

The development of a Water Cooled Ceramic Breeder (WCCB) Test Blanket Module (TBM) is being performed as one of the most important steps toward DEMO blanket in Japan. For the TBM testing and evaluation toward DEMO blanket, the module fabrication technology development by a candidate structural material, reduced activation martensitic/ferritic steel, F82H, is one of the most critical items from the viewpoint of realization of TBM testing in ITER. Fabrication of a real scale first wall, side walls, a breeder pebble bed box and assembling of the first wall and side walls have succeeded. Recently, the real scale partial mockup of the back wall was fabricated. The fabrication procedure of the back wall, whose thickness is up to 90 mm, was confirmed toward the fabrication of the real scale back wall by F82H. This paper overviews the recent achievements of the development of the WCCB TBM in Japan.

Journal Articles

Effect of sweep gas species on tritium release behavior from lithium titanate packed bed during 14MeV neutron irradiation

Kawamura, Yoshinori; Ochiai, Kentaro; Hoshino, Tsuyoshi; Kondo, Keitaro*; Iwai, Yasunori; Kobayashi, Kazuhiro; Nakamichi, Masaru; Konno, Chikara; Yamanishi, Toshihiko; Hayashi, Takumi; et al.

Fusion Engineering and Design, 87(7-8), p.1253 - 1257, 2012/08

 Times Cited Count:15 Percentile:78.3(Nuclear Science & Technology)

Tritium generation and recovery study on lithium ceramic packed bed was started by use of FNS in JAEA. Lithium titanate was selected as tritium breeding material. In this work, the effect of sweep gas species on tritium release behavior was investigated. In case of sweep by helium with 1% of hydrogen, tritium in water form was released sensitively corresponding to the irradiation. This is due to existence of the water vapor in the sweep gas. On the other hand, in case of sweep by dry helium, tritium in gaseous form was released first, and release of tritium in water form was delayed and was gradually increased.

Journal Articles

Simulation study of L/H transition with self-consistent integrated modelling of core and SOL/divertor transport

Yagi, Masatoshi; Shimizu, Katsuhiro; Takizuka, Tomonori; Honda, Mitsuru; Hayashi, Nobuhiko; Hoshino, Kazuo; Fukuyama, Atsushi*

Contributions to Plasma Physics, 52(5-6), p.372 - 378, 2012/06

 Times Cited Count:4 Percentile:20.17(Physics, Fluids & Plasmas)

Journal Articles

Self-consistent integrated modelling of core and SOL/divertor transports and simulation study on transient behavior of heat load on divertor targets

Shimizu, Katsuhiro; Takizuka, Tomonori; Hoshino, Kazuo; Honda, Mitsuru; Hayashi, Nobuhiko; Takayama, Arimichi*; Fukuyama, Atsushi*; Yagi, Masatoshi*

Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 6 Pages, 2011/03

We have developed a self-consistent integrated modelling of core and SOL/divertor transport. Thereby it enables us to investigate operation scenarios to be compatible with high confinement core plasma and detached divertor plasmas. To integrate a 1.5D core code (TOPICS-IB and TASK) and a 2D divertor code (SONIC), we introduce a new Multiple Program Multiple Data parallel computing system. For an integrated code including Monte-Carlo calculations, this system makes it possible to perform efficient simulations. The predictive simulation studies are carried out for JT-60SA with the integrated code (TOPICS-IB/SONIC) and the characteristics of the divertor heat load after the H-mode transition is clarified. We also discuss about the temporal behavior of divertor characteristics after an ELM crash.

Journal Articles

Modelling of ion kinetic effects for SOL flow formation

Takizuka, Tomonori; Hoshino, Kazuo; Shimizu, Katsuhiro; Yagi, Masatoshi*

Contributions to Plasma Physics, 50(3-5), p.267 - 272, 2010/05

 Times Cited Count:6 Percentile:26.32(Physics, Fluids & Plasmas)

The plasma flow in the scrape-off layer (SOL) plays an important role for the control of heat and particle including impurity in magnetic fusion reactors. SOL flow patterns have recently been studied by the particle simulations, and the effects of finite-orbit-size of ions are found to be essential for the flow-pattern formation. Based on these simulation results, a new model of the edge plasma flow is developed by introducing the "ion-orbit-induced flow" to the fluid equations. A tokamak plasma is divided into three regions; core region, transition layer and SOL region. The "ion-orbit-induced flow" is modeled by separating untrapped part and trapped part, and by taking account the collision effect and poloidal distribution. The "ion-orbit-induced flow" becomes large at the edge region.

Journal Articles

R&Ds of a Li$$_2$$TiO$$_3$$ pebble bed for a test blanket module in JAEA

Tanigawa, Hisashi; Hoshino, Tsuyoshi; Kawamura, Yoshinori; Nakamichi, Masaru; Ochiai, Kentaro; Akiba, Masato; Ando, Masami; Enoeda, Mikio; Ezato, Koichiro; Hayashi, Kimio; et al.

Nuclear Fusion, 49(5), p.055021_1 - 055021_6, 2009/05

 Times Cited Count:20 Percentile:64.19(Physics, Fluids & Plasmas)

This paper presents recent achievements of the research activities for the TBM being developed in JAEA, focusing on the pebble bed of the tritium breeder materials and tritium behaviour. For the breeder material, the chemical stability of Li$$_2$$TiO$$_3$$ has been improved by Li$$_2$$O additives. In order to analyze the pebble bed behaviour, thermo-mechanical properties of the Li$$_2$$TiO$$_3$$ pebble bed has been experimentally obtained. In order to verify nuclear properties of the pebble bed, the activation foil method has been proposed and a preliminary experiment has been conducted. For the tritium behaviour, the chemical densified coating method has been well developed and tritium recovery system has been modified taking account of the design change of the TBM.

Journal Articles

Development of fluorescent liquid penetrant test equipment

Yoshinaka, Kazuyuki; Otsuka, Masahiro*; Hoshino, Masato; Kikuchi, Kenji; Kawata, Tsuyoshi; Taki, Kiyotaka

Nihon Genshiryoku Gakkai Wabun Rombunshi, 7(3), p.268 - 279, 2008/09

The fluorescent liquid penetrant test equipment, for welding part in the evaporator for phosphate liquid waste generated by solvent waste treatment at Tokai reprocessing plant, was developed. It is composed of CCD camera and UV light for observation, sprinkling nozzles for fluorescent liquid, washing water and drying air, and positioning mechanism, which could be arranged position of the equipment to inspection object by 3 axes operation, insert length, bending angle and turn angle. Also, the equipment could be inserted by way of the nozzle, which inside diameter is 60 mm, into the evaporator for inspection. It was confirmed that it could be observed the standard faults, which was defined in JIS, by the equipment. Then, fluorescent liquid penetrant test for the evaporator, which has treated phosphate liquid waste for 18 years, and which heating temperature was about 105 centigrade degree, was done. As the result of the test, it was not observed fault in the evaporator.

Journal Articles

In search of zonal flows by using direct density fluctuation measurements

Nagashima, Yoshihiko*; Ito, Kimitaka*; Ito, Sanae*; Fujisawa, Akihide*; Yagi, Masatoshi*; Hoshino, Katsumichi; Shinohara, Koji; Ejiri, Akira*; Takase, Yuichi*; Ido, Takeshi*; et al.

Plasma Physics and Controlled Fusion, 49(10), p.1611 - 1625, 2007/10

 Times Cited Count:41 Percentile:81.77(Physics, Fluids & Plasmas)

It was found that the envelope of the ambient density fluctuation of the drift wave turbulence has spectral peaks aroound zonal flow frequencies. A method to detect the zonal flow using this characteristic was considered using the JFT-2M density fluctuation data. There is a possibility that the zonal flow will be able to be detected in the future burning plasmas by using the density fluctuations measured by some density fluctuation measurement by such as the microwave reflectometer and so on.

Journal Articles

Advanced studies by using the geodesic acoustic mode measurements; Experimental identification of the separatrix location and search for zonal flows from the envelope of turbulent density fluctuations

Nagashima, Yoshihiko*; Ito, Kimitaka*; Fujisawa, Akihide*; Ito, Sanae*; Yagi, Masatoshi*; Hoshino, Katsumichi; Shinohara, Koji; Ido, Takeshi*; Miura, Yukitoshi; Ejiri, Akira*; et al.

Europhysics Conference Abstracts (CD-ROM), 31F, 4 Pages, 2007/00

The recent results on the identification of the outer most magnetic surface and on the identification of the characteristic of the zonal flow are presented by using the measured data of the zonal flow which is a plasma flow in the tokamak plasma. The positon of the outermost magnetic surface was identified using the characteristic of the oscillating zonal flow called as the geodesic acoutic mode (GAM) that the mode exists only in the closed magnetic surface, and the position of the surface was in agreement with that by the magnetic equilibrium reconstruction. Some coincidence with the drift wave - zonal flow theory was obtained by using the finding that the envelope of the density fluctuation of the background turbulence is modulated by the GAM.

Journal Articles

Experimental study of nonlinear processes in edge turbulence of toroidal plasmas

Nagashima, Yoshihiko*; Hoshino, Katsumichi; Nagaoka, Kenichi*; Shinohara, Koji; Fujisawa, Akihide*; Uehara, Kazuya; Kusama, Yoshinori; Ida, Katsumi*; Yoshimura, Yasuo*; Okamura, Shoichi*; et al.

Plasma and Fusion Research (Internet), 1(9), p.041_1 - 041_15, 2006/09

Nonlinear processes between meso-scale structures and turbulent fluctuations in the edge region of the toroidal plasmas were studied using the bispectrum analysis. In the JFT-2M tokamak, divertor plasmas were investigated as well as the limiter plasmas, and the amplitude and phase of the bispectrum function of the potential fluctuation were found to be consistent with an analysis of the drift wave-zonal flow system. In the CHS machine, the edge plasmas during the H-mode were investigated. It was found that the edge potential begins to decrease before the decrease of the intensity of the deuterium line (by about 30ms), and the edge fluctuations are found to be composed of low frequency MHD fluctuations, drift wave like broad band electrostatic fluctuations and high frequency electromagnetic fluctuations. Nonlinear coupling between the MHD fluctuations and the electrostatic fluctuations or the electromagnetic fluctuations were found for the first time.

Journal Articles

Observation of coherent bicoherence and biphase in potential fluctuations around geodesic acoustic mode frequency on JFT-2M

Nagashima, Yoshihiko*; Ito, Kimitaka*; Ito, Sanae*; Hoshino, Katsumichi; Fujisawa, Akihide*; Ejiri, Akira*; Takase, Yuichi*; Yagi, Masatoshi*; Shinohara, Koji; Uehara, Kazuya; et al.

Plasma Physics and Controlled Fusion, 48(5A), p.A377 - A386, 2006/05

 Times Cited Count:21 Percentile:60.16(Physics, Fluids & Plasmas)

A bispector analysis and envelope moduration analysis of the potential oscillations of a low frequency (1kHz) oscillation, a high frequency (10-15kHz) oscillation and background turbulence are presented. The low frequency mode and the high frequency mode are considered to be a low frequency zonal flow and a geodesic acoustic mode respectively. We could found that the low frequency oscillation has a three wave interaction with the background turbulence as well as the high frequency oscillation does from the bicoherence (nonlinear coupling coefficient), biphase and envelope moduration relation. Apparently, the modulation of the high frequency mode by the low frequency mode was suggested, but it was found that the bicoherence between them is small and the modulation relation was not concluded. Therefore, it is concluded that the nonlinear interaction between the zonal flow - zonal flow system does not exist or the interaction of them is linear if any. Thus it was found that the marked nonlinear interaction occurs only in the turbulence - zonal flow system and not in the zonal flow - zonal flow system.

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