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Journal Articles

Design and actual performance of J-PARC 3 GeV rapid cycling synchrotron for high-intensity operation

Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.

Journal of Nuclear Science and Technology, 32 Pages, 2022/02

In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.

Journal Articles

Beam-loss monitoring signals of interlocked events at the J-PARC Linac

Hayashi, Naoki; Kato, Yuko; Miura, Akihiko; Futatsukawa, Kenta*; Miyao, Tomoaki*

Proceedings of 5th International Beam Instrumentation Conference (IBIC 2016) (Internet), p.368 - 371, 2017/03

It is important to understand why the beam loss occurs during user operation. It is understandable that the beam loss results from RF cavities failure. However, it would be still useful to study the beam loss detailed mechanism and to know which beam loss monitor (BLM) experiences the highest loss or is most sensitive. This may lead a reduction in the number of interlocked events and a more stable accelerator operation. The J-PARC Linac BLM has a simple data recorder that comprises multiple oscilloscopes. Although its functionality is limited, it can record events when an interlock is triggered. Of particular interest here are the events associated with only the BLM Machine Protection System (MPS). These may reveal hidden problems with the accelerator.

Journal Articles

Development of a control system at a 3 MeV linac in J-PARC

Sawabe, Yuki*; Ishiyama, Tatsuya; Takahashi, Daisuke; Kato, Yuko; Suzuki, Takahiro*; Hirano, Koichiro; Takei, Hayanori; Meigo, Shinichiro; Kikuzawa, Nobuhiro; Hayashi, Naoki

Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.647 - 651, 2016/11

In the J-PARC, a 3 MeV linac has been developed for the tests of beam scraper irradiation and charge exchange by high-power laser. To accomplish tests efficiently and safely, the control system for 3 MeV was designed and developed, and this system consists of four subsystems, personal protection system, machine protection system, timing system, and remote control system using the EPICS. In this paper, the details of control system for a 3 MeV linac are presented.

JAEA Reports

Research on engineering technology in the full-scale demonstration of EBS and operation technology for HLW disposal; Research report in 2010 (Joint research)

Nakatsuka, Noboru; Hatanaka, Koichiro; Sato, Haruo; Sugita, Yutaka; Nakayama, Masashi; Asano, Hidekazu*; Saito, Masahiko*; Suyama, Yasuhiro*; Hayashi, Hidero*; Honda, Yuko*; et al.

JAEA-Research 2013-026, 57 Pages, 2013/11

JAEA-Research-2013-026.pdf:7.48MB

JAEA and RWMC concluded the letter of cooperation agreement on the research and development of radioactive waste disposal in April, 2005, and have been carrying out the collaboration work described above based on the agreement. JAEA have been carrying out the Horonobe URL Project which is intended for a sedimentary rock in the Horonobe town, Hokkaido, since 2001. In the project, geoscientific research and research and development on geological disposal technology are being promoted. Meanwhile, the government (the Agency for Natural Resources and Energy, Ministry of Economy, Trade and Industry) has been promoting construction of equipments for the full-scale demonstration of engineered barrier system and operation technology for high-level radioactive waste (HLW) disposal since 2008, to enhance public's understanding to the geological disposal of HLW, using underground facility, etc. RWMC received an order of the project in fiscal year 2010 continuing since fiscal year 2008. Since topics in this project are included in the Horonobe URL Project, JAEA carried out this project as collaboration work continuing in FY 2008. This report summarizes the results of engineering technology carried out in this collaboration work in fiscal year 2010. In fiscal year 2010, part of the equipments for emplacement of buffer material was produced and a house for the equipments and apparatus was opened in the adjoining land of Public Information House of JAEA Horonobe.

JAEA Reports

Research on engineering technology in the full-scale demonstration of EBS and operation technology for HLW disposal; Research report in 2009 (Joint research)

Nakatsuka, Noboru; Hatanaka, Koichiro; Sato, Haruo; Sugita, Yutaka; Nakayama, Masashi; Miyahara, Shigenori; Asano, Hidekazu*; Saito, Masahiko*; Suyama, Yasuhiro*; Hayashi, Hidero*; et al.

JAEA-Research 2010-060, 50 Pages, 2011/02

JAEA-Research-2010-060.pdf:6.7MB

Japan Atomic Energy Agency (JAEA) and Radioactive Waste Management Funding and Research Center (RWMC) concluded the letter of cooperation agreement on the research and development of radioactive waste disposal in April, 2005, and have been carrying out the collaboration work described above based on the agreement. JAEA have been carrying out the Horonobe Underground Research Laboratory (URL) Project which is intended for sedimentary rock in the Horonobe town, Hokkaido, since 2001. In the project, geoscientific research and research and development on geological disposal technology are being promoted. Meanwhile, the government (the Agency for Natural Resources and Energy, Ministry of Economy, Trade and Industry) has been promoting construction of equipments for the full-scale demonstration of engineered barrier system and operation technology for high-level radioactive waste (HLW) disposal since 2008, to enhance publics understanding to the geological disposal of HLW, using underground facility, etc. RWMC received an order of the project in fiscal year 2009 (2009/2010) continuing in fiscal year 2008 (2008/2009). Since topics in this project are included in the Horonobe URL Project, JAEA carried out this project as collaboration work continuing in fiscal year 2008. This report summarizes the results of engineering technology carried out in this collaboration work in fiscal year 2009. In fiscal year 2009, a part of the equipments for equipment of buffer material and visualization test apparatus for water penetration in buffer material were produced and house for the equipments and apparatus was constructed.

JAEA Reports

Research on engineering technology in the full-scale demonstration of EBS and operation technology for HLW disposal; Research report in 2008 (Joint research)

Nakatsuka, Noboru; Hatanaka, Koichiro; Sato, Haruo; Sugita, Yutaka; Nakayama, Masashi; Miyahara, Shigenori; Asano, Hidekazu*; Saito, Masahiko*; Suyama, Yasuhiro*; Hayashi, Hidero*; et al.

JAEA-Research 2009-044, 53 Pages, 2010/01

JAEA-Research-2009-044.pdf:9.03MB

Japan Atomic Energy Agency (JAEA) and Radioactive Waste Management Funding and Research Center (RWMC) effect an agreement about research and development of high level radioactive waste (HLW) disposal and carried out research and technological development about geological disposal technology. JAEA has been carried out the Horonobe Underground Research Laboratory (URL) Project which is intended for sedimentary rock and the Project includes geoscientific research and geological disposal technology. RWMC carried out an investigation about full-scale demonstration of engineered barrier system (EBS) and operation technology for HLW disposal, under the contract with the Natural Resources and Energy Agency, Ministry of Economy, the Trade and Industry. The investigation aims to obtain the citizens' understanding of the geological disposal. This work includes the full-scale demonstration of operation technology in the Horonobe URL. This joint research is about engineering technology concerned with the work. In 2008 fiscal year (2008/2009), the master plan of the work was made, and a part of the device for transportation of engineered barrier was made, and it has begun the exhibition of full-scale bentonite block and overpack.

Journal Articles

Advanced neutron shielding material using zirconium borohydride and zirconium hydride

Hayashi, Takao; Tobita, Kenji; Nakamori, Yuko*; Orimo, Shinichi*

Journal of Nuclear Materials, 386-388, p.119 - 121, 2009/04

 Times Cited Count:64 Percentile:97.91(Materials Science, Multidisciplinary)

Neutron transport calculations have been carried out to assess the capability of zirconium borohydride (Zr(BH$$_{4}$$)$$_{4}$$) and zirconium hydride (ZrH$$_{2}$$) as advanced shield materials, because excellent shields can be used to protect outer structural materials from serious activation. The neutron shielding capability of Zr(BH$$_{4}$$)$$_{4}$$ is lower than ZrH$$_{2}$$, even though the hydrogen density of Zr(BH$$_{4}$$)$$_{4}$$ is slightly higher than that of ZrH$$_{2}$$. High-Z atoms are effective in neutron shielding as well as hydrogen atoms. The combination of steel and Zr(BH$$_{4}$$)$$_{4}$$ can improve the neutron shielding capability. The combinations of (Zr(BH$$_{4}$$)$$_{4}$$ + F82H) and (ZrH$$_{2}$$ + F82H) can reduce the thickness of the shield by 6.5% and 19% compared to (water + F82H), respectively. The neutron flux for Zr(BH$$_{4}$$)$$_{4}$$ is drastically reduced in the range of neutron energy below 100 eV compared to other materials, due to the effect of boron, which can lead to a reduction of radwaste from fusion reactors.

Journal Articles

Hydrogen retention and carbon deposition in plasma facing components and the shadowed area of JT-60U

Masaki, Kei; Tanabe, Tetsuo*; Hirohata, Yuko*; Oya, Yasuhisa*; Shibahara, Takahiro*; Hayashi, Takao; Sugiyama, Kazuyoshi*; Arai, Takashi; Okuno, Kenji*; Miya, Naoyuki

Nuclear Fusion, 47(11), p.1577 - 1582, 2007/11

 Times Cited Count:14 Percentile:48.36(Physics, Fluids & Plasmas)

In JT-60U, erosion/deposition analyses for the plasma facing wall have shown that deposition was dominant at the inner-middle first wall and the inner divertor, whereas erosion dominant at the upper first wall and the outer divertor. Assuming toroidal symmetry in the erosion and deposition patterns, the net carbon erosion and deposition in the divertor area were estimated to be 0.34 kg and 0.55 kg, respectively. In a whole, the increment of carbon in the divertor region was 0.21 kg, which should be originated from the first wall. The hydrogen concentration in the thick deposition layer of the inner divertor was 0.02 in (H+D)/C. In the plasma-shadowed area underneath the divertor region at around 420 K, re-deposited layers of 2 $$mu$$m-thick were found with high hydrogen concentration of 0.8 in (H+D)/C. The carbon deposition rate in the plasma-shadowed area, however, was 8$$times$$10$$^{19}$$ atoms/s, which was one order smaller than that (6$$times$$10$$^{20}$$ atoms/s) on the wall surface.

Journal Articles

Hydrogen retention and carbon deposition in plasma facing wall and shadowed area of JT-60U

Masaki, Kei; Tanabe, Tetsuo*; Hirohata, Yuko*; Oya, Yasuhisa*; Shibahara, Takahiro*; Hayashi, Takao; Sugiyama, Kazuyoshi*; Arai, Takashi; Okuno, Kenji*; Miya, Naoyuki

Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03

Evaluation of fuel inventory and its retention process are critical issues for a next-step fusion device, especially with carbon-based wall. In order to resolve the issues, the hydrogen retention and carbon deposition analyses for the plasma facing surfaces and plasma-shadowed area of JT-60U have been performed. In JT-60U, erosion/deposition analyses for the plasma facing wall have shown that deposition was dominant at the inner-middle first wall and the inner divertor, whereas erosion dominant at the upper first wall and the outer divertor. Assuming toroidal symmetry in the erosion and deposition patterns, the net carbon erosion and deposition in the divertor area were estimated to be 0.34 kg and 0.55 kg, respectively. In a whole, the increment of carbon in the divertor region was 0.21 kg, which should be originated from the first wall. The hydrogen concentration in the thick deposition layer of the inner divertor was $$sim$$0.02 in (H+D)/C. In the plasma-shadowed area underneath the divertor region at around 420 K, re-deposited layers of $$sim$$2$$mu$$m-thick were found with high hydrogen concentration of $$sim$$0.8 in (H+D)/C. The carbon deposition rate in the plasma-shadowed area, however, was 8$$times$$10$$^{19}$$ atoms/s, which was one order smaller than that (6$$times$$10$$^{20}$$ atoms/s) on the wall surface.

Journal Articles

$$mu$$SR study of magnetic order in La$$_{2-x}$$Ba$$_x$$CuO$$_4$$ under high pressure

Sato, Koki*; Goko, Tatsuro*; Takeshita, Satoshi*; Hayashi, Yuko*; Arai, Juichiro*; Higemoto, Wataru; Nishiyama, Kusuo*; Nagamine, Kanetada*

Physica B; Condensed Matter, 374-375, p.40 - 43, 2006/03

 Times Cited Count:4 Percentile:23.8(Physics, Condensed Matter)

We have performed muon spin relaxation and resistivity measurements under high pressure in La$$_{2-x}$$Ba$$_x$$CuO$$_4$$ with x=0.125 and 0.135. With increasing pressure, the superconducting critical temperature increases for both samples. Even by applying pressure, static magnetic order still exists. This result indicates the LTT structure is not always necessary for stabilizing the static magnetic order. However, the magnetic volume fraction estimated is reduced by applying pressure. The reduction of the magnetic volume fraction for x=0.125 is less than that for x=0.135. This means hole concentration is one of the important factors for the appearance of the static magnetic order.

Journal Articles

Neutronics assessment of advanced shield materials using metal hydride and borohydride for fusion reactors

Hayashi, Takao; Tobita, Kenji; Nishio, Satoshi; Ikeda, Kazuki*; Nakamori, Yuko*; Orimo, Shinichi*; DEMO Plant Design Team

Fusion Engineering and Design, 81(8-14), p.1285 - 1290, 2006/02

 Times Cited Count:20 Percentile:81.23(Nuclear Science & Technology)

Neutron transport calculations were carried out to evaluate the capability of metal hydrides and borohydrides as an advanced shielding material. Some hydrides indicated considerably higher hydrogen content than polyethylene and solid hydrogen. The hydrogen-rich hydrides show superior neutron shielding capability to the conventional materials. From the temperature dependence of dissociation pressure, ZrH$$_{2}$$ and TiH$$_{2}$$ can be used without releasing hydrogen at the temperature of less than 640 $$^{circ}$$C at 1 atm. ZrH$$_{2}$$ and Mg(BH$$_{4}$$)$$_{2}$$ can reduce the thickness of the shield by 30% and 20% compared to a combination of steel and water, respectively. Mixing some hydrides with F82H produces considerable effects in $$gamma$$-ray shielding. The neutron and $$gamma$$-ray shielding capabilities decrease in order of ZrH$$_{2}$$ $$>$$ Mg(BH$$_{4}$$)$$_{2}$$ and F82H $$>$$ TiH$$_{2}$$ and F82H $$>$$ water and F82H.

Journal Articles

Retention characteristics of hydrogen isotopes in JT-60U

Masaki, Kei; Sugiyama, Kazuyoshi*; Hayashi, Takao; Ochiai, Kentaro; Goto, Yoshitaka*; Shibahara, Takahiro*; Hirohata, Yuko*; Oya, Yasuhisa*; Miya, Naoyuki; Tanabe, Tetsuo*

Journal of Nuclear Materials, 337-339, p.553 - 559, 2005/03

 Times Cited Count:26 Percentile:85.9(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Soft X-ray emission and absorption spectra in the C K region of sputtered amorphous carbon films

Muramatsu, Yasuji; Hirono, Shigeru*; Umemura, Shigeru*; Ueno, Yuko*; Hayashi, Takayoshi*; Grush, M. M.*; Gullikson, E. M.*; Perera, R. C. C.*

Carbon, 39(9), p.1403 - 1407, 2001/06

 Times Cited Count:18 Percentile:58.31(Chemistry, Physical)

no abstracts in English

JAEA Reports

The First loading fuel elements and power-up for JRR-2

JRR-2 Control Office; Kambara, Toyozo; Shoda, Katsuhiko; Hirata, Yutaka; Shoji, Tsutomu; Kohayakawa, Toru; Morozumi, Minoru; Kambayashi, Yuichiro; Shitomi, Hajimu; Kokanezawa, Takashi; et al.

JAERI 1027, 57 Pages, 1962/09

JAERI-1027.pdf:4.76MB

no abstracts in English

JAEA Reports

Critical experiments and characteristic measurement for JRR-2

JRR-2 Critical Experiments Group; Kambara, Toyozo; Shoda, Katsuhiko; Hirata, Yutaka; Shoji, Tsutomu; Kohayakawa, Toru; Morozumi, Minoru; Kambayashi, Yuichiro; Shitomi, Hajimu; Kokanezawa, Takashi; et al.

JAERI 1025, 62 Pages, 1962/03

JAERI-1025.pdf:4.6MB

no abstracts in English

Oral presentation

TANPOPO (Astrobiology Exposure and Micrometeoroid Capture Experiments on ISS-JEM KIBO); Investigation of possible survivability of microorganisms in space

Yokobori, Shinichi*; Fujisaki, Kenta*; Kawaguchi, Yuko*; Yang, Y.*; Fushimi, Hidehiko*; Hashimoto, Hirofumi*; Yamashita, Masamichi*; Yano, Hajime*; Okudaira, Kyoko*; Hayashi, Nobuhiro*; et al.

no journal, , 

no abstracts in English

Oral presentation

Quest for microorganisms existing at high atmosphere and space

Yokobori, Shinichi*; Yang, Y.*; Sugino, Tomohiro*; Kawaguchi, Yuko*; Itahashi, Shiho*; Fujisaki, Kenta*; Fushimi, Hidehiko*; Hasegawa, Sunao*; Hashimoto, Hirofumi*; Hayashi, Nobuhiro*; et al.

no journal, , 

Oral presentation

Microbe space exposure experiment at International Space Station (ISS) proposed in "Tanpopo" mission

Yokobori, Shinichi*; Yang, Y.*; Sugino, Tomohiro*; Kawaguchi, Yuko*; Fushimi, Hidehiko*; Narumi, Issei; Hashimoto, Hirofumi*; Hayashi, Nobuhiro*; Kawai, Hideyuki*; Kobayashi, Kensei*; et al.

no journal, , 

Oral presentation

Tanpopo: astrobiology exposure and micrometeoroid-capture experiments; On the capture and space exposure experiments

Yokobori, Shinichi*; Yang, Y.*; Kawaguchi, Yuko*; Sugino, Tomohiro*; Takahashi, Yuta*; Narumi, Issei; Takahashi, Yuichi*; Hayashi, Nobuhiro*; Yoshimura, Yoshitaka*; Tabata, Makoto*; et al.

no journal, , 

no abstracts in English

Oral presentation

The Microbe capture experiment in space; Fluorescence microscopic detection of microbes captured by aerogel

Sugino, Tomohiro*; Yokobori, Shinichi*; Yang, Y.*; Kawaguchi, Yuko*; Hasegawa, Sunao*; Hashimoto, Hirofumi*; Imai, Eiichi*; Okudaira, Kyoko*; Kawai, Hideyuki*; Tabata, Makoto*; et al.

no journal, , 

26 (Records 1-20 displayed on this page)