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Journal Articles

High temperature gas-cooled reactors

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$$^{circ}$$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.

Journal Articles

Refresh project of virtual reality system for education and training

Numata, Masaaki; Ogura, Yuichi*; Nakagawa, Yosuke; Inoue, Naoko

Dai-41-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 3 Pages, 2020/11

JAEA/ISCN is actively using a virtual reality (VR) system for training in nuclear non-proliferation safeguards and nuclear security. The VR system allows participants to experience the environment of a nuclear power plant and a research reactor in a cyber space. It is beneficial for the participants who have never been in a nuclear power plant to see how they are even virtually, in order to learn their physical protection system. Workstations of OS for VR use Windows7 and the warrantee protection period expired in March 2020. For that reason, it was decided to renew those workstations over 2019-2020. This paper will describe its planning called "Refresh Project", which aims to minimize impacts on training and visitors, as well as first year achievement.

Journal Articles

A Prospect of development and use of the virtual tour of the physical protection exercise field

Nakagawa, Yosuke; Sukegawa, Hidetoshi; Naoi, Yosuke; Inoue, Naoko; Noro, Naoko; Okuda, Masahiro

Dai-41-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 4 Pages, 2020/11

The physical protection exercise field, a facility equipped with various types of equipment such as sensors, cameras and fences that are used at nuclear facilities, is an effective tool for training on nuclear security at ISCN/JAEA, if it is carried out in-person. Due to the COVID-19 pandemic, the virtual tour of the facility is developed for the online training courses so that they could be more effective. The article explains the initial development of the virtual tour with some improvement inspired by using it on some occasions as well as a prospect of effective use of the virtual tour based on its characteristics.

Journal Articles

Investigation of countermeasure against local temperature rise in vessel cooling system in loss of core cooling test without nuclear heating

Ono, Masato; Shimizu, Atsushi; Kondo, Makoto; Shimazaki, Yosuke; Shinohara, Masanori; Tochio, Daisuke; Iigaki, Kazuhiko; Nakagawa, Shigeaki; Takada, Shoji; Sawa, Kazuhiro

Journal of Nuclear Engineering and Radiation Science, 2(4), p.044502_1 - 044502_4, 2016/10

In the loss of forced core cooling test using High Temperature engineering Test Reactor (HTTR), the forced cooling of reactor core is stopped without inserting control rods into the core and cooling by Vessel Cooling System (VCS) to verify safety evaluation codes to investigate the inherent safety of HTGR be secured by natural phenomena to make it possible to design a severe accident free reactor. The VCS passively removes the retained residual heat and the decay heat from the core via the reactor pressure vessel by natural convection and thermal radiation. In the test, the local temperature was supposed to exceed the limit from the viewpoint of long-term use at the uncovered water cooling tube by thermal reflectors in the VCS, although the safety of reactor is kept. Through a cold test, which was carried out by non-nuclear heat input from gas circulators with stopping water flow in the VCS, the local higher temperature position was specified although the temperature was sufficiently lower than the maximum allowable working temperature, and natural circulation of water had insufficient cooling effect on the temperature of water cooling tube below 1$$^{circ}$$C. Then, a new safe and secured procedure for the loss of forced core cooling test was established, which will be carried out soon after the restart of HTTR.

Journal Articles

Investigation of characteristics of natural circulation of water in vessel cooling system in loss of core cooling test without nuclear heating

Takada, Shoji; Shimizu, Atsushi; Kondo, Makoto; Shimazaki, Yosuke; Shinohara, Masanori; Seki, Tomokazu; Tochio, Daisuke; Iigaki, Kazuhiko; Nakagawa, Shigeaki; Sawa, Kazuhiro

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 5 Pages, 2015/05

In the loss of forced core cooling test using High Temperature engineering Test Reactor (HTTR), the forced cooling of reactor core is stopped without inserting control rods into the core and cooling by Vessel Cooling System (VCS) to demonstrate the inherent safety of HTGR be secured by natural phenomena to make it possible to design a severe accident free reactor. In the test, the local temperature was supposed to exceed the limit from the viewpoint of long-term use at the uncovered water cooling tube by thermal reflectors in the VCS, although the safety of reactor is kept. The local higher temperature position was specified although the temperature was sufficiently lower than the maximum allowable working temperature, and natural circulation of water had insufficient cooling effect on the temperature of water cooling tube below 1$$^{circ}$$C. Then, a new safe and secured procedure for the loss of forced core cooling test was established, which will be carried out soon after the restart of HTTR.

JAEA Reports

Reconfirmation of facilities/instruments integrity by cold test of HTTR

Ono, Masato; Shinohara, Masanori; Iigaki, Kazuhiko; Tochio, Daisuke; Nakagawa, Shigeaki; Shimazaki, Yosuke

JAEA-Technology 2013-042, 45 Pages, 2014/01

JAEA-Technology-2013-042.pdf:10.51MB

In HTTR, it has passed about two years since the last performance confirmation test. During two years, the integrity of active equipment, leakage efficiency of coolant pressure boundary of piping and vessel and control system performance due to influence of damage and deterioration by earthquake and aging were not confirmed. To confirm them, the cold test by using HTTR was conducted and the system performances such as above mentioned items were evaluated by comparing with the plant data obtained by the past cold test. In the result, no abnormity was found in all the data in the cooling system of HTTR, and it was confirmed that the integrity of facilities and instruments of HTTR was maintained in good condition.

JAEA Reports

Pre-investigation of thermal load fluctuation test of the heat utilization system using the HTTR, 2

Tochio, Daisuke; Saito, Kenji; Shimazaki, Yosuke; Nakagawa, Shigeaki

JAEA-Technology 2011-033, 43 Pages, 2012/02

JAEA-Technology-2011-033.pdf:16.44MB

Thermal load fluctuation test of the heat utilization system using the HTTR are planned in order to demonstrate the reactor system stability in the case of thermal load fluctuation of the heat utilization system in the HTGR hydrogen production system. In the previous report, the investigation on the ACL fan stopping tests were conducted, and it was confirmed that the tests can be conducted under several conditions and provide the data needed to verify the plant dynamics simulation code for future HTGR. In this report, the investigations on the ACL pressurized water flow rate fluctuation tests were conducted. As the result, it is confirmed that the ACL pressurized water flow rate fluctuation tests can be conducted under several conditions and provide the data needed to verify the plant dynamics simulation code for future HTGR.

JAEA Reports

Pre-investigation of thermal load fluctuation test of the heat utilization system using the HTTR

Tochio, Daisuke; Saito, Kenji; Shimazaki, Yosuke; Nakagawa, Shigeaki

JAEA-Technology 2011-018, 43 Pages, 2011/06

JAEA-Technology-2011-018.pdf:2.44MB

In the HTTR, safety demonstration tests are performed after the first criticality achieved in 1998. Thermal load fluctuation test of the heat utilization system using the HTTR are planned in order to demonstrate reactor system stability in the case of thermal load fluctuation of the heat utilization system in HTGR hydrogen production system. So pre-investigations of thermal-load fluctuation tests using the HTTR are conducted to investigate the available test condition. As the result, it is confirmed that the ACL fan stopping tests can be conducted under a condition and provide the data needed to verify the plant dynamics simulation code for future HTGR.

Journal Articles

Pulse radiolysis study on free radical scavenger edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one), 2; A Comparative study on edaravone derivatives

Hata, Kuniki; Lin, M.; Katsumura, Yosuke*; Muroya, Yusa*; Fu, H. Y.*; Yamashita, Shinichi; Nakagawa, Hidehiko*

Journal of Radiation Research, 52(1), p.15 - 23, 2011/01

 Times Cited Count:18 Percentile:61.61(Biology)

JAEA Reports

Preliminary study on HTTR tests for development of commercial HTGRs

Goto, Minoru; Takamatsu, Kuniyoshi; Nakagawa, Shigeaki; Ueta, Shohei; Hamamoto, Shimpei; Ohashi, Hirofumi; Furusawa, Takayuki; Saito, Kenji; Shimazaki, Yosuke; Nishihara, Tetsuo

JAEA-Technology 2009-053, 48 Pages, 2009/10

JAEA-Technology-2009-053.pdf:3.41MB

Preliminary studies on the HTTR (High Temperature engineering Test Reactor) tests were conducted to obtain characteristics and demonstration data which were required to develop commercial HTGRs (high temperature gas-cooled reactors). The tests proposed in this study are as follows: nuclear heat supply characteristics tests, burned core tests, reactivity insertion tests, safety demonstration tests, fuel characteristics tests, annular core tests, fuel failure tests, tritium measurement tests, and health confirmation tests of high temperature equipments. Requirements for a development of commercial HTGRs and confirmation methods of the requirements by the HTTR tests were summarized. Preliminary analyses were performed for the burned core test and the safety demonstration test to obtain prediction data, which is compared with experimental data. Additionally, a feasibility analysis was performed on four types annular cores, which is composed of the HTTR's fresh fuels, from the point of view of shutdown margin and excess reactivity.

Journal Articles

Measurements of neutron capture cross section of $$^{237}$$Np for fast neutrons

Harada, Hideo; Nakamura, Shoji; Hatsukawa, Yuichi; Toh, Yosuke; Kimura, Atsushi; Ishiwatari, Yuki*; Yasumi, Atsushi*; Mabuchi, Yukio*; Nakagawa, Tsutomu*; Okamura, Kazuo*; et al.

Journal of Nuclear Science and Technology, 46(5), p.460 - 468, 2009/05

 Times Cited Count:4 Percentile:32.89(Nuclear Science & Technology)

The neutron capture cross section of $$^{237}$$Np has been measured for fast neutrons supplied at the center of the core in the Yayoi reactor. The activation method was used for the measurement, in which the amount of the product $$^{238}$$Np was determined by $$gamma$$-ray spectroscopy using a Ge detector. The representative neutron energy and the corresponding capture cross section of $$^{237}$$Np in the experiment were analytically deduced as 0.80 $$pm$$ 0.04 b at 0.214 $$pm$$ 0.009 MeV from the measured reaction rate by combining the energy dependence of the cross section in the nuclear data library ENDF/VII.0. The deduced cross section of $$^{237}$$Np at the representative neutron energy agrees with the evaluated data of ENDF/B-VII.0, but shows 15% larger value than that of JENDL-3.3 and 13% larger value than that of JENDL/AC-2008.

Journal Articles

Pulse radiolysis study on free radical scavenger edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one)

Lin, M.; Katsumura, Yosuke; Hata, Kuniki; Muroya, Yusa*; Nakagawa, Keiichi*

Journal of Photochemistry and Photobiology B; Biology, 89(1), p.36 - 43, 2007/11

Journal Articles

Free radical scavenger edaravone suppresses X-ray-induced apoptosis through p53 inhibition in MOLT-4 cells

Sasano, Nakashi*; Enomoto, Atsushi*; Hosoi, Yoshio*; Katsumura, Yosuke; Matsumoto, Yoshihisa*; Shiraishi, Kenshiro*; Miyagawa, Kiyoshi*; Igaki, Hiroshi*; Nakagawa, Keiichi*

Journal of Radiation Research, 48(6), p.495 - 503, 2007/11

 Times Cited Count:18 Percentile:51.76(Biology)

Oral presentation

A Study on antioxidative capacity of edaravone and its derivatives by pulse radiolysis

Hata, Kuniki; Katsumura, Yosuke; Lin, M.; Muroya, Yusa*; Kudo, Hisaaki*; Nakagawa, Keiichi*; Nakagawa, Hidehiko*

no journal, , 

no abstracts in English

Oral presentation

Study on fast-neutron capture cross section by an activation method

Nakamura, Shoji; Toh, Yosuke; Kimura, Atsushi; Hatsukawa, Yuichi; Harada, Hideo; Ishiwatari, Yuki*; Saito, Isao*; Yasumi, Atsushi*; Mabuchi, Yukio*; Nakagawa, Tsutomu*; et al.

no journal, , 

no abstracts in English

Oral presentation

A Study on antioxidative property of edaravone derivatives by pulse radiolysis

Hata, Kuniki; Katsumura, Yosuke; Lin, M.; Muroya, Yusa*; Fu, H.*; Kudo, Hisaaki*; Nakagawa, Keiichi*; Nakagawa, Hidehiko*

no journal, , 

The reactivity of edaravone with some oxidative radicals ($$^{.}$$OH, N$$_{3}$$$$^{.}$$, Br$$_{2}$$$$^{.-}$$, SO$$_{4}$$$$^{.-}$$, CClO$$_{3}$$O$$_{2}$$$$^{.}$$) has been measured by pulse radiolysis. The reaction product of edaravone with $$^{.}$$OH was different from those with other radicals. The rate constants of edaravone derivatives with $$^{.}$$OH have also been determined by both direct measurement and a competition method using CO$$_{3}$$$$^{2-}$$ and DMPO as competitors.

Oral presentation

A Study on free radical scavenging properties of edaravone and its derivatives by pulse radiolysis

Hata, Kuniki; Katsumura, Yosuke; Lin, M.; Muroya, Yusa*; Fu, H.*; Kudo, Hisaaki*; Nakagawa, Keiichi*; Nakagawa, Hidehiko*

no journal, , 

Oral presentation

A Study on the reactivity of Edaravone with oxidative radicals by pulse radiolysis

Hata, Kuniki; Katsumura, Yosuke; Lin, M.; Muroya, Yusa*; Kudo, Hisaaki*; Nakagawa, Keiichi*; Nakagawa, Hidehiko*

no journal, , 

Edaravone, 3-methyl-1-phenyl-2-pyrazolin-5-one, is a newly developed free radical scavenger that has been approved in Japan as a neuroprotective drug since 2001. In the present work, the transient intermediates and the reactivity of edaravone towards $$^{.}$$OH, N$$_{3}$$$$^{.}$$, Br$$_{2}$$$$^{.-}$$, SO$$_{4}$$$$^{.-}$$, and CCl$$_{3}$$O$$_{2}$$$$^{.}$$ are investigated by pulse radiolysis techniques. The oxidation of edaravone by N$$_{3}$$$$^{.}$$, Br$$_{2}$$$$^{.-}$$, SO$$_{4}$$$$^{.-}$$, and CCl$$_{3}$$O$$_{2}$$$$^{.}$$ results in an absorption band with $$lambda$$$$_{max}$$ = 345 nm ($$varepsilon$$$$_{345nm}$$ = 2600 M$$^{-1}$$cm$$^{-1}$$), which is assigned to the edaravone radical formed by H-abstraction or electron transfer. However, the transient species produced by the reaction of edaravone with $$^{.}$$OH radical shows an absorption band with $$lambda$$$$_{max}$$ = 320 nm ($$varepsilon$$$$_{320nm}$$ = 4900 M$$^{-1}$$cm$$^{-1}$$). Accordingly, the main transient species by the reaction of edaravone with $$^{.}$$OH radical in the absence of O$$_{2}$$ is attributed to OH-adducts. The rate constants of edaravone reacting with $$^{.}$$OH, N$$_{3}$$$$^{.}$$, SO$$_{4}$$$$^{.-}$$, and CCl$$_{3}$$O$$_{2}$$$$^{.}$$ are estimated to be 8.5$$times$$10$$^{9}$$, 5.4$$times$$10$$^{9}$$, 6.0$$times$$10$$^{8}$$, and 5.1$$times$$10$$^{8}$$ M$$^{-1}$$s$$^{-1}$$, respectively.

Oral presentation

Measurement of neutron capture cross section of $$^{237}$$Np for fast neutrons

Harada, Hideo; Nakamura, Shoji; Hatsukawa, Yuichi; Toh, Yosuke; Kimura, Atsushi; Ishiwatari, Yuki*; Yasumi, Atsushi*; Mabuchi, Yukio*; Nakagawa, Tsutomu*; Oka, Yoshiaki*

no journal, , 

Neutron capture cross section of $$^{237}$$Np for fast neutrons has been measured using an activation method. A small amount of $$^{237}$$Np sample was irradiated in the Grazing hole of the Yayoi reactor. The neutron flux at the irradiation point was monitored by Au activation foil. The duduced neutron capture cross section was compared with those in nuclear data libraries JENDL-3.3 and ENDF/B-VII.0.

Oral presentation

A Study on the reactivity of edaravone derivatives by pulse radiolysis

Hata, Kuniki; Katsumura, Yosuke; Lin, M.; Muroya, Yusa*; Fu, H.*; Kudo, Hisaaki*; Nakagawa, Keiichi*; Nakagawa, Hidehiko*

no journal, , 

no abstracts in English

40 (Records 1-20 displayed on this page)