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Watanabe, Yuki; Tsuji, Tomoya; Hirota, Seiko*; Hokama, Tomonori; Nakajima, Junya; Tsujiguchi, Takakiyo*; Kimura, Tatsuki*; Koike, Hiromi*; Nakamura, Kaori*; Kuwata, Haruka*; et al.
Hoken Butsuri (Internet), 57(1), p.54 - 64, 2022/03
no abstracts in English
Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Ishikado, Motoyuki*; Nakajima, Kenji; Kawamura, Seiko; Nakatani, Takeshi; et al.
JAEA-Conf 2015-002, p.319 - 329, 2016/02
Togo, Satoshi*; Takizuka, Tomonori*; Nakamura, Makoto; Hoshino, Kazuo; Ogawa, Yuichi*
Journal of Nuclear Materials, 463, p.502 - 505, 2015/08
Times Cited Count：9 Percentile：60.27(Materials Science, Multidisciplinary)A 1D SOL-divertor plasma simulation code introducing the anisotropic ion temperature with virtual divertor model has been developed. By introducing the anisotropic ion temperature directly, the second-derivative parallel ion viscosity term in the momentum transport equation can be excluded and the boundary condition at the divertor plate becomes unnecessary. In order to express the effects of the divertor plate and accompanying sheath implicitly, the virtual divertor model has been introduced which has an artificial sinks of particle, momentum and energy. The virtual divertor model makes the periodic boundary condition available. By using this model, SOL-divertor plasmas satisfying the Bohm condition has been successfully obtained. Also investigated are the dependence of the ion temperature anisotropy on the normalized mean free path of ion and the validity of the approximated parallel ion viscosity for the Braginskii expression and the limited one.
Hoshino, Kazuo; Asakura, Nobuyuki; Shimizu, Katsuhiro; Tokunaga, Shinsuke; Takizuka, Tomonori*; Someya, Yoji; Nakamura, Makoto; Uto, Hiroyasu; Sakamoto, Yoshiteru; Tobita, Kenji
Plasma and Fusion Research (Internet), 9(Sp.2), p.3403070_1 - 3403070_8, 2014/06
no abstracts in English
Uchida, Shunsuke; Hanawa, Satoshi; Nishiyama, Yutaka; Nakamura, Takehiko; Sato, Tomonori; Tsukada, Takashi; Kysela, J.*
Nuclear Technology, 183(1), p.119 - 135, 2013/07
Times Cited Count：5 Percentile：38.34(Nuclear Science & Technology)In-pile loop experiments are one of the key technologies which can provide an understanding of corrosion behaviors of structural materials in nuclear power plants (NPPs). The experiments should be supported not only by reliable measurement tools to confirm corrosive conditions under neutron and 
ray irradiations but also by theoretical models for extrapolating the measured data to predict corrosion behaviors in NPPs. The relationships among electrochemical corrosion potential (ECP), metal surface conditions, exposure time and other environmental conditions have been determined from in situ measurements of corrosion behaviors of stainless steel specimens exposed to H
O and O in high temperature water. Based on the relationships, a model to evaluate ECP of stainless steel was developed by coupling an electrochemical model and a double oxide layer model. Major conclusions obtained from the evaluation model are as follows. (1) The difference in ECP behaviors of the specimens exposed to HO and O were mainly from the thickness and developing rate of the inner oxide layers. (2) Calculated ECP behaviors, e.g., the different responses to HO and O and hysteresis and memory effects, agreed with the measured ones. (3) Neutron exposure might decrease ECP due to radiation-induced diffusion in the oxide layer. The ECP evaluation model will be applied to evaluation of corrosive conditions in the JMTR in-pile loop.
Ueda, Yoshio*; Oya, Kaoru*; Ashikawa, Naoko*; Ito, Atsushi*; Ono, Tadayoshi*; Kato, Daiji*; Kawashima, Hisato; Kawamura, Gakushi*; Kenmotsu, Takahiro*; Saito, Seiki*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 88(9), p.484 - 502, 2012/09
no abstracts in English
Hoshino, Kazuo; Shimizu, Katsuhiro; Asakura, Nobuyuki; Takizuka, Tomonori; Nakamura, Makoto; Tobita, Kenji
Contributions to Plasma Physics, 52(5-6), p.550 - 554, 2012/06
Times Cited Count：22 Percentile：67.57(Physics, Fluids & Plasmas)The power handling in the divertor is one of the most important issues for fusion tokamak reactor design. In this study, the effect of the divertor leg length on the power handling in the SlimCS DEMO reactor is investigated for future divertor design. The SONIC simulation shows enhancement of recycling in the outer divertor region due to effects of the long divertor leg and deep V-shaped corner. As a result, the ion and electron temperature at the outer divertor significantly decreases. In addition, peak of the Ar impurity radiation, which is located close to the outer divertor target in the standard divertor geometry, moves upstream. The former decreases the heat load to the outer divertor due to the ion conduction and convection, and the latter reduces the heat load due to the impurity radiation. The peak of the total heat load on the outer divertor decreases by about 30%.
Nakamura, Kinya*; Ogata, Takanari*; Kikuchi, Hironobu; Iwai, Takashi; Nakajima, Kunihisa; Kato, Tetsuya*; Arai, Yasuo; Uozumi, Koichi*; Hijikata, Takatoshi*; Koyama, Tadafumi*; et al.
Nihon Genshiryoku Gakkai Wabun Rombunshi, 10(4), p.245 - 256, 2011/12
Sodium-bonded metallic fuel elements were fabricated for the first time in Japan for the irradiation test in the experimental fast test reactor JOYO. U-20Pu-10Zr fuel slugs of 200 mm in length and approximately 5 mm in diameter were fabricated in a small-scale injection casting furnace. Each fuel slug was loaded into the ferritic martenstic stainless steel (PNC-FMS) cladding tube with the sodium thermal bond, thermal insulator and reflector in a helium gas atmosphere glove box. After top-end plug welding to the cladding tube and heat treatment of the welding area, each fuel element was subjected to the sodium bonding process. After the inspection such as element length, gas plenum length and helium-leak tightness, six metallic fuel elements are transported to the JOYO site for the coming irradiation test.
Nakamura, Kinya*; Ogata, Takanari*; Kikuchi, Hironobu; Iwai, Takashi; Nakajima, Kunihisa; Kato, Tetsuya*; Arai, Yasuo; Koyama, Tadafumi*; Itagaki, Wataru; Soga, Tomonori; et al.
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 8 Pages, 2011/12
CRIEPI and JAEA have fabricated sodium-bonded metallic fuel elements for the first time in Japan as a collaborative research, for use in the irradiation test at the experimental fast test reactor Joyo. The irradiation test aims to assess the irradiation behavior of the fuel and the internal wastage of the stainless-steel cladding by rare-earth fission products at a maximum cladding temperature above 873 K. U-20 wt% Pu-10 wt% Zr alloy fuel slugs of 200 mm length were fabricated in an injection-casting furnace using U metal, U-Pu alloy and Zr metal. Two types of fuel slug were fabricated, i.e., 5.05 mm and 4.95 mm in diameter, and loaded into a ferritic-martensitic stainless-steel cladding tubes, respectively. After top-end-plug welding to the cladding tube, each fuel element was subjected to sodium bonding to fill the annular gap between the fuel slug and the cladding with melted sodium. The fabrication results indicated that the characteristics of the fuel elements were within the required specifications.
Mukai, Yasunobu; Nakamura, Hironobu; Yoshimoto, Katsunobu; Tamura, Takayuki*; Iwamoto, Tomonori*
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-32-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2011/11
JNFL and JAEA are collaboratively developing an advanced solution monitoring and measurement system (ASMS) that is direct Pu measurement NDA system in the solution tank containing plutonium nitrate solution for the improvement of current safeguards subjects to be solved, and for next generation safeguards instrument. The target measurement uncertainty of ASMS is set less than 6% that is equivalent to detection level of partial defect at interim inventory verification by NDA. The ASMS detector was designed based on MCNPX calculation, and then manufactured. As an actual test, the detector was set in a process tank at Plutonium Conversion Development Facility, the calibration tests (known-alpha) for quantitative measurement was conducted. As a result, the total measurement uncertainty for Pu mass is about 3.4% except for the low liquid height region that is satisfied the target value. In addition, the monitoring capability of ASMS was confirmed.
Nakamura, Hironobu; Mukai, Yasunobu; Yoshimoto, Katsunobu; Tamura, Takayuki*; Iwamoto, Tomonori*
Proceedings of INMM 52nd Annual Meeting (CD-ROM), 9 Pages, 2011/07
JNFL and JAEA are collaboratively developing an Advanced Solution Measurement and monitoring System (ASMS) that is direct Pu measurement NDA system in the large scale solution tank containing purified plutonium nitrate for the improvement of current safeguards subjects to be solved, and for next generation safeguards instrument (NGSI). In this report, we summarize the first step results of ASMS development regarding quantitative measurement methodology. In order to establish quantitative measurement, accurate MCNPX modeling and calculations are very important and necessary. After calibration exercise implementation, we successfully obtained calibration constants (slope), and the total measurement uncertainty was about 3% for 
Pu effective mass for 2 hours measurement except for the low level region. In addition, the image of safeguards by design and collaboration of SMMS are also presented.
Mukai, Yasunobu; Nakamura, Hironobu; Hosoma, Takashi; Yoshimoto, Katsunobu; Tamura, Takayuki*; Iwamoto, Tomonori*
Proceedings of INMM 51st Annual Meeting (CD-ROM), 9 Pages, 2010/07
JNFL and JAEA are collaboratively developing an advanced solution monitoring and measurement system (ASMS) for Rokkasho Reprocessing Plant (RRP). In this study, as a second trial, we designed and fabricated a new demonstration-type detector for ASMS, then installed it to another process tank in PCDF. Using two detectors, tests for process monitoring capability were performed for several operational conditions such as sampling, bubbling, circulation, solution transfer between two tanks, followed by studies in sensitivity of monitoring and studies in stability for the duration of storage. As a result, excellent performances and advantages of ASMS compared with conventional SMMS were confirmed. It is concluded that ASMS can provide very useful information of operation status and Pu amount shared between operator and inspector. It is sure that the combination of current SMMS and the ASMS is very powerful tool to improve transparency in the future safeguards design.
Nakamura, Takahiro; Sanada, Hiroyuki; Sugita, Yutaka; Teshima, Minoru*; Kasagi, Toshio*; Kishimoto, Munemaru*; Deguchi, Tomonori*; Makuuchi, Ayumu*
JAEA-Research 2010-006, 68 Pages, 2010/06
JAEA-Research-2010-006.pdf:33.19MB
The present document is to report the result of geophysical survey by electric survey around a site proposed for the Horonobe Underground Research Laboratory Project at Horonobe-cho, Hokkaido by the Japan Atomic Energy Agency. This Electric survey using pole-pole array in Horonobe Underground Research Laboratory Area was the third survey. Resistivity distribution near surface was about 20 
m and it become to about 2 m as the depth increasing. Resistivity distribution was good agreement with existing survey results and existing electrical resistivity log data. By comparing resistivity model with hydrology model, it was confirmed that resistivity reflected the density of salinity. The range and distribution trends of apparent resistivity in this year were similar to the results of last year. It is thought that the data in which reproducibility is high is acquired in this survey. The influence on the underground water flow by construction is not admitted now.
Nakamura, Hironobu; Takaya, Akikazu; Mukai, Yasunobu; Hosoma, Takashi; Yoshimoto, Katsunobu; Tamura, Takayuki*; Iwamoto, Tomonori*
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-30-Kai Nenji Taikai Rombunshu (CD-ROM), 9 Pages, 2009/11
JNFL and JAEA have collaboratively started to develop an ASMS for RRP since 2007. The purpose of the development is to establish direct plutonium mass measurement technique by NDA of high concentrated pure plutonium nitrate solution in a strategic process tank. If it is established, ASMS provides direct Pu mass measurement and monitoring capability, substitutes for sampling and destructive analysis at IIV, and extends process monitoring to safety purposes. The target of the measurement uncertainty is set less than 6% which is equivalent to the detection level of partial defect at IIV by NDA. The principle is similar to the one of NDA for MOX powder, but extended such as introducing variable alpha depends on solution properties. As a first trial, a simple prototype system was constructed and calibrated at PCDF (Plutonium Conversion Development Facility) using plutonium nitrate solution. Consequently, good consistency between MCNP (Monte Carlo Neutron and Photon Transport Code) calculation and measured singles/doubles count rate were obtained. As a feasibility study, it was necessary to find out subjects to be solved. We would like to present benefits of ASMS, review installation and detector setup and summarize preliminary calibration results.
Oya, Kaoru*; Inai, Kensuke*; Shimizu, Katsuhiro; Takizuka, Tomonori; Kawashima, Hisato; Hoshino, Kazuo; Hatayama, Akiyoshi*; Toma, Mitsunori*; Tomita, Yukihiro*; Kawamura, Gakushi*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 85(10), p.695 - 703, 2009/10
no abstracts in English
Nakamura, Hironobu; Takaya, Akikazu; Mukai, Yasunobu; Hosoma, Takashi; Yoshimoto, Katsunobu; Tamura, Takayuki*; Iwamoto, Tomonori*
Proceedings of INMM 50th Annual Meeting (CD-ROM), 9 Pages, 2009/00
JNFL and JAEA have collaboratively started to develop an ASMS for RRP since 2007 as a trial base. The purpose of the development is to establish quantitative plutonium mass measurement technique directly by NDA of high concentrated pure plutonium nitrate solution in a process tank. If it is established, ASMS provides direct Pu mass measurement and monitoring capability, substitutes for sampling and analysis at IIV, and extends process monitoring to safety purposes. The target of the measurement uncertainty is set less than 6% (1 
) which is equivalent to the detection level of partial defect at IIV by NDA. The principle is similar to the one of NDA for MOX powder, but extended such as introducing variable alpha depends on solution properties. As a first trial, a simple prototype system was constructed and tested at Plutonium Conversion Development Facility of JAEA. Prior to the installation, MCNP calculations for entire cell and tank were performed. Two detectors with a gap were installed just center of the annular tank, then we carried out calibration using plutonium nitrate solution in the range up to 52 kgPu. Consequently, good consistency between calculation and measured singles/doubles count rate were obtained. As a feasibility study, it was necessary to find out subjects to be solved. We would like to present benefits of ASMS, review installation and detector setup and summarize preliminary calibration results.
Takenaga, Hidenobu; Ogawa, Yuichi*; Takizuka, Tomonori; Yagi, Masatoshi*; Yamada, Hiroshi*; Sakamoto, Yoshiteru; Toi, Kazuo*; Fukuda, Takeshi*; Fukuyama, Atsushi*; Fujita, Takaaki; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 84(7), p.465 - 467, 2008/07
no abstracts in English
Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.
Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06
Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.
Sasao, Mamiko*; Kusama, Yoshinori; Kawano, Yasunori; Kawahata, Kazuo*; Mase, Atsushi*; Sugie, Tatsuo; Fujita, Takaaki; Fukuda, Takeshi*; Fukuyama, Atsushi*; Sakamoto, Yoshiteru; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 83(9), p.779 - 782, 2007/09
This is a report of highlights from 2007 spring meetings of seven Topical Groups (TG) of International Tokamak Physics Activity (ITPA). In each meeting, high priority issues in physics of International Thermonuclear Experimental Reactor (ITER) and other burning plasma experiments have been discussed and investigated. Twenty-seven scientists from Japan have participated in those meetings. Dates and places of the meetings are shown below. (1) Diagnostics TG: 26-30 March, Princeton (USA), (2) Transport Physics TG: 7-10 May, Lausanne (Switzerland), (3) Confinement Database and Modeling TG: 7-10 May, Lausanne (Switzerland), (4) Edge Pedestal Physics TG: 7-10 May, Garching (Germany) (5) Steady State Operation TG: 9-11 May, Daejeon (South Korea), (6)MHD TG: 21-24 May, San Diego (USA), (7) Scrape-off-layer and Divertor Physics TG: 7-10 May, Garching (Germany).
Tomita, Yukihiro*; Smirnov, R.*; Nakamura, Hiroaki*; Zhu, S.*; Takizuka, Tomonori; Tskhakaya, D.*
Journal of Nuclear Materials, 363-365, p.264 - 269, 2007/06
Times Cited Count：5 Percentile：37.16(Materials Science, Multidisciplinary)In the study of dust behavior in plasma it is usually assumed that plasma particles are Maxwell distributed. If the dust is located on the conducting wall, the surrounding particle distribution can significantly differ from the Maxwellian. In this work we study the effect of truncation of electron velocity distribution on release conditions of a spherical dust particle from a plasma-facing wall. The truncation effect enlarges the electric field at the wall compared compared to the Maxwellian. The stronger electric field at the wall makes the released region smaller when the gravitational force is directed from the wall.
