Stepwise renewal of JRR-3 process control computer system

Isaka, Koji; Suwa, Masayuki; Kimura, Kazuya; Suzuki, Makoto; Ikekame, Yoshinori; Nagadomi, Hideki

JAEA-Technology 2021-039, 48 Pages, 2023/02

JAEA-Technology-2021-039.pdf:6.97MB

JRR-3 Process control system is used from the initial criticality (1990) after remodeling JRR- 3 as equipment used for monitoring and control of flow rate, temperature, pressure, water level, etc. of coolant and operation of nuclear reactor equipment, and it became necessary to renew as the aging progressed and spare parts could not be obtained sufficiently. Upon renewal, from the viewpoint of ensuring conservation of the core such as decay heat removal and minimizing the impact on reactor users and minimizing costs, it is important not to stop long-term reactor shutdown we planned to divide it into three stages and make it on a continuous basis. This report summarizes the renewal plan and renewal work divided into three stages.

In-situ dismantling of the liquid waste storage tank LV-1 in the JRTF; The Dismantling preparation work

Yokozuka, Yuta; Sunaoshi, Mizuho*; Fujikura, Toshiki; Suzuki, Shota; Muraguchi, Yoshinori; Handa, Yuichi; Mimura, Ryuji; Terunuma, Akihiro

JAEA-Technology 2020-017, 56 Pages, 2021/01

JAEA-Technology-2020-017.pdf:7.88MB

JAEA has dismantled equipment and instrument in the JAERI's Reprocessing Test Facility (JRTF) since 1996 as a part of its decommissioning. Starting in JFY 2007, in the annex building B which stored liquid waste generated in wet reprocessing tests, the liquid waste storage tank LV-1 installed in the LV-1 room of the first basement was dismantled with the in situ dismantling method. The dismantling preparation work is described in this report. Data on manpower, radiation control, and waste in the preparation work were collected, and its work efficiency was analyzed.

The -electron state of the heavy fermion superconductor NpPdAl and the isostructural family

Metoki, Naoto; Aczel, A. A.*; Aoki, Dai*; Chi, S.*; Fernandez-Baca, J. A.*; Griveau, J.-C.*; Hagihara, Masato*; Hong, T.*; Haga, Yoshinori; Ikeuchi, Kazuhiko*; et al.

JPS Conference Proceedings (Internet), 30, p.011123_1 - 011123_6, 2020/03

https://doi.org/10.7566/JPSCP.30.011123

Rare earths (4) and actinides (5) provide variety of interesting states realized with competing interactions between the increasing number of electrons. Since crystal field splitting of many-body electron system is smaller than the bandwidth, (1) high resolution experiments are needed, (2) essentially no clear spectrum with well defined peaks is expected in itinerant Ce and U compounds, and (3) Np and Pu is strictly regulated. Therefore, systematic research on magnetic excitations by neutron scattering experiments of localized compounds and rare earth iso-structural reference is useful. We describe the electron states of heavy electron compounds NpPdAl and actinide and rare earth based iso-structural family.

Study of the dust behavior on the laser and plasma cutting

Soejima, Goro; Iwai, Hiroki; Kadowaki, Haruhiko; Nakamura, Yasuyuki; Tsuzuki, Satoshi*; Yasunaga, Kazushi*; Nakata, Yoshinori*; Kume, Kyo*

Heisei-28-Nendo Koeki Zaidan Hojin Wakasawan Enerugi Kenkyu Senta kenkyu Nempo, 19, P. 9, 2017/10

http://www.werc.or.jp/research/kenkyuseika_houkoku/img/1houkokusyuH28.pdf

no abstracts in English

Maintaining formation of multiple robotic wheelchairs for smooth communication

Suzuki, Ryota*; Kobayashi, Yoshinori*; Kuno, Yoshinori*; Yamada, Taichi; Yamazaki, Keiichi*; Yamazaki, Akiko*

International Journal on Artificial Intelligence Tools, 25(5), p.1640005_1 - 1640005_19, 2016/10

https://doi.org/10.1142/S0218213016400054

To meet the demands of an aging society, research on intelligent/robotic wheelchairs have been receiving a lot of attention. In elderly care facilities, care workers are required to communicate with the elderly in order to maintain both their mental and physical health. While this is regarded as important, having a conversation with someone on a wheelchair while pushing it from behind in a traditional setting would interfere with their smooth and natural conversation. So we are developing a robotic wheelchair system which allows companions and wheelchair users to move in a natural formation. This paper reports on an investigation to learn the patterns of human behavior when the wheelchair users and their companions communicate while walking together. The ethnographic observation reveals a natural formation of positioning for both companions and wheelchair users. Based on this investigation, we propose a multiple robotic wheelchair system which can maintain desirable formations for communication between wheelchairs.

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2014

Watanabe, Hitoshi; Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Inoue, Kazumi; Yoshii, Hideki*; Otani, Kazunori*; Hiyama, Yoshinori*; Kikuchi, Masaaki*; Sakauchi, Nobuyuki*; et al.

JAEA-Review 2015-030, 115 Pages, 2015/12

JAEA-Review-2015-030.pdf:25.28MB

Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2014. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.

Recent progress on tritium technology research and development for a fusion reactor in Japan Atomic Energy Agency

Hayashi, Takumi; Nakamura, Hirofumi; Kawamura, Yoshinori; Iwai, Yasunori; Isobe, Kanetsugu; Yamada, Masayuki; Suzuki, Takumi; Kurata, Rie; Oyaizu, Makoto; Edao, Yuki; et al.

Fusion Science and Technology, 67(2), p.365 - 370, 2015/03

https://doi.org/10.13182/FST14-T31

R&D status on water cooled ceramic breeder blanket technology

Enoeda, Mikio; Tanigawa, Hisashi; Hirose, Takanori; Nakajima, Motoki; Sato, Satoshi; Ochiai, Kentaro; Konno, Chikara; Kawamura, Yoshinori; Hayashi, Takumi; Yamanishi, Toshihiko; et al.

Fusion Engineering and Design, 89(7-8), p.1131 - 1136, 2014/10

https://doi.org/10.1016/j.fusengdes.2014.01.035

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. Regarding the fabrication technology development using F82H, the fabrication of a real scale mockup of the back wall of TBM was completed. Also the assembling of the complete box structure of the TBM mockup and planning of the pressurization testing was studied. The development of advanced breeder and multiplier pebbles for higher chemical stability was performed for future DEMO blanket application. From the view point of TBM test result evaluation and DEMO blanket performance design, the development of the blanket tritium simulation technology, investigation of the TBM neutronics measurement technology and the evaluation of tritium production and recovery test using D-T neutron in the Fusion Neutronics Source (FNS) facility has been performed.

High power laser developments with femtosecond to nanosecond pulse durations for laser shock science and engineering

Kiriyama, Hiromitsu; Mori, Michiaki; Suzuki, Masayuki*; Daito, Izuru*; Okada, Hajime; Ochi, Yoshihiro; Tanaka, Momoko; Sato, Masatoshi*; Tamaoki, Yoshinori*; Yoshii, Takehiro*; et al.

Reza Kenkyu, 42(6), p.441 - 447, 2014/06

http://ci.nii.ac.jp/naid/40020137371

We describe three specific high power laser systems that are being developed in our laboratory for many applications in high field science, nonlinear optics and material processing. We report on a femtosecond petawatt-class Ti:sapphire chirped-pulse amplification laser system that can produce a pulse energy of 20 J of 40 fs pulse duration, a picosecond high intensity Yb:YAG chirped-pulse amplification laser system that can generate a pulse energy of 100 mJ of 0.5 ps pulse duration, and a nanosecond high repetition rate Nd:YAG laser system that can provide an average power of 360 W with a pulse duration of 30 ns delivered at a 1 kHz repetition rate. We discuss the basic design aspects and present the results from our experimental investigations of these laser systems.

Ponded melt at the boundary between the lithosphere and asthenosphere

Sakamaki, Tatsuya*; Suzuki, Akio*; Otani, Eiji*; Terasaki, Hidenori*; Urakawa, Satoru*; Katayama, Yoshinori; Funakoshi, Kenichi*; Wang, Y.*; Hernlund, J. W.*; Ballmer, M. D.*

Nature Geoscience, 6(12), p.1041 - 1044, 2013/12

https://doi.org/10.1038/ngeo1982

The bounday between Earth's rigid lighosphere and the underlying, ductile ashenosphere is marked by a distinct siseismic discontinuity. We measure the density, viscosity and structure of basaltic magmas using high-pressure and high-temperature experiments and in situ X-ray analysis under pressure of up to 5.5 GPa. We find that the magmas rapidly become denser with increasing presure and show a viscosity minimum near 4 GPa. Magma mobility determined by the density and viscosity data exhibits a peak at pressures corresponding to depths of 120-150 km, within the asthenosphere. The diminishing mobility of magma in Earth's asthenosphere as the mlets ascend could lead to excessive melt accumulation at depths of 80-100 km, at the lithosphere-asthenosphere boundary. It is concluded that the observed seismic discontinuity at the lithosphere-asthenosphere boundary records this accumulation of melt.