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Iguchi, Satoshi; Yoshida, Masato; Hirano, Hiroshi*; Kitamura, Akihiro
Nuclear Technology, 15 Pages, 2026/00
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)The size reduced materials resulting from the dismantling of the plutonium-contaminated gloveboxes are eventually packed into the containers as radioactive waste. Conventionally, the execution of this task has been entrusted to workers equipped with air-fed suits, a practice that carries inherent risks, including potential suit damage and inhalation hazards. Moreover, in order to mitigate these risks, the size reduced materials are covered with rags or plastic to enhance safety for workers. However, this approach entails the separation of non-flammable waste and flammable waste during the disposal process. To circumvent these issues, we have designed a glove operation compartment that enables waste handling and packing activities through glove operations instead of air-fed suits. This reduces the risks associated with air-fed suit operations and eliminates the need to cover size reduced materials with rags and plastic. The procedure involves packing the size reduced materials into metal cans, weighing the cans, and storing them in the containers. We tested these operations using the compartment's test bed and modified them through mock-up experiments to ensure feasibility. This report presents the features of the glove operation compartment, the assumed handling procedures, and the insights obtained from the test results.
Tokunaga, Sho; Horiguchi, Hironori; Nakamura, Takemi
JAEA-Technology 2023-001, 37 Pages, 2023/05
JAEA-Technology-2023-001.pdf:1.39MB
The cold neutron source (CNS) of the research reactor JRR-3 converts thermal neutrons generated in the reactor into low-energy cold neutrons by moderating them with liquid hydrogen stored in the moderator cell. Cold neutrons generated by the CNS are transported to experimental instruments using neutron conduits, and are used for many studies of physical properties, mainly in life science, polymer science, environmental science, etc. Improvement of cold neutron intensity is essential to maintain competitiveness with the world's research reactors in neutron science, and we are developing a new CNS that incorporates new knowledge. The current moderator cell for the CNS of JRR-3 is a stainless-steel container which is a canteen bottle type, and the cold neutron intensity can be improved by changing the material and shape. Therefore, the basic specifications of the new moderator cell were changed to aluminum alloy which has a smaller neutron absorption cross section, and the shape was optimized using a Monte Carlo code MCNP. Since these changes in specifications will result in changes in heat generation and heat transfer conditions, the CNS of JRR-3 was re-evaluated in terms of self-regulating characteristic, heat transport limits, heat resistance and pressure resistance, etc., to confirm its feasibility in thermal-hydraulic design. This report summarizes the results of the thermal-hydraulic design evaluation of the new moderator cell.
Itoi, Tatsuya*; Iwaki, Chikako*; Onuki, Akira*; Kito, Kazuaki*; Nakamura, Hideo; Nishida, Akemi; Nishi, Yoshihisa*
Nihon Genshiryoku Gakkai-Shi ATOMO
, 60(4), p.221 - 225, 2018/04
no abstracts in English
Arai, Kenji*; Umezawa, Shigemitsu*; Oikawa, Hirohide*; Onuki, Akira*; Nakamura, Hideo; Nishi, Yoshihisa*; Fujii, Tadashi*
Nihon Genshiryoku Gakkai-Shi ATOMO, 58(3), p.161 - 166, 2016/03
no abstracts in English
Li, J.; Kishimoto, Yasuaki
Physics of Plasmas, 11(4), p.1493 - 1510, 2004/04
Times Cited Count：60 Percentile：84.25(Physics, Fluids & Plasmas)The electron temperature gradient (ETG) driven turbulence in tokamak core plasmas is numerically investigated based on three-dimensional gyrofluid model with adiabatic ion response. Attentions are focused on the zonal flow dynamics in ETG fluctuations and the resultant electron heat transport. A high electron energy confinement mode is found in the weak magnetic shear regime, which is closely relevant with self-organization behavior of turbulence through the enhanced zonal flow dynamics rather than the weak shear stabilization of ETG fluctuations. It is demonstrated that the weak shear is favorable for the enhancement of zonal flows in ETG turbulence.
Tamada, Masao; Kasai, Noboru; Seko, Noriaki; Hasegawa, Shin; Kawabata, Yukiya*; Onuma, Kenji*; Takeda, Hayato*; Katakai, Akio; Sugo, Takanobu
JAERI-Tech 2001-065, 39 Pages, 2001/11
JAERI-Tech-2001-065.pdf:5.24MB
Positioning and monitoring system for marine component in recovery equipment of significant metals from seawater by using adsorbent was designed and assembled to avoid unexpected accidents. This system which was set on float part of the marine component obtains the position data by means of GPS satellites and send them to Takasaki and Mutsu establishments through satellite communication. As characteristic test for 20 days in the real sea, 256 data were obtained every 2 hours. The wrong data was eight and the positioning accuracy was 200.7m. To improve these characteristics, two new functions were added to the present firmware. These are to raise positioning resolutions in longitude and latitude from 0.001 to 0.00001 degree and to average remaining three data of positioning after maximum and minimum data were removed from continuous five times positioning. The improved system shows no wrong datum, average positioning of 6.74m. This performance is enough to prevent marine equipment from its drifting accident.
Hiroki, Seiji; Abe, Tetsuya; Obara, Kenjiro; Murakami, Yoshio
J. Vac. Sci. Technol., A, 9(1), p.154 - 157, 1991/01
no abstracts in English
Ebinuma, Yukio
Int.Inf.Commun.Educ., 6(1), p.45 - 54, 1987/01
no abstracts in English
Hiroki, S.; ; ; ; Murakami, Yoshio
JAERI-M 84-012, 14 Pages, 1984/02
no abstracts in English
Murakami, Yoshio; ; ;
J.Vac.Sci.Tecnol.,A, 2(4), p.1589 - 1592, 1984/00
no abstracts in English
Journal of Nuclear Science and Technology, 18(8), p.629 - 639, 1981/00
Times Cited Count：4 Percentile：52.06(Nuclear Science & Technology)no abstracts in English
JAERI-M 5374, 15 Pages, 1973/08
no abstracts in English
Nakamura, Hideo; Arai, Kenji*; Oikawa, Hirohide*; Fujii, Tadashi*; Umezawa, Shigemitsu*; Onuki, Akira*; Nishi, Yoshihisa*; Abe, Yutaka*; Sugimoto, Jun*; Koshizuka, Seiichi*; et al.
no journal, ,
