PSTEP: Project for solar-terrestrial environment prediction

Kusano, Kanya*; Ichimoto, Kiyoshi*; Ishii, Mamoru*; Miyoshi, Yoshizumi*; Yoden, Shigeo*; Akiyoshi, Hideharu*; Asai, Ayumi*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Goto, Tadanori*; et al.

Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12

https://doi.org/10.1186/s40623-021-01486-1

The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.

Demonstration of -ray pipe-monitoring capabilities for real-time process monitoring safeguards applications in reprocessing facilities

Rodriguez, D.; Tanigawa, Masafumi; Nishimura, Kazuaki; Mukai, Yasunobu; Nakamura, Hironobu; Kurita, Tsutomu; Takamine, Jun; Suzuki, Satoshi*; Sekine, Megumi; Rossi, F.; et al.

Journal of Nuclear Science and Technology, 55(7), p.792 - 804, 2018/07

https://doi.org/10.1080/00223131.2018.1439412

Nuclear material in reprocessing facilities is safeguarded by random sample verification with additional continuous monitoring applied to solution masses and volume in important tanks to maintain continuity-of-knowledge of process operation. Measuring the unique rays of each solution as the material flows through pipes connecting all tanks and process apparatuses could potentially improve process monitoring by verifying the compositions in real time. We tested this ray pipe-monitoring method using plutonium-nitrate solution transferred between tanks at the PCDF-TRP. The rays were measured using a lanthanum-bromide detector with a list-mode data acquisition system to obtain both time and energy of -ray. The analysis and results of this measurement demonstrate an ability to determine isotopic composition, process timing, flow rate, and volume of solution flowing through pipes, introducing a viable capability for process monitoring safeguards verification.

Survey and countermeasures on radiocesium inflow into a laboratory building for radioactivity analysis

Kurita, Yoshiyuki; Saegusa, Jun; Maeda, Satoshi

Nihon Hoshasen Anzen Kanri Gakkai-Shi, 15(2), p.180 - 185, 2016/11

http://doi.org/10.11269/jjrsm.15.180

In 2012, JAEA has established a laboratory in Fukushima-city to implement radioactivity analysis of environmental samples. Key nuclides measured in this laboratory are Cs and Cs (radiocesium). For the purpose, situation of radiocesium inflow into the laboratory building and its effects were investigated based on high-resolution gamma-spectrometry with germanium detectors. As a result, the surface density of radiocesium in the laboratory was found to be far below the minimum detectable activities of survey instruments routinely used for radiation control purposes.

Development of sample assay system equipped with He Alternative Neutron Detectors (ASAS), 1; Design and fabrication of ASAS detector

Ozu, Akira; Tobita, Hiroshi; Kureta, Masatoshi; Tanigawa, Masafumi; Mukai, Yasunobu; Nakamichi, Hideo; Nakamura, Hironobu; Kurita, Tsutomu; Seya, Michio

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2015/12

Against the background of the serious shortage of He gas, the Japan Atomic Energy Agency (JAEA) has newly developed an alternative ZnS ceramic scintillation neutron detector for the safeguards, with the support of the government (MEXT). A demonstrator of plutonium inventory sample assay system (ASAS) has been also developed as an alternative HLNCC (High Level Neutron Coincidence Counter). The results from numerical simulations using Monte-Carlo code MCNPX showed that the fundamental performances of ASAS equipped with the 24 alternative neutron detectors, such as neutron detection efficiency and die-away time, equal to or higher than those of conventional HLNCC could be obtained. Here we present the inner mechanical structure of ASAS, together with the results of the simulating design.

Demonstration result of sample assay system equipped alternative He-3 detectors

Nakamura, Hironobu; Mukai, Yasunobu; Tobita, Hiroshi; Nakamichi, Hideo; Ozu, Akira; Kureta, Masatoshi; Kurita, Tsutomu; Seya, Michio

Proceedings of 37th ESARDA Annual Meeting (Internet), p.45 - 53, 2015/08

JAEA conducted an R&D project to develop a new type of neutron detector using ZnS/BO ceramic scintillator (as an alternative neutron detector to He-3) with support of Japanese government. The design of the JAEAs alternative system (ASAS: Alternative Sample Assay System using ceramic scintillator tubes) refers basically to the INVS (INVentory Sample assay system) which is the passive type of neutron assay system equipped total 18 He-3 tubes and capable of measuring the small amount of Pu in the MOX powder or Pu nitrate solution in a vial for nuclear material accountancy and safeguards verification. In order to prove the alternative technology and the performance instead of He-3 detector, and to establish Pu measurement capability, JAEA developed and fabricated ASAS equipped 24 alternative ceramic scintillator tubes (which is equivalent to the same counting efficiency of INVS) and demonstrated. The demonstration activity implemented the confirmation of reproducibility about sample positioning, optimization of detector parameters, counting statistical uncertainty, stability check and figure of merit (FOM) using Cf check source and actual MOX powder in PCDF (Plutonium Conversion Development Facility). In addition, performance comparison between the current INVS and the ASAS was also implemented. In this paper, we present demonstration results with design information with Monte-Carlo simulation code (MCNP).

Development of an alternative plutonium canister assay system (APCA) using He-3 alternative neutron detector

Ozu, Akira; Kureta, Masatoshi; Haruyama, Mitsuo; Takase, Misao; Kurata, Noritaka; Kobayashi, Nozomi; Soyama, Kazuhiko; Nakamura, Tatsuya; Sakasai, Kaoru; To, Kentaro; et al.

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-34-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2013/10

no abstracts in English

Conceptual design of the SlimCS fusion DEMO reactor

Tobita, Kenji; Nishio, Satoshi*; Enoeda, Mikio; Nakamura, Hirofumi; Hayashi, Takumi; Asakura, Nobuyuki; Uto, Hiroyasu; Tanigawa, Hiroyasu; Nishitani, Takeo; Isono, Takaaki; et al.

JAEA-Research 2010-019, 194 Pages, 2010/08

JAEA-Research-2010-019-01.pdf:48.47MB
JAEA-Research-2010-019-02.pdf:19.4MB

This report describes the results of the conceptual design study of the SlimCS fusion DEMO reactor aiming at demonstrating fusion power production in a plant scale and allowing to assess the economic prospects of a fusion power plant. The design study has focused on a compact and low aspect ratio tokamak reactor concept with a reduced-sized central solenoid, which is novel compared with previous tokamak reactor concept such as SSTR (Steady State Tokamak Reactor). The reactor has the main parameters of a major radius of 5.5 m, aspect ratio of 2.6, elongation of 2.0, normalized beta of 4.3, fusion out put of 2.95 GW and average neutron wall load of 3 MW/m. This report covers various aspects of design study including systemic design, physics design, torus configuration, blanket, superconducting magnet, maintenance and building, which were carried out increase the engineering feasibility of the concept.

Flowability measurement of coarse particles using vibrating tube method

Ishii, Katsunori; Suzuki, Masahiro; Yamamoto, Takuma; Kihara, Yoshiyuki; Kato, Yoshiyuki; Kurita, Tsutomu; Yoshimoto, Katsunobu; Yasuda, Masatoshi*; Matsusaka, Shuji*

Journal of Chemical Engineering of Japan, 42(5), p.319 - 324, 2009/05

https://doi.org/10.1252/jcej.08we250

The flowability of coarse particles has been experimentally investigated using the vibrating tube method, to evaluate the applicability of this method to MOX (mixed oxide of PuO and UO) particles which are nuclear fuel used for electric power production. Five sizes of non-radioactive model particles, smaller than 850 micrometers, made of ZrO were prepared, and the experiments were carried out using vibrating tubes with an outlet diameter from 2 to 4 mm. The outlet diameter significantly affected the flowability measurements. When using the tube with a 4-mm-outlet diameter, the flowability of all the model particles was successfully measured. The inclination angle of the tube, also, affected the flowability measurements. From the advantages of high sensitivity, short measurement time, simple structure, and easy operation, the vibrating tube method is expected to be applied to the remote flowability measurement of the MOX particles.

Overview of national centralized tokamak program; Mission, design and strategy to contribute ITER and DEMO

Ninomiya, Hiromasa; Akiba, Masato; Fujii, Tsuneyuki; Fujita, Takaaki; Fujiwara, Masami*; Hamamatsu, Kiyotaka; Hayashi, Nobuhiko; Hosogane, Nobuyuki; Ikeda, Yoshitaka; Inoue, Nobuyuki; et al.

Journal of the Korean Physical Society, 49, p.S428 - S432, 2006/12

To contribute DEMO and ITER, the design to modify the present JT-60U into superconducting coil machine, named National Centralized Tokamak (NCT), is being progressed under nationwide collaborations in Japan. Mission, design and strategy of this NCT program is summarized.

Overview of the national centralized tokamak programme

Kikuchi, Mitsuru; Tamai, Hiroshi; Matsukawa, Makoto; Fujita, Takaaki; Takase, Yuichi*; Sakurai, Shinji; Kizu, Kaname; Tsuchiya, Katsuhiko; Kurita, Genichi; Morioka, Atsuhiko; et al.

Nuclear Fusion, 46(3), p.S29 - S38, 2006/03

https://doi.org/10.1088/0029-5515/46/3/S05

The National Centralized Tokamak (NCT) facility program is a domestic research program for advanced tokamak research to succeed JT-60U incorporating Japanese university accomplishments. The mission of NCT is to establish high beta steady-state operation for DEMO and to contribute to ITER. The machine flexibility and mobility is pursued in aspect ratio and shape controllability, feedback control of resistive wall modes, wide current and pressure profile control capability for the demonstration of the high-b steady state.