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Sato, Tatsuhiko; Kubo, Yuki*
Purazuma, Kaku Yugo Gakkai-Shi, 100(5), p.218 - 223, 2024/05
One of the space weather hazards is the sudden occurrence of cosmic radiation exposure due to high-energy protons associated with massive solar flares. This paper focuses on cosmic radiation exposure for airline crew members, explaining the mechanisms and current regulations. Additionally, it introduces an overview of the recently developed Aircraft Radiation Exposure Warning System (WASAVIES) in Japan.
Maekawa, Fujio; Takei, Hayanori
Purazuma, Kaku Yugo Gakkai-Shi, 98(5), p.206 - 210, 2022/05
In developing an accelerator-driven nuclear transmutation system (ADS), it is necessary to solve technical issues related to proton beams, such as the development of materials that can withstand high-intensity proton beams and the characterization of subcritical cores driven by proton beams. Therefore, at the high-intensity proton accelerator facility J-PARC, a transmutation experimental facility that actually conducts various tests using a high-intensity proton beam is being planned. This paper introduces the outline and future direction of the transmutation experimental facility.
Kondo, Yasuhiro; Takei, Hayanori; Yee-Rendon, B.; Tamura, Jun
Purazuma, Kaku Yugo Gakkai-Shi, 98(5), p.222 - 226, 2022/05
A superconducting accelerating cavity is indispensable to realize a driver linac that meets the requirements of ADS. The low-energy section of the accelerators, which is normal conducting one, was redesigned to reflect the recent progress in the development of superconducting accelerator cavities. In addition, we are developing a prototype cavity for the spoke-type cavity that has not been developed well. This section reports on the latest research and development of ADS linacs at the Japan Atomic Energy Agency.
Sasa, Toshinobu
Purazuma, Kaku Yugo Gakkai-Shi, 98(5), p.211 - 215, 2022/05
Lead-bismuth eutectic (LBE) alloy is promising as a spallation target for next-generation reactor coolants and accelerator drive systems (ADS) due to its nuclear and chemical properties. LBE is a heavy metal, and it has good properties both as a spallation target and as a coolant for nuclear transmutation systems of long-lived radioactive nuclei. On the other hand, to improve compatibility with structural materials is one of the major issues in its utilization. The latest research results such as high-temperature operation of LBE and oxygen concentration control to ensure corrosion resistance with the aim of early commercialization of nuclear conversion technology by ADS is introduced.
Maekawa, Fujio
Purazuma, Kaku Yugo Gakkai-Shi, 98(5), p.201 - 205, 2022/05
The nuclear transmutation technology is a powerful solution to the "nuclear waste" problem that accompanies nuclear power generation. The Accelerator Driven System (ADS), which combines a high-intensity accelerator and a subcritical core, is a promising tool for nuclear transmutation. In this paper, we will explain the significance and principle of nuclear transmutation by ADS, design examples of ADS, partitioning and transmutation technology and its effects, required performance of high-intensity accelerators, overseas trends, etc.
Meigo, Shinichiro; Nakano, Keita; Iwamoto, Hiroki
Purazuma, Kaku Yugo Gakkai-Shi, 98(5), p.216 - 221, 2022/05
For the realization of accelerator-driven transmutation systems (ADS) and the construction of the ADS target test facility (TEF-T) at J-PARC, it is necessary to study the proton beam handling technology and neutronics for protons in the GeV energy region. Accordingly, the Nuclear Transmutation Division of J-PARC has studied these issues with using J-PARC's accelerator facilities, and so on. This paper introduces these topics.
Asahi, Yuichi; Fujii, Keisuke*
Purazuma, Kaku Yugo Gakkai-Shi, 97(2), p.86 - 92, 2021/02
The 5D gyrokinetic simulation data has been analyzed with the data-driven analysis methods. By defining an entropy-like quantity with singular values, we have quantitatively evaluated the randomness of the plasma state. We found that the randomness of plasma increases after the avalanche like transport and then gradually decrease. Since the decrease of the randomness is expected to be relevant to the phase space structure formation, we have developed a method to extract the phase space structures from the time series of 5D data. The relationship between the avalanche-like transport and phase space structures is discussed based on the contribution of each principal component to the energy transport.
Kumada, Takayuki
Purazuma, Kaku Yugo Gakkai-Shi, 96(4), p.176 - 180, 2020/04
We have developed time-resolved reflectivity measurement system using femtosecond laser pulses, which can measure structure of thin films generated by non-thermal effect.
Oguri, Hidetomo
Purazuma, Kaku Yugo Gakkai-Shi, 95(7), p.340 - 344, 2019/07
no abstracts in English
Sato, Satoshi; Kondo, Keitaro
Purazuma, Kaku Yugo Gakkai-Shi, 92(4), p.266 - 268, 2016/04
In the nuclear analysis of ITER, fusion DEMO reactor and IFMIF, etc., radiation transport calculations are conducted by using MCNP geometry data automatically created from 3-dimensional CAD data with CAD/MCNP conversion codes. In this review paper, we introduce the present status of the development on the CAD/MCNP conversion codes and examples of application. Also, we introduce how to visualize calculation results by MCNP.
Konno, Chikara
Purazuma, Kaku Yugo Gakkai-Shi, 92(4), p.261 - 265, 2016/04
Useful information to not only beginners but also experts is introduced mainly for important points, which are basic but surprisingly unknown in, about calculation codes and nuclear data libraries in nuclear analyses for fusion reactors.
Ohara, Hiroshi; Hayashi, Jennifer*
Purazuma, Kaku Yugo Gakkai-Shi, 92(3), p.236 - 237, 2016/03
no abstracts in English
Ishizawa, Akihiro*; Idomura, Yasuhiro; Imadera, Kenji*; Kasuya, Naohiro*; Kanno, Ryutaro*; Satake, Shinsuke*; Tatsuno, Tomoya*; Nakata, Motoki*; Nunami, Masanori*; Maeyama, Shinya*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 92(3), p.157 - 210, 2016/03
The high-performance computer system Helios which is located at The Computational Simulation Centre (CSC) in The International Fusion Energy Research Centre (IFERC) started its operation in January 2012 under the Broader Approach (BA) agreement between Japan and the EU. The Helios system has been used for magnetised fusion related simulation studies in the EU and Japan and has kept high average usage rate. As a result, the Helios system has contributed to many research products in a wide range of research areas from core plasma physics to reactor material and reactor engineering. This project review gives a short catalogue of domestic simulation research projects. First, we outline the IFERC-CSC project. After that, shown are objectives of the research projects, numerical schemes used in simulation codes, obtained results and necessary computations in future.
Kawano, Yasunori; Akiyama, Tsuyoshi*; Ishikawa, Masao; Isobe, Mitsutaka*; Itami, Kiyoshi; Ejiri, Akira*; Peterson, B.*
Purazuma, Kaku Yugo Gakkai-Shi, 92(2), P. 145, 2016/02
no abstracts in English
Sakamoto, Yoshiteru
Purazuma, Kaku Yugo Gakkai-Shi, 92(2), P. 149, 2016/02
Recent activities of DEMO Design Joint Special Team are reported. The team has been organized the working groups to treat important issues. The operation plan working group will identify what should DEMO carry out. The blanket working group will summarize the design guideline for DEMO blanket. The superconducting magnet working group will summarized the basic guideline and development strategy for the magnet design.
Shimada, Michiya; Miyazawa, Junichi*
Purazuma, Kaku Yugo Gakkai-Shi, 92(2), p.119 - 124, 2016/02
Actively convected liquid metal divertor is promising for providing a solution for issues of DEMO reactors including heat removal and disruptions. This chapter gives an overview of the motivation, research history, recent development, future perspective and issues to be resolved.
Hoshino, Kazuo; Matsunaga, Go; Okumura, Yoshikazu
Purazuma, Kaku Yugo Gakkai-Shi, 92(2), p.146 - 147, 2016/02
no abstracts in English
Yamanishi, Toshihiko
Purazuma, Kaku Yugo Gakkai-Shi, 92(1), p.21 - 25, 2016/01
In a fusion reactor, the hydrogen isotope separation system is required in the fuel cycle system to supply deuterium (D) and tritium (T) as its fuel. In ITER, 90% of T must be recycled through the isotope separation system. On the other hand; since the hydrogen (H) gas is finally exhausted to the environment, the T concentration in the H gas from the isotope separation system should be as low as reasonable achievable. Hence, the isotope separation system of a fusion reactor must have a large separation factor. The flow rate of the isotope separation system of a fusion reactor reaches to 300 mol/h. Only the cryogenic distillation method can meet the above conditions (large flow rate and separation factor) and is most likely used as a hydrogen separation system in a fusion reactor. In this chapter, several simulation methods and a set of experimental data of the cryogenic distillation columns are described in detail.
Ohara, Hiroshi; Moriyama, Setsuko*; Hayashi, Jennifer*
Purazuma, Kaku Yugo Gakkai-Shi, 92(1), p.48 - 50, 2016/01
no abstracts in English
Shinohara, Koji; Hayashi, Nobuhiko; Isayama, Akihiko; Miyato, Naoaki; Urano, Hajime; Aiba, Nobuyuki
Purazuma, Kaku Yugo Gakkai-Shi, 91(12), p.797 - 800, 2015/12
no abstracts in English
