Overview of event progression of evaporation to dryness caused by boiling of high-level liquid waste in Reprocessing Facilities

Yamaguchi, Akinori*; Yokotsuka, Muneyuki*; Furuta, Masayo*; Kubota, Kazuo*; Fujine, Sachio*; Mori, Kenji*; Yoshida, Naoki; Amano, Yuki; Abe, Hitoshi

Nihon Genshiryoku Gakkai Wabun Rombunshi (Internet), 21(4), p.173 - 182, 2022/09

https://doi.org/10.3327/taesj.J21.021

Risk information obtained from probabilistic risk assessment (PRA) can be used to evaluate the effectiveness of measures against severe accidents in nuclear facilities. The PRA methods used for reprocessing facilities are considered immature compared to those for nuclear power plants, and to make the methods mature, reducing the uncertainty of accident scenarios becomes crucial. In this paper, we summarized the results of literature survey on the event progression of evaporation to dryness caused by boiling of high-level liquid waste (HLLW) which is a severe accident in reprocessing facilities and migration behavior of associated radioactive materials. Since one of the important characteristics of Ru is its tendency to form volatile compounds over the course of the event progression, the migration behavior of Ru is categorized into four stages based on temperature. Although no Ru has been released in the waste in the high temperature region, other volatile elements such as Cs could be released. Sufficient experimental data, however, have not been obtained yet. It is, therefore, necessary to further clarify the migration behavior of radioactive materials that predominantly depends on temperature in this region.

Gamma-ray observations at the coastal area of Japan Sea in winter seasons

Tsuchiya, Harufumi; Enoto, Teruaki*; Wada, Yuki*; Furuta, Yoshihiro; Nakazawa, Kazuhiro*; Yuasa, Takayuki*; Umemoto, Daigo*; Makishima, Kazuo*; GROWTH Collaboration*

Proceedings of Science (Internet), 358, p.1163_1 - 1163_6, 2021/07

https://doi.org/10.22323/1.358.1163

Thundercloud project; Exploring high-energy phenomena in thundercloud and lightning

Yuasa, Takayuki*; Wada, Yuki*; Enoto, Teruaki*; Furuta, Yoshihiro; Tsuchiya, Harufumi; Hisadomi, Shohei*; Tsuji, Yuna*; Okuda, Kazufumi*; Matsumoto, Takahiro*; Nakazawa, Kazuhiro*; et al.

Progress of Theoretical and Experimental Physics (Internet), 2020(10), p.103H01_1 - 103H01_27, 2020/10

https://doi.org/10.1093/ptep/ptaa115

High peak-current lightning discharges associated with downward terrestrial gamma-ray flashes

Wada, Yuki*; Enoto, Teruaki*; Nakamura, Yoshitaka*; Morimoto, Takeshi*; Sato, Mitsuteru*; Ushio, Tomoo*; Nakazawa, Kazuhiro*; Yuasa, Takayuki*; Yonetoku, Daisuke*; Sawano, Tatsuya*; et al.

Journal of Geophysical Research; Atmospheres, 125(4), p.e2019JD031730_1 - e2019JD031730_11, 2020/02

https://doi.org/10.1029/2019JD031730

Gamma-ray glow preceding downward terrestrial gamma-ray flash

Wada, Yuki*; Enoto, Teruaki*; Nakamura, Yoshitaka*; Furuta, Yoshihiro; Yuasa, Takayuki*; Nakazawa, Kazuhiro*; Morimoto, Takeshi*; Sato, Mitsuteru*; Matsumoto, Takahiro*; Yonetoku, Daisuke*; et al.

Communications Physics (Internet), 2(1), p.67_1 - 67_9, 2019/06

https://doi.org/10.1038/s42005-019-0168-y

Photonuclear reactions triggered by lightning discharge

Enoto, Teruaki*; Wada, Yuki*; Furuta, Yoshihiro*; Nakazawa, Kazuhiro*; Yuasa, Takayuki*; Okuda, Kazufumi*; Makishima, Kazuo*; Sato, Mitsuteru*; Sato, Yosuke*; Nakano, Toshio*; et al.

Nature, 551(7681), p.481 - 484, 2017/11

https://doi.org/10.1038/nature24630

An Inference method of team situation awareness based on mutual awareness

Shu, Y.; Furuta, Kazuo*

Cognition, Technology & Work, 7(4), p.272 - 287, 2005/11

Team Situation Awareness (TSA) is a critical contributing factor in establishing collaborative relations among team members involved in cooperative activity. Currently, however, there is still a lack of a clearly understandable and commonly agreeable model of TSA. To resolve misunderstanding or conflict among team members or between a team and machines, our research aim is to find out the underlying mechanism of TSA that reflects team cognitive process in a way consistent with team cooperative activity, and to focus on how to achieve mutual understanding, and how to effectively incorporate human teams into a socio-technological system. In this paper, we argue that earlier models of TSA, where TSA was discussed as the intersection of situation awareness (SA) owned by individual team members, are inadequate for study of a sophisticated team reciprocal process. We suggest that it is necessary for the definition of TSA to integrate the notion of individual SA into cooperative team activity. In particular, understanding of mutual awareness is an essential element in cooperative activity. We propose a new notion of TSA, which is reducible to mutual beliefs as well as individual SA at three levels. Further, we develop an operational TSA inference method and discuss human competence and system-related factors that are required to build TSA. We then try to demonstrate how TSA is actively constructed via inferencing practices. We also develop criteria to assess appropriateness of TSA from two aspects: soundness and completeness of mutual beliefs. Comparison of evaluation results indicates that the notion of TSA proposed in this work is more suitable to depict team cooperative activity than conventional ones.

Enhancing team situation awareness of plant operators through team-level mutual awareness inference

Shu, Y.; Nakajima, Norihiro; Furuta, Kazuo*

Proceedings of 8th World Multi-Conference on Systemics, Cybernetics and Informatics (SCI 2004), p.184 - 185, 2004/07

Team Situation Awareness (TSA) is a critical contributing factor in enhancing reliability of team performance. How to effectively incorporate between human teams and artifacts, how to achieve mutual understanding, is the major topic in this paper. Based on our previous study on TSA, an argument will be presented that recognition, SA inferring, and mutual responsiveness are the prerequisite abilities to engage in cooperative activity. We also develop the principle to assess appropriateness of TSA from two aspects: the soundness and completeness of mutual belief. Simulation results will be given to indicate that team uses the information from external environment to establish effective TSA based on internal knowledge.

Radiation measurements associated with lightning and thunderclouds in winter at the coastal area of the Japan Sea

Tsuchiya, Harufumi; Enoto, Teruaki*; Wada, Yuki*; Furuta, Yoshihiro*; Nakazawa, Kazuhiro*; Yuasa, Takayuki*; Okuda, Kazufumi*; Makishima, Kazuo*; Sato, Mitsuteru*; Sato, Yosuke*; et al.

no journal, , 

no abstracts in English