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Futemma, Akira; Kudo, Tamotsu
no journal, ,
During a nuclear emergency, aerial radiation monitoring (ARM) via manned helicopters could be utilized as a way of radiation measurement. Natural background radiation maps surrounding twelve nuclear facilities in Japan are developed by ARM to contribute to make an appropriate evaluation of the environmental radiological effect during a nuclear emergency.
Yamano, Hidemasa; Takai, Toshihide; Emura, Yuki; Higashi, Hideo*; Fukuyama, Hiroyuki*; Nishi, Tsuyoshi*; Ota, Hiromichi*; Morita, Koji*; Nakamura, Kinya*; Fukai, Hirofumi*; et al.
no journal, ,
A research project has been conducting thermophysical property measurement of a eutectic melt, eutectic melting experiments and material analysis, physical model development for the eutectic melting reaction, and reactor application analysis in order to simulate the eutectic melting reaction and relocation behavior of boron carbide as a control rod material and stainless steel during a core disruptive accident in an advanced sodium-cooled fast reactor designed in Japan. This paper describes the project overview and progress until JFY2020.
Sato, Rina; Yoshimura, Kazuya; Sanada, Yukihisa; Sato, Tetsuro*; Takagi, Marie*
no journal, ,
no abstracts in English
Futagami, Satoshi; Ando, Masanori; Yamano, Hidemasa
no journal, ,
To enhance resilience of next-generation nuclear power plants, the authors have performed a three-dimensional analysis of structures with an earthquake-resistant lower support structure, assuming a protected loss of heat sink event, which may cause all decay heat removal systems to lose their functions immediately after reactor shutdown. The results show how the reactor vessel and guard vessel deform at extremely high temperatures.
Okada, Toyofumi; Shibanuma, Tomohiro; Honda, Fumiya; Komeno, Akira; Kikuno, Hiroshi
no journal, ,
Am is generated by beta-decay of Pu. In the case of treating MOX, it is important for shielding about 60keV gamma-ray emitted by Am. Also getting dose rate data of MOX containing Am is valuable. In this work, we measured gamma-ray dose rate from MOX containing Am by changing thickness of shielding materials and range between MOX and measuring instruments. Also we confirmed that calculating analysis is useful for evaluation of shielding material's performance.
Ozu, Akira; Maeda, Makoto; Komeda, Masao; Toh, Yosuke
no journal, ,
no abstracts in English
Ogawa, Rina; Totsuka, Masayoshi*; Nakata, Hisakazu; Sakai, Akihiro
no journal, ,
no abstracts in English
Uchita, Masato*; Miyagawa, Takayuki*; Murakami, Hisatomo*; Suzuno, Tetsuji*; Yamamoto, Tomohiko
no journal, ,
no abstracts in English
Yoshimura, Kazuya; Fujiwara, Kenso; Nakama, Shigeo; Abe, Tomohisa
no journal, ,
no abstracts in English
Takano, Kazuya; Kato, Atsushi; Uchita, Masato*; Okazaki, Hitoshi*; Ikari, Risako*
no journal, ,
Primary Heat Transport System (PHTS) flow rate is the most promising signal to detect the pump/diagrid link rupture in pool type SFR. The electromagnetic flowmeter is considered to measure the PHTS flow rate and is designed to install nearby outlet of the PHTS circulation pump in the current design of pool-type SFR with 600 MWe. The flowmeter could be significantly affected by the noise from pump motor. In order to improve the signal strength, the structure of flowmeter is drastically modified with the D-shape yokes and the magnetic circuits above and below an electrode.
Asakura, Kazuki; Shimomura, Yusuke; Donomae, Yasushi; Abe, Kazuyuki; Kitamura, Ryoichi
no journal, ,
no abstracts in English
Iwamoto, Hiroki; Iwamoto, Osamu; Kunieda, Satoshi
no journal, ,
no abstracts in English
Shikaze, Yoshiaki
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no abstracts in English
Nishino, Hiroyuki; Onoda, Yuichi; Kurisaka, Kenichi; Yamano, Hidemasa; Demachi, Kazuyuki*
no journal, ,
In order to evaluate the effectiveness of the measures for improving resilience against excessive earthquake, this study assumed to improve seismic safety margin of components of heat removal system as the measures against loss of heat removal systems event after reactor shutdown. The core damage frequency was calculated and the reduction effect of it was estimated by comparing it before and after the introduction of the measures for improving resilience.
Onoda, Yuichi; Nishino, Hiroyuki; Kurisaka, Kenichi; Yamano, Hidemasa; Demachi, Kazuyuki*
no journal, ,
In order to evaluate the effectiveness of the measures for improving resilience at ultra-high temperatures, a concept of evaluation focusing on core damage frequency was proposed. Assuming loss of heat removal systems event after reactor shutdown which may result in core damage in sodium-cooled fast reactors, the measures for improving resilience which enable to recover the safety functions at ultra-high temperatures are identified: one is to retain the primary coolant using failure mitigation technology, and the other is to add a heat removal system that can be used under ultra-high temperature conditions. The core damage frequencies were calculated preliminarily and their reduction effect was estimated by comparing them before and after the introduction of the measures for improving resilience.
Okamura, Shigeki*; Kinoshita, Takahiro*; Nishino, Hiroyuki; Yamano, Hidemasa; Kurisaka, Kenichi; Futagami, Satoshi; Fukasawa, Tsuyoshi*
no journal, ,
no abstracts in English
Kinoshita, Takahiro*; Okamura, Shigeki*; Nishino, Hiroyuki; Yamano, Hidemasa; Kurisaka, Kenichi; Futagami, Satoshi; Fukasawa, Tsuyoshi*
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no abstracts in English
Demachi, Kazuyuki*; Kuwabara, Yuto*; Chen, S.*; Kasahara, Naoto*; Nishino, Hiroyuki; Onoda, Yuichi; Kurisaka, Kenichi
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no abstracts in English
C-SS eutectic molten materialsFukuyama, Hiroyuki*; Higashi, Hideo*; Yamano, Hidemasa
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The purpose of this study is to develop the thermophysical property model needed to simulate the behavior of the eutectic compound of the control rod material (boron carbide (BC)) and the structural material of a reactor vessel (stainless steel: SUS316L (SS)) during a core disruptive accident in a sodium-cooled fast reactor. This paper describes the liquidus temperature, density and surface tension of the molten compound of 15mass% BC-SS systematically measured with the High-Temperature Thermophysical Property Measurement System (PROSPECT).
Suzuki, Risa; Nomi, Takayoshi; Nagatani, Taketeru; Shiromo, Hideo; Shiba, Tomooki; Kaburagi, Masaaki; Okumura, Keisuke; Kosuge, Yoshihiro*; Takada, Akira*; Nauchi, Yasushi*
no journal, ,
no abstracts in English