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Shirafuji, Masaya; Sano, Kyohei; Horiuchi, Masakazu; Kato, Akane; Watanabe, Kazuki; Tanigawa, Masafumi; Maruyama, Hajime; Kitao, Takahiko; Conner, J.*; LaFleur, A.*; et al.
Dai-46-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 4 Pages, 2025/12
Nancekievill, M.*; Espinosa, J.*; Watson, S.*; Lennox, B.*; Jones, A.*; Joyce, M. J.*; Katakura, Junichi*; Okumura, Keisuke; Kamada, So*; Kato, Michio*; et al.
Sensors (Internet), 19(20), p.4602_1 - 4602_16, 2019/10
Times Cited Count：11 Percentile：47.15(Chemistry, Analytical)In order to contribute to fuel debris search at the Fukushima Daiichi Nuclear Power Station, we developed a system to search for submerged fuel debris by mounting a sonar on the remotely operated vehicle (ROV). The system can obtain 3D images of submerged fuel debris in real time by using the positioning system, depth sensor, and collected sonar data. As a demonstration test, a simulated fuel debris was installed at the bottom of the water tank facility at the Naraha Center for Remote Control Technology Development, and a 3D image was successfully obtained.
Kamada, So*; Kato, Michio*; Nishimura, Kazuya*; Nancekievill, M.*; Watson, S.*; Lennox, B.*; Jones, A.*; Joyce, M. J.*; Okumura, Keisuke; Katakura, Junichi*
Progress in Nuclear Science and Technology (Internet), 6, p.199 - 202, 2019/01
As a technology development to investigate the distribution of submerged fuel debris in the primary containment vessel (PCV) of the Fukushima Daiichi Nuclear Power Station, we are conducting development experiments of sonar system to be mounted in a compact ROV. The experiments were conducted in two types of water tanks with different depths, simulating the PCV, using sonar with different sizes, ultrasonic frequencies, and beam scanning method, and simulated fuel debris. As a result, we characterized the shape discrimination performance of the simulated debris, and the noise due to multi-path in narrow closed space.
Nancekievill, M.*; Jones, A. R.*; Joyce, M. J.*; Lennox, B.*; Watson, S.*; Katakura, Junichi*; Okumura, Keisuke; Kamada, So*; Kato, Michio*; Nishimura, Kazuya*
IEEE Transactions on Nuclear Science, 65(9), p.2565 - 2572, 2018/09
Times Cited Count：32 Percentile：92.47(Engineering, Electrical & Electronic)In order to contribute to the development of technology to search fuel debris submerged in water inside the primary containment vessel of the Fukushima Daiichi Nuclear Power Station, we are developing a remotely operated vehicle (ROV) system equipped with a compact radiation detector and sonar. A cerium bromide (CeBr
) scintillator detector for dose rate monitoring and 
ray spectroscopy was integrated into ROV and experimentally validated with a 
Cs source, both in the conditions of laboratory and submerged. In addition, the ROV combined with the IMAGENEX 831L sonar could characterize the shape and size of a simulated fuel debris at the bottom of the water pool facility.
Kuroda, Kenta*; Ochi, Masayuki*; Suzuki, Hiroyuki*; Hirayama, Motoaki*; Nakayama, Mitsuhiro*; Noguchi, Ryo*; Bareille, C.*; Akebi, Shuntaro*; Kunisada, So*; Muro, Takayuki*; et al.
Physical Review Letters, 120(8), p.086402_1 - 086402_6, 2018/02
Times Cited Count：65 Percentile：91.27(Physics, Multidisciplinary)Nancekievill, M.*; Jones, A. R.*; Joyce, M. J.*; Lennox, B.*; Watson, S.*; Katakura, Junichi*; Okumura, Keisuke; Kamada, So*; Kato, Michio*; Nishimura, Kazuya*
Proceedings of 5th International Conference on Advancements in Nuclear Instrumentation Measurement Methods and their Applications (ANIMMA 2017) (USB Flash Drive), 6 Pages, 2017/06
We are developping a submersible ROV system, coupled with radiation detectors aimed at mapping the interior of the reactors at the Fukushima Daiichi Nuclear Power Station. To map the -ray intensity environment a cerium bromide (CeBr) inorganic scintillator detector sensitive to -rays has been incorporated into the ROV to measure -ray intensity and identify radioactive isotopes. The ROV is a cylindrical shape with a diameter of about 150 mm, and it have two end caps of five pumps each allowing control of the ROV in 5 degree of freedom. It is possible to directly replace the CeBr detector with a single crystal chemical vapour deposition (CVD) neutron detector with a 
Li convertor foil that is capable of mapping the thermal neutron flux.
Savage, D.*; Soler, J. M.*; Yamaguchi, Kohei; Walker, C.; Honda, Akira; Inagaki, Manabu; Watson, C.*; Wilson, J.*; Benbow, S.*; Gaus, I.*; et al.
Applied Geochemistry, 26(7), p.1138 - 1152, 2011/07
Times Cited Count：21 Percentile：46.27(Geochemistry & Geophysics)The use of cement and concrete as fracture grouting or as tunnel seals in a geological disposal facility for rad wastes creates potential issues concerning chemical reactivity. From a long term safety perspective, it is desirable to be able model these interactions and changes quantitatively. As part of the LCS (Long-term Cement Studies) project programme, a modelling inter-comparison has been conducted, involving the modelling of two experiments describing cement hadration and cement-rock reaction, with teams representing the NDA (UK), Posiva (Finland), and JAEA. This modelling exercise showed that the dominant reaction pathways in the two experiments are fairly well understood and are consistent between the different modelling teams, although significant differences existed amongst the precise parameterisation. Future modelling exercises of this type should focus on a suitable natural or industrial analogue that might aid assessing mineral-fluid reactions at these longer timescales.
Kitao, Takahiko; Shirafuji, Masaya; Sano, Kyohei; Watanabe, Kazuki; Horiuchi, Masakazu; Kato, Akane; Conner, J.*; LaFeur, A.*; Watson, M.*
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