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Journal Articles

Application of USV to marine monitoring after Fukushima Daiichi Nuclear Power Plant Accident and its applicability as a nuclear disaster prevention tool

Sanada, Yukihisa; Misono, Toshiharu; Shiribiki, Takehiko*

Kaiyo Riko Gakkai-Shi, 27(2), p.37 - 44, 2023/12

https://doi.org/10.14928/amstec.27.2_37

This paper summarizes the general situation of marine monitoring conducted after the Fukushima Daiichi Nuclear Power Plant accident, the experience of development and operation of USVs, and the possibility of applying unmanned vessels as a tool for nuclear disaster prevention in the future. 0.01 Bq/L or less for seawater and 10 Bq/L or less for seabed soil. Operational tests of three USVs have been continuously conducted for use in such environmental radiation monitoring. Development of these UAVs is underway with a view to utilizing them for seawater sampling, direct measurement of the seafloor soil surface layer, and seafloor soil sampling, depending on their performance. It is necessary to promote the development of USVs for future nuclear power plant accidents.

Journal Articles

Detection of Simulated Fukushima Daiichi Fuel Debris Using a Remotely Operated Vehicle at the Naraha Test Facility

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

https://doi.org/10.3390/s19204602

Times Cited Count：9 Percentile：44.74(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.

Journal Articles

Transition of near surface resistivity of tunnel wall during drift closure test

Ozaki, Yusuke; Ishibashi, Masayuki; Matsushita, Tomoaki*; Masumoto, Kazuhiko*; Imasato, Takehiko*

Proceedings of 13th SEGJ International Symposium (USB Flash Drive), 4 Pages, 2018/11

In the Mizunami Underground Research Laboratory, Groundwater REcoverty Experiment in Tunnel (GREET) is performed to understanding the recovery process of geological environment after the closure of drift. In this experiment, we performed 2D electrical resistivity surveys three times. First survey was performed before the closure of test drift. Second and third surveys were performed after the closure test. The first survey detected two layers conformation that consists of conductive and resistive zones at shallower and deeper part from the drift surface, respectively. These layers correspond to the shotcrete and host rock, respectively. Second and third measurements show that the conductive zone expanded to deeper resistive part while the shallower conductive part did not change. We concluded that we captured the saturation process of dried fractures near the drift wall by closure of drift as an electrical resistivity response.

JAEA Reports

Regional hydrogeological study project; Results from 1992-1999 period

Koide, Kaoru; Nakano, Katsushi; Takeuchi, Shinji; Hama, Katsuhiro; ; Ikeda, Koki;

JNC TN7400 2000-014, 83 Pages, 2000/11

JNC-TN7400-2000-014.pdf:4.84MB

The Japan Nuclear Cycle Development Institute (JNC) has been conducting a wide range of geoscientific research in order to build a firm scientific and technological basis for the research and development of geological disposal. One of the major components of the ongoing geoscientific research programme is the Regional Hydrogeological Study (RHS) project in the Tono region, central Japan. The main goal of the RHS project is to develop and demonstrate surface-based investigation methodologies to characterize geological environments at a regional scale in Japan. The RHS project was initiated in 1992. The first five years of the project were devoted mainly to develop methodologies and techniques for deep borehole investigations in crystalline rock in Japan. Investigations to verify the performance of new instruments and methods for borehole drilling, hydraulic testing and groundwater sampling were conducted. In the last four years, surface-based investigations and a stepwise development of models of the geological environment have been carried out. To date, remote sensing, geological mapping, airborne and ground geophysical investigations, and measurements in eleven deep boreholes have been carried out. Hydro monitorring is continuing in these boreholes. Important results that have been obtained from these investigations include multi-disciplinaly information about the heterogeneity of lithology and hydraulic, geochemical and rock mechanical properties of the granitic rock, and evolution of the groundwater geochemistry. Technical knowledge and experience have been accumulated, which allow application of the methodologies and techniques to characterize the geological environment in crystalline rock. The results from these R%D activities were used as prime inputs for the H12 report that JNC submitted to the Japanese Government in l999. Results from such R&D is also acknowledged by other geoscientific studies in general. JNC will synthesize the results from R&D ...

JAEA Reports