Nakano, Masanao; Fujii, Tomoko; Nagaoka, Mika; Koike, Yuko; Yamada, Ryohei; Kubota, Tomohiro; Yoshii, Hideki*; Otani, Kazunori*; Hiyama, Yoshinori*; Kikuchi, Masaaki*; et al.
JAEA-Review 2020-070, 120 Pages, 2021/02
Based on the regulations (the safety regulation of Tokai Reprocessing Plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and by law of Ibaraki Prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2019. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.
Fukaya, Masaaki*; Takeda, Nobufumi*; Miura, Norihiko*; Ishida, Tomoko*; Hata, Koji*; Uyama, Masao*; Sato, Shin*; Okuma, Fumiko*; Hayagane, Sayaka*; Matsui, Hiroya; et al.
JAEA-Technology 2016-035, 153 Pages, 2017/02
The researches on engineering technology in the Mizunami Underground Research Laboratory (MIU) project in FY2016, detailed investigations of the ( mechanical )behaviors of the plug and the rock mass around the reflood tunnel through ongoing reflood test were performed as part of (5) development of technologies for restoration and/or reduction of the excavation damage. As the result, particularly for the temperature change of the plug, its analytical results agree fairly well agree with the measurement ones. This means cracks induced by temperature stress can be prevented by the cooling countermeasure works reviewed in designing stage. In addition, for the behaviors of the plug and the bedrock boundary after reflooding the reflood tunnel, comparison between the results obtained by coupled hydro-mechanical analysis (stress-fluid coupled analysis ) with the ones by several measurements, concluded that the model established based on the analysis results is generally appropriated.
Fukaya, Masaaki*; Hata, Koji*; Akiyoshi, Kenji*; Sato, Shin*; Takeda, Nobufumi*; Miura, Norihiko*; Uyama, Masao*; Kaneda, Tsutomu*; Ueda, Tadashi*; Hara, Akira*; et al.
JAEA-Technology 2016-002, 195 Pages, 2016/03
The researches on examination of the plug applied to the future reflood test was conducted as a part of (5) development of technologies for restoration and/on reduction of the excavation damage relating to the engineering technology in the MIU (2014), specifically focused on (1) plug examination (e.g. functions, structure and material) and the quality control methods and (2) analytical evaluation of rock mass behavior around the plug through the reflood test. As the result, specifications of the plug were determined. These specifications should be able to meet requirements for the safety structure and surrounding rock mass against predicted maximum water pressure, temperature stress and seismic force, and for controlling the groundwater inflow, ensuring the access into the reflood gallery and the penetration performance of measurement cable. Also preliminary knowledge regarding the rock mass behavior around the plug after flooding the reflood gallery by installed plug was obtained.
Sato, Toshinori; Mikake, Shinichiro; Miura, Norihiko*; Ishida, Tomoko*
Tonneru To Chika, 46(12), p.901 - 911, 2015/12
The Japan Atomic Energy Agency conducts studies and research associated with the excavation of underground research facility at the Mizunami Underground Research Laboratory in Mizunami City, Gifu Prefecture. The research laboratory is an underground facility consisting of two shafts and some drifts and excavation has currently extended to a depth of 500 m. One of in-situ experiments, groundwater recovery experiment to understand groundwater pressure and geochemical properties change due to groundwater flooded has been performed in the GL.-500m drift. This report contains the results of design work of concrete plug for groundwater recovery experiment. Structural analysis and thermal stress analysis were performed to check resistant ability to over 5 MPa. Measurement plan was also discussed in this report.
Kudo, Kushi*; Ishida, Junichi*; Syuu, G.*; Sekine, Yurina; Fukazawa, Tomoko*
Journal of Chemical Physics, 140(4), p.044909_1 - 044909_8, 2014/01
To investigate the mechanism of structural changes of water and polymer networks with drying and swelling, we measured the Raman spectra of a physically cross-linked poly(vinyl alcohol) (PVA) hydrogel synthesized using the freezing thawing method. On the basis of the dependence of the frequency shifts on the PVA concentration of the original solution, it was found that the structure of the polymer network in the reswollen hydrogel becomes inhomogeneous due to shrinkage of the polymer network with drying. Furthermore, to investigate the effects of the cross-linking structure on the drying process, these results were compared with those of a chemically cross-linked PVA hydrogel synthesized using glutaraldehyde as a cross-linker. The results show that the structures of the polymer network and water change with the gel preparation process, cross-linking method, and drying and reswelling processes.
Tanaka, Tatsuya*; Uyama, Masao*; Ishida, Tomoko*; Nakanishi, Tatsuro; Onishi, Yuzo*
Proceedings of 7th Asian Rock Mechanics Symposium (ARMS-7) (USB Flash Drive), p.702 - 711, 2012/10
This paper describes the planning, material selection, execution and interpretation of the grout injection test carried out at the end of 2011 at the Grimsel Test Site (GTS) in Switzerland as part of grouting technology project of the Japan Atomic Energy Agency (JAEA). Based on the findings of the rockmass characterization part of the GTS grouting study (Nakanishi et al, 2012, Bruines et al., 2012), it was decided to perform the grout injection test in a 5 m interval with the highest expected hydraulic conductivity. During the grouting test the viscosity of the grout was continuously measured. Both the injected volume and pressure in the injection section were recorded. In the observation sections the pressure over time as well as the electric conductivity, which can be used to measure the arrival of the higher salinity silica grout, was recorded. As the grout reached the observation sections before the grout hardened the grout injection test was a success. The gathered data of the grouting test presents an important data set for further modeling efforts of the grouting process.
Nakayama, Masashi; Miura, Norihiko*; Ishida, Tomoko*; Takeda, Nobufumi*; Niunoya, Sumio*; Jo, Mayumi*
no journal, ,
no abstracts in English
Motoshima, Takayuki*; Usui, Tatsuya*; Sakamoto, Atsushi*; Niunoya, Sumio*; Ishida, Tomoko*; Miura, Norihiko*; Nakayama, Masashi; Ono, Hirokazu
no journal, ,
Japan Atomic Energy Agency is conducting the in-situ experiment for verification of performance of engineered barrier system in Horonobe Underground Research Laboratory. The purpose of this paper is reporting the mix design of high-workable low-alkaline plug concrete. This paper also reports the thermal stress analysis of plug concrete and results of in-situ thermal measurements.