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Matsui, Hiroya; Yahagi, Ryoji*; Okihara, Mitsunobu*; Toguri, Satohito*
no journal, ,
This report describes the overall plan of in-situ test to backfill a part of Mizunami Underground Research Laboratory, which is planned for development of tunnel backfilling method.
Yahagi, Ryoji*; Ishizuka, Hikaru*; Toguri, Satohito*; Matsui, Hiroya
no journal, ,
This repot summarize about the selection of the material and machines for in-situ experiment for the backfilling in a small scale drift by spray method funded by METI.
Ishizuka, Hikaru*; Yahagi, Ryoji*; Toguri, Satohito*; Matsui, Hiroya
no journal, ,
This repot summarize about the results of the in-situ experiment for the backfilling in MIU by spray method funded by METI.
Takayama, Yusuke; Kikuchi, Hirohito*; Yamamoto, Yoichi*; Goto, Takahiro*
no journal, ,
In this report, permeability, swelling characteristics, and consolidation characteristics of kaolinite were examined and these characteristics of kaolinite were are compared with kunigel V1.
Yahiro, Hanae*; Motoshima, Takayuki*; Sanoki, Satoru*; Miyakawa, Kazuya
no journal, ,
no abstracts in English
Mori, Takuo*; Niunoya, Sumio*; Kobayashi, Masato*; Nishimura, Masanobu*; Nakayama, Masashi
no journal, ,
Prefabricated Engineered barrier system Module (PEM) is one of option for Radioactive waste emplacement. Narrow gap between Tunnel and PEM must be backfilled with Bentonite, to prevent water permeability. Authors developed Bentonite Pellet Backfilling Method for the narrow gap. In-site test was executed at Horonobe URL -350m. Bentonite Pellet was backfilled two gaps (Minimum width: 110 mm) between an actual size PEM and the Tunnel. A 1.37 Mg/m
backfill dry density is achieved. It was proofed that the Bentonite Pellet Backfilling Method is averrable for the Radioactive waste emplacement.
Iso, Sachie*; Motoshima, Takayuki*; Shirase, Mitsuyasu*; Kobayashi, Masato*; Nakayama, Masashi
no journal, ,
In the high-level radioactive waste disposal project, backfilling the disposal tunnel using soil-bentonite mixtures has been developed. Authors have developed the shotclay method and machinery through elemental test on ground test site, and conducted in-situ verification test on Horonobe URL, underground test site deeper than 300m. In this paper, authors confirmed the workability and the quality of shotclay method in the underground conditions.
Sakai, Akihiro
no journal, ,
Plan of disposal of LLW generated from research facilities and recent topics of technical development of the disposal are explained. At first, regarding the radioactivity evaluation of waste, a study about the reduction of the number of important nuclides by the method that enhances the safety functions of the trench disposal facility is introduced. The installation of impermeable layers and sorption layers in order to reduce the leaching of nuclides and the installation of a cover structure with resistance to human intrusion into the waste layer are examined as the safety functions. Then, regarding the design and operation of trench disposal facilities, a measure that increase the slope angle of the cover soil beforehand is explained in order to prevent the cover soil from settlement caused by voids in the waste containers at the trench disposal facility. We will continue to study the specific design of trench disposal facilities to realize the measures to these issues.
Horikawa, Shigeo*; Sasaki, Takeshi*; Koshigai, Masaru*; Fukushima, Shigeru; Ohara, Yoshiyuki
no journal, ,
no abstracts in English
Nishida, Akemi
no journal, ,
To meet new regulatory standards and to improve the safety of nuclear plants, stability and fragility evaluation is being promoted against natural external events, such as earthquakes and tsunamis, for the buildings, foundation ground, surrounding slopes, and underground structures of nuclear plants. These are often evaluated via numerical analysis using a simplified analysis model, such as a two-dimensional one. Meanwhile, the research and development of high-performance computing, in which extra-large-scale models can be analyzed with high speed and accuracy, is progressing owing to advances in computers and solving methods for simultaneous equation. Research and development are conducted to analyze nuclear structures by employing a three-dimensional model using the aforementioned technology at a practical level. Here, we will discuss the use of such high-performance computing in the design and safety evaluation of nuclear power plants, as well as the potential issues that may arise.