Investigation on sealing in geological disposal (II)

not registered; Toida, Masaru*; Shiogama, Yukihiro*; Yasui, Shingo*; Kawabata, Junichi*; not registered; Tanaka, M.*

For the geological disposal of high level radioactive wastes, after placement of the wastes, it is necessary to close off (to be called "sealing" hereafter) the underground potential passages (disposal pits, disposal tunnels, liaison tunnel and construction tunnels) with an effective combination of engineered barriers such as buffers, backfilling materials, plugs and grout. It is necessary to ensure the long-term liability to isolate disposed wastes in the system. The results of the research works this year are as follows ; (1)To determine the deformation properties of unsaturated sand-bentonite mixture three cyclic triaxial tests were carried out. (2)The objectives are to discuss the design of tunnel sealing experiments at URL site. The results of research are about (a)instrumentation and monitoring, (b)tracer experiment.