Research for the erosion of buffer material with the vertical disposal concept, 3; In situ tests on engineering scale at Horonobe URL

Ono, Makoto*; Motoshima, Takayuki*; Shirase, Mitsuyasu*; Yokoyama, Satoshi*; Jo, Mayumi*; Ishii, Tomoko*; Nakayama, Masashi ; Ono, Hirokazu 

To understand phenomenon of buffer material erosion in the vertical disposal concept, in situ tests on engineering scale have been carried out at Horonobe URL. As results of water injection with flow rate control, when water flowed in a continuous large flow rate, buffer materials did not swell enough to stop the water flow and the water flow path was confirmed to be formed by aggregated into a single pipe. Further, it was suggested that water pressure of the injection side contributes to the erosion of buffer materials.