Buffer Construction Methodology in Demonstration Test For Cavern Type Disposal Facility -9182

ABSTRACT A number of studies concerning a cavern type disposal facility have been carried out for disposal of low level radioactive waste mainly generated by power plant decommissioning in Japan 1) . The disposal facility is composed of an engineered barrier system with concrete pit and bentonite buffer, and planed to be constructed in sub-surface 50 -100 meters depth. Though the previous studies have mainly used laboratory and mock-up tests, we conducted a demonstration test in a full-size cavern. The main objectives of the test were to study the construction methodology and to confirm the quality of the engineered barrier system. The demonstration test was planned as the construction of full scale mock-up. It was focused on a buffer construction test to evaluate the construction methodology and quality control in this paper. Bentonite material was compacted to 1.6 Mg/m 3 in-site by large vibrating roller in this test. Through the construction of the buffer part, a 1.6 Mg/m 3 of the density was accomplished, and the data of workability and quality is collected