Laboratory gas injection tests of compacted bentonite buffer material for TRU waste disposal

Abstract

The Radioactive Waste Management Funding and Research Center (RWMC) is leading a research programme to evaluate the gas transport mechanisms through a TRU (TRans-Uranium) waste disposal facility in Japan and acquire information on gas migration properties. In this paper we describe a series of laboratory gas injection tests using the bentonite adopted for use in Japanese TRU disposal, as well as an attempted visualization of the gas migration path inside the bentonite used as a buffer. By building a conceptual model from the results of these tests, the characteristics of gas migration through to breakthrough for bentonite can now be better understood in the context of Japanese TRU disposal. Thanks to the outcome of this research project, advanced knowledge may be applied to the conceptualization of TRU waste disposal.