Thermal and physical properties of candidate buffer–backfill materials for a nuclear fuel waste disposal vault

Abstract

As part of the Canadian Nuclear Fuel Waste Management Program, Ontario Hydro has, over several years, conducted research into the behaviour and performance of buffer–backfill for the proposed nuclear fuel waste disposal vault. In this paper, a review has been made of laboratory studies made at Ontario Hydro on the thermal properties, strength, hydraulic conductivity, and compactability of clay-based buffer materials. The results of this work have enabled the formulation of selection criteria for the buffer material mix for the prototype Canadian nuclear fuel waste disposal scheme. Key words: bentonites, buffer, backfill, nuclear waste disposal, thermal conductivity, clays, hydraulic conductivity, compaction, clay barriers, clay seals, shrinkage.