aAtomic Energy of Canada Limited, Whiteshell Nuclear Research Establishment, Pinawa, Man. Canada
Abstract:
In-situ emplacement of clay-based buffers in a nuclear fuel waste disposal vault limits the maximum attainable buffer density. This will vary with the composition of the buffer. A study of the maximum attainable densities of candidate Na bentonite/sand and illite/sand buffers is described. The addition of sand significantly increases the achievable compacted density. This increase may be obtained without any decrease in the swelling pressures developed by Na bentonite buffers. Sand decreases the shrinkage potential of the buffer and may also decrease the mass diffusion coefficient. A mixture of 50% sand and 50% clay by mass appears to optimise the physical properties of the buffer.