HEAT TRANSFER AND STABILISING APPARATUS

A metal compressible bellows-type container or canister is used in a hot uniaxial pressing process with a mixture of high level radioactive nuclear waste material and a synthetic rock forming material filling the canister. The canister has a bottom wall, a convoluted bellows-like side wall, a lid or top wall and transverse metal apertured plates dividing the canister into three equally sized zones. Preferably the apertures are of a clover leaf configuration and are located at the center of the plates. Cylindrical liners can be provided to maintain a zone between each liner and the bellows-like side wall to prevent ingress of the particulate mixture of waste and synthetic rock forming material.