Abstract: A containment structure (1) for storage of nuclear fuel or liquids which have been in contact with nuclear fuel includes a concrete wall (3) and a concrete floor (2) with a corrosion resistant liner (5) fixed to and in contact with the walls and floor except at the junctions of the walls and floor at which the liner is curved to provide "soft corners" (7) to permit movement of the liner relative to the concrete walls and floor.The term "soft corner" as used in the context of the present specification denotes a region providing a gap or empty space or collapsible or compressible material, eg foam, between the stainless steel liner and the concrete walls and floor. Any collapsible or compressible material employed needs to be stable to the radioactive environment and for this reason it is preferred that a gap or empty space is employed.