Most of the considerable developments in the commonly used construction materials and especially concrete and steel, on their own or compositely, are not specific to containment. Prestressing can greatly assist crack control and lightweight concrete can prove advantageous (18). Material development has thus been boosted by the needs of many industries and every kind of construction. Some high density/ less permeable concretes are now achieved using such additives as micro-silica and better plasticisers aid concrete flow and its compaction during construction. These have special relevance to containment of low viscosity liquids or sensitive materials. The long trouble free life demanded of containers for storing fissile or other hazardous materials has lead to research into longer term material behaviour and crack control. The need to conserve scarce resources and the high cost of dumping waste is leading to other research into more effective recycling, e.g the use of crushed concrete as aggregate.