CURRENT STATE OF KNOWLEDGE ON THE BEHAVIOR OF STEEL LINERS IN CONCRETE CONTAINMENTS SUBJECTED TO OVERPRESSURIZATION LOADS

In the US, concrete containment buildings for commercial nuclear power plants have steel liners that act as the internal pressure boundary. The liner abuts the concrete, acting as the interior concrete form. Th e liner is attached to the concrete by either studs or by a continuous structural shape (such as a T-section or channel) that is either cont inuously or intermittently welded to the liner. Studs are commonly use d in reinforced concrete containments, while prestressed containments utilize a structural element as the anchorage. The practice in some co untries follows the US practice, while in other countries the containm ent does not have a steel liner. In this latter case, there is a true double containment, and the annular region between the two containment s is vented. This paper will review the practice of design of the line r system prior to the consideration of severe accident loads (overpres surization loads beyond the design conditions). An overpressurization test of a 1:6 scale reinforced concrete containment at Sandia National Laboratories resulted in a failure mechanism in the liner that was no t fully anticipated. Post-test analyses and experiments have been cond ucted to understand the failure better. This work and the activities t hat followed the test are reviewed. Areas in which additional research should be conducted are given.