Design and behaviour of French containments

Abstract

In this report, the point is made that the French nuclear installations have two types of containments: • - The first consisting of a pre-stressed concrete inner containment with a leakproof liner. • - The second consisting of a pre-stressed concrete inner containment without a leaktight liner and an outer containment of reinforced concrete concentric with the former. The space between the two containments is maintained at a negative pressure, to intercept any leaks from the internal containment, which are filtered and discharged outside in the event of an accident. After covering the mechanical design of these two types of containments, this report examines the existing safety margins for aircraft crashes and explosions resulting from the industrial environment. The report then considers in greater detail the leaktightness results of the double containments obtained during acceptance tests, as well as the leaktightness conditions while the reactor is operating. Finally, the report describes, for the case of containments with leakproof liners, the conditions of aging of the concrete and the associated pre-stressing.