[en] In many parts of the world, increasing attention is being given to determining the ultimate load capacity of nuclear containments in order to improve the quantification of the risk analyses involved in determining probability and magnitude of nuclear release from a reactor under extreme loading conditions following postulated accident scenarios. A nuclear containment building for a typical commercial power reactor consists of a cylindrical structure built around the entire reactor and heat exchange system to the steam generation plant, and forms the final barrier to the environment against any form of radioactive release. Some of the work performed at the Council for Nuclear Safety (CNS) on the reactor containment building of the Koeberg Nuclear Power Station is described as an example of an aspect of the work of the CNS in the safety assessment of nuclear installations. 3 tabs., 2 ills., 1 fig