There has been an emphasis, recently, on the calculation of potential hazards beyond the primary containment of liquid-metal fast breeder reactors. A number of analyses have been conducted in order to follow the progression of a highly energetic core disruptive accident from its inception to its consequences in secondary containment. The investigation is limited to the direct mechanical effects of the initial core disassembly phase. An effort has been made to develop an integrated treatment of the accident sequence by extending the capability of primary containment codes, when necessary, to treat as broad a range of accident phenomena as possible. Beginning with the initiation phase, the release of energy to reactor internals and primary containment boundary is discussed. Emphasis must be placed on highly energetic accidents if the intent is to generate such severe phenomena as missiles and sodium spillage. Characterization of energetic events is accomplished by deriving work potential as a function of reactivity insertion in the reactor core. This source term is used for the primary containment analysis. Energy partitioning for hypothetical core disruptive accidents within the primary containment provides information concerning the system integrity and the potential for consequences that go beyond the primary containment boundary. The behavior of the reactor cover deserves special attention. During the slug impact phase, forces transmitted to the head would be the source for potential missiles and can open leak paths for sodium spillage. Studies on missile generation and sodium spillage are currently being performed to estimate the potential effects on secondary containment. Scoping calculations of generic missiles, generated by sodium slug impact loadings, as well as the coupled motion of an unrestrained reactor plug during the impact transient have been completed. Modeling of penetrations in the reactor cover for sodium spillage has been accomplished and spillage due to sodium impact on the reactor cover has been investigated.