plutonium powered nuclear fission reactor

In some cases, the heat released by the chain reaction will cause the fissile (and other nearby) materials to expand. This is because all the design features needed to make a nuclear warhead cannot arise by chance. Though dangerous and frequently lethal to humans within the immediate area, the critical mass formed would not be capable of producing a massive nuclear explosion of the type that fission bombs are designed to produce. A criticality accident occurs if the same reaction is achieved unintentionally, for example in an unsafe environment or during reactor maintenance. Under normal circumstances, a critical or supercritical fission reaction (one that is self-sustaining in power or increasing in power) should only occur inside a safely shielded location, such as a reactor core or a suitable test environment. Criticality accidents can release potentially fatal radiation doses, if they occur in an unprotected environment. Any such event involves the unintended accumulation or arrangement of a critical mass of fissile material, for example enriched uranium or plutonium. It is sometimes referred to as a critical excursion, critical power excursion, or divergent chain reaction.

Uncontrolled nuclear fission chain reactionĪ criticality accident is an accidental uncontrolled nuclear fission chain reaction.

Plutonium powered nuclear fission reactor