Criticality safety-practices and experience

The most important aspect of criticality control is accident prevention because of the potentially serious consequences that can result. In all activities involving fissile materials, the plant authorities should exercise control such that the probability of a criticality incident is held at the lowest practical level. Criticality safety must be evaluated not only for the normal operating conditions of the plant but also for those off-standard or mal-operating conditions, which are physically possible and might lead to a nuclear chain reaction