Dangers in Safety Systems

Reactor safety systems have failed in such a way as to destroy the reactor which they were intended to protect. Safety rods, when released, can, through malfunction, increase rather than decrease reactivity. The electronic and sensing portions of the safety system are usually arranged so that random failures may on rare occasions result in a slight impairment of protection. The total loss of protection should not in itself lead to damage to the reactor. Systematic failures have occurred however, such that the safety and control systems have become coupled either deliberately or through oversight in such a way that the loss of protection and reactor runaway have been caused by a single event.