Zero power critical is a condition of nuclear fission reactors, that is useful for characterizing the reactor core. A reactor is in the zero power critical state if it is sustaining a stable fission chain reaction with no significant growth or decay in the reaction rate, and at a low enough level that thermal considerations are not important to the reaction. For example, a reactor that can produce gigawatts of heat might be considered zero-power critical when producing 100 watts of heat through a fission chain reaction.
Most nuclear reactors are held at a zero-power critical condition as part of the start-up sequence, to assess the condition of the reactor itself.
Famous quotes containing the words power and/or critical:
“If Paris lived now, and preferred beauty to power and riches, it would not be called his Judgment, but his Want of Judgment.”
—Horace Walpole (1717–1797)
“Much of what contrives to create critical moments in parenting stems from a fundamental misunderstanding as to what the child is capable of at any given age. If a parent misjudges a child’s limitations as well as his own abilities, the potential exists for unreasonable expectations, frustration, disappointment and an unrealistic belief that what the child really needs is to be punished.”
—Lawrence Balter (20th century)