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:
“I had some short struggle in my mind whether I should resign my lover or my liberty, but this lasted not long. I found myself as free as air and could not bear the thought of putting myself in any man’s power for life only from a present capricious inclination.”
—Sarah Fielding (1710–1768)
“A third variety of drama ... begins as tragedy with scraps of fun in it ... and ends in comedy without mirth in it, the place of mirth being taken by a more or less bitter and critical irony.”
—George Bernard Shaw (1856–1950)