Control Poisons
During operation of a reactor the amount of fuel contained in the core decreases monotonically. If the reactor is to operate for a long period of time, fuel in excess of that needed for exact criticality must be added when the reactor is fueled. The positive reactivity due to the excess fuel must be balanced with negative reactivity from neutron-absorbing material. Movable control rods containing neutron-absorbing material is one method, but control rods alone to balance the excess reactivity may be impractical for a particular core design as there may be insufficient room for the rods or their mechanisms.
Read more about this topic: Neutron Poison
Famous quotes containing the words control and/or poisons:
““Have we any control over being born?,” my friend asked in despair. “No, the job is done for us while we’re sleeping, so to speak, and when we wake up everything is all set. We merely appear, like an ornate celebrity wheeled out in a wheelchair.” “I don’t remember,” my friend claimed. “No need to,” I said: “what need have us free-loaders for any special alertness? We’re done for.””
—Marvin Cohen, U.S. author and humorist. The Self-Devoted Friend, New Directions (1967)
“Vices enter into the composition of virtues as poisons into the composition of certain medicines. Prudence and common sense mix them together, and make excellent use of them against the misfortunes that attend human life.”
—François, Duc De La Rochefoucauld (1613–1680)