Question

which procedure will most increase the energy output of a nuclear reactor?
exposing the core to the outside world
removing fissile material from the core
decreasing the amount of steam produced
raising the control rods out of the reactor

Explanation:

Control rods in a nuclear reactor absorb neutrons. Raising them out of the reactor reduces neutron - absorption, allowing more fission reactions to occur and increasing energy output. Exposing the core to the outside world is dangerous and not a normal operation for increasing energy. Removing fissile material reduces fuel for reactions. Decreasing steam production is related to energy conversion and not directly to increasing the nuclear reaction rate.

Answer:

raising the control rods out of the reactor