If a control rod is pulled rapidly out of a nuclear reactor core, what controls the response time (how fast the power level increases)?
A)the speed at which the rod can be removed
B)the speed at which neutrons are captured
C)the rate at which delayed neutrons from beta decay of fission fragments are emitted
D)the rate at which the coolant circulates in the core
E)the time between when a neutron is captured and when the nucleus actually fissions

Question

Quizplus · Accepted Answer

The rate at which delayed neutrons from beta decay of fission fragments are emitted controls the response time because these delayed neutrons are responsible for a significant portion of the nuclear chain reaction. Without them, the power level would increase much more quickly. By removing the control rod, the delayed neutrons are able to contribute to the reaction, but the rate at which they are emitted determines how quickly the power level will rise. The other options are not directly related to the response time of the reactor.

If a Control Rod Is Pulled Rapidly Out of a Nuclear