In a well-designed water-cooled thermal fission reactor, the water is acting as a moderator for the neutrons. If some of this water is lost, the chain reaction in the reactor core will slow down because neutrons in the reactor core will
A) remain positively charged and will not be able to cause uranium 235 nuclei to fission.
B) not be magnetic enough to stick to uranium 235 nuclei and cause them to fission.
C) be traveling too fast and will be absorbed by uranium 238 nuclei.
D) be traveling too slowly and will be unable to cause uranium 235 nuclei to fission.

Question

Quizplus · Accepted Answer

Water in a thermal fission reactor serves as a moderator, slowing down neutrons so they can more effectively cause fission in uranium-235 nuclei. If water is lost, neutrons remain too fast, making them more likely to be absorbed by uranium-238 without causing fission.

In a Well-Designed Water-Cooled Thermal Fission Reactor, the Water Is