Which of the following is NOT required as a component in a typical nuclear fission reactor?

Correct Answer: Accelerator

Subject: chemistry

Moderator (e.g., Heavy water or Graphite)
Control rods (e.g., Boron or Cadmium)
Accelerator
Coolant (e.g., Liquid Sodium)

Explanation: • Key Fact Accelerators are used to speed up particles in high-energy physics, but they are NOT needed in a nuclear fission reactor. • Supporting Detail Reactors need Moderators (to slow down fast neutrons), Control rods (to absorb excess neutrons), and Coolants (to transfer heat). • Related Concept U-235 is used as the standard fission material (fuel rod). • Why wrong options are wrong Moderators, Control rods, and Coolants are all indispensable parts of a controlled nuclear chain reaction. • Exam Trick Moderator = SLOWS down (Graphite/D₂O). Control Rod = ABSORBS (Boron/Cadmium). • Additional Info An atomic bomb is an uncontrolled chain reaction, whereas a nuclear reactor is a controlled chain reaction.