In a nuclear reactor what absorbs the fast moving neutrons? control rod an accelerator a moderator a detector

## Step 1<br />In a nuclear reactor, the fast-moving neutrons are absorbed by a moderator. The moderator's role is to slow down these fast-moving neutrons to thermal speeds. This is done by a process called moderation.<br />## Step 2<br />The slowed-down neutrons, also known as thermal neutrons, are then available to be captured by the fuel, which in turn produces more nuclear reactions. This process is known as a chain reaction.<br />## Step 3<br />Control rods are used to absorb these thermal neutrons, which slows down the chain reaction. This is done to prevent the reactor from overheating.<br />## Step 4<br />Accelerators and detectors, on the other hand, do not play a role in the absorption of fast-moving neutrons in a nuclear reactor.