Definition

1. Noun:
   • A fast reactor is a type of nuclear reactor in which the nuclear fission chain reaction is sustained primarily by fast neutrons. This is achieved by using little to no moderator material to slow down the neutrons.

Usage

• The term fast reactor is used in the context of nuclear physics and energy technology. It describes a specific reactor design that operates with high-energy neutrons.
• It is often discussed in comparison to thermal reactors, which use a moderator to slow neutrons down.

Examples

• Noun:
  • The experimental fast reactor achieved criticality this morning.
  • One advantage of a fast reactor is its potential to reduce long-lived radioactive waste.
  • The country is investing in research for next-generation fast reactor technology.

Advanced Usage

• "Fast breeder reactor (FBR)": A specific and common type of fast reactor designed to produce more fissile material than it consumes.
  • The fast breeder reactor is a key concept in closing the nuclear fuel cycle.

Variants and Related Words

• Fast-neutron reactor: A synonymous technical term.
• Fast spectrum reactor: Another term emphasizing the energy spectrum of the neutrons.
• Breeder reactor: A broader category that often, but not always, uses fast neutrons.

Synonyms

• Fast-neutron reactor
• Fast spectrum reactor

Related Phrases

• Fast reactor fuel: Refers to the specific nuclear fuel, often a metal or oxide mixture, used in such reactors.
  • The facility specializes in fabricating fast reactor fuel.
• Fast reactor coolant: The substance, typically liquid metal (e.g., sodium, lead), used to remove heat from the reactor core.
  • Sodium is a common choice for a fast reactor coolant.

Noun

1. nuclear reactor in which nuclear fissions are caused by fast neutrons because little or no moderator is used