### Question
What is the definition of fast neutron?


### Answer
The definition of **fast neutron** is as follows in *42 U.S.C. § 16271*:

> a neutron with kinetic energy above 100 kiloelectron volts

#### Citation:
  - *42 U.S.C. § 16271*
  - Heading: **CHAPTER 149-NATIONAL ENERGY POLICY AND PROGRAMS > SUBCHAPTER IX-RESEARCH AND DEVELOPMENT > Part E-Nuclear Energy**

