Which statement correctly describes fissile materials?

Which statement correctly describes fissile materials?

• A. A material that emits no radiation.
• B. A fuel grade radioactive material capable of undergoing a nuclear chain reaction.
• C. A non-radioactive material.
• D. A material that cannot cause a chain reaction.

Answer: (B)

Fissile materials are defined by their ability to sustain a nuclear chain reaction once they absorb a neutron. That capability is what makes them suitable as reactor fuel, hence the description “fuel grade.” They are radioactive because their nuclei are unstable and decay, emitting radiation. In a chain reaction, the fission event releases neutrons that go on to cause more fissions in other fissile nuclei, allowing the reaction to continue. Descriptions that say the material emits no radiation, is non-radioactive, or cannot cause a chain reaction don’t fit, because fissile materials must be both radioactive and capable of sustaining fission with neutrons. Common examples include uranium-235 and plutonium-239.

Fissile materials are defined by their ability to sustain a nuclear chain reaction once they absorb a neutron. That capability is what makes them suitable as reactor fuel, hence the description “fuel grade.” They are radioactive because their nuclei are unstable and decay, emitting radiation. In a chain reaction, the fission event releases neutrons that go on to cause more fissions in other fissile nuclei, allowing the reaction to continue. Descriptions that say the material emits no radiation, is non-radioactive, or cannot cause a chain reaction don’t fit, because fissile materials must be both radioactive and capable of sustaining fission with neutrons. Common examples include uranium-235 and plutonium-239.