A delayed neutron is emitted by what kind of products?

A delayed neutron is emitted by what kind of products?

• A. Stable isotopes
• B. Neutron-rich fuel
• C. Water molecules
• D. Fission products

Answer: (D)

Delayed neutrons come from the fission products—the unstable fragments created when a heavy nucleus splits. After fission, many of these fragments are neutron-rich and undergo beta decay. In a subset of those decays, the daughter nucleus is left in an excited state and releases a neutron as part of the decay process. This neutron is emitted with a delay compared to the prompt neutrons produced directly at fission. Water and the fuel itself don’t produce these delayed neutrons, and stable isotopes don’t emit neutrons at all. Because delayed neutrons arise from the decay of fission fragments over milliseconds to seconds, they provide a critical time window that helps control the reactor.

Delayed neutrons come from the fission products—the unstable fragments created when a heavy nucleus splits. After fission, many of these fragments are neutron-rich and undergo beta decay. In a subset of those decays, the daughter nucleus is left in an excited state and releases a neutron as part of the decay process. This neutron is emitted with a delay compared to the prompt neutrons produced directly at fission. Water and the fuel itself don’t produce these delayed neutrons, and stable isotopes don’t emit neutrons at all. Because delayed neutrons arise from the decay of fission fragments over milliseconds to seconds, they provide a critical time window that helps control the reactor.