IGNOU MPHE 26 2026 - What are prompt and delayed neutrons? Discuss the role of delayed neut

Question

What are prompt and delayed neutrons? Discuss the role of delayed neutrons in reactor safety.

19 Jan 2026

Answer :

Word Count : 273

Prompt neutrons are those emitted almost immediately (within about 10⁻¹⁴ seconds) during the fission process of a heavy nucleus like uranium-235 or plutonium-239. They are released directly from the splitting of the nucleus and constitute the majority of neutrons in a fission event, typically around 99% of the total neutrons produced. These neutrons are highly energetic and play a primary role in sustaining the chain reaction in a nuclear reactor. Delayed neutrons, on the other hand, are emitted not directly from the

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