Question

Distinguish between controlled and uncontrolled chain reactions.

Answer 1

Parameter	Controlled Chain Reaction	Uncontrolled Chain Reaction
Nature	A chain reaction in which the neutrons created during the initial fission reaction induce only one additional fission reaction and the excess neutrons get eliminated by control rods.	In a chain reaction in which all the neutrons are produced during the initial fission, they again react with the uranium atom causing further fission and leading to an explosion.
Rate of reaction	The reaction rate is low, as only 60 uranium-235 atoms undergo fission in one minute.	The rate of reaction is fast, as ${10}^{20}$ Uranium-235 atoms undergo fission in one minute.
Energy released	The rate of producing energy is slow and steady and can be regulated as well.	The rate of producing energy is quite fast and can't be managed.
Usage of energy	The produced energy through the controlled chain reaction is useful to generate electricity.	The produced energy can be used for only destructive purposes.