What happens if a chain reaction is uncontrolled

The chain reaction continues as long as atoms absorb neutrons and undergo fission. Nuclear materials can undergo a controlled chain reaction without causing an explosion. For this to happen, the reaction rate must never exceed a critical value. If the rate is less than critical, the reaction involves fewer and fewer atoms until it stops completely. If the rate equals the critical amount, the reaction proceeds at the same speed until it runs out of atoms with which to react.

When the reaction is one in which the rate exceeds the critical value, the number of affected atoms increases exponentially with time; this reaction becomes uncontrolled. To achieve an uncontrolled chain reaction with uranium, the material must be refined to a purity of over 90 percent. When an atom undergoes radioactive decay, it may release neutrons, alpha or beta particles or gamma radiation; each of these carries energy.

Given the right radioactive substance, the energy builds up as heat. It is a series of industrial processes which involve the production of electricity from uranium in nuclear power reactors.

The nuclear fuel cycles start with the mining of uranium and end with the disposal of nuclear waste. To prepare uranium for use in a nuclear reactor, it undergoes the steps of mining, milling, conversion, enrichment, and fuel fabrication. Choose the correct answer from the options given below:. The source of renewable energy in stars is due to -.

James Chadwick Photoelectric 2. Albert Einstein Neutron 3. Marie Curie Radium Select the correct answer using the code given below:. The process responsible for enormous energy in the sun is. Twinkling of stars is due to.

The energy radiated by the Sun is because of. The process of fission occurs mainly in? More Nuclear Physics Questions Q1. The term radioactivity was coined by:. What do we call the atomic species of the same element differing in mass? What is the value of Avogadro number? What is the force that bind protons and neutrons in a nucleus? What is Uncontrolled Chain Reaction 4. A controlled chain reaction is a chain of nuclear reactions that take place subsequently under controlled conditions.

Let us understand this concept using nuclear fission reactions as an example. A fission chain reaction takes place when a neutron and a fissile isotope interact with each other. This interaction causes the release of some neutrons from the fissile nucleus. These released neutrons can interact with other fissile isotopes and cause the initiation of subsequent fission reactions. When these reactions are controlled and regulated properly, it is called a controlled chain reaction. Controlled fission reactions can be carried out in the presence of moderators.

Nuclear power plants use controlled chain reactions. There, the chain reactions are controlled by controlling the rate of nuclear reactions. Controlled chain reactions can easily be converted into uncontrolled form.

The reactions can be controlled by regulating the amount of starting material used the fissile isotope. For example, if the amount of Uranium used is high, then the reaction speed will also be high because then the probability of a neutron interacting with a fissile isotope is high. Then the reaction becomes uncontrollable.

And also, by regulating the time of the reaction, a nuclear chain reaction can be made into a controlled reaction. When the time of reaction is reduced, the probability of a neutron interacting with a fissile isotope is low.