The MIT Nuclear Reactor Laboratory (MIT-NRL) is an interdepartmental center that operates a high performance 6 MW research reactors known as the MITR-II. It is the second largest university research reactor in the U.S. and the only one located on the campus of a major research university.

A nuclear reactor is a system that contains and controls sustained nuclear chain reactions. Reactors are used for generating electricity, moving aircraft carriers and submarines, producing medical isotopes for imaging and cancer treatment, and for conducting research.

What Are The Components of a Nuclear Reactor ?

1. Core  It’s the focal point of the reactor, where fuel is contained and nuclear fission reactions take place.
2. Fuel – Generally, fuel is made of small-enriched uranium oxide rods, stacked so as to form cylinders, approx. 4 meters long and with a diameter of about one centimetre. These rods are wrapped in metal sheathes (steel or zirconium alloy), which allow heat to pass through while blocking the radioactive elements produced by fission.
3. Moderator – This is a material placed in the reactor to slow down the neutrons produced by fission, in order to reach the most suitable speed allowing the chain reaction to continue.
   Depending on the various reactor models, the moderator may consist of graphite, water or heavy water
4. Heat-transfer fluid (or coolant) – This fluid cools the core and carries outside the heat that is produced there. The most commonly used fluid is water, but some types of reactors use different fluids .
5. Control rods – These are rods used in specific materials to control fission inside the core. Since they absorb neutrons, they are capable of controlling the chain reaction which – depending on how deep down the rods are inserted into the core – can be accelerated, slowed down or even stopped, thus changing the capacity of the reactor. Indeed, if necessary, the reactor can be immediately stopped when they are fully inserted.
6. Vessel – The large steel recipient containing the core, the control rods and the heat-transfer fluid.

What Is A Chain Reaction

The neutron-fission chain reaction: a neutron plus a fissionable atom causes a fission resulting in a larger number of neutrons than was consumed in the initial reaction.  Chemical reactions, where a product of a reaction is itself a reactive particle, which can cause more similar reactions. For example, every step of H2 + Cl2 chain reaction consumes one molecule of H2 or Cl2, one free radical H· or Cl· producing one HCl molecule and another free radical. Electron avalanche process: Collisions of free electrons in a strong electric field forming  new electrons to undergo the same process in successive cycles.