How does a nuclear reactor work?


I was watching the HBO series Chernobyl and in the second episode, Professor Legasov explains the working of a nuclear reactor. Unfortunately the explanation wasn’t enough. Enlighten me.


When Uranium decays and atoms split, it releases heat which is used to boil water and rotate a turbine with the steam that is generated.

When nuclear atoms gets hit with neutrons it gets hot. And tosses out more neutrons. Those new neutrons cause more atoms to get hot and toss out neutrons.

It’s a sort of self-sustained effect in a material that rapidly heats itself up.

Well. For a while. Eventually it’ll be crap at tossing electrons, and heat less. But let’s overlook that for a bit.

That heat is nifty to make use of. If you place the material in a tank full of water, it’ll make steam. High pressure steam.

The steam is used to move a turbine on a generator.

That’s pretty much what there is to it.

Very advanced and very dangerous kettle. Kind of like when you make tea in your kitchen. Except larger. Lots larger.

It’s literally advanced machinery that boils water in a fashion that makes it important to monitor it closely and add tons of safety features.

Edit; spelling.

A uranium atom absorbs a neutron, becomes unstable and splits. It splits into 2 smaller elements and more neutrons, as well as releasing energy in the form of heat. These neutrons are absorbed by more uranium atoms and the process repeats.

The coolant (water, molten salt, etc) moves this heat from the core to steam generators (boiler water reactors work a bit differently here), where steam is created to drive turbines for propulsion or electricity.

Control rods also absorb neutrons, but don’t react like the fuel. They are used to control the nuclear reaction and shut the reactor down when needed.

Rule 7: please search before posting

There are different different types of reactors, the one used in the Chernobyl plant was rather unique.

At a high level, all fossil, nuclear, gas power plants tend to do the same thing. They make steam. Steam is then used to make the power.

In a nuclear plant the heat that creates the steam is comes from nuclear fission. There is a core of nuclear fuel, which is bombarded by neutrons which creates a reaction of which one of the by-products is heat.

That heat is used to heat up water to the point that it creates steam, the steam is then used to turn a turbine, which spins a power generator and makes power.