Nuclear Reactor - Understanding how it works | Physics Elearnin

Nuclear Reactor - Understanding how it works | Physics Elearnin video

Nuclear reactors are the modern day devices extensively used for power generation as the traditional fossil fuels, like coal, are at the breach of extinction. A nuclear reactor is the source of intense heat which is in turn used for generation of power in nuclear power station. Its mechanism is similar to that of a furnace in a steam generator; the steam is used to drive the turbines of the electric generator system.
A nuclear reactor consists of three crucial components: Fuel elements, moderator and control rods.
Fuel elements come usually in the shape of thin rods of about 1cm in diameter and contain fissionable nuclei, like Uranium (235 92U or 238 92U). These rods vary in number according to the size of the reactor, in large power reactor thousands of fuel elements are placed close to each other. This region where these fuel elements are placed is called the reactor core. These fuel elements are normally immersed in water which acts as a moderator.
The objective of a moderator is to slow down the energy neutrons in a nuclear reactor which are produced during the nuclear fission process by the fuel elements. Thermal neutrons, which are neutrons with energy of about 0.04 electron volts, are capable of producing fission reaction with 235 92U. During the fission reaction process, new neutrons are given out which have energies of about 1 MeV. These neutrons of typically escape from participating in another fission process as they are accompanied by enormous energy release. In f -ct, the probability of these neutrons produce another fission reaction is 500 times less than as compared to that of a thermal neutron. This is where moderator is extremely useful. Moderator has the capability to slow down, or in other words moderate, the speed of these high-energy neutrons, so that they can in turn be used for a chain reaction to trigger multiple fission reactions of other 235 92U nucleus.
Commonly, ordinary or heavy water is used as moderator in nuclear reactors because of the deuterons present in them which are capable of slowing the neutron speed. Water molecules in the moderator are useful in slowing down the high-energy neutrons which leave the fuel-element after nuclear fission. These high-energy neutrons collide with water molecules thereby losing out on some energy with every collision and therefore slow down substantially. A new fission reaction can now be triggered using this slow neutron by striking it with the fuel element.
The third and of the most prominent part of a nuclear reactor are the control rods. In order to get a steady output of energy from the nuclear reactor, every single nuclear fission reaction should trigger another fission reaction and ensure the availability of a spare neutron released to trigger the chain reaction. By controlling the number of spare neutrons available at any given time, the rate of the nuclear fission chain reaction can be controlled. This control on the fission reaction can be maintained using the control rods.
The main function of the control rods is to absorb any excess or spare neutron in the moderator in order to prevent any further fission reaction. Usually such control rods are made of Boron or Cadmium. To increase the rate of fission reactions, these rods can be removed from the moderator. A steady output of energy can be thus maintained by inserting or removing the control rods in the nuclear reactor.
Now that we know the components of a nuclear reactor, let us understand the working of a nuclear reactor. It is usually enclosed in a shield made of thick concrete walls. It consists of a reactor core, pump and heat exchanger. The reactor core and pump are in placed in contact with the water, which is usually the heat exchanger used in reactors. Due to the enormous amount of heat released dusing nuclear fission reaction, this surrounding water gets heated up and changes to steam, which is in turn used to turn the turbines. Thus huge heat energy gets converted into electrical energy. Water is continuously flown in and out of the nuclear reactor using the pump.
Thus a nuclear reactor successfully generates nuclear energy from fission reaction.

[triphazard]

Everyone's talking about how they came from Chernobyl, but I came from my Physics homework ...

[icetheking]

I love how we're basically just using high powered energy and nuclear power to heat up water

[alassanefaye]

Watches Chernobyl once... Becomes Nuclear Physicist through YouTube

[BrianD]

Thank you so much for this optimistic piece about nuclear power.
I just wanted to add more about the positive effects.
In the worst case scenarios of a massive earthquake and tidal wave with Fukushima no one died of radiation poisoning. But rather from the overreaction of the government not allowing people to return to their homes.
A lot of people could have returned to their homes with very few mitigating factors.
With Chernobyl, the RBMK reactors primary design was to create plutonium for nuclear weapons. Electricity was just a byproduct.
The accident occurred because of the reckless ambitions of the lead engineer on duty. The deaths were created by the Soviet government not being upfront about the disaster.
Just hundreds of feet away was reactor number three and then reactor number two and one. They kept running for about another 15 years.
In both these scenarios today there is tourism including people that are walking right up to the reactor for a limited amount of time.
Everyone knows that the news sells fear and anger. The news is part of the problem with keeping this truly green energy source from being deployed.
There are forces that want to make nuclear power so expensive it can never be bilt. Principle among them are oil companies.
The deaths and expense of global warming with its extreme weather is obvious and plays out everyday.
I'm excited about generation 4 reactors. They're about six different designs and they have about six different characteristics.
Some of the best characteristics are
-They're considered walk away safe.
-They burn more nuclear waste than they create.
-The waste is considered hazardous for far less time.
-They're non-proliferation so they can't be used for nuclear weapons.
- The designs are small and can be as common as a hospital. They take up the footprint of about a Walmart. A truly local power grid to accompany wind and solar.
This is truly the future that's going to power our electric cars and trucks. Some of the byproducts of nuclear power is creating hydrogen. This could power our airplanes, trains and ships.
I look forward to clean skies without smog or inversion layers.
I would much rather live next door to a nuclear power plant then a power plant admitting CO2 gas in other poisons and toxins.

[Jim_]

Humanity’s rejection of Nuclear power was a massive mistake, and the environment has payed dearly for it as we continue to rely on fossil fuels for our electricity

[Baderasiri]

"Now I know how does a nuclear reactor work" Boris Shcherbina.

[OhKopo]

I want to add that there are many reactor models, the one shown in this video is a PWR (pressurized water reactor), whereas some can boil the water directly in the RPV, these are called BWRs (boiling water reactor)

[jemimasinger]

I'm doing GCSE Physics and this really helped me understand the process, thank you! x

[komocode]

hey you. reading this. just continue watching Chernobyl. k.

[kenansalkovic]

Good video and understandable animations, but you missed 3 key elements (especially for a PWR system, like the one in your video). A pressurizer to keep the water in the containment shell circuit liquid. This water would otherwise turn into steam. The next key element is a third circuit to cool the steam from the second circuit. And the last element is the condenser. The place where the steam from the second circuit (high and low pressure turbines) will collect and condense to water, with the help of the third circuit. Other from these 3 points good vid

[mathmage]

U235 is the only isotope that's fissinable. U238 doesn't have a chain reaction. U238 is enriched to around 5% U235 in order to be used for nuclear power. The U235 is what creates the energy.

[rmachayes]

While I was onboard nuclear boats I was continually asked by friends and family members about the nuclear reactor. most did not realize that the reactor was used to eventually produce steam for our turbines. nothing hard to understand about that. I used to tell them that once the steam was produced, our propulsion system was like a typical 1, 200 psi sytem similar to a typical destroyer. They still were in awe as I but I was more so in realizing how a highly engineered system came into existence.

[dirkdiggler]

So much technology has advanced and when we look at steam engines from the 1800s people laugh of how primitive it was, yet they don't realize that we're still relying on steam engines for energy.

[Uksmaster]

"Ok, now I know how a nuclear reactor works and I don't need you"

[fckinnonstick]

Sometimes a random teenage boy is much more understandable than some of our fellow old man professors out there 😁

[zackaryfowler]

i agreed with everything until you said "fusion reaction" fission bro. fission.

[MrCrossover]

i was expecting at any moment for you to say "This is your life and it's ending one minute at a time."
great video..

[OTsornos]

You did a good job there mate, really simple yet educative video.

[AlwaysaFangirl]

Am I the only one here because they just find Nuclear processes extremely interesting?

[Opinionteer]

Boron in the reactor coolant is also used to control the neutron population. When a reactor is first started up the boron concentration is high. And the fuel is used up the boron is removed from the water.