Eli5: How are Nuclear Weapons different from Nuclear Power Plants?

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Eli5: How are Nuclear Weapons different from Nuclear Power Plants?

In: Physics

13 Answers

Anonymous 0 Comments

Nuclear bombs have an uncontrolled nuclear reaction where it is forced to go “critical” nuclear reactors have inhibitors which stop the reaction from being out of control and going “critical”.

Anonymous 0 Comments

Nuclear weapons are devices designed for **uncontrolled** releases of energy.

Nuclear power plants use nuclear material to produce heat in a very controlled fashion to release very modest amounts of energy/heat. The amount of heat produced is **controllable** and is used to boil water and create steam. That steam is used to turn turbines which creates electricity.

Anonymous 0 Comments

One uses the rapid fission of radioactive material to create a gigantic explosion.

The other uses the controlled fission of radioactive material to heat steam and turn a turbine to generate electricity.

Anonymous 0 Comments

They differ in (i) the amount of power produced and (ii) the speed at which it is produced (I am using the word power in a general way).

I am really making it sound easy and simple here, risking to sound wrong even. The attempt is to point to the process not explain it faithfully….

When a nuclear reaction begins, each neutron from an atom knocks three more neutrons from other three atoms, releasing heat in the process. Each of these three neutrons knock 3 new ones each releasing three times more heat. And those 9 neutrons then end up knocking 27 neutrons, releasing even more heat. Thus, it becomes an ever-intensifying chain reaction releasing catastrophic amounts of heat. That’s nuclear bomb (based on fission). Since the release happens VERY fast and a tremendous amount of heat escapes, the result is devastation.

In nuclear power plants, the same principle applies. One neutron knocks out three more, releasing heat in the process. However, this time control rods are interspersed that absorb 2-3 excess neutrons, thus leaving only 1-2 more neutrons to go their merry way knocking out more neutrons. Heat does get released, but it is less in amount, and it is produced slowly, in a controlled fashion. So this is a controlled chain reaction. And it can be controlled depending on how many free neutrons you want knocking around. This is how nuclear power plants generate heat.

Anonymous 0 Comments

A nuclear power plant is nothing more than a steam factory. It takes something that’s hot (the nuclear material) and uses it to heat up water into steam and then the steam spins a turbine that creates electricity. You can do this with anything that is hot and can heat up water into steam. You could burn things, like oil or coal or trash or wood. We just like to use nuclear material because we can keep it hot for a LONG LONG LONG time without needing to replace it, unlike the other materials.

A nuclear explosion is a very (very) tightly controlled runaway reaction of a small amount of material using explosives to compact and crush the material in a very specific manner. You cannot just accidentally have a nuclear explosion. It needs to be done in a very particular way to have the desired effects.

Anonymous 0 Comments

A nuclear power plant we put in radioactive rods. These rods do not explode. They just generate a ton of heat. The heat causes water to turn to steam, just like in a gas or coal power plant. The steam then rises, and turns a turbine, which then creates electricity. The steam is then cooled back into water, and then ran back through the system again and again, creating more and more electricity.

In a nuclear weapon, we use weapons grade radioactive material, uranium or plutonium, and we surround it with another type of conventional explosive, usually in a ball shape (for the first stage). Then, when the outer conventional explosion happens it pushes the highly radioactive material in on itself, and causes the radioactive material to explode. It’s a lot more complicated than this because it actually involves a bit of fission and fusion to make modern day nuclear weapons, but that’s the simplified version.

So in a nutshell: Nuclear Power Plants heat up water, and have no explosions. Nuclear bombs use explosives to compress radioactive material so it causes a big explosion.

Anonymous 0 Comments

Nuclear weapons are designed to split as many atoms as possible in as short as time as possible. A lot of engineering goes into this since you have a very small window of time because the uranium that is being split can no longer react once it’s spread out by the explosion.

A nuclear power plant on the other hand is designed to maintain a very controllable and steady rate of reaction. It needs to split atoms fast enough to generate the needed energy but anything over that is wasted energy and unnecessary load on the cooling system. In the worst case an uncontrolled reaction could literally melt it’s way through the containment vessel and contaminate the environment with radiation.

Anonymous 0 Comments

Nuclear materials get “angry”*.

The stuff in a nuke would just punch you in the face, while the stuff in a power plant will talk about it instead.

The energy released is useful, either for making things disappear, or for boiling water to spin a fan to make power.

*Note; I am not qualified in this field, but that won’t stop me.

Anonymous 0 Comments

One is like driving your car using the petrol in the tank.

The other is like pouring the petrol out and setting fire to it.

They use the same energy source, but release it in different ways at very different speeds.

Anonymous 0 Comments

My reactor uses 5% enriched fuel.

A bomb uses 99% enriched fuel.

My reactor has an automatic shutdown system and is designed to minimize reactivity.

A bomb doesn’t stop once started.