B Understanding Nuclear Bombs: The Physics Behind Their Devastation

[Metals]

Now I'm familiar with how nuclear fission works to produce thermal energy and alpha/ beta/gamma radiation, but how do they work in the bomb? When is the high energy neutron fired into the uranium-235, and when does the chain reaction producing the heat begin?

Why is it that there's a huge explosion all of a sudden when the bomb impacts with a surface with high force?

If 0.1% of the uranium's mass is converted to energy, what happens to the uranium after the bomb explodes? Is it just melted and dissipated?

I understand these are not really good questions, but I'd like to better understand the practicality of the bombs. Also, are the answers the same thing for plutonium-239 bombs?
Much appreciated.

 

[berkeman]

Now I'm familiar with how nuclear fission works to produce thermal energy and alpha/ beta/gamma radiation, but how do they work in the bomb? When is the high energy neutron fired into the uranium-235, and when does the chain reaction producing the heat begin?

Why is it that there's a huge explosion all of a sudden when the bomb impacts with a surface with high force?

If 0.1% of the uranium's mass is converted to energy, what happens to the uranium after the bomb explodes? Is it just melted and dissipated?

I understand these are not really good questions, but I'd like to better understand the practicality of the bombs. Also, are the answers the same thing for plutonium-239 bombs?
Much appreciated.

Have you read the wikipedia page on this yet? https://en.wikipedia.org/wiki/Nuclear_weapon#Fission_weapons

 

[mfb]

Why is it that there's a huge explosion all of a sudden when the bomb impacts with a surface with high force?

There is not. The explosion has to be started deliberately, and with very precise timing. If the bomb just hits something, in the worst case the explosives inside detonate, but you don't get a nuclear explosion.

If 0.1% of the uranium's mass is converted to energy, what happens to the uranium after the bomb explodes? Is it just melted and dissipated?

The fission products (not uranium any more) get distributed in the environment.

See the Wikipedia article for the details how the explosion process works.

 

[Lord Crc]

There is not. The explosion has to be started deliberately, and with very precise timing. If the bomb just hits something, in the worst case the explosives inside detonate, but you don't get a nuclear explosion.

One example of this is https://en.wikipedia.org/wiki/1966_Palomares_B-52_crash

 

[mfb]

The US alone had so many officially recognized incidents that the Wikipedia page just lists the most noteworthy (and links to a really long list of military accidents involving nuclear weapon materials). At least according to what got made public, some nuclear weapons have never been found. A few times the chemical explosives exploded, but no accidental nuclear explosion.