Calling all physicists!

[Rei]

I'm working on a short story which focuses on nuclear mishap. (No, this has absolutely nothing to do with Japan. I hadn't even thought of the timing until writing up this post.) In simple terms, how does one separate/select a neutron for a nuclear reaction? And once it is separated, how does one hang onto it long enough to initiate a reaction?

[Caspian]

I'm not a physicist, but Uranium 235 is naturally radioactive, which means it decays at a slow rate by shedding neutrons. If you have enough Uranium 235 gathered together to create critical mass, then the natural decay splits one atom which sheds neutrons at a faster rate, splitting more atoms as it does so, which produces a vast amount of heat, which turns the water into steam which turns the turbine which makes the electricity.

In a nuclear reactor, control rods, made of something like silver or boron that is capable of absorbing the radioactivity from the naturally decaying uranium, are added to the mass of fuel. Then all you need to do is remove the control rods to start the reaction. It's kind of (but not really) like if you had a pile of baking soda in an upside down glass in a puddle of vinegar. You don't need to do anything to start the reaction except take the glass away. Uranium 235 reacts with itself, but only if there's enough of it and nothing is interrupting the reaction. Take the silver out, the reaction starts.

[jotabe]

What Caspian said

Just don't include nuclear explosions in that misshap, k?

[Rei]

Caspian: Thanks! That helped massively

Jota: It's a piece in something closer to the style of the golden age of science fiction, so no promises

[jotabe]

Ok, if you make it entertaining, i can forgive you.
I mean, i have forgiven The Core just because it's so frigging awesome and funny XD

[Eaquae Legit]

There is no forgiveness for The Core.

[jotabe]

Oh yes, there is!
It's the one single sci-fi/disaster flick that manages to plow through the most of tropes of the genre. I think it only lacks the "superfluous, annoying kids"...

It doesn't even take itself seriously i mean, when the hermit scientist who discovered the unobtanium tells them how much it would cost make a vehicle suitable for the mission, the hunk scientist tells the army dude to pay with a credit card, they will give him points XD

[Bean_wannabe]

Natural uranium is about 0.5% (I think) uranium-238.

In all reactors (except one in Russia) they use an enriched form with about 3% Uranium-238. It's the higher-mass uranium which is broken down to give the energy.

However, it does result in the waste product containing a lot of still-radioactive uranium-235.

[jotabe]

And if i am correct, the refuses of this enrichment process are what is called "depleted uranium", which can be used in militar industry as tank plating or as bombshells.

Bombshells...

[Syphon the Sun]

Numbers are backwards. You enrich the 235 and get leftover 238.