關於核電廠同核彈既問題!!PHYSICSS!!

Although both nuclear power reactor and atomic bomb utilize nuclear fission reaction, the former cannot explode like a bomb.

The main difference is the different degree of fuel enrichment in each case. In a nuclear power plant, the amount of uranium-235 occupies only around 3% of the uranium fuel (most of the uranium in the fuel is uranium-238). Only uranium-235 can undergo nuclear fission to generate heat energy. Uranium-238 atoms absorb nuetrons and do not undergo fission.

In an atomic bomb, almost pure uranium-235 is used (or at least up to 99% of the total amount of uranium is uranium-235). Such high enrichment of uranium-235, when fission reaction is once triggered, releases a tremendous amount of heat energy and causing an explosion.


2015-02-09 19:46:47 補充：
A nuclear power reactor, even under an uncontrol situation (e.g. in a core melt scenario), would not explode like a bomb. It only catch fire. This is because of the low enrichment of U-235 in the nuclear fuel.

2015-02-09 19:49:49 補充：
This is the reason why the production of atomic bombs requires more advanced technique in enriching U-235 from the natural U-238 ore.

Nuclear chain reactions are pretty much similar in both power reactors and bombs though, one of the greatest differences is that there is a set of "control rods" in the reactors. The rods are for limiting the reactive elements available for chain reactions in order to "control" the reactions. That's why in normal condition the reactors would not explode like a bomb.

Reference: https://upload.wikimedia.org/wikipedia/commons/thumb/1/15/Boiling_water_reactor_english.svg/820px-Boiling_water_reactor_english.svg.png