Why doesn't uranium ore spontaneously undergo a chain reaction?
A)Uranium ore must be "weapons' grade" in order for it to undergo chain reaction.
B)Uranium ore is mostly non-fissionable isotope U-238.
C)Uranium ore does spontaneously undergo slow chain reaction over time finally resulting in it becoming lead.
D)Uranium ore, mostly U-235, must be enriched with U-238 in order for it to undergo a chain reaction.

Question

Quizplus · Accepted Answer

Uranium ore is mostly composed of the non-fissionable isotope U-238. In order for a chain reaction to occur, there needs to be a sufficient concentration of the fissionable isotope U-235, which is only present in trace amounts in natural uranium ore. This is why uranium must be enriched with U-235 to make it usable for nuclear power or weapons.

Why Doesn't Uranium Ore Spontaneously Undergo a Chain Reaction