What could cause a spike in the natural uranium depletion rate?
What is a possible event${^*}$ that would cause a spike in the speed of $^{235}$U fission and reduce its average concentration in ore worldwide?
As I understand the physics of the process, it is impossible to alter the fission speed itself, but if there is a way to have a thermal neutron source in the ore volume or some kind of neutron moderator for neutrons which are emitted by $^{235}$U itself that will lead to chain reaction and then depletion, like in Oklo.
The problem I am struggling with is to come up with an event that will look not completely made up.
${^*}$ The event should not be magic or alien-related.
P.S. This is my first question here if I am doing something wrong I will be happy to do it right.
This post was sourced from https://worldbuilding.stackexchange.com/q/165064. It is licensed under CC BY-SA 4.0.
1 answer
I agree that a possible solution would be to add in a source of high-energy ambient neutrons. Cosmic rays are a possible neutron source, at least at high enough altitudes and assuming the uranium does not have adequate shielding. A strong spike in cosmic rays could then provide such a neutron source; in turn, as one of the major sources of Galactic cosmic rays are supernovae and supernova remnants (for cosmic rays below $\sim10^{15}$ eV), it's possible that one or more supernovae nearby could produce enough neutrons to raise the rate of uranium fission enough to be detected.
Supernovae, of course, can be dangerous when close enough to Earth. Fortunately for us, that critical distance is on the order of about ten light-years. However, this means that the cosmic ray flux would be lower than if the supernova was closer, so it's something of a tradeoff. That said, for an event to cause an increase in fission worldwide, rather than just in one spot, I suspect it would likely have to be astronomical in nature, meaning you'd need some sort of energetic phenomenon. This of course means that you'll be dealing with the same sort of issue with many of the answers you'll get.
0 comment threads
0 comment threads