As a physics student I can assure you that there is no mechanic by which you can put a stick of uranium in a rifle and "make it go boom more," as you say. We have no knowledge of uranium or the means to refine it, no substantial basis in atomic theory and definitely no nuclear weapons, tactical or not. Furthermore, in order to create nuclear fission you need some fairly large devices which could not fit inside of a gun even with modern technology.
As someone who is also studying physics, Uranium was discovered in 1789, and discovered to be radioactive in 1896. In terms of not being able to refine it, we were using it in nuclear reactors as early as 1934 and it was Uranium that was inside the first nuclear weapon! So I would argue we had both the knowledge and the means.
Atomic theory was being explored as early as the 18th Century and by the time frame we're looking at we more than understood nuclear particles as well, but I supposed you can put the discovery of nuclear fission itself in 1938, but that's still in the time frame. And again, this is not a nuclear weapon! Far from it, that's a whole other department as far as I'm concerned, this is simply making use of the vast energy involved in nuclear fission.
In terms of size, fair enough you've got me there, I just used some creative licence to make it practical.
I am no radiation expert or science expert, but I can easily call out BS on this. I know for a fact that uranium needs more power than something a gun or even a heavy ass back pack can produce in order to use as substitute for gunpowder. I'm not even sure if you could get it to work without violently exploding and killing your own guys accuming it would work.
Also, may I ask how the hell did your entire nation get radiation fallout? If that's the case, the entire fucking world would be having some trace of fallout with wind currents and stuff.
In short, where the hell is all of this stuff coming from? How the hell does a former colony have such advanced nuclear tech that they can make guns out of it (that wouldn't work). The rest of the world is most likely just getting started with nuclear reactors and you're chilling over there with uranium guns and nuclear fallout which some how doesn't affect anyone else.
Again, the size of the reactor was my creative licence, so you've got me there. However in terms of volatile, nuclear reactors tend to not blow up that often if carefully monitored, otherwise we'd all have three eyes by now.
The radiation poisoning comes from the elusive "Fall" which I was going to keep mysterious, but as you seem so eager for answers, it was the breakdown and failure of the prototype nuclear reactors that the Republic had just created. Basically a triggered fallout of four or five nuclear fission reactors simultaneously. And no, that wouldn't effect the whole world at all, just look at Chernobyl. That reactor went into meltdown but none of us have radiation poisoning do we? So times that by four or five spread out a little bit and you have a nation caught in the fallout zone but not reaching any of the neighbours.
The "stuff" comes from the rich uranium deposits underneath my little nation that were exploited by the previous owners, albeit poorly, triggering the Fall. This allowed Sophia, one of the greatest nuclear scientists ever, so use the abundance of uranium and vast funding and scientific knowledge at her disposal and decided to have a little tinker.
But I know when the people are against me, and seeing as the responses are starting to slip from helpful advice to almost rudeness when I try to defend myself, I'll take back my nation. Say goodbye to my nuclear happy people, and I'm sorry that you couldn't fit them in.