(n,2n) Nuclear Reactions

Howdy. I'm currently writing a Physics research briefing for A2 on the subject of a Thorium Fuel Cycle in Nuclear Power, but I've hit an impasse at a point where I explain how the Uranium-233 in a Thorium fuel cycle may be proliferation resistant due to Uranium-232 contamination (and subsequent gamma emissions from its decay series). The problem is explaining how Uranium-232 is produced. All Uranium-232 would be produced by a (n,2n) reaction with various nuclei in the fuel; the problem is, I've never encountered an (n,2n) reaction in my Physics course before and I can't find a concrete explanation anywhere on the internet, other than it being referred to as an uncommon mode of nuclear decay which only occurs with faster neutrons (at around 10MeV).

An example of an (n,2n) reaction would be:


What I need for this is a solid physical explanation as to why this happens, and a source that I can cite in my bibliography of the briefing which backs that explanation up.

Thanks in advance!

Thanks for the response! Would I be right to say then that the ejection of the neutron is merely an unusual way of the nucleus conserving energy whilst going down to its ground state? I'm looking for ways to keep my word count down.

You're right in that U-233 can still be used for weaponry, but of what I'm aware from my research is that the U-232 makes it much less appealing in a weapon due to a greater amount of gamma emissions than Plutonium, and the inability to chemically separate the U-232 from the U-233. Whilst you can time weapon fabrication around the decay cycle or treat workers as expendable, this is significantly less appealing than bomb fabrication using other fissile materials.

An economic cost-benefit analysis rules Uranium-233 as being a pretty awful fuel. It'd probably be easy for a terrorist cell/rogue state to try to highly enrich natural Uranium rather than deal with transmuting Thorium and then worry about copious amounts of radiation from the core.