This is no doubt meant as a proof of concept and an electronically controlled neutron generator would solve some of the problems, but I still can't think of any use for this that isn't better solved some other way.
What about this?
"In some safety-critical scenarios, such as concerning the integrity of reactor containments, and metal vaults and bulkheads in maritime structures, it can be important to minimise the number of penetrations made through such metal structures for communications cabling. The use of neutrons for information transmission through such structures could negate the need for such penetrations and is perhaps also relevant to scenarios where limited transmissions are desirable in difficult circumstances, such as for emergency rescue operations."
Neutrons are also relatively short ranged and more-or-less isotropic in emission (not able to be focused effectively), meaning you need really high fluence (=dangerous) to transmit more than a few meters. For submarines, water actually attenuates neutrons extremely quickly making it completely useless there. And also let's not forget that neutrons activate materials and make them radioactive for long periods even after you stop with the neutrons. For totally sealed rooms there are better solutions (e.g an acoustic transducer). On top of all this, the physics of neutrons mean this will always be very low bandwidth.
None of the applications mentioned in the article are remotely credible, IMO, and this is my area of expertise. Perhaps there is some application where this is the best solution. My point is that at best it's extremely niche; the article makes it out like this is revolutionary but it is definitely not nor is it even particularly interesting. This is not military research with an intended application, this is someone slowly moving a block of plastic back and forth in front of a californium source in a university lab and a press release declaring victory. The actual article published by the scientists in NIM is much more reasonable, but the one linked here is greatly playing up the utility.
A fairly reasonable analogy that captures some of the downsides of using neutrons for this is that you could also transmit information by shooting at a metal plate with a pellet gun and having someone listen for the pinging sound. Sure it's possible, but the list of drawbacks is pretty long.
sounds like a primitive logic gate to me :) One can imagine a self powered logic circuits built along this way.