http://www.lenr-canr.org/Collections/USNavy.htm
In the data extracts, they mention the diameter of the triple-track and that it is the same as would be expected in an energetic emission of a neutron stream.
Considering the difference in size from a full carbon atom and that of a neutron...
Speculating somewhat wildly here, but:
Neodymium (NdFeB) MAGNETSSince each triple-track is the evidence of the trinary disintegration of a single atom, it wouldn't take much in the way of "contamination" by the boron atoms into the heavy water to provide an opportunity for Hydrogen plus Boron yields Carbon, which immediately explodes into three Helium ions (alpha particles).
Neodymium permanent magnets (Nd-Fe-B) are composed of neodymium, iron, boron and a few transition metals. These magnets are extremely strong for their small size, metallic in appearance and found in simple shapes such as rings, blocks and discs.
So even if there is NO source of carbon, there is a potential for a boron source.
Of course, how a few meandering boron atoms could get themselves lined up in the cross-hairs of a really fast moving proton is yet another excellent question.
By the way, I'm not insisting on the presence of a disintegrating carbon atom, I'm just not familiar with the nuclear event that triggers the expulsion of three neutrons, but I had heard of the proton/boron reaction.
Also, even if we are (or they are) only observing a spontaneous neutron cascade, that's a bit of an interesting phenomenon itself ...