One of the researchers "has been accused of a few crimes, including tax fraud and illegally importing gold, which are unrelated to his research."
I hope this pans out and they become billionaires!
But I'm not betting any money on it.
ETA: Now that I've read the paper (which was 'published' in a journal founded by the researchers), the most suspicious thing to me is:
"No radioactivity has been found also in the Nickel residual from the process."
If the dingus works as claimed, nickel nuclei are absorbing protons (i.e. hydrogen) which transforms them into copper nuclei, which then decay by positron emission or electron capture into a nickel nucleus with a one higher mass number. So the overall effect is to change the isotopic abundances of the nickel, skewing it toward higher masses. This would provide a crucial test of the device to measure the 'fuel' before and after. But the SIMS analysis that was performed (though too insensitive to differentiate isobaric isotopes) still provide important info:
"The peak in the mass spectrum at a.m.u.=64, due to Ni64and Zn64(both caming from Cu64 decay) requires the existence of Ni63 which, absent in natural Ni composition, must have been in precedence produced starting by more light nickel isotopes."
The reason there's no natural Ni63 is that it has a half-life of 100 years, i.e. it's pretty radioactive. Similarly, Ni59 has a half-life of 78,000 years, and (since YEC is wrong) there is basically none of that isotope naturally occurring.
The most common nickel isotope is Ni58 (68%) - so this process should be producing a lot of Ni59 at least as a step on the ladder. And their explanation requires the creation of Ni63.
when they turn the dingus off, there should be plenty of these radioactive nuclei present in the fuel, and given the magnitude of the effect they're seeing, this radiation should be detectable, since all the garden variety nickel isotopes are stable.
As a rough estimate, they give the total released energy for the complete series taking Nickel from 58 to 64 as about 35 MeV. One of their tests produced 3768 kWh of energy. Dividing one by the other gets 2.4 x 10^21 atoms of nickel being transformed. Or .004 moles. [Yay - Google knows "Avagadro's number"] or a quarter gram of nickel. That's if the process was entire conversions of Nickel all the way from a mass number of 58 to 64. But in the stepwise way this would happen, plenty of atoms should be stranded along the way at different isotopes, including the radioactive one.
If we conservatively said there was a hundredth of a gram of Ni63...
With a halflife of 100 years, the decay constant is 2.2*10^-10 s^-1
So with a hundredth of a gram, carry the one, if I've done this right, there should be about 2.1*10^10 decays per second (Becquerel), or a little more than half a curie of radiation.
For comparison, a pound of Uranium 238 has an activity of 0.00015 Curies.