Once again, there is a claim receiving attention from various media sources (here, here, here) that someone has demonstrated some gadget that produces so much "excess heat" that the conjectured source of the energy is some kind of nuclear reaction taking place in a condensed matter environment. This time, it's two Italian researchers, and they have demonstrated (in some very restricted way, more on this below) a device that they say uses a reaction involving nickel and ordinary hydrogen. The claim is that for a steady state input power of 400 watts, they can produce around 12 kW steady state of power in the form of heat. The device when running supposedly takes in room temperature water at some rate and outputs dry steam, and doing the enthalpy balance and water flow rate is how one gets the 12 kW figure. Crucially, the claim is that this whole process only consumes a tiny amount of hydrogen (far too little for some kind of chemical combustion to be the source of all the heat). The conjectured nuclear reaction is some pathway from 62Ni + p -> 63Cu. No big radiation produced, though of course the demo doesn't really allow proper measurements. Don't even bother reading the would-be theoretical "explanation" - it's ridiculously bad physics, and completely beside the point. What's really of interest is the experimental question.
As always in these cases, there are HUGE problems with all of this. The would-be paper is "published" in an online journal run by one of the claimants. The claimants won't let independent people examine the apparatus. They also don't do the completely obvious demonstration - setting up a version that runs in closed cycle (that is, take some of that 12 kW worth of steam flow, and generate the 400 W of electrical power needed to keep the apparatus running, and just let the system run continuously). If the process really is nuclear in origin, and the hydrogen accounting is correct, it should be possible to run such a system continuously for months or longer. The claimants say that they've been using a 10 kW version of such a unit to heat a factory in Italy for the past year, but they conveniently don't show that to anyone.
The burden of proof is on these people - if they've really done this, the world will beat a path to their door, and that would be great. I'm not buying my nickel futures yet, however. Once again there will be people out there who claim that evil scientists are suppressing these unorthodox geniuses; this is such a ridiculous mischaracterization of science that it still ticks me off every time I read it. Of course I wish this were a genuine discovery - it would be world-changing and reveal enormous new physics. However, so far no version of this kind of low energy nuclear reaction business has passed the bar of reasonable reproducibility in controlled circumstances. (See here for a past discussion concerning the palladium variety and its reproducibility. Read the comments there before posting angrily below that I don't understand the situation, or that I haven't looked at this, or that I'm otherwise hugely ignorant on the subject.) That's not the establishment being oppressive, it's the way good science works. Extraordinary claims require extraordinary evidence. The self-sustaining demo I described above with independent verification and measurements would go a long way. I'm not holding my breath.