If the source of Rossi Reactor energy is association of nascent hydrogen, there is an easy test. All you have to do is detect 277 nm far-ultraviolet photons whose energy is equal to 4.476 eV.
Now that I mention it, I recall a window in the reactor in one of the Defkalion photos which could have been for detection of these photons. It would tell them at what point the reaction has begun. So, how are the 277 nm photons turned into heat? T