Pyrex is borosilicate glass. Any system using pyrex would involve boron as a potential low level contaminant.
Papp claimed that the boron powder that appeared in his cylinder was a reaction *product*. However, no one was ever able to get his engine to work in the absence of his careful preparation of the "fuel". The fission reaction p+B11 => 3He4 + energy is well known as an aneutronic reaction which produces Helium ash. I don't pretend to understand the mechanism by which the proton could overcome the coloumb barrier in either of these systems, but it would explain a lot if they were p+B11 => 3He4 + energy systems. Did Rossi figured this out and start using the well known catalyst Nickel Boride as his secret "catalyst"? Did Papp throw everyone yet another curve-ball by secretly including boron and hydrogen in his "noble gas fuel"? I only ask these questions.
