For a long time, going back to Claytor and the production of tritium in the early nineties, some observers have been suggesting that there appear to be several distinct pathways for LENR -- especially since similar but slightly different experiments were showing helium with no tritum.
At ICCF-14 Mitchell Swartz introduced a "three region hypothesis" (3RH), in which he documents LENR reactions as taking place in three distinctive regions. Since the situation is not always "either/or" - the combinations and permutations of those three regins could allow many possibilities, depending on the parameters of the experiment. His three active zones are: 1) deep in a metallic lattice 2) near the surface 3) in micrometer and nanometer particles He suggests that each location may have differing rates of excess heat, or none at all, and either tritium or helium production or both. I believe Mitchell has even documented helium-3 production in years past . In addition, there is mention of nickel/protium cells - and the beneficial effect of adding heavy water to those parameters - which is somewhat counterintuitive. Swartz explains the 3RH hypothesis and the latest results from his continuing, well-researched experiments in the Sept/Oct issue of IE.
