Since some of the results seem to be consistent with my theory, let me clarify exactly what I propose.
I propose the NAE is a gap slightly wider than the normal distance between the planes of Pd atoms in the fcc structure. Such a gap can form at several different places in a structure. The gap can form between two different metals, for example between Pd and Ni, it can form between Pd and an inert material present as an inclusion, for example between Pd and CaO or B2O3, and can form at grain boundaries in the Pd structure. Once formed, this gap becomes populated by many hydrogen atoms (any isotope) by forming a chemical molecule as result of a normal chemical process. This chemical molecule, which I call the Hydroton, has the very unusual ability to cause fusion between the hydrogen atoms in the molecule. This molecule can also interact with surrounding atoms to cause their transmutation. The presence of hydrogen in the material causes dimensional changes that can cause these gaps to form. Consequently, hydrogen isotopes are both a fuel and also provide the mechanism by which the gaps are formed. The challenge is to keep the gaps from growing too wide for the Hydroton to form.
My explanation of the NAE is totally consistent with normal chemical and observed behavior. Once the NAE forms, the nuclear process begins without further intervention as long as hydrogen isotopes are present. The nature of this reaction is novel and not understood. Nevertheless, this unusual kind of nuclear reaction plays no role in causing or influencing the NAE. Formation of the NAE and the resulting nuclear process are two separate and independent events. This being the case, other molecules might become nuclear active under certain very rare and special circumstances. In other words, some of the behavior reported to cause transmutation might result thanks to this unusual ability of certain chemical molecules to support a nuclear process. This idea is new and will, I'm sure, blow the minds of some people. Pass the word and see what happens.