Display MoreI'm going to guess that fractionation of Hg in the case of the CFL bulbs was a hand-wavy explanation adopted to explain away a mysterious phenomenon while maintaining current understanding of nuclear physics, rather than an explanation that was necessarily adopted after having ruled out all of the alternatives (incl. LENR).
Imagine two people with lab coats:
A: What's going on with the changes in the isotopic ratios of Hg in CFL bulbs? They're regular, predictable and well above the noise floor.
B: Beats me. Maybe it's fractionation.
A: What about something nuclear going on?
B: Then you'd have all these theoretical problems, and we can't think of possible ways through them, so it has to be fractionation.
A: Ok.
Alas I can't post Mead's paper, which is very well written, and resolves the issue nicely. But I can summarise it which I will do here. I'll also post some pics. They analyse the Hg vapour in old CFL bulbs and the Hg present in the bulb glass.
The key data is the correlation between isotopic ratios of Hg in the lamp glass and isotopic ratios of Hg in the vapour, of used bulbs. They cannot compare this for the same bulb, because the two collection procedures each destroy the bulb and cannot both be used on one bulb. however, they can compare bulbs with similar lifetimes and as you can see the results are striking. The changes in isotopic rations for the vapour and the glass, from natural composition, are in opposite directions as expected from fractionation (it is a closed system) but not transmutation
Less clear is why this fractionation happens. But they have a proposed mechanism - "self-shielding" which has resulted in isotopic anomalies in other systems and is understood theoretically. They have a curve-fitting exercise based on what is known about self-shielding:
There are still some aspects of the data they cannot explain (the odd/even split) but they have most of it.
This shows undoubtedly that there are detailed mechanisms relating to fractionation in these systems we do not yet understand. That is expected, and not a sign of any fundamental new physics, just detailed application of known physics in complex systems.