David,
I strongly disagree with the conclusions you have expressed regarding the ash sample isotope fraction. First, as I explain in this (rather-long-winded) mail from yesterday, the ENTIRE ASH SAMPLE BULK was analyzed by ICP-MS as consisting of 99.3% enriched Ni-62. ( see: http://www.mail-archive.com/vortex-l%40eskimo.com/msg98350.html ) Allow me to repeat this crucially-important point: The 2.13mg ash sample contained 2.12mg of PURE Nickel-62. Only the SEM/EDS and ToF-SIMS methods are restricted to analyzing the surface-layer composition. While this still only represents a small sample of the complete reactor ash, I have a difficult time believing that a substantial fractionation of nickel isotopes occurred. I suspect that most of the other fuel elements are not appearing in the ash because they migrated elsewhere in the reactor vessel and were missed by sample bias, but I have a difficult time imagining how the 99.3% Ni62 grain could be the result of isotope fractionation, all things considered here. -Bob From: David Roberson Sent: Saturday, October 11, 2014 9:56 AM That is what I concluded as well when I reread the article carefully. The small quantity tested would thus not represent a total sample in the analysis, so there is no way to ensure that all of the input nickel was converted into that single 62Ni isotope. This fact leaves unanswered the question as to whether or not all of the input nickel was consumed and any discussion about the concern that the reaction was near its conclusion moot. We have no way of knowing whether or not the enhanced nickel is merely remaining on the surface of the ash sample or throughout its volume. -----Original Message----- From: Eric Walker Sent: Sat, Oct 11, 2014 11:29 am On Wed, Oct 8, 2014 at 8:52 PM, David Roberson <dlrober...@aol.com <mailto:dlrober...@aol.com> > wrote: I may have missed the paragraph that stated the amount of material that was taken from within the reactor as ash. Did they recover approximately the same amount as was put in? Approximately 1 gram of fuel was added at the start of the trial. At the end of the trial, one (and I think only one) of the experimenters was present to choose 10 mg from the spent fuel. From this smaller sample, they appear to have set aside two (or three?) grains of different shapes and compositions for analysis.
