See below ... On Tue, Mar 29, 2016 at 9:49 PM, Eric Walker <eric.wal...@gmail.com> wrote:
> On Tue, Mar 29, 2016 at 5:07 PM, Bob Higgins <rj.bob.higg...@gmail.com> > wrote: > > First of all, it is reasonable to presume that any Zn contamination would >> have a natural isotopic ratio. The natural abundance for 64Ni is 0.9%. >> So, for the reported 4.4% of m=64 to be 64Zn + natural 64Ni, there would >> have to be a 64Zn contamination of about 3.5 atom%. 64Zn is about 50% >> natural isotopic ratio for Zn, so there would have to be about 7 atom% >> concentration of Zn in the Ni powder for this to be the answer for the >> measured concentration at m=64. This would be a huge contamination. >> > > Just to play devil's advocate, the contamination would not need to have > been in the pure nickel powder. It could have come from another source, > and somehow gotten into the fuel mixture. The 7 atom% concentration would > thus be for the composite fuel mixture. (I will have to trust your > calculation! My number for both zinc isotopes together was ~ 3.5 atom%.) > The composite fuel mixture appears to have been what was measured in > the laser-atomic emission spectrometry assay [1]. > I believe laser atomic emission spectroscopy is also a bulk measurement like ICP-MS (-probably done as a flame measurement), so it would be a measure of the composite composition as you suggest. > > Also, Parkhomov's jar of Ni powder claimed it to be 99.9% Ni. Even if all >> of the 0.1% were Zn, that would only mean 0.05atom% of 64Zn to contaminate >> the 64Ni measurement. That would be consistent with the non-measurement of >> Zn in the EDS and the low value for Zn atomic percent reported by laser >> atomic emission spectroscopy in the same Sochi presentation. >> > > Perhaps you are referring to an EDS assay that was reported elsewhere and > not in the slides. The one in the slides (SEM-EDS) was of Rossi's reactor. > On page 11 of the Sochi report, there is an EDS of Parkhomov's AP2 fuel. EDS would measure the particles on the surface and at the points selected. There was analysis of the Ni powder particles and the LAH particles. Of course, none showed any Zn. > > ICP-MS is a bulk measurement. 1-2 mg of Ni powder would be dissolved in >> acid, diluted, and then introduced into the ionization chamber. So the 7% >> concentration of Zn could not be just a tiny spot on a particle, it would >> have to be 7% of the entire sample mass digested in the acid. When MFMP >> tested the powder it received from Parknomov (ICP-MS), it was found to have >> the normal, natural concentration of 64Ni. >> > > For the ICP-MS assay in the slides, I take it the fuel and ash will have > been dissolved, and that the composite powder, a prominent part of which > was nickel, but not by any means all nickel, will have been analyzed. Or > are you explaining that it was the pure nickel powder from the jar whose > label was shown earlier in the thread that was analyzed in the ICP-MS? If > it was the fuel and not the pure nickel from the jar that was analyzed in > the ICP-MS assay, it is easy to imagine there having been zinc impurity > present. > For ICP-MS, the sample, whatever is being tested, must be dissolved in an acid. Ni and Zn (if present) would probably dissolve in the same digesting fluid. I don't know if, for the fuel, the Ni powder and LAH were separately digested of if a whole sample of the fuel was analyzed at once (may have required multiple runs with different digesting fluids). Obviously for the ash, the entire ash sample would have to be used - but perhaps with multiple runs having different digesting fluids. Zn impurity is more likely in the ash because it could have been contaminated by the reactor vessel. However, for AP2, the fuel was in a SS can inside alumina and Parkhomov sealed the ends of the long tube with epoxy, not his homemade alumina cement that may have contained ZnO. One possible opportunity for contamination is Parkhomov's mixing process. He mixed the Ni and LAH in a ceramic mortar and pestle. Could this mortar and pestle have also been used in preparation of his homemade alumina cement on a prior occasion? Possibly. Yet it is hard to imagine even that producing a 7% Zn contamination of his fuel. I think 7% would have to be an intentional inclusion if that were the explanation (which I think is not the explanation). > > According to the slides, the ICP-MS assay was done by the Vernadsky > Institute. I take it there was a second ICP-MS assay done by MFMP? Or are > the two the same? > MFMP had ICP-MS analysis done for the Ni powder that was supplied to Bob Greenyer by Parkhomov. The isotopic ratio was found to be natural. We have asked if what he supplied to Bob Greenyer was also what was analyzed for AP2 - no answer yet. > > The 64Ni concentration is inconsistent with the explanation of Zn >> contamination. I have asked Bob Greenyer to review this with Parkhomov and >> arrive at a less flip answer. >> >> For now, we simply cannot trust the m=64 data in his Sochi ICP-MS report >> - neither the fuel or the ash - until a better explanation of the anomalous >> values is supplied. >> > > Yes -- I have no idea what's going on. Perhaps there's a simple > explanation. Little makes sense to me at the moment. > > Eric > > > [1] > https://drive.google.com/file/d/0B5Pc25a4cOM2cHBha0RLbUo5ZVU/view?pref=2&pli=1 > >
