It is not clear from the report exactly how much ash was extracted from the reactor. In the SEM of the 2 ash particles on page 45 in Appendix 3, particle 2 is silica - known to be in the grain boundaries of alumina. In 96% alumina, there are 4% of other oxides and and in 99.8% alumina, there are still these oxides between the grains, only less of them. This silica is almost certainly a particle from an alumina grain boundary.
Note that the Ni "particle" is really a lump. It is almost a 0.5mm chunk of sintered Ni. The fact that it came out at all (as opposed to being sintered to the side) probably means it came from a cooler portion of the reactor. From working on a replica design of this reactor, the 5 cm ends of the convection tube are probably not heated with the heater wire. This means that there are probably places inside the reaction tube that are cooler and where sintering may occur between the Ni grains but not necessarily to the alumina wall. Sintering is not the same as crystal growth, and I wouldn't consider the large Ni ash grain as a crystal growth. It is more like the features of the individual grains that come in contact melt together slightly permanently bonding them with a grain boundary of oxides and contaminants remaining in the boundary. For all we know, the inside of the reaction tube was first coated with an isotopically enriched 62Ni powder which was bonded or sintered to the inside wall. Then when the reactor was open, a few of the wall particles became dislodged and became part of the ash. These were not necessarily transmuted from the fuel, because I believe we only saw some consumable powder (probably the hydride) and maybe some obfuscation Ni powder. The point is that what was put in was not representative of the active fuel - it is a clue, but not statistically representative of the active portion of the fuel. Obviously this is an opinion. Given the high temperature, none of what Rossi originally put in would have come back out, except perhaps some small amount of the Ni that had collected in a colder spot in the reaction tube. What more likely came out were small pieces that had flaked off of the sides of the reactor tube due to thermal expansion mismatch as it was heated and cooled, that were in the tube before he put in the ~1g of consumables taken to be the fuel. I don't know that he put in enough powder to ever plug up a 4 mm hole. The big agglomerate of Ni in the ash was about 0.5mm. Bob On Thu, Oct 16, 2014 at 6:28 PM, David Roberson <dlrober...@aol.com> wrote: > Bob, how would we explain the appearance of the ash material that was > extracted from the tube? According to the testers the device can operate > at higher powers than they experienced which would certainly lead to > complete melting of the nickel. What are the chances that some of the > other materials in the fuel mix might result in 'slag' that prevents the > Nickel crystals from growing very large. > > It would seem likely for the condensing nickel to form a blockage of the > small interior channel into which the fuel was inserted. If that happened, > the amount of material that could be analyzed would be quite limited. > That might explain the large amount of Ni62 if the sample were constricted > to the material near the end cap and not an average. > > I asked about the amount of material that was collected as ash from which > the samples were drawn and do not recall getting an answer. > > One last comment. If the true temperature of the fuel reached the level > that the IR measurements suggested then I would be very surprised to find > that a gram was extracted after the test was completed. Local melting and > crystallization would very likely plug up the charging hole in several > locations. > > Just my thoughts. > > Dave
