Clean nuclear waste? How?
The only way that I know of to clean nuclear waste is to bombard the waste with neutrons which transmutes it to isotopes which have much shorter lifetimes, or possibly stable isotopes. I have not seen any LENR claims for neutron production. Certainly no reports of bulk neutrons outside of the metal matrix, which would be very easy to measure. Transmutation that has been reported by some involves the metal matrix of the reactor itself- transmuting nickel, helium, etc. through some mechanism which does not include the release of measurable neutrons. The mechanism of how this occurs without easily measured neutron output is a mystery. But, even if this is accepted, the reactor would have to be made out of the waste material. Just sitting beside the material would not work. The whole issue of hydrogen/ deuterium absorption into the metal matrix becomes virgin territory. Do these actinides series radioactive isotopes have any propensity for absorbing hydrogen? Will LENR reactions occur (if they are even real) as is claimed for nickel and a dozen other metals?
In the same regard, a D-D Polywell might make a good neutron source for cleaning up nuclear waste. But a P-B11 Polywell reactor, while producing plenty of heat/ energy, is a complete failure from a nuclear waste clean up perspective because it produces essentially no neutrons. High energy alpha particles from the P-B11 reactor might be useful if you can get them out of the reactor without slowing and they are used to bombard thin sheets of the nuclear waste material. But a LENR, in those instances where helium production (alpha particles) is claimed wouldn't work because if present these helium are not at high energy once they get outside of the metal matrix of the LENR (at least I have not heard of any energetic alpha production in LENRs and that would be extremely easy to measure , even at tiny doses). Neutrons are unique in their ability to easily escape a reactor core and then be slowed for efficient absorption into various isotopes, thereby transmuting the material.
Take WB6 output claims. With only ~1 milli Watt of fusion output the neutron flux from the D-D reactions was almost a billion neutrons per second. This is stupendously easy to measure in a steady state machine. Even in the pulsed WB6 a quarter of a milli second run was enough to measure some neutron output. The same applies to other Fusors where ~ 10 million neutrons per second has been achieved. Some amateur Fusioneers have measured neutrons with only ~ 100,000 or less neutrons per second outputs. This would represent a feeble fusion output of ~ 1 micro Watt. A LENR that is reported to output dozens of Watts at times would produce gazillions of neutrons per second (actually ~ 10^13-14 neutrons per second). That no neutrons have been reported implies that the claimed reactions are stupendously aneutronic. Even P-B11 reactors at dozens of Watts of output would produce ~10^5 neutrons per second from the extremely rare side reaction that occurs every ~ 1/40,000,000 fusions.
PS: There has been a report of neutron production with a LENR device by a Navy lab~10 years ago. They measured pits in a CR39 plastic that is a well accepted modality. The problem was that there was criticism that the chlorine ions in the electrolyte solution might also create pits. Once challenged it would have been easy for them to control for this, but I have not heard any results with this control. Also, the plastic proton recoil that happens with fast neutron interception by the plastic, followed by etching produces the visible pits. As it is fast neutrons that are measured in this way it would seem difficult to explain away lack of measurement of neutrons outside of the chamber. Bubble detectors also detect fast neutrons and could be placed inside the chamber as well. They would avoid chlorine issues as they are sealed inside a test tube. That such efforts were not tried, or at least not reported, pretty much voids their conclusions.
To error is human... and I'm very human.