There have a number of comments about images from the Parkhomov/Rossi reactors which appear to show dark wires in front of a brightly glowing background.
Yet . we know that these wires should be strongly incandescent (unless the photo was taken immediately after the current was turned off). and if the wires are powered, they will be glowing so brightly by themselves that they should not be seen as dark, even if the interior of the reactor were brighter than the wires themselves. There is no evidence that the current was off - so we should look for other explanations. Another explanation which has not been voiced till now -is the "dark matter in operation" explanation J If "dark matter" can be defined as hydrogen in the Deep Dirac Level - the lowest orbital, and there is recent evidence from Cosmology that this could be the case, then we can explain the dark wires as being actively shielded. The mechanism for that shielding could go something like this: Hydrogen in the DDL is greatly reduced in diameter so that it cannot be contained by the ceramic - and the isomer atoms would diffuse through the alumina (which is a dielectric) as soon as they are formed. This species would also be strongly paramagnetic and thus attracted to a current carrying wire. Therefore, it can be proposed that a very thin layer of DDL -possibly only a few atoms in thickness would attach to the wires uniformly, following which they would actually become "dark" in the sense of strongly blocked in the visible spectra but emitting photons which are invisible (soft x-rays). . or not. But it makes for an interesting hypothesis.