Liquid metal cooled reactor Clementine was the first liquid metal cooled nuclear reactor and used mercury coolant, thought to be the obvious choice since it is liquid at room temperature. However, because of disadvantages including high toxicity, high vapor pressure even at room temperature, low boiling point, producing noxious fumes when heated, relatively low thermal conductivity, and a high neutron cross-section, it has fallen out of favor. Sodium and NaK (a eutectic sodium-potassium alloy) do not corrode steel to any significant degree and are compatible with many nuclear fuels, allowing for a wide choice of structural materials. They do, however, ignite spontaneously on contact
Room-temperature superconductor explained as room-temperature superconductivity within a phase formed on the surface of oxygen-doped type IIa diamonds in a vacuum. In 2003, a group of researchers published results on high-temperature superconductivity in palladium hydride (PdH: x>1) and an explanation in 2004. In 2007 the same group published results suggesting a superconducting transition temperature of 260 K. The superconducting critical temperature increases as the density of hydrogen inside the palladium lattice increases. This work has not been corroborated by other groups. In 2012, an "Advanced Materials" article claimed superconducting behavior of graphite powder after treatment with pure water at temperatures as high