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 and the Japanese Pharmacopeia defines "ordinary temperature" as , with room temperature being . Merriam-Webster gives as a medical definition a range of as being suitable for human occupancy, and at which at which laboratory experiments are usually performed. People traditionally serve red wine at room temperature. This practice dates from before central heating, when room temperature in wine-drinking countries was considerably lower than it is today, usually in the range between and . The advice is therefore to serve the wine at, at most, about . Room temperature Colloquially, room temperature is the range of air temperatures that most