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 of the English Language" identifies room temperature as around , while the "Oxford English Dictionary" states that it is "conventionally taken as about ". Owing to variations in humidity and likely clothing, recommendations for summer and winter may vary; a suggested typical range for summer is , with that for winter being , although by other considerations the maximum should be below – and to avoid sick building syndrome, below . Some studies have suggested that thermal comfort preferences of men and women may differ significantly, with women on average preferring higher ambient temperatures. The World Health Organization's standard for