building for heavy machinery; machine house
Technical term used in industrial and engineering contexts for a structure that houses large equipment such as turbines, generators, or pumps.
A large turbine is installed in the power plant's machine building.
nuclear reactor building
Compound of 建 (たて, 'build') and 屋 (や, 'house/structure'). The exact historical derivation is uncertain, but the word is conventionally associated with industrial buildings.