containing a gas cooled nuclear reactor 1 the reactor is somewhat similar to a gas turbine u2014 modular helium reactor gt mhr in that the reactor core is graphite and cooled by helium however the reactor 1 may be about two thirds the size of a typical gt mhr additionally the turbines 2 as well as compressors 4 and 5 of the reactor plant do not operate at a constant speed as is required if the turbines rotate an electrical generator the compressors 4 and 5 and heat exchangers 33 34 65 and 66 are located within a compact steel vessel for protective purposes the turbine 2 and compressors 4 and 5 are oriented horizontally instead of the gt mhr vertically orientation to properly mate with the air compressors and main electrical generator the reactor 1 is preferably located underground and the reactor plant components are also located in a steel and concrete containment building for further protection the reactor 1 heats a pressurized gaseous cooling medium such as helium serving as the working fluid that is routed through ducting 000 and expanded through multi stage turbine 2 multi stage turbine 2 is mounted to shafts or spooling b and c that drive compressors 4 and 5 the turbine 2 is also mounted to a shaft or spooling a and b that drive compressors 11 and 12 compressors 11 and 12 pressurize the open system working fluid of the compressor plant ii the closed system working fluid is expanded.