Russians and the Americans tried after world war 2 but due to limitations of technology they failed. There were 2 approaches tried 1) Direct drive approach whe

Russians and the Americans tried after world war 2 but due to limitations of technology they failed. There were 2 approaches tried 1) Direct drive approach where weight was comparatively less but the radioactive gases were thrown as exhaust hence was deemed unsafe. 2) Indirect drive (lockheed martin worked on this) which drove the steam turbine which ran the rotors but thrust to weight ratio was so less that it was shelved. Meanwhile there was an internal competition between U.S. airforce and navy for getting a nuclear fueled vehicle that would have unlimited range. This competition ended when Navy got their 1st Nuclear powered submarine. Also nuclear powered aircraft if crashed in enemy territory or in any other place will attract serious consequences. Hence NO Nuclear-Powered Aircraft!