Unitary, transportable, assembled nuclear steam supply system with life time fuel supply and method of operating same

A nuclear steam supply system with a life of at least 10 years, comprising:

• an upright pressure vessel containing a pool of light water;
• a fast or epithermal spectrum reactor core immersed in said pool of light water;
• a plurality of steam generators immersed in said pool of light water within said pressure vessel and each having a secondary circuit extending outside said pressure vessel, said plurality of steam generators exceeding a predetermined number of said steam generators needed to operate said reactor core at full power and selected from among said plurality of steam generators;
• and
• means within said pressure vessel inducing a flow within said pool of light water through said reactor core and said at least one steam generator and back to said reactor core.