Heavy water moderated organic cooled nuclear fission reactor

Claim 1

A NUCLEAR FISSION REACTOR COMPRISING A SEALED MODERATOR TANK, SPACED COOLANT TUBES HAVING END ASSEMBLIES EXTENDING COMPLETELY THROUGH SAID TANK, FISSIONABLE FUEL ASSEMBLIES WITHIN EACH OF SAID COOLANT TUBES FORMING THE REACTIVE CORE OF SAID REACTOR, MEANS FOR PERMITTING THE REPLACEMENT OF FUEL AT REGULAR INTERVALS DURING NORMAL OPERATION OF SAID REACTOR, THE LATTER SAID MEANS INCLUDING SPACER MEANS FOR MAINTAINING SAID ASSEMBLIES IN PREDETERMINED AXIAL POSITIONS WITHIN SAID COOLANT TUBES, SAID FUEL ASSEMBLIES IN EACH COOLANT TUBE BEING IN AXIAL ARRAY AND WITHOUT POSITIVE INTERCONNECTION, SAID SPACER MEANS ALIGNED AXIALLY WITH THE FUEL ASSEMBLIES IN EACH COOLANT TUBE SIMILARLY IN SURFACE CONTACT WITH THE END ASSEMBLIES TO PERMIT THE SELECTIVE REMOVAL AND REPLACEMENT OF FUEL ASSEMBLIES FROM EACH FUEL COOLANT TUBE BY WITHDRAWING AND PUSHING SAID SPACER MEANS THROUGH EACH SAID TUBE, MEANS FOR PUMPING HEAVY WATER AT RELATIVELY LOW PRESSURE THROUGH SAID MODERATOR TANK AND AROUND AID COOLANT TUBES TO MODERATE THE NEUTRONS PRODUCED AS THE RESULT OF THE FISSION OF SAID FISSIONABLE FUEL IN SAID FUEL ASSEMBLIES, AND MEANS FOR CIRCULATING THROUGH SAID COOLANT TUBES IN CONTACT WITH SAID FUEL ASSEMBLIES AT A RELATIVELY LOW PRESSURE AN INERT LIQUID COOLANT TO REMOVE THE HEAT OF FISSION OF SAID REACTOR.