Nuclear reactors

Claim 1

IN A LIQUID MODERATED, LIQUID COOLED NUCLEAR REACTOR, A PRESTRESSED CONCRETE PRESSURE VESSEL CONTAINING THE REACTOR CORE AND WITH THE LIQUID MODERATOR/COOLANT IN CONTACT WITH THE INTERNAL SURFACE OF THE VESSEL, THE VESSEL HAVING AN INTRNAL METAL LINING IN CONTACT WITH THE INTERNAL SURFACE OF THE CONRETE THEROF, THERMAL INSULATION MEMBERS DISPOSED ADJACENT TO BUT SPACED FROM SAID METAL LINING, SAID THERMAL INSULATION MEMBR BEING SEPARATED FROM ONE ANOTHER BY GAPS OF SUCH WIDTH AS TO ALLOW RESTRICTED COMMUNICATION BETWEEN THAT PART OF THE VESSEL INTERIOR WHICH CONTAINS THE REACTOR CORE AND THE SPACE BETWEEN THE THERMAL INSULATION MEMBERS AND THE METAL LINING OF THE VESSEL, WHEREBY LIQUID MODERATOR/ COOLANT IS ALLOWED, BY VIRTUE OF SAID RESTRICTED COMMUNICATION, TO OCCUPY SAID SPACE WITHOUT SAID THERMAL INSULATION MEMBERS BEING SUBJECTED TO DIFFERENTIAL PRESSURE, THE RESTRICTED COMMUNICATION BEING SUCH AS SUBSTANTIALLY TO PREVENT HEAT TRANSFER BY CONVECTION BETWEEN THE MAIN BODY OF MDERATOR/COOLANT LIQUID AND THE MODERATOR/ COOLANT LIQUID IN SAID SPACE.