Flow restrictor for a fuel channel in a nuclear reactor

Claim 1

A GAS-COOLED NUCLEAR REACTOR ARRANGED TO BE REFUELED UNDER LOAD COMPRISING WALLS FORMING UPRIGHT FUEL CHANNELS, UPWARDLY EXTENDING FUEL ELEMENTS DISPOSED WITHIN SAID FUEL CHANNELS AND ARRANGED TO BE UPWARDLY WITHDRAWN THEREFROM, MOVABLE COOLANT FLOW RESTRICTOR ASSEMBLIES LOCATED WITHIN SAID FUEL CHANNELS AND POSITIONED BENEATH SAID FUEL ELEMENTS, SAID RESTRICTOR ASSEMBLIES COMPRISING A RESTRICTOR MMEBER HELD IN A NORMALLY INOPERATIVE POSITION BY THE DOWNWARD FORCE OF AT LEAST ONE SAID FUEL ELEMENT CONTACTING AND ACTING DOWNWARDLY UPON THE RESTRICTOR ASSEMBLY, INWARDLY DIRECTED PROJECTIONS IN THE LOWER END OF SAID CHANNEL ABOVE SAID RESTRICTOR MEMBER TO PROVIDE A STOP THEREFOR, SAID FLOW RESTRICTOR MEMBER TO PROVIDE A STOP THEREAFTER, SAID FLOW RESTRICTOR MEMBERS BEING MOVED INTO OPERATIVE RESTRICTING POSITION BY THE ACTION OF THE DIFFERENTIAL PRESSURE OF THE REACTOR COOLANT ACTING THEREON AS IT FLOWS UPWARDLY THROUGH SAID FUEL CHANNELS WHEN SAID FUEL ELEMENTS ARE LIFTED UPWARDLY OUT OF CONTRACTING ENGAGEMENT WITH SAID RESTRICTOR ASSEMLIES, WHEN SITUATED IN THE RESTRICTING POSITION SAID FLOW RESTRICTOR MEMBERS SERVE TO LIMIT THE RATE OF FLOW OF COOLANT THROUGH SAID CHANNELS.