Forced circulation boiling nuclear power reactor

Claim 1

A NUCLEAR POWER REACTOR COMPRISING A REACTOR CORE WHICH INCLUDES AN ACTIVE REGION CONTAINING NUCLEAR FUEL MATERIAL AND HAVING PASSAGEWAYS FORMED THEREIN WHICH EXTEND THERETHROUGH, SAID REACTOR CORE HAVING FORMED THEREIN A FUEL-FREE REGION, MEANS CONNECTING SAID FUELFREE REGION IN SERIES FLUID COMMUNICATION WITH SAID PASSAGEWAYS, AND MEANS FOR CIRCULATING A FLUID THAT IS BOTH A COOLANT AND A MODERATOR THROUGH SAID PASSAGEWAYS AND THEN THROUGH SAID FUEL-FREE REGION, SAID NUCLEAR FUEL MATERIAL HAVING A NEGATIVE TEMPERATURE COEFFICIENT OF REACTIVITY, THE FLUID IN SAID PASSAGEWAYS HAVING A PREDETERMINED POSITIVE DENSITY COEFFICIENT OF REACTIVITY, AND THE FLUID IN SAID FUEL-FREE REGION HAVING A PREDETERMINED NEGATIVE DENSITY COEFFICIENT OF REACTIVITY, SAID PREDETERMINED DENSITY COEFFICIENTS OF THE FLUID BEING SO SELECTED THAT IN RESPONSE TO A CHANGE IN OPERATING CONDITIONS THE DIFFERENCE OF THEIR REACTIVITY CONTRIBUTIONS IS BALANCED BY THE REACTIVITY CONTRIBUTION RESULTING FROM THE NEGATIVE TEMPERATURE COEFFICIENT OF THE NUCLEAR FUEL MATERIAL, WHEREBY A VARIATION IN THE POWER LOAD UPON THE REACTOR IS AUTOMATICALLY COMPENSATED FOR WITHIN THE REACTOR WITHOUT REQUIRING ANY EXTERNAL ADJUSTMENT OF REACTOR REACTIVITY AND WITHOUT CAUSING AN UNDESIRABLE AMOUNT OF CHANGE IN FUEL TEMPERATURE.