Epithermal to intermediate spectrum pressurized heavy water breeder reactor

Claim 2

IN A PRESSURIZED HEAVY WATER MODERATED AND COOLED EPITHERMAL NUCLEAR BREEDER REACTOR COMPRISING AN ACTIVE CORE HAVING A PLURALITY OF FUEL MODULES CONTAINING FISSILE AND FERTILE MATERIAL, SAID MODULES INCLUDING MOVABLE AND STATIONARY REGIONS EACH OF SAID REGIONS HAVING FUEL RODS CONTAINING SAID FISSILE AND FERTILE MATERIAL, EACH OF SAID STATIONARY REGIONS SURROUNDING ONE OF SAID MOVABLE REGIONS; MEANS FOR AXIALLY POSITIONING SAID MOVABLE REGIONS WHEREBY SAID REACTOR REACTIVITY IS CONTROLLED BY VARIABLE GEOMETRY CONTROL, SAID FISSILE AND FERTILE MATERIAL RESPECTIVELY SELECTED FROM URANIUM-233 AND THORIUM-232 AND HAVING A FERTILE TO FISSILE ATOM RATIO IN THE RANGE FROM 5 TO 50; AND A REFLECTOR SURROUNDING THE FISSILE AND FERTILE MATERIAL, THE IMPROVEMENT COMPRISING SAID ACTIVE CORE HAVING A MODERATOR-TO-FUEL ATOM RATIO IN THE RANGE FROM 3.5 TO 1.00, EACH OF SAID MOVABLE AND STATIONARY MODULE REGIONS ARRANGED INTO A UNIFORM ROD LATTICE WITH UNIFORM FISSILE AND FERTILE FUEL LOADING AND DIVIDED INTO FIRST AND SECOND AXIALLY ALIGNED ZONES, SAID FIRST MOVABLE ZONE ALIGNED ADJACENT TO THE FIRST STATIONARY ZONE, SAID FIRST MOVABLE ZONE AND SAID SECOND STATIONARY ZONE HAVING A WEIGHT PERCENT UO2 DIFFERENT FROM THAT OF SAID SECOND MOVABLE AND FIRST STATIONARY ZONES, AND FIRST MOVABLE AND SECOND STATIONARY ZONES HAVING FROM ABOUT 9 TO ABOUT 14 WEIGHT PERCENT UO2 AND SAID SECOND MOVABLE AND FIRST STATIONARY ZONES HAVING FROM ABOUT 4 TO ABOUT 8 WEIGHT PERCENT UO2, SAID FUEL RODS RANGING IN DIAMETER FROM 0.250 TO ABOUT 0.500 INCHES, SAID RODS HAVING A TRIANGULAR PITCH ARRAY WITH A ROD SPACING FROM 0.055 TO 0.095 INCHES.

Claim 3

In a pressurized heavy water moderated and cooled epithermal nuclear breeder reactor comprising an active core having a plurality of fuel modules containing fissile and fertile material, said modules including movable and stationary regions, each of said regions having fuel rods containing said fissile and fertile material, each of said stationary regions surrounding one of said movable regions; means for axially positioning said movable regions whereby said reactor reactivity is controlled by variable geometry control, said fissile and fertile material respectively selected from uranium-233 and thorium-232 and having a fertile to fissile atom ratio in the range from 5 to 50; and a reflector surrounding the fissile and fertile material, the improvement comprising said active core having a moderator-to-fuel atom ratio in the range from 3.5 to 1.00, each movable region comprises an array of fuel rods defining a movable seed region and each stationary region comprises an array of fuel rods defining a stationary seed region and a stationary blanket region of Th232, said stationary seed region surrounding said movable seed region and said blanket region surrounding said stationary seed region, said movable and stationary seeds are divided into first and second axially aligned zones, said first movable seed zone aligned adjacent to said secondary seed zone, said first and second seed zones haveng different weight percent UO2, said first seed zones have from about 20 to about 25 weight percent UO2 and said second seed zones having from about 15 to about 19 weight percent UO2, said movable seed and stationary seed fuel rods having a rod diameter from 0.250 to 0.499 inches and the blanket fuel rods having a rod diameter from 0.500 to 0.650 inches, all of said fuel rods having a triangular pitch array with a rod spacing from 0.055 to 0.095 inches.

Claim 4

In a pressurized heavy water moderated and cooled epithermal nuclear breeder reactor comprising an active core having a plurality of fuel modules containing fissile and fertile material, said modules including movable and stationary regions, each of said regions having fuel rods containing said fissile and fertile material, each of said stationary regions surrounding one of said movable regions; means for axially positioning said movable regions whereby said reactor reactivity is controlled by variable geometry control, said fissile and fertile material respectively selected from uranium-233 and thorium-232 and having a fertile to fissile atom ratio in the range from 5 to 50; and a reflector surrounding the fissile and fertile material, the improvement comprising said active core having a moderator-to-fuel atom ratio in the range from 3.5 to 1.00, each movable region comprises an array of fuel rods defining a movable seed region and each stationary region comprises an array of fuel rods defining a stationary seed region and a stationary blanket region of Th232, said stationary seed region surrounding said movable seed region and said blanket region surrounding said stationary seed region, said movable and stationary seeds are divided into first and second axially aligned zones, said first movable seed zone aligned adjacent to said secondary seed zone, said first and second seed zones haveng different weight percent UO2, said first seed zones have from about 20 to about 25 weight percent UO2 and said second seed zones having from about 15 to about 19 weight percent UO2, said movable seed and stationary seed fuel rods having a rod diameter from 0.250 to 0.499 inches and the blanket fuel rods having a rod diameter from 0.500 to 0.650 inches, all of said fuel rods having a triangular pitch array with a rod spacing from 0.055 to 0.095 inches.