Abstract A core configuration for a liquid metal cooled fast breeder nuclear reactor includes a generally cylindrical breeder region, a first fissile region which completely embraces the central breeder region, a second fissile region wholly or partially surrounding said first fissile region with axial and radial clearance, an inner breeder region occupying said clearance, and an outer breeder region extending from the outer boundary of the second fissile region to the boundary of the core itself, which is generally cylindrical. A variation envisages the second fissile region only partially surrounding the first fissile region, the ''''corner'''' portions being occupied by breeder material in place of the fissile material of a completely embracing second fissile region.
A nuclear reactor according to claim 1, wherein said second fissile region only partially surrounds the first fissile region, the ''''corner'''' fissile portions of a wholly surrounding fissile region being replaced by breeder material.
Claim 2
Dependent Claim
58 words
A nuclear reactor according to claim 2, wherein the annular region between the first and second fissile regions is entirely breeder and of full core height, and structural core elements constituting said annular region are of greater diameter than the structural core elements which include fissile material, whereby to enable a higher breeder/structural material ratio to be achieved.
Claim 3
Dependent Claim
33 words
A nuclear reactor according to claim 3, wherein the height of the radial portion of the second fissile region is the same as that of the hollow cylinder constituting the first fissile region.
Claim 4
Dependent Claim
24 words
A nuclear reactor according to claim 1, wherein the fissile material is mixed uranium and plutonium oxides, and the breeder material is uranium carbide.