Patent Number: 
Section: claims

1. A fuel bundle surrogate for the irradiation of a target material in a heavy water reactor for the production of an isotope, the fuel bundle surrogate comprising:a plurality of tube sheaths, each tube sheath being parallel to a longitudinal center axis of the fuel bundle surrogate;a plurality of end caps, each end cap being disposed on a corresponding end of a tube sheath;a pair of end plates, wherein the end plates are disposed at opposing ends of the plurality of tube sheaths; anda first target comprised of a first target material suitable for producing the isotope by way of a neutron capture event, the first target being disposed in a first tube sheath of the surrogate fuel bundle,wherein the first tube sheath of the plurality of tube sheaths comprises an elongated thickened wall portion and a pair of annular end portions, each annular end portion and corresponding end cap forming an unimpeded cylindrical void that is disposed on a corresponding end of the thickened wall portion and extends an entire length of the annular end portion, and the annular end portion has a wall thickness that is less than a wall thickness of the thickened wall portion. 2. The fuel bundle surrogate of claim 1, wherein the first target further comprises an outer capsule defining an interior volume, wherein the outer capsule is comprised of the first target material and the first target material is disposed in the interior volume of the outer capsule. 3. The fuel bundle surrogate of claim 2, wherein the first target material disposed in the interior volume of the outer capsule is in the form of pellets. 4. The fuel bundle surrogate of claim 1, further comprising a second target comprised of a second target material, wherein the second target is disposed in a second tube sheath of the fuel bundle surrogate. 5. The fuel bundle surrogate of claim 1, further comprising an identification indicia on an outer surface of the first tube sheath, wherein the identification indicia is one of a bar code, an appendage or a bearing pad. 6. The fuel bundle surrogate of claim 1, wherein each end cap is rigidly affixed to the corresponding end of the corresponding tube sheath by a weld. 7. The fuel bundle surrogate of claim 1, wherein one of the end caps of the plurality of end caps is secured to a corresponding one of the annular end portions of the first tube sheath.