Patent Number: 
Section: claims

1. An isotope production target rod for a light water nuclear power reactor, said isotope production target rod comprising:at least one rod central body including an outer shell that defines an internal cavity, the at least one rod central body configured to be inserted into the light water nuclear power reactor;a plurality of irradiation targets within the internal cavity, the irradiation targets not being nuclear fuel; anda low nuclear cross-section separating medium separating each of the irradiation targets from each other and positioning each of the irradiation targets in a spatial arrangement, the low nuclear cross-section separating medium having a neutron absorption cross-section less than about 1 barn for neutrons produced through nuclear fission in the light water nuclear power reactor and incident on the separating medium; and whereinthe irradiation targets and the low nuclear cross-section separating medium are not disposed in a container within the rod central body; andthe separating medium comprises at least one irradiation target receptacle within the internal cavity of each respective rod central body, each irradiation target receptacle including a plurality of target reservoirs in a pattern within at least a portion of an outer surface of each irradiation target receptacle. 2. The isotope production target rod of claim 1, wherein each target reservoir is sized to retain a single irradiation target. 3. The isotope production target rod of claim 1, wherein each target reservoir is sized to retain the respective target in a particular orientation. 4. The isotope production target rod of claim 2, wherein each target reservoir is sized to retain the respective target in a random orientation. 5. The isotope production target rod of claim 1, wherein each irradiation target receptacle is fabricated of at least one of zirconium and aluminum. 6. The isotope production target rod of claim 1, wherein each irradiation target receptacle comprises a solid body having the target reservoirs in the pattern along the at least a portion of an outer surface of the solid body. 7. The isotope production target rod of claim 6, wherein the target reservoirs are equally spaced around the body outer surface between opposing axial end portions of the body outer surface such that each target reservoir is a substantially equal distance from each adjacent target reservoir. 8. The isotope production target rod of claim 6, wherein the target reservoirs are equally spaced about at least one of opposing axial end portions of the body outer surface such that each target reservoir is a substantially equal distance for each adjacent target reservoir. 9. The isotope production target rod of claim 6, wherein each irradiation target receptacle comprises an axially threaded bore in at least one axial end portion. 10. The isotope production target rod of claim 1, wherein each irradiation target receptacle comprises a tubular body having the target reservoirs in the pattern equally spaced around an outer surface. 11. The isotope production target rod of claim 10, wherein the tubular body includes a longitudinal center cavity therethrough, the axial bore having threads in at least one axial end portion. 12. The isotope production target rod of claim 1, wherein each irradiation target receptacle comprises:a perforated tubular sleeve having a plurality of holes therein in the pattern; anda solid core fitted within the sleeve. 13. An isotope production target rod for a light water nuclear power reactor, comprising:at least one rod body including an outer shell that defines an internal cavity, the at least one rod body configured to be inserted into the light water nuclear power reactor;a separating structure disposed within the cavity that defines separate target spaces;a plurality of irradiation targets, the plurality of irradiation targets not being nuclear fuel, each of the plurality of irradiation targets being disposed in a different one of the target spaces such that the plurality of irradiation targets are separated from each other by the separating structure, and the irradiation targets not being disposed in a separate container within the rod body. 14. An isotope production target rod for a light water nuclear power reactor, comprising:at least one rod body including an outer shell that defines an internal cavity, the at least one rod body configured to be inserted into the light water nuclear power reactor;a cylinder disposed in the cavity of at least one of the rod bodies, the cylinder having a plurality of reservoirs formed in an outer lateral surface thereof;a plurality of irradiation targets, each irradiation target disposed in a different one of the plurality of reservoirs such that the plurality of irradiation targets are separated from one another, and each irradiation target not being nuclear fuel, wherein at least one of the plurality of reservoirs has an elliptical cross-section. 15. The isotope production target rod of claim 14, further comprising:a target container within the cavity of the at least one of the rod bodies, and the cylinder being disposed in the target container. 16. A fuel bundle for a light water nuclear power reactor, comprising:a plurality of fuel rods;at least one isotope production rod as recited in claim 1;a plurality of spacer grids maintaining the plurality of fuel rods and the isotope production rod in a spaced relationship in the light water nuclear power reactor; andan outer channel housing the plurality of fuel rods, the isotope production rod and the plurality of spacer grids. 17. The fuel bundle of claim 16, further comprising:an upper tie plate;a lower tie plate; and whereinthe plurality of fuel rods and the isotope production rod are disposed between the upper and lower tie plates.