Patent Number: 
Section: claims

1. A method of forming graphical representations of fuel bundle groups, comprising:selecting, with a computer interface, a graphical representation of a nuclear reactor core;creating a loading map, with the computer interface, using the graphical representation of the nuclear reactor core, the loading map representing the nuclear reactor core; andexecuting a grouping operation on the loading map by performing at least one of,assigning, by a user with the computer interface, at least one fuel bundle within the loading map into one of a plurality of bundle groups, the assigning being based on a user-selected symmetry and a user-selected fuel bundle characteristic, andusing an automated process available on the computer interface to automatically assign at least one fuel bundle within the loading map into one of the plurality of bundle groups, the automated assigning being based on a user-selected symmetry and a user-selected fuel bundle characteristic. 2. The method of claim 1, wherein the associated fuel bundle characteristic is a fuel bundle type, the fuel bundle type being one of a fresh fuel bundle, a reinserted fuel bundle, and a lock fuel bundle, a locked fuel bundle being an unmovable fuel bundle. 3. The method of claim 1, wherein each of the plurality of bundle groups includes an associated symmetry. 4. The method of claim 3, wherein the associated symmetry is one of rotational and mirror. 5. The method of claim 3, wherein the associated symmetry is based on equally divided and symmetric portions of the core. 6. The method of claim 5, wherein the associated symmetry is one of octant, quadrant, and semi. 7. The method of claim 1, wherein the fuel bundle characteristics are a constraint on fuel bundle placement in an optimization function. 8. The method of claim 7, wherein the constraint is fuel bundles in a given bundle group may only be exchanged with other fuel bundles in the given bundle group. 9. The method of claim 1, wherein the bundle groups are a constraint in a user-based, trial and error process. 10. The method of claim 9, wherein the constraint is fuel bundles in a given bundle group may only be exchanged with other fuel bundles in the given bundle group. 11. The method of claim 1, wherein the plurality of bundle groups include a first bundle group with a first associated symmetry attribute and a second bundle group with a second associated symmetry attribute.