Patent Number: 
Section: claims

1. A method for adjusting quantities of materials in a first cell, comprising:(a) determining an average rate of change of amount of a material in said first cell based on a previous amount of said material in said first cell and a flux in said first cell;(b) determining an updated amount of said material in said first cell based on said average rate of change; and(c) adjusting said updated amount of said material in said first cell by a quantity. 2. The method of claim 1, wherein said average rate of change is a weighted average of a plurality of instantaneous rates of change of amount of said material in said first cell. 3. The method of claim 1, further comprising:(d) adjusting a second amount of said material in a second cell by said quantity. 4. The method of claim 3, further comprising:(e) transferring a mass, approximately equivalent to said quantity, of a substance corresponding to said material from a first physical location corresponding to said first cell to a second physical location corresponding to said second cell. 5. The method of claim 3, further comprising:(e) further adjusting said second amount of said material in said second cell by a second quantity. 6. The method of claim 5, further comprising:(f) transferring a mass, approximately equivalent to said quantity, of a substance corresponding to said material from a first physical location corresponding to said first cell to a second physical location corresponding to said second cell; and(g) transferring a second mass, approximately equivalent to said second quantity, of said substance from said second physical location to a third location. 7. The method of claim 5, further comprising:(f) adjusting a third amount of said material in a third cell by said second quantity. 8. The method of claim 7, further comprising:(g) transferring a mass, approximately equivalent to said quantity, of a substance corresponding to said material from a first physical location corresponding to said first cell to a second physical location corresponding to said second cell; and(h) transferring a second mass, approximately equivalent to said second quantity, of said substance from said second physical location to a third physical location corresponding to said third cell. 9. The method of claim 7, further comprising:(g) adjusting a fourth amount of said material in a fourth cell by a third quantity; and(h) further adjusting said updated amount of said material in said first cell by said third quantity. 10. The method of claim 3, further comprising:(e) adjusting a third amount of said material in a third cell by a second quantity;(f) further adjusting said second amount of said material in said second cell by said second quantity; and(g) distributing at least a portion of said second amount of said material in said second cell to said first cell, thereby leaving a remaining amount of said material in said second cell, including:(i) further adjusting said second amount of said material in said second cell by a third quantity, and(ii) further adjusting said updated amount of said material in said first cell by said third quantity. 11. The method of claim 10, further comprising:(h) after completing acts (a)-(f) and before completing act (g),(i) determining a second average rate of change of amount of said material in said first cell based on said updated amount of said material in said first cell and a second flux in said first cell,(ii) determining a second updated amount of said material in said first cell based on said second average rate of change. 12. The method of claim 1, further comprising:(d) before act (a), determining said flux in said first cell based on an amount of said material in said first cell. 13. The method of claim 12, wherein said determining of act (d) is further based on an amount of a second material in said first cell. 14. The method of claim 12, wherein said determining of act (d) is further based on respective amounts of each of a plurality of materials in said first cell. 15. The method of claim 12, wherein act (d) comprises:(i) determining an average rate of change of flux in said first cell based on said previous amount of said material in said first cell; and(ii) determining said flux in said first cell based on said average rate of change of flux. 16. The method of claim 12, further comprising determining an updated flux in said first cell based on said updated amount of said material. 17. The method of claim 12, further comprising:repeating acts (a)-(d). 18. The method of claim 1, wherein said flux is a neutron flux. 19. The method of claim 1, wherein said first cell corresponds to a region of a plurality of regions of a nuclear reactor system. 20. The method of claim 1, wherein said first cell corresponds to a region having a homogeneous composition of materials. 21. The method of claim 1, wherein said first cell corresponds to a region including a heterogeneous composition of materials. 22. The method of claim 1, wherein said first cell corresponds to a region having a first shape different than a second shape of a second region corresponding to a second cell of a plurality of cells. 23. The method of claim 1, wherein said first cell corresponds to a first region having a first volume different than a second volume of a second region corresponding to a second cell of a plurality of cells. 24. The method of claim 1, further comprising:(d) transferring a mass, approximately equivalent to said quantity, of a substance corresponding to said material from a first physical location corresponding to said first cell. 25. The method of claim 1, further comprising:determining a recommended movement of a neutron absorber in a nuclear reactor system. 26. The method of claim 1, further comprising:moving a neutron absorber in a nuclear reactor system. 27. The method of claim 1, further comprising:automatically moving a neutron absorber in a nuclear reactor system. 28. The method of claim 1, further comprising:determining a recommended coolant flow rate in a nuclear reactor system. 29. The method of claim 1, further comprising:automatically adjusting a coolant flow rate in a nuclear reactor system.