Patent Number: 052290662
Section: claims

1. An axial rod position determination system for a control rod in a nuclear reactor core, said system comprising: fixed incore detectors;  analytical, on-line signature means for periodically creating a response signature database of expected detector response deviations for assumed rod positions from a reference detector response produced at the current rod position by said fixed incore detectors; and  rod position determination means for continuously determining a moved rod position of the control rod by scanning the signature database for a signature match between the expected detector response deviations and current detector response deviations produced by said fixed incore detectors with the control rod at the moved rod position.  fixed incore detectors;  signature means for creating a response signature database of expected detector response deviations for assumed rod positions from a reference detector response produced at the current rod position by said fixed incore detectors, said signature database being divided into inward and outward movement directions from the current rod position and according to control rod bank and individual control rod;  rod position determination means for determining a moved rod position of the control rod by scanning the signature database for a signature match between the expected detector response deviations and current detector response deviations produced by said fixed incore detectors with the control rod at the moved rod position;  classification means for classifying the current detector responses according to direction and bank and individual control rod; and  said determination means scanning a portion of the signature database corresponding to the direction and the bank and individual control rod.  fixed incore detectors;  signature means for creating a response signature database of expected detector response deviations for assumed rod positions from a reference detector response produced at the current rod position by said fixed incore detectors; and  rod position determination means for determining a moved rod position of the control rod by scanning the signature database for a signature match between the expected detector response deviations and current detector response deviations produced by said fixed incore detectors with the control rod at the moved rod position and selecting a closest expected detector response deviation; and  incremental search means for incrementally searching for an incremental match between calculated expected detector response deviation and the current detector response deviation starting with the closest expected detector response deviation when the signature match is not found.  fixed incore detectors;  signature means for creating a response signature database of expected detector response deviations for assumed rod positions, a reference detector response produced at the current rod position by said fixed incore detectors and current core conditions, said signature database is divided into inward and outward move directions from the current rod position and according to control rod bank;  rod position determination means for determining a moved rod position of the control rod by scanning the signature database for a signature match between the expected detector response deviations and current detector response deviations produced by said fixed incore detectors with the control rod at the moved rod position and selecting a closest expected detector response when the signature match does not exist;  classification means for classifying the current detector responses according to direction and bank or individual control rod and said determination means scanning a portion of the signature database corresponding to the direction and the bank or individual control rod; and  incremental search means for searching for an incremental match between calculated expected detector responses and the current detector responses starting from the closest expected detector response when a signature match does not exist.  (a) creating a signature database of expected detector response deviations and corresponding rod positions;  (b) detecting a change in a detector signal producing a detector signal deviation;  (c) scanning the signature database for a match between the detector signal deviation and the expected detector response deviation;  (d) outputting the corresponding rod position when a match occurs;  (e) selecting, when a match does not occur, the closest match between the detector signal deviation and the expected detector response deviation to determine a closest rod position;  (f) incrementing the closest rod position by a predetermined step movement producing an incremented position;  (g) determining a calculated detector response deviation from the incremented position; and  (h) outputting the incremented position if the calculated detector response deviation matches the detector signal deviation. 2. An axial rod position determination system for a control rod in a nuclear reactor core, said system comprising; 3. An axial rod position determination system for a control rod in a nuclear reactor core, said system comprising: 4. A rod position determination system for a control rod in a reactor core, said system comprising: 5. A position determination method for determining a position of a control rod in a reactor core using a fixed incore detector, comprising: