Comparison of CECOR Algorithm to Lagrange Multiplier Method to Estimate Reactor Power Distributions

The Lagrange Multiplier method was tested to determine its capability for replacing the current Combustion Engineering Core (CECOR) method for estimating the Palo Verde Nuclear Generating Station reactor power distributions. The Lagrange Multiplier method involves minimizing the sum of the squared residuals of 241 coupling equations subject to 61 constraint equations. The CECOR method solves 180 (241 - 61) coupling equations subject to the 61 constraint equations. The Lagrange method is more complex because it includes the 61 additional coupling equations. The "consistency test" was used to test the accuracy of both methods for computing the power in uninstrumented assemblies, i.e., one-by-one, each of the detectors is considered not available, and the remaining detectors are used to compute the powers in the uninstrumented assemblies. There is potential for expanding the Lagrange method to a three-dimensional approach that could produce even better results, and that is a consideration.