GENERATION OF SPATIAL WEIGHTING FUNCTIONS FOR EX-CORE DETECTORS BY ADJOINT TRANSPORT CALCULATION

The response rate of ex-core detectors depends on the power level, pow er distribution, and reactor configuration. For the analysis of the de tector response rate for various core power distributions, it is impor tant to generate spatial weighting functions that are insensitive to s mall changes in the core power distribution and determined by the reac tor configuration. Two-dimensional discrete ordinates adjoint transpor t calculations are used to calculate the core axial weighting function s. The effects of the reactor operating conditions on the core axial w eighting functions are analyzed, and it is found that the soluble boro n concentration in the reactor coolant has little effect while the cor e power level affects the core axial weighting functions significantly . A comparison between the results of the adjoint and forward transpor t calculations shows an excellent agreement. However, the adjoint tran sport method provides more detailed data and requires less computing t ime than the forward transport method.