Improving Accuracy of the Calculation of In-core Power Distributions for Light Water Reactors
Makoto Tsuiki, William H. Beere
Comparisons have been made of VNEM prototype system to the measured data obtained from Ringhals unit 3 NPP at its beginning of life, hot-stand-by state. Three cases with difference control rod bank positions and Boron concentrations have been compared:
Case 1: nearly all rod banks withdrawn, Boron = 1315 ppm
Case 2: bank C = nearly half-inserted, bank D = fully inserted, Boron = 1131 ppm
Case 3: banks C and D = fully inserted, Boron = 1060 ppm
The results can be summarized as:
error: maximum detector reading (%) error: keff (%)
Case 1 -2.1 -0.175
Case 2 1.5 -0.022
Case 3 -0.5 -0.044
Excellent agreement was observed in the comparison of the neutron detector readings and the core eigenvalues.
The method of core modelling and parameters used in calculation of VNEM is completely the same as the "PWR standard option" determined from similar comparisons of VNEM and other PWRs. No empirical, or any sort of adjustment was done.
VNEM; Ringhals; unit 3; PWR; neutron detector; keff; IACIP: NKS_R_2008_61