Analysis of Dosimetry Measurements in EBR-II

Analyses of an extensive series of reaction-rate measurements done recently in the Experimental Breeder Reactor II (EBR-II) runs 50G and 50H were performed with transport theory and diffusion theory codes using detailed representations of the loadings in XY, RZ, and XYZ geometry and broad-group cross sections derived from the ENDF/B-I and -III data files. It was found possible to predict the measured relative reaction rates quite accurately within the core region; however, there are substantial differences in the radial blanket and axial reflector regions. Analyses of the absolute reaction-rate measurements in EBR-II run 50H have provided additional evidence that the reactor operates ≅ 9% below the nominal power level of 62.5 MW(th). Differences were observed between the calculated reaction rates using the ENDF/B-I and -III data files for the stainless-steel/sodium axial reflector regions in the EBR-II