A Critical Experimental Study of Integral Physics Parameters in Simulated Liquid-Metal Fast Breeder Reactor Meltdown Cores

Abstract

Integral physics parameters of several representative, idealized meltdown liquid-metal fast breeder reactor (LMFBR) configurations were measured in mockup critical assemblies on the Zero Power Reactor 9 at Argonne National Laboratory. The experiments were designed to provide data for the validation of analytical methods used in the neutronics part of LMFBR accident analyses. Large core distortions were introduced in these experiments (involving 18.5% core volume), and the reactivity worths of configuration changes were determined. The neutronics parameters measured in the various configurations showed large changes on core distortion. Both diffusion theory and transport theory methods were shown to mispredict the experimental configuration eigenvalues. In addition, diffusion theory methods were shown to result in a nonconservative misprediction of the experimental configuration change worths.