Interpretations of Pin/Plate Sodium-Void Reactivity Measurements in the Fast Critical Assembly ZPPR-5A Using RRC Codes and Data System

摘要

A brief description of different methods followed in different laboratories for the predictions of sodium void reactivity effect in fast critical assemblies is first presented. A code system that has been developed at RRC to reliably predict sodium void reactivity effect to be used in the safety analysis of fast breeder power reactors is then described. The basic formulation used for the preparation of cell averaged broad group cross sections involves the use of collision probability methods for the treatment of spatial heterogeneity and Tone's method for the treatment of resonance heterogeneity. The code system has options to treat the anisotropic diffusion effects in both pin and plate type cells. Using this code system and the multigroup cross section set available at RRC, an analysis of pin/plate sodium voiding experiments in ZPPR-5A assembly has been made. The pin voiding experiments as well as the plate voiding experiments are well predicted by our codes and data system. (ERA citation 08:005095)