The Large Scale U-233 Thoria Reactor Physics Experiment at Chalk River Nuclear Laboratories

Abstract

Part of the advanced Core Concepts program at Chalk River Nuclear Laboratories (CRNL) consisted of the fabrication of Zircaloy-clad fuel elements containing sintered pellets of (Th,²³³U)O₂. The elements were designed for assembly into special bundles for zero energy activation experiments in the ZED-2 reactor.

In the ZED-2 reactor, a mock-up lattice of bundles is arranged around the special demountable element bundles for low power activation. The foils contained in the demountable elements are then removed in the laboratory and counted to determine the neutron reaction rates at various points in the fuel. This sequence of events is repeated for different coolant temperatures and moderators.