The thorium uranium-233 thermal-neutron breeder reactor is a conceptive and perspec-ive reactor. In this article the well established thermal-neutron cross-sections are employed study the consumption of thorium and the generation of 233U

in order to better unders-and the physical properties of such reactor. Upon the assumption that the period of uel changing is not shorter than the time for the induced 233U to reach its saturation toncentration

it turns out that the reactor apparently possesses the physical properties: 1

high thorium consumptivity

2. high neutron flux operation preferable; 3. low input 233U-Th ratio and 4. high fuel burn-up.