THERMAL-RADIATION PROPERTIES OF INTERFACES BETWEEN NUCLEAR-REACTOR MATERIALS

In analyzing radiant energy exchange between fuel and coolant in a reactor, it is necessary to know the reflection, absorption, and all wavelengths. characteristics of the fuel and its interface with the coolant. Because of the unavailability and great uncertainty of these radiation properties, they are calculated from the electromagnetic theory of optics, and results are presented here. Depending on the contacting medium, six types of surfaces received consideration. They are the interfaces between uranium dioxide and sodium, uranium dioxide and steel, uranium dioxide and a gas, water and a gas, steel and a gas, as well as sodium and a gas. The spectral interface reflectance and the spectral absorptance from one side of the medium to the other side are evaluated for all wavelengths. These spectral properties are further integrated to yield the total hemispherical properties for a black body source over a temperature range from 1200 to 6000 K. Comparisons are made with available experimental data or calculated values, and the agreement is found to be generally good.