Thermal profiles determined on instrumented silicon carbide radiant tubes were used to quantify thermoelastic stress distributions during steady-state operation at temperatures up to 1260°C. Tube failure probabilities were calculated using finite-element analysis incorporating Weibull strength data compiled on tubular sections at high temperature. Results indicate the significance of the axial and radial temperature gradients on the thermoelastic stresses and failure probabilities as well as the viability of a reaction bonded silicon carbide material for radiant tube applications up to 1260°C.