Radiative Heat Transfer in a Pressurized Water Reactor Fuel Bundle Under Accident Conditions

A simple model is applied for the analysis of radiative heat transfer in a pressurized water reactor fuel assembly during steady state and under a loss-of-coolant accident. The method includes a matrix calculation of view factors, performed dividing the bundle into unit cells composed by portions of fuel rods and by a coolant subchannel. The cells are correlated considering imaginary faces among them, and the pertinent equations are simultaneously solved for the whole assembly. Some results are related for various values of the heat flux in different operational and accidental conditions.