sentences:  The temperature of the fuel varies as a function of the distance from the centre to the rim.At distance x from the centre the temperature (Tx) is described by the equation where ρ is the power density (W m−3) and Kf is the thermal conductivity.To explain this for a series of fuel pellets being used with a rim temperature of 200 oC (typical for a BWR) with different diameters and power densities of 250 Wm−3 have been modeled using the above equation.