3-D THERMOELASTIC ANALYSIS OF THE STRAIGHT SECTION OF A PWR HOT LEG CONTAINING A HOT-SPOT USING BEM

A 3-D steady state thermoelastic analysis using the boundary element m ethod has been successfully employed tb investigate the structural res ponse of the straight section of a pressurised water reactor hot leg c ontaining a localised hot spot. With the present severe accident therm al boundary conditions, the analysis produces a nonuniform expansion a cross the hot leg thickness. This expansion was most predominant on th e inner surface, especially at the hot spot location where surface swe lling was obtained. Furthermore, the hot spot generates large tangenti al and axial tensile stresses on the outer surface. These could be det rimental to the integrity of the hot leg by acting as potential sites of crack initiation and subsequent propagation.