THE EFFECT OF VARIOUS CONSTRAINT CONDITIONS IN THE FREQUENCY RESPONSE MODEL OF THERMAL STRIPING

Abstract— Thermal fatigue damage may be caused when incompletely mixed hot and cold fluid streams pass over the surface of a component or structure. This kind of thermal fatigue, known as thermal striping, is of particular concern in various types of nuclear reactors and for rapid shut-downs of hot plant. A computer code, known as TBL, is an engineering design tool which has been developed to assess thermal striping damage for fully constrained plates. This model is further developed to account for various plate-constraint conditions. It is compared with two other methods of assessing thermal striping damage. Good agreement is found for the cases when the component is (a) a plate, constrained in various ways and exposed to a sinusoidally varying temperature time striping history and (b) a shroud tube found in the above-core region of a fast reactor pressure vessel and striped with a random temperature time history.