Thermal Fatigue and Creep Assessment for the ITER Tritium SDS bed

As the tritium is absorbed and desorbed, the primary vessel is heated to 500 .deg. C and cool down to the room temperature. During this procedure, high alternating thermal stress occurs in the primary vessel. Fatigue analysis is conducted with the information of the magnitude and the number of the calculated cyclic load. In case that the duration for which the bed stay in high temperature increases, thermal creep effects should be evaluated. This paper describes the thermal fatigue and creep assessment for the SDS bed. For the ITER tritium SDS bed, thermal fatigue and creep assessments were performed. A new operation procedure to obtain more integrity margin was recommended. On the contrary, the other operation procedure should be considered which makes the rapid heating and cooling operation possible at the cost of giving up the marginal integrity