Thermal Shock Testing of Fillet-Type Tube-to-Tubesheet Welds

To prove the inherent integrity of the fillet-type tube-to-tubesheet welds proposed in the initial design of the Intermediate Heat Exchanger for the Liquid Metal Fast Breeder Program Fast Flux Test Facility, a seven-tube model was built with prototypical tubes and welds. The welds were subjected to thermal shocks well in excess, both in severity and numbers, of those that the plant units may be expected to experience. Post-test examinations of the welds confirmed that no failures had occurred during the test. However, minor cracks were observed in the weld root area upon microscopic examination of the weld cross sections. This paper describes the test model and the results obtained from it.