Benchmarking dynamic strain predictions of pulsed mercury spallation target vessels

Pulsed mercury spallation targets like that used in the Spallation Neutron Source (SNS) feature a target vessel that strains with each burst of protons. A robust simulation method for predicting the strain response of the target vessel is needed to evaluate the target’s fatigue life. The interaction of pressure waves in the mercury with the vessel is a complex problem made more difficult by cavitation. The importance of benchmarking simulations had been recognized by SNS and its R&D program included experiments for measuring strains in various mercury-filled targets responding to single-beam pulses. Recent progress with simulations is reported. Results for two experimental targets are presented and compared to their test data, and the development of simulation parameters improved predictions is discussed. Overall the recent simulations do a fairly good job of predicting strain magnitude and dynamic response. In some target locations the predictions match data quite well, but this quality is not universally achieved.