At the Hanford Waste Treatment and Immobilization Plant (WTP), various vessels are designed to be agitated with internal pulse jet mixers (PJMs) in order to provide a means of mixing with no moving parts local to the vessel. PJMs are operated by use of an applied vacuum to draw liquid in followed by motive air to force liquid out (while not completely discharging all the liquid). This continual operation results in mixing of the vessel contents. In off-normal conditions, PJMs may completely discharge resulting in air rapidly injected into the vessel (PJM overblow).
An evaluation is complete to determine the statically applied transient acoustic event loads resulting from Pulse Jet Mixer (PJM) overblow on a vessel’s internal submerged structures. The high-frequency acoustic load on internal structures is determined via analysis of overblow hydrophone test data, vessel modal and harmonic analysis, determination of an overblow forcing function through a Fourier analysis of test data compared to modal analysis of the vessel, application of the overblow forcing function in a finite element analysis model with acoustic fluid elements, use of a displacement-response spectra, and Hooke’s Law. Compared to previous analyses, this improved method can account for changes to PJM cavity pressure, PJM nozzle diameter, and more accurately represents the loads because it considers geometric constraints.