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One of the events postulated in the hazard analysis for the Waste Treatment and Immobilization Plant (WTP) and other U.S. Department of Energy (DOE) nuclear facilities is a breach in process piping that produces aerosols with droplet sizes in the respirable range. The current approach for predicting the size and concentration of aerosols produced in a spray leak event involves extrapolating from correlations reported in the literature. These correlations are based on results obtained from small engineered spray nozzles using pure liquids that behave as a Newtonian fluid. The narrow ranges of physical properties on which the correlations are based do not cover the wide range of slurries and viscous materials that will be processed in the WTP and in processing facilities across the DOE complex.To expand the data set upon which the WTP accident and safety analyses were based, an aerosol spray leak testing program was conducted by Pacific Northwest National Laboratory (PNNL). PNNL's test program addressed two key technical areas to improve the WTP methodology (Larson and Allen 2010). The first technical area was to quantify the role of slurry particles in small breaches where slurry particles may plug the hole and prevent high-pressure sprays. The results from an effort to address this first technical area can be found in Mahoney et al. (2012). The second technical area was to determine aerosol droplet size distribution and total droplet volume from prototypic breaches and fluids, including sprays from larger breaches and sprays of slurries for which literature data are mostly absent. To address the second technical area, the testing program collected aerosol generation data at two scales, commonly referred to as small-scale and large-scale testing. The small-scale testing and resultant data are described in Mahoney et al. (2013), and the large-scale testing and resultant data are presented in Schonewill et al. (2012). In tests at both scales, simulants were used to mimic the relevant physical properties projected for actual WTP process streams.Examination of the results from the initial (subsequently referred to as Phase I) aerosol spray leak testing described in the preceding paragraph highlighted some uncertainties in evaluating aerosol generation that remained after the original scope of work was completed. Specifically, there was uncertainty with respect to aerosol behavior (namely aerosol release fraction and generation rates) for:  simulant(s) near the WTP rheological boundaries of (6 Pa/6 mPa·s and 30 Pa/30 mPa·s)  simulant(s) with solids loadings greater than 20 wt%  simulant(s) with a small solids fraction of particles that have a relatively high density  lower spray pressures (i.e., specifically 100 and 200 psig in the small-scale tests)  in-spray measurements.The need for additional (subsequently referred to as Phase II) aerosol spray leak testing was identified. The purpose of the study described in this report is to provide experimental data and analyses to supplement the results obtained during P...

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