Solid State Characterizations of Long-Term Leached Cast Stone Monoliths

Asmussen, Robert M.¹  Pearce, Carolyn I.¹  Parker, Kent E.¹  Miller, Brian W.¹  Lee, Brady D.¹  Buck, Edgar C.¹  Washton, Nancy M.¹  Bowden, Mark E.¹  Lawter, Amanda R.¹  McElroy, Erin M.¹  Serne, R. Jeffrey¹ 

[1] Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

DOI  :  10.2172/1328842
RP-ID  :  PNNL--25578 Rev.0
PID  :  OSTI ID: 1328842
Others  :  Other: 830403000

美国|英语

来源: SciTech Connect

【 摘 要 】

This report describes the results from the solid phase characterization of six Cast Stone monoliths from the extended leach tests recently reported on (Serne et al. 2016),that were selected for characterization using multiple state-of-the-art approaches. The Cast Stone samples investigated were leached for > 590 d in the EPA Method 1315 test then archived for > 390 d in their final leachate. After reporting the long term leach behavior of the monoliths (containing radioactive ⁹⁹Tc and stable ¹²⁷I spikes and for original Westsik et al. 2013 fabricated monoliths, ²³⁸U), it was suggested that physical changes to the waste forms and a depleting inventory of contaminants of potential concern may mean that effective diffusivity calculations past 63 d should not be used to accurately represent long-term waste form behavior. These novel investigations, in both length of leaching time and application of solid state techniques, provide an initial arsenal of techniques which can be utilized to perform such Cast Stone solid phase characterization work, which in turn can support upcoming performance assessment maintenance. The work was performed at Pacific Northwest National Laboratory (PNNL) for Washington River Protection Solutions (WRPS) to characterize several properties of the long- term leached Cast Stone monolith samples.