Review of Alternative Enhanced Chemical Cleaning Options for SRS Waste Tanks

Actual-Waste Testing of Ultraviolet Light to Augment the Enhanced Chemical Cleaning of SRS Sludge

“…Enhanced Chemical Cleaning (ECC) was identified as a potential method for greatly reducing the impact of oxalate additions to the SRS Tank Farms without adding additional components to the waste that would significantly alter waste composition, extend processing times, or increase waste form volumes. 3,4 In support of Savannah River Site (SRS) tank closure efforts, the Savannah River National Laboratory (SRNL) conducted Real Waste Testing (RWT) to evaluate an alternative to the baseline 8 wt. % OA chemical cleaning technology for tank sludge heel removal.…”

Alternative and Enhanced Chemical Cleaning: Basic Studies Results Fy2010

“…Although studies have been conducted previously to compare the effectiveness of these complexing acids (Hay, 2009), the recent discovery of the importance of pH control was sufficient cause for additional evaluations. Since oxalic acid is a particularly strong organic acid (pK a1 = 1.3, pK a2 = 4.3), it was possible that it was the acidity of the acid that lead to the superior performance in previous comparisons.…”

“…Oxalic acid is the preferred cleaning reagent for heel dissolution, particularly for iron-based sludge. Several recent literature reviews (AduWusu, 2003;Ketusky, 2007;Hay, 2009) and a Systems Engineering Evaluation (Martino, 2009) have considered the various known methods for sludge dissolution, and oxalic acid remains the chemical dissolution reagent of choice. Oxalic acid is an industry standard used for the cleaning and maintenance of nuclear power plants, although these operations often involve the removal of relatively small volumes of chemical scale materials with dilute acid followed by regeneration of the acid for reuse (Bertholdt, 1999).…”

Alternative Enhanced Chemical Cleaning Basic Studies Results FY09

“…Early in this testing, it became apparent that existing sludge simulants were inadequate with regard to their solubility properties. As discussed in the a literature review on chemical cleaning 3 , inconsistent results were frequently observed in previous testing which may have arisen from non-representative simulants and lack of pH control. As a result, testing in the current work has focused on the use of pure metal phases known to be present in SRS waste, pH control using mineral acids, and a focus on solutions with a pH near 1.…”