Studies of Potential Inhibitors of Sodium Aluminosilicate Scales in High-Level Waste Evaporation

Abstract

For a decade, the evaporation of highly alkaline High-Level nuclear wastes as practiced in some DOE nuclear waste facilities has produced sodium aluminosilicate scales causing both operation and criticality hazards. Segregation of aluminum-rich wastes from silicate-rich wastes minimizes the amount of scale produced and reduces cleaning expenses but does not eliminate scaling nor increase operational flexibility in waste processing. Similar issues have affected the aluminum refining industry for many decades. Over the past several years, successful commercial products have been identified to eliminate aluminosilicate fouling in the aluminum industry but have not been utilized in a nuclear environment.

Laboratory quantities of three proprietary aluminosilicate scale inhibitors produced by Cytec industries have been shown to prevent formation of aluminosilicate scales. The Savannah River National Laboratory (SRNL) has been actively testing these potential scale inhibitors to examine their radiation stability, radiolytic degradation behaviors, and downstream impacts to determine their viability within the High-Level nuclear waste system at the Savannah River Site (SRS). One of the tested polymers has been found to successfully meet the established criteria for application in the nuclear waste environment.

Keywords:

• Antiscalant
• cancrinite
• nuclear waste evaporator
• scale inhibitor
• sodalite
• sodium aluminosilicate