Chemical Species in the Vapor Phase of Hanford Double-Shell Tanks: Potential Impacts on Waste Tank Corrosion Processes

Felmy, Andrew R. ; Qafoku, Odeta ; Arey, Bruce W. ; Boomer, Kayle D.

关键词: CARBON STEELS;    CHEMICAL COMPOSITION;    CHEMICAL WASTES;    CHEMISTRY;    CONDENSATES;    CORROSION;    DRYING;    EVALUATION;    RECOMMENDATIONS;    STEELS;    TANKS;    TESTING;    WASTES Environmental Molecula;   

DOI  :  10.2172/993347
RP-ID  :  PNNL-19767
PID  :  OSTI ID: 993347
Others  :  Other: 39930
Others  :  830403000
Others  :  TRN: US201102%%41

美国|英语

来源: SciTech Connect

【 摘 要 】

The presence of corrosive and inhibiting chemicals on the tank walls in the vapor space, arising from the waste supernatant, dictate the type and degree of corrosion that occurs there. An understanding of how waste chemicals are transported to the walls and the affect on vapor species from changing supernatant chemistry (e.g., pH, etc.), are basic to the evaluation of risks and impacts of waste changes on vapor space corrosion (VSC). In order to address these issues the expert panel workshop on double-shell tank (DST) vapor space corrosion testing (RPP-RPT-31129) participants made several recommendations on the future data and modeling needs in the area of DST corrosion. In particular, the drying of vapor phase condensates or supernatants can form salt or other deposits at the carbon steel interface resulting in a chemical composition at the near surface substantially different from that observed directly in the condensates or the supernatants. As a result, over the past three years chemical modeling and experimental studies have been performed on DST supernatants and condensates to predict the changes in chemical composition that might occur as condensates or supernatants equilibrate with the vapor space species and dry at the carbon steel surface. The experimental studies included research on both the chemical changes that occurred as the supernatants dried as well as research on how these chemical changes impact the corrosion of tank steels. The chemical modeling and associated experimental studies were performed at the Pacific Northwest National Laboratory (PNNL) and the research on tank steel corrosion at the Savannah River National Laboratory (SRNL). This report presents a summary of the research conducted at PNNL with special emphasis on the most recent studies conducted in FY10. An overall summary of the project results as well as their broader implications for vapor space corrosion of the DST???s is given at the end of this report.