CORROSION BEHAVIOR OF AISI 304L STAINLESS STEEL FOR APPLICATIONS IN NUCLEAR WASTE REPROCESSING EQUIPMENT

摘要

Developed by the Advanced Fuel Cycle Initiative of the Department of Energy, UREX+ is an advanced solvent extraction process to separate uranium from nuclear waste. The material selection for constructing the centrifugal contactor that is utilized in the operation of this process is very critical in order to ensure its reliable performance. Our work focuses on assessing the corrosion of 304L stainless steel in acidic aqueous solutions mimicking the environments present in a centrifugal contactor as the key equipment of UREX+ process during its operation. Corrosion tests are conducted in the following aqueous solutions: 5.0M HNO_3; 5.0M HNO_3 + 0.1M HF; and 5.0M HNO_3 + 0.1M HF + 0.1M Zr~(4+). Electrochemical impedance spectroscopy (EIS) tests are considered to assess the corrosion mechanisms. X-ray photoelectron spectroscopy is also used to study the surface analysis. The results show that 5.0M HNO_3 + 0.1M HF solution is the most corrosive environment and addition of Zr~(4+) ions reduces the corrosion caused by HF to levels similar to those found in HNO_3 solutions.