Determination of Trace Tellurium in Lead-Bismuth Eutectic Distilled Catch

Lead-bismuth coolant in nuclear reactors generates and accumulates 210Po during operation, which has strong toxicity and high volatility. When the coolant leaks or the reactor is opened, some of the 210Po on the surface of the coolant and in the covering gas will diffuse out of the main system if not properly handled and released into the environment, posing a potential serious threat to the ecological environment and human health. The high-temperature distillation capture technology can effectively extract large amounts of 210Po from the lead-bismuth coolant. Since 210Po is an extremely toxic radioactive isotope with no stable isotope, and to facilitate the experimental study of the capture process, this study ultimately chose its isotopic cousin, Te, as a substitute for 210Po for experimental research. Measuring the trace amount of Te in the distillation capture product can provide strong support for the 210Po extraction process. In the experiment, Te was extracted from the distillation capture film using nitric acid, and the 717 strong basic anion resin was used to separate Te from the extraction solution to eliminate the interference of impurity ions. SnCl2 reduced Te4+ to Te in HCl medium, and the absorbance was measured on a spectrophotometer to obtain the content of trace Te in the sample. The influence of interfering ions in the extraction solution on the measurement value of Te was investigated; the effects of the pH of the column liquid, the concentration and amount of the elution agent, and the washing rate on the separation of Te were explored; and a spectrophotometric method for the determination of trace Te in the distillation capture product of lead-bismuth coolant was established. The results show that at room temperature, the HCl concentration of the column liquid is 4 mol/L, the eluent is ultrapure water, the washing rate is 2 mL/min. The 717 strong basic anion resin demonstrates excellent separation performance for Te across a concentration range of 0 to 10 mg/L, where the absorbance shows a strong linear correlation with Te concentration. The correlation coefficient is r2=0.999 9, with a relative standard deviation of measurement ranging from 0.3% to 2.7%(n=6). The recovery rate is between 96.0% and 101.9%. This measurement method satisfies the requirements for researching the 210Po extraction process.