Analysis of hot coolants of nuclear power plants by sonoluminescence spectroscopy

The use of sonoluminescence spectroscopy to analyse hot salt coolants of nuclear power plants, such as caesium and lithium chlorides, was studied. The influence of temperature on the intensity of sonoluminescence of caesium and lithium was experimentally tested. At the same time, with increasing temperature of the solution, the intensity of sonoluminescence of caesium decreased slightly and reached its minimum value at a temperature of 80–82 °C and then increased, reaching its maximum possible value at a temperature of 97–100 °C and decreased again. The intensity of sonoluminescence of lithium also decreased with decreasing temperature of the solution, but this decrease was less significant than that of caesium. The study of the influence of temperature on the results of the determination of the main substance in solutions of salt coolants showed the possibility of accurate determination of the content of caesium and lithium in salt coolants up to a temperature of 150 °C. To achieve better metrological characteristics of the analysis results, ultrahigh-frequency ultrasound with a frequency of 10−12 MHz at an intensity of 20 W∕cm2 should be used to initiate sonoluminescence. A method of determining the content of the main substance in solutions of salt coolants of NPP has been developed. The correctness of the technique was verified by the method of standard additives, as well as by the analysis of coolant samples with different contents of the main substance. At the same time, the value of the relative standard deviation of the results of the determination of the content of lithium chloride (400 g∕l) was 0.076−0.084, and the determination of the content of caesium chloride (600 g∕l) was 0.060−0.069.