Development of Methods of Gas Chromatographic Analysis of Technological Media of the Main Circulation Pumps of a Nuclear Power Plant

Abstract

During the operation of power plant equipment, technological media are used – water, turbine oils. Diagnostics of equipment by gas chromatographic determination of diagnostic components (gases Н2, СН4, С2Н6, С2Н4, С2Н2, СО, СО2, О2, N2), water, "Ionol" in these media is urgent. For this, 5 chromatographs are used. An increase in the reliability of the main circulation pumps of a nuclear power plant can be due to an increase in the reliability of its oil system. The influence of ultrasonic vibrations on the generation of gases in the systems "oil – diagnostic gas", "oil – water – diagnostic gas" with the use of turbine oil Тп-22s is studied. Gas concentrations increase with an increase in the duration of exposure for 1600 s at a frequency of 35–125 kHz and a power of 20 W. The dependences of the concentrations Ci of dissolved gases on the irradiation time τ of technological media is expressed by the equation Сi=А∙τ+В Coefficients A, B and correlation coefficients R2 have specific values for each dissolved gas. So, 0.95≤R2≤0.995, which indicates the adequacy of the obtained equations to the experimental data. This makes it possible to determine turbine oil in water after irradiation and subsequent gas chromatographic determination of the generated dissolved gases. The technical requirements for a 5-channel gas chromatograph were established and its structural diagram was developed. This makes it possible to reduce the number of measurement operations and chromatographs. The thresholds for determining the diagnostic components in the corresponding technological environments have been determined: 2 ррm (Н2); 1 ррm (СН4, С2Н6, С2Н4); 0,5 ррm (С2Н2); 5 ррm (СО, СО2); 1,5 ppm (О2, N2); 0.05 wt. % ("Ionol"); 2 g/t (water in turbine oil) 0.02 mg/dm3 (turbine oil in water).

The basic technological scheme of the oil system for the main circulation pumps of the NPP has been developed. It is proposed to continuously: degassing the turbine oil flow; sorption purification of cooling water, analysis of turbine oil and cooling water by gas chromatography methods. This will reduce the degradation of turbine oil and increase the reliability of the oil system of the NPP main circulation pumps.

Keywords: gas chromatography; turbine oil; cooling water; diagnostic component; nuclear power plant