Problems of chemical-analytical monitoring in nuclear power

Abstract

Further increase of the reliability and efficiency of the operation of nuclear power plants depends on the comprehensive solution of many problems, of which the problem of optimization and increase of the informativeness of chemicotechnological monitoring is gaining in importance. There is a clear rift between the level of scientific ideas and technical solutions on which nuclear power plants are based and the existing approach to the organization of chemical monitoring. Everyone understands the necessity of chemical monitoring, but many people do not regard it as a necessary element for ensuring normal operation of a nuclear power plant. The lack of standard requirements and a standard methodical base markedly lowers the reliability of the results of analyses, and behind this lies possible breakdowns of the water-chemical conditions. How can this situation be explained? The consequences of deviations of water-chemical conditions from regulation standards are by no means manifested immediately. Apparent wellbeing at any given time creates the impression that the requirements of the chemical laws can be ignored with impunity. But there is also another reason for the disdainful attitude toward chemical monitoring. Chemical-technological monitoring at a nuclear power plant reduces to the determination of ~20 water-quality indicators for the basic and auxiliary systems. Considering the number of existing points at which samples are extracted in each block of a nuclear power plant and the frequency with which the analyses are performed, it is not difficult to imagine the impressive number of the overall volume of data obtained. Thus the total number of analyses per month for one block of a nuclear power plant with RBMK-1000 approaches 15,000 [i]. In addition, as a rule, these are single measurements, whose error it is virtually impossible to estimate exactly. Moreover, regardless of how conscientious the chemists-analysts at the technological laboratories are, in the monotony of repeating values it is difficult to escape big blunders in the case of unforeseen deviations of the parameters in the water-chemical conditions. Under these conditions there is no hope of obtaining reliable information for each of the measurements, making sense of the observational results, and drawing correct conclusions. We arrive at a p~r~dox, By increasing the number of parameters monitored and the number of points at which samples are extracted we strive to increase the information content of chemical monitoring, but we actually achieve the opposite result. At the present time, when nuclear power has transformed from a unique source of energy to one of the most important elements of the power production in the country, it is essential to reexamine the concepts forming the basis for the implementation of chemical-analytical monitoring at nuclear power plants. At the first nuclear power plants the research and technological functions of analytical monitoring were balanced, and preference was often given to obtaining research information. For serially produced nuclear power plants research programs are a rare episode. It is evident that the main reason for this situation is hidden in the existing standards and requirements imposed on the chemical monitoring system at nuclear power plants. At the first stages of development of nuclear power the striving toward performing as much analysis as possible and over the entire technolgocial loop was justified, whereas at the present time, as experience in operating nuclear power plants in this country and abroad shows, the time has come to search for new approaches to the problem of analytical monitoring of the quality of water heat carriers. The successful solution of the problem of analytical monitoring is often linked primarily with the instrumentation. But the number of methodical and instrumentation developments continues to increase, and the chemical-technological monitoring remains as before one of the laborious and unreliable elements in the overall chain of operational monitoring of nuclear power plants. Fundamental restructuring of the overall scheme of such monitoring is possible only based on automatic or, at least, automated means of chemical analysis.