On the question of creating operational life monitoring of the nuclear power plant equipment and systems

摘要

The unmonitored degradation processes that develop and accumulate over the course of a long time of service may lead to sudden failures that are unacceptable for the potentially hazardous objects. To prevent these catastrophes, it is necessary to create an operational monitoring process, the basic principles of which are described herein for the example of the nuclear power plants (NPPs). The substantiation of the guaranteed safety of the NPPs over the course of a long time of service (40 to 60 years) with a utilization factor of about 90% requires highly reliable information on the nature and the history of the actions to which the construction materials are subjected during production, assembly, and the subsequent operation of the constructive elements - including the decommissioning stages. A considerable part of these actions (the dynamic thermomechanical loading, the irradiation, the action of the working media, and so on) cause in the course of the entire time of service of the equipment and the systems transformations of differing nature of the initial structure of the material and also the degradation processes - after the original physical/mechanical and strength characteristics of the construction materials. The information on these processes not complete at the time of the design of the reactor unit and must be refined and supplemented in the course of the production, assembly, and operation of the unit. In this case it becomes possible to substantiate the specified service life and ensure the conditions for the safe operation of the NPP equipment and systems - and resolve the questions of justifying the optimal overhaul periods in the course of operation. The latter is very important for improving the competitiveness of the atomic power generation units, considering the very large values of the specific capital expenditures in comparison with the traditional generating plants. The solution of these problems on the basis of the traditional approaches is made difficult in practice by the complex composition and structure of the construction materials that are used, by the action on the structure of the materials of the technological processes during fabrication and assembly, and by the small numbers of the atomic plants - all of which makes the results of the operation of the equipment of the same type statistically nonrepresentative. What is needed is the purposeful development of the methodology for monitoring the rates of the degradation processes in the critical constructive components of the equipment and systems in all the vital stages of the plants - starting with the design process.