Double Expert Methodology of NPP Power Equipment Inspection to Increase the Exploitation Lifetime – I.A. Aretinskaya, O.A. Chulkin, V.N. Kolykhanov, A.N. Kharabet, O.E. Zoteev, V.O. Zoteev

The problem of the lifetime extension of NPP power equipment is actual at present time. In our previous research, we were applying fuzzy sets and fuzzy algorithm methods that yielded positive results for solving this problem. The practice has shown that a forecast tool, based on stochastic theory, cannot be fully acceptable. The stopping of equipment after some operational time, to carry out maintenance, has sometimes revealed that equipment did not receive significant damage as well as there are no factors, which would testify the approach to failure. Probably, it was due to overly conservative estimation of resource. Therefore, a more accurate forecast of the time interval to failure is needed.

Fuzzy sets, mathematics, linguistic sets and fuzzy algorithms have become an integral part of applied cybernetics. This class of methods, sometimes used to assess equipment reliability, is characterized by high uncertainty of results. Therefore, the choice of the method of two-stage assessment of the resource life of the equipment, precisely in the conditions of insufficient information about the reliability of the equipment, is reasonable.

Significant correction of forecast results can be reached when applying such an operation of fuzzy evaluation like contrasting. It can be noticed that fuzzy contrasting can serve as a tool to clarify significantly the inspection results. The presented results demonstrate the updated concept of peer review of power nuclear power plants, which is focused on increasing the accuracy of the forecast of its safe operation. Therefore, it is possible to gain a significant resource extension of valuable equipment. Furthermore, application of this methodology makes it possible to save all types of costs during repairs significantly.

Keywords: operational time, damage, forecast, resource extension