Modelling and Assessment of Risk of Failure Auxiliaries Supply System of Nuclear Power Plant from External Independent Sources

Abstract

Problematics. In the conditions of objectively existing aging of electric equipment, climatic conditions deterioration, hard work schedule of operation personnel at modern EES of NPS, there grows the problem of ensuring reliability and safety of functioning of the NPS in the emergencies in a power supply system. That requires carrying out the complex risk analysis of EES subsystems and NPS operation in the case of refusal of electrical equipment. Research objective . Development of mathematical support and software for assessment of circuits reliability and refusal risk of NPS MV external power supply system under conditions of internal MV power supply loss for providing the mode of shut-down cooling and cold start of the block. Implementing procedure. In the condition of essential incompleteness and uncertainty of statistical information on refusals of external network electric equipment, the hybrid fuzzy-stochastic models of certain electrical equipment failure for an assessment of refusal risk of NPP MV external power source method of electrical equipment failure function of distribution is attached. It is based on use of statistical data on refusals of main population of certain type and voltage class electric equipment as well as the expert estimates of refusal intensity of certain units of equipment. Results of research. The hybrid fuzzy-stochastic models of refusals of the main power and switching equipment of power supply systems and own needs of the NPS and fuzzy-stochastic models of refusal risk assessment of MV external power supply system are developed. The probability assessment of no-failure operation and fuzzy ranging on reliability is carried out for four versions of power supply circuits of the NPS HV distributing device; the refusal risk assessment of the external power supply system from remote power plants and substations is executed. Conclusions. In order to estimate schemes reliability and risk failure of electrical equipment and system of power supply MV from external supplies, fuzzy mathematical models were developed and failure risk estimation of four power supplies schemes for high-voltage NPS highways.