TIME DEPENDENT RELIABILITY OF EMRGENCY DIESEL GENERATOR STATION

As a consequence of Emergency diesel generators (EDGs) are in stand-by status through normal operation of nuclear power plants (NPPs), it is required to make certain about their start-up in demand. Due to the fact that they are in standby mode for a long period of time, it is essential to consider time effect in system reliability during reactor age. This (Ageing) would be influence on component’s reliability for plants, which are designed for more than 25 years operation. In this paper, dynamic reliability block diagram (DRBD) is used as one of time dependent methods in reliability assessment of emergency diesel generator station (EDGS) which that its unavailability would lead to a severe accident such as Fukushima. In order to consider that an appropriate time dependent reliability distribution has been selected. Time-dependent reliability models have been utilized to study EDGS’s reliability. All mechanical subsystems properties including: fuel storage & pumping, lubrication, cooling, starting air and air cooling system compared with each other by taking into account scheduled, corrective and preventive tasks and dependency of all sub sub systems in point of the view of considering time dependent behaviour of all components of EDGS. At the end, by applying discrete event simulation and considering maintenance policy, availability of the system is calculated for 30 years operation of a typical NPP EDGS.

کلیدواژه ها:

Ageing ، Dynamic reliability block diagram ، Discrete event simulation ، Maintenance ، Time dependent reliability