In the event of loss of the main feed water in a Pressurised Water Reactor the reactor system turns to the backup system, the Auxiliary Feed Water (AFW) supply system, to provide water to the steam generator. By neglecting other components such as piping, valves, control systems, etc, a simplified model of the AFW supply system is shown in the figure below: Electric Pump 1 Electric Storage Power Tank 1 Supply Electric Pump 2 Storage Tank 2 Storage Tank 3 Steam Turbine Pump > Steam Generator The success of the AFW system requires the following: At least one of three of the Storage Tanks At least one of the three pumps. One of the pumps is steam-turbine driven, whereas the other two are electric pumps that depend on the functioning of electric power supply from diesel generators. Assume the following probability data for the initiating event and the system responses: Event Description Probability Frequency of Occurrence IE Loss of main feed water P(IE) 0.2/year E1 No water supply from three storage P(E1) 0.00001/year tanks E2 Failure of both electric pumps, P(E2) 0.002/year including failure caused by malfunction of the electric power supply E3 Failure of turbine pump P(E3) 0.01/year IE = Initiating Event; E1 = First Event; E2 = Second Event; E3 - Third Event2(a).1: Construct a Fault Tree diagram for the loss of AFW supply system. 2(a].2: Construct an event tree for loss of main feed water as an initiating event. 2(a].3: From the Event Tree, calculate the likelihood of the loss of the main feed water and AFW supply system failure