The storage tank system shown in the below figure is used to store process feedstock. Overfilling of storage tanks is a common problem in the process industries. To prevent overfilling, the storage tank is equipped with a high-level alarm and a high-level shutdown system. The high-level shutdown system is connected to a solenoid valve that stops the flow of input stock. Here, the failure of level indicator as the initiating event. Given that the level indicator fails 4 times/yr.

Compute the probability of failure and reliability for the level indicator system.