1. Determine the consequence frequency of a cooling water system if it is used only three months every year and if it is given preventive maintenance each three weeks of operation.
2. If a plant has a consequence frequency of 10^-3, how many IPLs are needed to reduce this frequency to 10^-9?
3. If a regulator has a consequence frequency of 2.2x10^-2 failure/year, what will be the frequency if this regulator is given preventive maintenance twice a month?
4. If there are three scenarios with the same consequence, clearly describe the process for determining the frequency of this consequence.
5. Determine the consequence frequency for a regulator failure if the system is designed with five IPLs.
6. Assume that a company decides to characterize an acceptable risk as a Category 1 failure every 100 years and a Category 5 failure every 1300 years. Are the following scenario acceptable or not:

1. Category 4 every 700 years
2. Category 2 every 500 years
3. Category 3 every 900 years
4. What would you do to move the unacceptable scenarios into the acceptable region?
5. Was the analysis method used in this problem acceptable? Why?

Calculate the MTBF, failure rate, reliability and probability of failure of the top event of the system shown in Figure 1 below.

Top event 7 5 6 2 3