1668087512 Exam 11062021 AB

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First name and Last name: Student number: ______________________________________________________________________________________________________________ RELIABILITY SAFETY AND RISK ANALYSIS A+B 11/06/2021 Note: 1. Make sure you write your first name, last name, student number and sign every exam sheet; 2. The exam consists in 2 exercises and 2 open questions; 3. The exam time is 2 hours and 15 minutes (1 hour and 45 minutes for the students attending the exam remotely). Exercise 1 [7.5 points] A fire emergency system is made by a liquid Storage Tank (ST), and three pumps in parallel. Pump P1 is powered by two Electric Generators (EG1, EG2), which work in parallel. Pump P1 stops when both EGs fail. Pumps P2 and P3 are Electric Pumps (EP) that depend on the functioning of a common standby diesel generator G. The failure of the system occurs if the storage tank is empty or if all the three pumps fail to function. The system is represented in the figure below and the failure probabilities of each component are reported in the table below: Description Failure Probability 𝑝𝑖 Probability that the storage tank ST is empty pST = 10-5 Probability that the pump P1 fails pP1 = 10-3 Probability that the pump P2 fails pP2 = 10-3 Probability that the pump P3 fails pP3 = 10-3 Probability that the electric generator EG1 fails pEG1 = 0.5∙10-3 Probability that the electric generator EG2 fails pEG2 = 0.5∙10-3 Probability that the generator G fails pG = 0.5∙10-3 E1.1) Draw the fault tree of the top event “failure of the system”; E1.2) Write the structure function; E1.3) Find the minimal cut sets; E1.4) Find the probability of the top event; E1.5) Compute the Birnbaum Importance Measure of the Tank and the three pumps. Comment the results. E1.6) Consider now a common cause failure for pumps…