Event Tree Analysis Developed for and used primarily for nuclear power Underlying single chain of events model of accidents Forward search Simply another form of decision tree Problems with dependent events reson-146 Event Tree EXample 2 Pipe break: Electric power: ECCS Fission product: Containment removal ntegrity Succeeu-Pl Succeeds 1一P4 Fails P1xP5 P5 Succeeds Succeeds P1xP4 Fails P1xP4x P5 Available Succeeds 1-P4 P1x P3 Initiating event Fails Fails P1xP3X P4 P4c Leveson − 145 Event Tree Analysis Developed for and used primarily for nuclear power. Underlying single chain of events model of accidents. Forward search Simply another form of decision tree. Problems with dependent events. Leveson − 146 Event Tree Example P1 P1 x P5 P1 x P4 P1 x P4 x P5 P1 x P3 P1 x P3 x P4 c 1−P5 P5 1−P5 P5 P4 1−P4 P4 1−P4 P3 1−P3 1−P2 P1 Fails Fails Fails Fails Fails Succeeds Succeeds Succeeds Succeeds Succeeds Available Initiating event Containment integrity Fission product removal Pipe break Electric power ECCS 1 2 3 4 5 Fails P1 x P2 P2