Risk-Based Allowed Outage Time and Surveillance Test Interval Extensions for Angra 1

Table 2

Modifications on pump probabilities to simulate CM.

System/pump	Modification of independent failures	Modification of common-cause failures
SIS—train A pump	𝑄FS→1(true)(𝑄^(2)1)	𝑄CC→𝛽(𝑄^(2)2)
	𝑄FR→1(true)
	𝑄MA→1(true)
SWS—train A pump	𝑄FR→1(true)(𝑄^(3)1)	𝑄CCABC→𝛽𝛾(𝑄^(3)3)
		𝑄CCAB→0(𝑄^(3)2)
		𝑄CCAC→0(𝑄^(3)2)
		𝑄CCBC→0(𝑄^(3)2)
AFWS—train A motor-operated pump	𝑄FS→1(true)(𝑄^(2)1)	𝑄CC→𝛽(𝑄^(2)2)
	𝑄FR→1(true)
	𝑄MA→1(true)

𝑄_FS stands for the pump A failure to start probabilities, 𝑄_FR stands for the pump A failure to run probabilities, and 𝑄_MA stands for the pump A unavailability due to maintenance.