Weibull distribution is frequently applied for lifespan data analysis.Taking the data of the level measurement instrument of the main feed water flow control system and the history overhaul data of temperature measurement instrument of the reactor coolant system as an example,the weibull distribution reliability model is established and the estimated failure time of the instruments is calculated.The results show that:when the instrument has 95% reliability,the failure time of the instruments is greater than the extended 1.5-year verification experiment cycle,these two...