Sensitivity analysis of a passive thermal-hydraulic system

Liu, Q.

Passive safety features are now of interest to the design of future generation reactors. Though passive safety systems are considered to be more reliable, the large uncertainty associated with the system response can not be ignored. It is necessary to identify the uncertain inputs that have the important impact on the uncertainty of the system performance. In this study, the total-order sensitivity index is applied to a passive decay heat removal system of a gas-cooled fast reactor for identifying the key uncertainty inputs. It is found that the uncertainty in the system pressure contributes the most to the uncertainty in the system output. In addition, the cooler wall temperature, the Nusselt number in the mixed convection and the friction factor also have small impact on the uncertainty of the system output.