UNCERTAINTY EVALUATION BY CIAU METHODOLOGY
(0) The evaluation of uncertainty constitutes the necessary supplement of Best Estimate (BE) calculations performed to understand accident scenarios in water cooled nuclear reactors. The needs come from the imperfection of computational tools on the one side and from the interest in using such tool to get more precise evaluation of safety margins. In the present paper the approaches to uncertainty are outlined and the CIAU (Code with capability of Internal Assessment of Uncertainty) method proposed by the University of Pisa is described including ideas at the basis and results from applications. Two approaches are distinguished that are characterized as propagation of code input uncertainty and propagation of code output errors. For both methods, the thermalhydraulic code is at the centre of the process of uncertainty evaluation: in the former case the code itself is adopted to compute the error bands and to propagate the input errors, in the latter case the errors in code application to relevant measurements are used to derive the error bands.The CIAU method exploits the idea of the status approach for identifying the thermal-hydraulic conditions of an accident in any Nuclear Power Plant (NPP). Errors in predicting such status are derived from the comparison between predicted and measured quantities and, in the stage of the application of the method, are used to compute the uncertainty.
Alessandro Petruzzi Francesco DAuria
University of Pisa, DIMNP, 56100 Pisa, Italy
国际会议
上海
英文
170-180
2007-03-12（万方平台首次上网日期，不代表论文的发表时间）