Community Research and Development Information Service - CORDIS


Probabilistic Accident Consequence Uncertainty Assessment Using COSYMA: Overall Uncertainty Analysis, EUR 18826

Funded under: FP5-EAECTP C


This report describes the final stages of an analysis of the uncertainty in the predictions of the probabilistic risk assessment (PRA) code, COSYMA. The probability distributions describing the uncertainty on the values of input parameters were obtained using formal techniques of expert judgement; this part of the study was undertaken jointly by the European Commission and the United States Nuclear Regulatory Commission. A full uncertainty analysis of COSYMA would require consideration of many hundreds of uncertain input parameters. This was considered to be unfeasible in a single analysis. Therefore a series of analyses of the uncertainly in different parts of the code was undertaken. Those parameters whose uncertainties make major contributions to the overall uncertainties were identified for each part of the code. A final, overall analysis was then undertaken using the parameters identified in the earlier analyses. This report describes the overall analysis; the earlier stages of the project are described in a series of reports. The complete set of reports on this project is listed in Appendix A.
The main aims of the study can be summarised as:
1. to formulate a state-of-the-art judgement methodology which is capable of finding broad acceptance;
2. to apply the methodology to estimate uncertainties associated with the prediction of the PRA code COSYMA;
3. to provide an input into identifying future R&D priorities.

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Record Number: 8145 / Last updated on: 2006-10-17
Category: PROJ