Approaches, Relevant Topics, and Internal Method for Uncertainty Evaluation in Predictions of Thermal-Hydraulic System Codes
The evaluation of uncertainty constitutes the necessary supplement of best-estimate 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 the interest in using such a tool to get mo...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2008-01-01
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| Series: | Science and Technology of Nuclear Installations |
| Online Access: | http://dx.doi.org/10.1155/2008/325071 |
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| Summary: | The evaluation of uncertainty constitutes the necessary supplement of best-estimate 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 the interest in using such a tool to get more precise evaluation of safety
margins. The paper
reviews the salient features of three independent approaches for estimating uncertainties associated with
predictions of
complex system codes. Namely, the propagations of code input error and calculation output error constitute
the keywords
for identifying the methods of current interest for industrial applications, while the adjoint sensitivity-analysis
procedure
and the global adjoint sensitivity-analysis procedure, extended to performing uncertainty evaluation in
conjunction with
concepts from data adjustment and assimilation, constitute the innovative approach. Throughout the
developed methods,
uncertainty bands can be derived (both upper and lower) for any desired quantity of the transient of
interest. For one case,
the uncertainty method is coupled with the thermal-hydraulic code to get the code with capability of internal
assessment of
uncertainty, whose features are discussed in more detail. |
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| ISSN: | 1687-6075 1687-6083 |