algorithm-assisted_assessment_in_criticality_safety_icnc_2011 [Promethee]

Algorithm-assisted Assessment in Criticality Safety (ICNC 2011)

by J.Crevel, G. Caplin, Y. Richet

Abstract

Nuclear criticality safety evaluations aim at avoiding any criticality accident in both normal and abnormal conditions. The most penalizing configuration is to be identified by moving several physical and chemical parameters within their credible range of variation. Exhaustive analyses, very expensive in calculations for day-to-day usage, have already highlighted the limitations of both “parameter-by-parameter” or even “crossed-parameters” approaches to identify the maximum value of the effective neutron multiplication factor (keff).
Illustrated by a basic example of an interim storage of wet PuO2 powder, this paper shows that an algorithm-assisted search of the maximum value of keff would be able to help a nuclear criticality safety assessor to identify, with a few calculations, the interest zone(s) of high keff values of multi-parameters problems. Nevertheless, expert’s skills remain necessary to make an adequate nuclear criticality safety assessment.
The algorithm described, based on surrogate optimisation procedures to manage an adaptive design of experiments, was designed through the DICE industrial research consortium [6] and then tested within computer tools supporting the French CRISTAL criticality safety code package [6].

Key Words

Algorithm, Optimization, Monte Carlo, Design of Experiments.
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