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Impact of nuclear data uncertainties on the reactivity coefficients of ALFRED

Jun 28, 2017, 5:50 PM
1h 10m
Yekaterinburg

Yekaterinburg

POSTER Track 6. Test Reactors, Experiments and Modeling and Simulations Poster Session 2

Speaker

Dr Giacomo Grasso (Italian National Agency for New Technology, Energy and Sustainable Economic Development (ENEA))

Description

The advancement of the design of ALFRED – the Advanced Lead-cooled Fast Reactor European Demonstrator – beyond the conceptual phase, passes through the analysis of the impact of uncertainties, notably to what concerns safety-related conditions. Focusing on the design of the core, nuclear data are the main source of uncertainties, so that their evaluation is of utmost importance in order to assess the favourable behaviour of the system under beyond-Design Basis transients, as resulting from previous best estimate analyses standing on nominal values of the system parameters. This work presents the results of the sensitivity/uncertainty (S/U) analysis of the ALFRED core on the reactivity (k-eff) and safety coefficients. The sensitivity analysis allowed pointing out firstly the most relevant cross sections for every response function and the key regions where safety parameters needed to be evaluated. Uncertainty analysis allowed then establishing a possible range of confidence for the reactivity coefficients. The adjoint-based technique involved in TSUNAMI-3D module from SCALE6 system was used. The confidence intervals identified for each reactivity coefficient will permit transient calculations to propagate uncertainties into transient behaviour, after pointing out the most unfavourable – yet physical – set of reactivity coefficients for the selected transient scenarios. This will in turn provide an exhaustive picture of the influence of nuclear data uncertainties on core performance, identifying key parameters and possibly indicating specific actions required to achieve the aimed safety performances.

Country/Int. Organization

Italy

Primary author

Prof. Nuria Garcia-Herranz (Universidad Politécnica de Madrid (UPM))

Co-authors

Mr Daniel Lopez (Centro de Investigaciones Científicas, Medioambientales y Tecnológicas (CIEMAT)) Mr Francesco Lodi (Univerity of Bologna) Dr Francisco Alvarez-Velarde (Centro de Investigaciones Científicas, Medioambientales y Tecnológicas (CIEMAT)) Dr Giacomo Grasso (Italian National Agency for New Technology, Energy and Sustainable Economic Development (ENEA)) Mr Pablo Romojaro (Universidad Politécnica de Madrid (UPM))

Presentation materials