Paul N. Smith

Goal-based angular adaptivity applied to a wavelet-based discretisation of the neutral particle transport equation

A method for applying goal-based adaptive methods to the angular resolution of the neutral particle transport equation is presented. The methods are applied to an octahedral wavelet discretisation of the spherical angular domain which allows for anisotropic resolution. The angular resolution is adapted across both the spatial and energy dimensions. The spatial domain is discretised using an inner-element sub-grid scale finite element method. The goal-based adaptive methods optimise the angular discretisation to minimise the error in a specific functional of the solution. The goal-based error estimators require the solution of an adjoint system to determine the importance to the specified functional. The error estimators and the novel methods to calculate them are described. Several examples are presented to demonstrate the effectiveness of the methods. It is shown that the methods can significantly reduce the number of unknowns and computational time required to obtain a given error. The novelty of the work is the use of goal-based adaptive methods to obtain anisotropic resolution in the angular domain for solving the transport equation. Wavelet angular discretisation used to solve transport equation.Adaptive method developed for the wavelet discretisation.Anisotropic angular resolution demonstrated through the adaptive method.Adaptive method provides improvements in computational efficiency.

Accelerator Driven Systems for Transmutation: Safety Considerations and Analyses of EFIT Type Cores

European R&D for Accelerator Driven System (ADS) design and fuel development in the 6th EC Framework Programme is driven by the Intgrated Project EUROTRANS. In EUROTRANS two ADS design routes are followed, the XT-ADS and the EFIT. The XT-ADS is designed to provide the experimental demonstration of transmutation in an. The longer-term EFIT development (European Facility for Industrial Transmutation) aims at a generic conceptual design of a full transmuter. Within EUROTRANS, the domain 3 (DM3) named ‘AFTRA’, is responsible for a deeper assessment of the behavior of the dedicated fuels and for development of the fuel database for the EFIT core design. To test and assess the behavior of the currently chosen CERCER (MgO-matrix) and CERMET (Mo-matrix) fuels under normal operation and transient conditions, the AFTRA domain has performed some preliminary core design studies on an EFIT (coined AFTRA-EFIT). In this paper, design data and transient analyses of multi-zone high/lower power density cores are presented and important safety phenomena are analyzed.