Engineering design of the EURISOL multi-MW spallation target

The European Isotope Separation On-Line Radioactive Ion Beam project (EURISOL) is set to design the 'next-generation' European Isotope Separation On-Line (ISOL) Radioactive Ion Beam (RIB) facility. It will extend and amplify current research on nuclear physics, nuclear astrophysics and fundamental interactions beyond the year 2010. In EURISOL, four target stations are foreseen, three direct targets of approximately 100 kW of beam power and one multi-MW target assembly, all driven by a high-power particle accelerator. In this high power target station, high-intensity RIBs of neutron-rich isotopes will be obtained by inducing fission in several actinide targets surrounding a liquid metal spallation neutron source. This article summarises the work carried out within Task 2 of the EURISOL Design Study, with special attention to the coupled neutronics of the mercury proton-to-neutron converter and the fission targets. The overall performance of the facility, which will sustain fast neutron fluxes of the order of 1014 n/cm2/s, is evaluated, together with the production of radionuclides in the actinide targets, showing that the targeted 1015 fissions/s can be achieved. Some of the greatest challenges in the design of high power spallation sources are the high power densities, entailing large structural stresses, and the heat removal, requiring detailed thermo-hydraulic calculations. The use of a thin martensitic steel beam-window and a well-controlled mercury flow has been shown to reduce the von-Misses stress in the former below the 200 MPa limit, with reasonable maximum flow rates of ~6 m/s. Alternatively, a windowless target configuration has been proposed, based on a liquid mercury transverse film. With this design, higher power densities and fission rates may be achieved, avoiding the technical difficulties related to the beam window. Experimentally, several tests have been performed at IPUL (Riga, Latvia) in order to study the stability of the liquid metal flow and validate the mercury loop design

Simulation of Spray Formation and Mixing in Diesel Engines with Novel Injector Designs

Improvement of the Diesel engine and optimization of the combustion process continues to be an important aspect in the efforts to meet new emissions regulations. The most important factors which directly influence the performance of the Diesel engine are related to the spray formation and vaporization of the liquid fuel upon injection into the cylinder. Therefore, in order to improve Diesel engines new studies need to be undertaken to further develop the injection system and, in particular, the nozzle layout and subsequent spray formation. This thesis describes the computational modelling of spray formation and atomization for a novel type of Diesel injector with a new nozzle layout that consists of a group of upper and lower sets of holes. The KIVA-3V code with extended capability of Large Eddy Simulation (LES) was utilized for this work. This particular version of KIVA can predict two-phase flows where the fluid dynamics behaviour of an annular fuel jet and the effects of the initial ambient swirl on the flow field need to be captured. The original code did not support the modelling of two-row injectors with different velocity profiles, hence certain modifications were implemented. The developed version of KIVA is capable of simulating two or more rows with different input parameters such as velocity, angle of injection and injection pressure. It also includes a new formulation for modelling the collisions processes of liquid droplets based on initial droplet diameter ratio, Weber number and impact parameter. The yielded results were post-processed and validated against experimental data in terms of penetration length for the vapour and liquid phases of the fuel and spray curvature. Significant improvement was observed in comparison to predictions obtained with the previous version of the code and good agreement was obtained with experimental data

Beam influence on thermal-hydraulics of EURISOL DS

The analysis documented in this report is a continuation of the numerical investigationwith CFD of the Eurisol DS liquid metal target, in particular the liquid metal flow underchanged beam characteristics.An optimisation of the window design is carried out for a σ = 25mm beam. In additionan analysis of the pulsed beam option is also detailed

Thermo-Hydraulic Optimisation of the EURISOL-DS MMW Hg target

The present document describes the thermal and the stress analysis of the final design of the EURISOL DS target. The preliminary design by Q. Prétet, R. Milenkovic and B. Smith was used as a starting point for further improvements to reduce stresses in the hull; the results of these computations are summarised in this document. All variants studied to attain the objective are documented using CFD to assess the effects of different flow configurations on the temperature distribution in the target liquid metal and structural analysis for determining the stresses and temperatures in the target structure

Design of a compact high-power neutron source - The EURISOL converter target

Nuclear Instruments and Methods in Physics Research Section A, 4991 (2009

The multi megawatt target station integration of the MAFF/PIAFE fission target design

The European Isotope Separation On-Line Radioactive Ion Beam Facility (EURISOL) is set to be the ‘next-generation’ European Isotope Separation On-Line (ISOL) Radioactive Ion Beam (RIB) facility. It will extend and amplify current research on nuclear physics, nuclear astrophysics and fundamental interactions beyond the year 2010.In EURISOL, four target stations are foreseen, three direct targets of approximately 100 kW of beam power and one multi-MW liquid metal proton-to-neutron converter, all driven by a high-power particle accelerator. In the aforementioned multi-MW target assembly, high-intensity RIBs of neutron-rich isotopes will be obtained by inducing fission in several actinide targets surrounding a liquid metal spallation neutron source.This article summarises the work carried out within Task 2 of the EURISOL Design Study, with special attention to the coupled neutronics of the liquid converter and fission target (MAFF/PIAFE design like) and the overall performance of the facility, which will sustain fast neutron fluxes of the order of 1014 n/cm2/s/MW of beam. The production of radionuclides in the actinide targets as well as in the liquid metal is also evaluated, showing that an in-target production of 1013 Sn132/s per actinide target can be achieved.Some of the greatest challenges in the design of high power spallation sources are the high power densities, entailing large structural stresses, and the heat removal, requiring detailed thermo-hydraulics calculations. Alternatively, a windowless target configuration has been proposed, based on a liquid mercury transverse film design. With this design, higher power densities and fission rates may be achieved, also avoiding the technical issues related to the beam window