Modelling and analysis of the JET EP2 neutral beam full energy ion dump curved end plate

This paper describes enhanced modelling of the power loading on the current JET full energy ion dump (FEID) curved end plate, and the new end plate design with improvements to the power handling capabilities and additional features to improve fatigue life. Monte-Carlo simulations of each of the nine residual ion components which are intercepted by the plate shows a peak power density of 20 MW/m2 and compares well with recently installed fast thermocouple measurements. Analytical calculations and simulations with the Charged Particle Optics (CPO) code are used to investigate the potential for movement of the residual ion focus due to space charge effects. Cooling performance is significantly enhanced by improved water channel flow which is both modelled and confirmed by experiment. Fatigue life, calculated from ANSYS modelling is improved using a slot arrangement to relieve stresses created from focussed heat load distribution.