Fusion Engineering and Design 84 (2009) 49–56 Contents lists available at ScienceDirect Fusion Engineering and Design journal homepage: www.elsevier.com/locate/fusengdes Computational modelling of the IFMIF lithium target V.A. Titarev a,∗ , E. Romenski b , D. Drikakis a , E. Surrey c a Cranfield University, Cranfield, Beds MK43 0AL, UK b Sobolev Institute of Mathematics, Novosibirsk, Russia c EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, OX14 3DB, UK article info Article history: Received 27 August 2008 Accepted 27 October 2008 Available online 30 December 2008 Keywords: Target IFMIF Ion beam abstract The present work is devoted to the computational modelling of the process of beam action on a lithium target. The aim of the investigation is to determine the maximum values of temperature and pressure as well as general pattern of the process. The analysis is based on the compressible Euler equations with the stiffened gas equation of state with parameters corresponding to lithium. The energy influx allo- cation caused by the beam interaction with the target is described by the source term in the energy balance law. The formulated problem is solved numerically by a high-resolution Godunov-type method. The obtained results show a moderate rise in the lithium temperature and relatively large pressure variations. © 2008 EURATOM/UKAEA. Published by Elsevier B.V. All rights reserved. 1. Introduction Recent years have seen a rapid surge in the energy demand with particular emphasis on environmental acceptability and safety. Fusion power appears to be one of the promising future sustainable energy sources and much effort has gone into research on the devel- opment of fusion power plants. The construction of such plants will entail the development of radiation resistant and low activation materials, which must also survive exposure to damage from neu- trons with high energy spectrum. Testing of candidate materials thus requires a reliable high-flux source of high-energy neutrons. The International Fusion Material Irradiation Facility (IFMIF) is an international scientific research program designed to test materials for suitability for use in a fusion reactor. The IFMIF will use a par- ticle accelerator-based neutron source to produce a large neutron flux, in a suitable quantity and time period to test the long-term behaviour of materials under conditions similar to those expected at the inner wall of a fusion reactor. The IFMIF comprehensive design report [1] proposes the use of high order magnetic elements in the High Energy Beam Trans- port (HEBT) section to condition the beam profile to meet the requirements of the liquid lithium target, namely a beam of dimen- sions 200 mm × 50 mm, tapered at the edges and uniform to 5%. The production and monitoring of such a distribution is a com- ∗ Corresponding author. E-mail addresses: v.a.titarev@cranfield.ac.uk (V.A. Titarev), evrom@math.nsc.ru (E. Romenski), D.Drikakis@cranfield.ac.uk (D. Drikakis), Elizabeth.Surrey@jet.uk (E. Surrey). plex engineering problem. In an attempt to simplify the design, the development of beam raster scanning technique has recently been proposed as an alternative to the high order optic elements in the IFMIF high-energy beam transport section. It can be shown [2] that, in order to reproduce the flux and uniformity of neutron produc- tion in the time integrated case, the scanned beam would require an rms beam radius of ≈ 3 mm. To prevent boiling of the lithium the beams must be scanned at a rather high velocity of the order 1 km/s. Whilst the earlier work demonstrated the problems associated with engineering such a scanning system [2], it did not investigate the effect of such a rapidly moving thermal source, which may be important. Indeed, one may expect the action of the beam to gen- erate strong pressure waves in the liquid lithium, which would be sufficiently strong to induce disruption of the flow, leading to cav- itation and damage. On the other hand, the physical problem of unsteady heating of the lithium target by a particle beam is worth studying by itself, since it allows us to better understand physical effects occurring in such conditions. The present paper is devoted to the computational modelling of the process of beam action on a lithium target with the primary aim to determine the maximum values of temperature and pressure as well as general pattern of the process. We develop an axisymmetric model which is based on compressible Euler equations in the cylin- drical coordinate system and uses the stiffened gas equation of state with parameters corresponding to lithium. The energy influx allo- cation caused by the beam interaction with the target is described by the source term in the energy balance law. The formulated problem is solved numerically by a high-resolution Godunov-type method. 0920-3796/$ – see front matter © 2008 EURATOM/UKAEA. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.fusengdes.2008.10.006