Potential and limits of water cooled divertor concepts based on monoblock design as possible candidates for a DEMO reactor

Efficiency of water coolant for DEMO divertor

“…DEMO concepts that use steel (e.g., Eurofer) as a heat sink material and tungsten as armour must be tested for incident fluxes at least up to 25 MW/m 2 in case of transient heat loads. One of the main concerns in this case is the Eurofer embrittlement at around 300 • C under neutron irradiation [4] and there would be * Corresponding author. Tel.…”

“…The W armour is 3.5 mm thick at its thinnest position. The described design has been found to be the optimum in terms of thermo-mechanical properties for stationary heat loads of 10 MW/m 2 and water cooling with inlet water temperature 325 • C, pressure 15.5 MPa, and velocity 20 m/s [4]. Water temperature and pressure correspond to the cooling conditions in http://dx.doi.org/10.1016/j.fusengdes.2014.11.012 0920-3796/© 2014 Elsevier B.V. All rights reserved.…”

“…pressurized water reactors (PWR). The critical heat flux at the given coolant and design parameters is 17.7 MW/m 2 [4].…”

“…Material properties of irradiated materials are considered throughout the study. As there are no data available for the expected 20 dpa, the effect of 5 dpa is assumed, i.e., heat conductivity is reduced by 10% for W and Eurofer and by 20% for Cu OFHC compared to the values of unirradiated materials [4]. The thermal analysis is performed with the code MEMOS [6], which has also the capability to account for tungsten evaporation with consequent screening effect.…”

Residual stress generation in tungsten-copper brazed joint using brazing alloy

“…Tungsten has been proposed as potential armour material in high heat flux components such as the divertor in a future thermonuclear fusion demonstration reactor (DEMO) [1][2][3][4]. The divertor will undergo standard heat loads from 10MW/m 2 up to 20MW/m 2 during plasma instabilities [5].…”