Casting light on tungsten for ITER: Unraveling irradiation effects

ITER is a fusion reactor on the final stage of construction in France, which will be used to demonstrate feasibility of a fusion reaction for commercial energy production. Thanks to its outstanding properties, tungsten (W) will be used in ITER as plasma-facing material, exposed to extreme operation conditions: (i) high heat flux, (ii) high-energy plasma particles and (iii) high-energy neutron flux simultaneously. This will degrade the mechanical and thermal properties of W during operation. One of important factors deteriorating mechanical properties is formation of non-equilibrium non-coherent precipitates caused by neutron-induced transmutation of W into rhenium (Re) and osmium (Os).

Development and qualification of materials for future nuclear installations requires early assessment of their operational endurance to ensure technical and financial justification of the exploitation. Main worldwide players in the investigation of neutron irradiation effects in W are ORNL (USA), KIT (Germany), FZJ (Germany), QST (Japan) as well as SCK CEN, where this investigation has been ongoing over the last 20 years, principally relying on irradiation campaigns in BR2, a unique irradiation facility – a high-flux material test reactor (MTR) located on the premises of SCK CEN.

The purpose of the present project is to investigate mechanisms of irradiation damage in various tungsten products exposed to the ITER-representative neutron irradiation at SCK CEN.

The irradiation damage will be evaluated in terms of modification of ductility, modification of the fracture mode, increase of hardness and, possibly, micro-structural/chemical characterization.

The project is embedded in the broad frame of the European fusion programme (www.euro-fusion.org).

La durée estimée