Fabrication of tungsten and tungsten alloy and its high heat load testing for fusion applications

Tungsten is one of the most promising candidate materials for an application as plasma facing material (PFM) in future thermonuclear fusion devices. In the divertor region PFM will be exposed to very severe heat load conditions. Steady state heat loads will be around 5 MW/m² - 10 MW/m² and in some parts of the divertor even 20 MW/m² for short periods. These steady state heat loads are accompanied by transient events such as edge localised modes (ELMs), vertical displacement events (VDEs) and plasma disruptions which deposit very high heat loads of up to several MJ/m² on the PFMs. Important properties which enable tungsten to withstand such environmental conditions are its high melting point, high thermal conductivity and low erosion rate. In present study, we have fabricated Pure Tungsten (W) and Tungsten +1wt. % La₂O₃ (WL) pallets of size 50 mm (dia) and 9 mm (height) through Powder Metallurgical process using graphite mould and sintered in Direct Sintering Press (DSP) at 2390 °C with 40 MPa pressing force. The crack formations and surface modification behaviours under transient high heat load condition were investigated. Detailed characterization of the exposed sample for its various properties evaluation will be discussed and presented in the paper