Infrared detection of tungsten cracking on actively cooled ITER-like component during high power experiment in WEST

• DOI: 10.1016/j.nme.2023.101537
• Publication Date: 2023-10-18T08:01:20Z
• Authors: Q. Tichit; A. Durif; J. Gaspar; Y. Anquetin; Y. Corre; M. Diez; L. Dubus; M. Firdaouss; J. Gerardin; A. Grosjean; J.P. Gunn; K. Krieger; M. Missirlian; S. Ratynskaia; P. Reilhac; M. Richou; F. Rigollet
• Keywords: Brittleness; Groove (engineering); Temperature cycling

The consequences of tungsten (W) damaging processes, such as cracking and melting, on divertor lifetime plasma operation are high priority issues for ITER. A sustained melting experiment was conducted in WEST using a 2 mm deep groove geometry the upstream mono-block (MB) to overexpose sharp leading edge (LE) downstream MB. W-cracking has been evidenced first time with very spatial resolution infrared camera before reached. These cracks develop when monoblock temperature is about 2600°C, thus higher than both ductile brittle transition softening threshold tungsten, suggesting that these different from ones observed previous campaigns where failure involved, because transient events cold monoblock. Post-exposure analyses have performed damaged monoblock, highlighting 12 main LE, width varying 33 µm 77 µm, an average spacing 0.45 mm. Parallel heat flux 90 MW/m2 derived measurements, decay length target 4 T-REX modelling code suggest here thermal inputs, crack can initiates due cycling without disruption, failure, under 1 5 cycles DBTT 400°C 500°C.