Table 1 Key properties of C and metals as wall materials and diagnostic components

C

Low-Z. Resilience to thermal shocks and no melting λ of some CFC > 300 W m⁻¹K⁻¹.

Chemical erosion by fuel atoms, C_xH_y formation, high erosion rate and fuel inventory in co-deposits.

PFMC in most tokamaks [8, 14–21, 27, 50–55] and stellarators [56–58] because of excellent power handling capabilities.

Be

Low-Z, no chemical erosion

Low T_m and high sputter yield.

Used in JET-ILW in the main chamber wall [29, 31, 59]; the same decided for ITER wall [49].

W

High T_m and low sputter yield by fuel

High-Z, risk for plasma contamination and disruptions. Activation and transmutation.

ASDEX Upgrade wall and divertor [60, 61]. JET-ILW divertor [29, 32–34, 62]; the same decided for ITER divertor [49].

Mo

High T_m and low sputter yield by CXN

High activation.

Tested candidate for first mirrors in ITER diagnostic systems [63–67]