Three graphite tiles coated with B4C were mounted in the X-point strik
e region of JET during operations in 1991. The coatings remained adher
ent, though areas reached temperatures at which local melting occurred
. Boron and deuterium analyses in the area surrounding the tiles sugge
st sublimation of boron was an important release mechanism, and that t
he region between the strike zones (the private flux region) is a majo
r redeposition area.