A breeding blanket in ITER-FEAT

At the beginning of life ITER-FEAT will be equipped with a shielding blanket; nevertheless since many advantages can be envisaged in having a breeding blanket in the machine, such a concept has been investigated as well. It is a water-cooled blanket in which both ceramic breeder and beryllium multiplier are present in the form of single sized pebble beds. The lithium ceramic breeder is in contained in cylindrical tubes surrounded by the beryllium pebble bed. For several years, studies have been devoted to observing the heat transfer in pebble beds. Since the experimental activities aiming at estimating the relationships between thermal parameters, temperature and stresses in the pebble beds in relevant temperature range have not been completed yet, a sensitivity analysis has been performed in order to verify the variations of breeder and multiplier temperatures in the breeding blanket by assuming different thermal conductivity for the beryllium pebble bed. The thermal analyses performed show that a breeding blanket in ITER-FEAT can be operated by keeping minimum temperature of the breeder and maximum temperature of the multiplier within allowable limits. Neutronic calculations indicate the possibility of having a breeder blanket with a significant TBR in ITER-FEAT.