NEUTRONIC PERFORMANCE OF 2 EUROPEAN BREEDER-INSIDE-TUBE (BIT) BLANKETS FOR DEMO - THE HELIUM-COOLED CERAMIC LIALO2 WITH BE MULTIPLIER AND THE WATER-COOLED LIQUID LI17PB

In support of ENEA activity in the European Community Test Programme, neutron analysis has been performed on the two latest blanket designs: helium-cooled ceramic breeder-inside-tube (BIT) (with LiAlO2 and Be m ultiplier) and water-cooled liquid Li17Pb in cylindrical modules (CM). The powerful MCNP Monte Carlo code was used (version 4.2). A detailed and accurate description of the geometrical model has been performed by inserting the main reactor details and avoiding breeder material di lution inside the modules. The tritium breeding ratio (TBR) performanc e is low for the solid breeder BIT blanket (with 10 ports 1.011) due m ainly to low blanket coverage near the exhaust duct, and this solution should be revised. The CM Li17Pb blanket leaches a sufficient TBR (1. 059, with ports) to rely on tritium self-sufficiency. Shielding proper ties, with respect to the toroidal field coils, have been estimated in a simplified model by means of the ANISN code, supplied with a nuclea r data library consistent with that used by MCNP. The analysis suggest s that a careful shield thickness/composition design should be used to ensure the shielding capability of the whole blanket plus shield syst em.