Neutronics design of the low aspect ratio tokamak reactor, VECTOR

A neutronic study has been carried out for VECTOR, which is a low aspect ratio tokamak with the aspect ratio of 2.3, to achieve simultaneously sufficient shielding for super-conducting toroidal field coils (TFCs) and tritium breeding ratio (TBR) larger than unity, using the three-dimensional Monte Carlo neutron transport code MCNP-4C. The tritium production is mainly made by outboard blankets consisting of the self-cooled lithium lead (LiPb) as tritium breeding and neutron multiplying material, and the reduced activation ferritic steel F82H as structural material. The inboard blanket consisting of vanadium hydrate (VH2) and F82H as structural material plays the role of radiation shield for the TFCs. Adding Be layers to the LiPb layers effectively improves the TBR. By employing a 0.8 m thick inboard blanket with a 0.13 m thick LiPb layer, sufficient shielding for the inboard TFC and a total TBR of 1.08 are achieved.