Neutron radiation effects of the center conductor post in a spherical tokamak reactor

A Li metal center conductor post (Li metal CCP) is proposed for spherical tokamak reactors. The construction and materials of the core assembly for a Li metal CCP are described. 316Ti stainless steel is proposed for the can of the core and cooling tubes. Flowing water inside cooling tubes removes ohmic heat and nuclear heat in the CCP. Thermal hydraulic and neutronic calculations show that the average temperature of the Li conductor in operation is about 86 °C and the resistivity increases by about 20% after one year of operation. After operating one year the Li conductor can be melted by ohmic heating (no cooling water), and the liquid metal passed through a purification system to return the core assembly by an auxiliary liquid metal loop. The purified liquid metal can be cooled down to form the Li conductor again. The advantage of the proposed concept is discussed.