Possibilities for breakeven and ignition of D-³He fusion fuel in a near term tokamak

The feasibility of D- 3 He reactor plasma conditions in a tokamak of the NET/INTOR class is investigated. It is found that, depending on the energy confinement scaling law, energy breakeven can be achieved in NET without significant modification of its design. Significant improvement in Q (ratio of fusion power to injected power) can be achieved by removing the tritium producing blanket and replacing the inboard neutron shield by a thinner shield optimized for the neutron spectrum in D- 3 He; this allows the plasma major radius and aspect ratio to be reduced and higher beta and Q-values (up to about 3) to be achieved. The implications of D- 3 He operation for neutron shielding, the heat loads on the first wall and the divertor as well as plasma refuelling are considered.