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

Abstract

The feasibility of D-3He 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-3He; 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-3He operation for neutron shielding, the heat loads on the first wall and the divertor as well as plasma refuelling are considered.

Fusion: a true challenge for an enormous reward

“…However, one has to remember that in a magnetic fusion device, tokamak or stellarator, the operating pressure p = nkT is limited due to various instabilities and turbulence in the plasma (see, e.g., [7]; for recent experimental progress towards the reduction of plasma turbulence, see [8,9]). The fusion reaction rate R = n 2 4 σv can thus be written as R = 1 4 σv T 2 and the maximum reactivity is determined by the maximum of this function [10] as shown in fig. 5.…”

Fusion: a true challenge for an enormous reward

“…However, one has to recall that in a magnetic fusion device, tokamak or stellarator, the operating pressure p = nkT is constant, and that therefore there is an inverse relation between temperature and density. The fusion reaction rate R = n 2 4 σv can thus also be written as R = 1 4 σv T 2 and the operating temperature of a reactor will be determined by the maximum of this function [6] as shown in fig. 5.…”

“…EPJ Web of Conferences 189, 00015 (2018) https://doi.org/10.1051/epjconf/201818900015 LNES 2017 Table V. -Tritium production from Lithium. 7 Li + n → 4 He + T + n − 2.47 MeV 6 Li + n → 4 He(2.05 MeV) + T (2.73 MeV)…”

Fusion: A true challenge for an enormous reward

“…2 below), the operating pressure p = nkT is constant, and thus as the temperature is increased, the density has to decrease, and consequently the number of fusion reactions also. The fusion reaction rate R = and the operating temperature of a reactor will be determined by the maximum in this function [7]. This is shown in fig.…”

“…Two approaches are currently being pursued: inertial and magnetic confinement. In the first [7]). approach, lasers or particle beams are used to rapidly compress the nuclear fuel in order to achieve the conditions required for fusion.…”