The promise of
Nuclear fusion is the process that powers the sun and the stars.
Under extreme temperatures and pressures, light atomic elements join together to release enormous amounts of energy.
If this energy can be reproduced and harnessed on Earth, it could provide an energy source of unparalleled potential.
- Does not produce long-lived radioactive waste.
- Is inherently safe, with no risk of a runaway nuclear reaction causing meltdown.
- Does not produce greenhouse emissions.
- Has abundant primary fuels.
The mission to recreate a star on Earth – considered to be one of the greatest scientific challenges in human history – has driven dedicated research into fusion for over half a century. Various approaches are being explored to create the conditions required for fusion. Most efforts are focused on the reaction between two isotopes of hydrogen: deuterium and tritium (D-T) fusion. While reactor designs vary, all approaches attempt to produce and harness the energy from the fusion reaction via the following key steps:
- 1 –Deuterium and tritium are fused together at high temperature and pressure – these conditions are achieved differently depending on the reactor.
- 2 –The reaction yields a neutron and a helium atom (see figure below), and large amounts of energy. 80% of the energy is carried by the neutron, and 20% of the energy is carried by the helium atom.
- 3 –The uncharged neutron is ejected towards the walls of the reactor, interacting with lithium in a “blanket” (see figure below). The blanket has two key functions:
- a –To breed tritium through fission of lithium by a neutron (see figure above), from which to refuel the reactor and allow a self-sufficient fuel cycle (see figure below).
- b –Theneutrontransfersitskinetic energy as heat to the blanket, which is used to produce power (see figure below).
- 4 –Helium and other impurities in the plasma are removed via an exhaust. Unburnt fuel from the exhaust is added to the tritium produced in the blanket, where it is processed and then reused to allow the reactor to be self-sufficient on fuel (see figure below).