Existing nuclear power plant sites may offer favourable conditions for future fusion power plants, including grid connection, cooling infrastructure and industrial support facilities.

Energy From Water and Rocks

The energy from a fusion power plant could be low-carbon and sustainable. No fossil fuel is burned during operation, and the fusion reaction itself produces no carbon dioxide. Fusion fuel can figuratively be described as coming from “water and rocks”: deuterium can be extracted from water, while lithium-containing materials will be used inside the reactor’s breeding blanket to produce tritium.

Minimum Waste

The product of the deuterium–tritium reaction is helium, a stable and non-toxic gas. Fusion does not produce spent nuclear fuel, but high-energy neutrons will activate structural components such as the first wall, blanket and divertor. Replaced components will therefore require remote handling and interim storage. Considerable research is focused on low-activation materials that could allow much of this material to be recycled or reused after its radioactivity has sufficiently decreased.

Construction

A fusion power plant will combine specialised fusion-reactor technology with many components already familiar from conventional thermal power stations. The reactor itself will contain superconducting magnets, a breeding blanket, shielding and remotely maintained plasma-facing components. Several coolants are being considered for future plants, including pressurised water, helium and liquid metals. In many designs, the heat removed from the reactor will ultimately be transferred to a conventional power cycle with heat exchangers, a turbine and an electrical generator.

Steam Turbine

Many proposed fusion power plants would convert reactor heat into electricity through a conventional steam turbine. The achievable efficiency will depend mainly on the temperature of the reactor coolant and the selected power cycle. Water–steam Rankine cycles are among the leading options for early demonstration plants, while more advanced power-conversion systems may be considered for later reactors operating at higher temperatures.

Safe Operation

Fusion has important inherent safety advantages. Maintaining a fusion reaction requires very precise plasma conditions; if these conditions are disturbed, the plasma rapidly cools and the fusion reaction stops. Fusion is not a chain reaction and cannot run away spontaneously. Nevertheless, a fusion power plant will still require robust safety systems for tritium confinement, activated materials and residual heat removal.

Costs

It is still too early to determine the cost of electricity from commercial fusion power plants. The fuel itself — principally deuterium and lithium — should represent only a small part of the total cost, but fusion plants will require complex reactor components, remote maintenance, tritium-processing systems, powerful cooling and vacuum systems, cryogenic equipment and, in many designs, auxiliary plasma heating and current drive. A burning plasma will obtain most of its heating from fusion-produced alpha particles, but substantial electrical power may still be required to operate the plant. The economic competitiveness of fusion can therefore only be assessed reliably once representative power plants have been built and operated.

Steady Production

A major potential advantage of fusion power is that its electricity production would not depend on weather, season or daylight. Future plants are intended to achieve high availability and predictable power output, although some tokamak concepts may initially operate in long pulses rather than continuously. Maintenance periods and replacement of plasma-facing components will also determine the achievable capacity factor.

Location

Unlike solar or wind generation, a fusion power plant would not need to be located according to local weather conditions. Its siting would instead depend on factors such as access to the electricity grid, cooling and heat-rejection systems, transport and industrial infrastructure, and regulatory requirements. With suitable infrastructure, fusion could therefore provide large-scale electricity in many different regions.