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Relative costs breakdown of a fusion power plant
Buildings and land
Reactor systems and in-vessel components
Replaceable in-vessel components
Magnets including power supplies
Heating and vacuum sysems
Heat extraction and power generation systems
Miscellaneous plant
Construction costs
Contingency
Interest during construction
Fig. 5.6 Breakdown of projected costs for a fusion power plant. Approximately half the total
costs are fusion-specific and dominated by the magnet systems. Around a quarter of the costs are
construction and project management, with the balance conventional plant, land, and buildings.
From the PROCESS reactor design code Kovari M, et al. PROCESS: a systems code for fusion
power plants—part 1: physics, Fusion Eng Des, 2014; 89(12): 3054–3069.

(Fig. 5.6). In addition, we can use these models to try to assess the main global param-
eters upon which the cost of electricity depends [26]:

β
η
P
CoE∝A 0:6 0:5 0:4 0:4 N 0:3
th e N
where A is the plant availability; η th is the plant thermal efficiency (electrical power
over thermal power); P e is plant output power; β N is the plasma normalized beta; and
N is the normalized density (the plasma density relative to the Greenwald density limit
I
n G ¼ 2 ). The first of two of these are limited by available technology; the unit size is a
πa
design choice although strongly limited by technology and the capital funding avail-
able to build a power plant; and the available normalized beta and density are func-
tions of the plasma physics scenario that can be achieved. What these studies reinforce
is that technological developments are at least as important as physics for fusion
power plant economics, and that therefore fusion for energy is as much a technology
research program as a physics one.

5.5 Status of current research

The current largest tokamak and only magnetic device still operating, which has
burnt D-T is JET, the Joint European Torus, located at Culham Centre for Fusion
Energy, Oxfordshire, United Kingdom. It is the world’s most powerful tokamak
and is the focal point of the European fusion research program, collectively used
by >40 European laboratories. Built in 1983, it holds the world record for fusion
power (16MW, in 1997 [27]). JET has been continuously upgraded to remain at