DEMO is the next step after iter in the implementation of nuclear fusion as energy source

TECFIR / UNED provides with nuclear analysis regularly to EUROfusion


From 2011, TECFIR / UNED provides Nuclear Analysis to EUROfusion Consortium supporting the current conceptual design of the DEMO Fusion Reactor.

DEMO is intended to be a Tokamak Fusion Power Plant able to achieve two main goals:

  • Produce net electricity for the grid by 2050
  • Convinces commercial Power Plant developers to invest in a prototype fusion Power Plant (referred to as PROTO) without the need for a further fusion reactor “demonstration” plant after DEMO  

In the European strategy developed under the framework of the EUROfusion Consortium, DEMO is the only step between ITER and a commercial Fusion Power Plant. This strategy also considers additional objectives as to breed the amount of tritium needed to close its fuel cycle, and to demonstrate all the technologies for the construction of a commercial Fusion Power Plant, including an adequate level of availability.

To achieve fusion electricity by 2050, DEMO construction has to start in the early 2030s, immediately after ITER achieves the milestone of a net energy surplus. Currently, the activities related to DEMO have the goal of a conceptual design of the main systems of the facility by 2020. Then, DEMO engineering design will become a major activity after 2020.

Despite DEMO will largely build on the ITER experience, it will require a significant amount of innovation in critical areas such as heat exhaust, materials and tritium breeding. DEMO will have to rely on simple and robust technical solutions and well established and reliable regimes of operation, as far as possible extrapolated from ITER, and on the use of materials adequate for the expected level of neutron fluence.

In addition, DEMO must be capable of testing advanced components and technical solutions that will be developed in parallel for application in a fully-fledged Fusion Power Plant, thus playing the role of a component test facility as part of its mission. The technologies desirable for advanced Fusion Power Plants and as risk reduction elements, but not mature enough to be incorporated in DEMO, will have to be pursued in parallel.

In this sense, innovation plays a major role in fusion, both in industry and in research laboratories and Universities. This requires promoting cutting-edge research activities in advanced concepts in the most critical areas of the project.


Thus, as in all large science projects, success relies on the balance between pragmatism and innovation. This approach, will promote innovation taking full benefit of the ITER experience and ensuring a single step to a commercial fusion power plant.

The EUROfusion roadmap also envisages that DEMO will be complemented by other activities:

  • Parallel development of technologies “desirable for advanced Fusion Power Plants but not mature enough to be incorporated into DEMO”.
  • Development of a comprehensive materials database for structural steels at 30 dpa and for high heat flux divertor materials at 10 dpa, by 2026.
  • Development of a set of codes & standards for the key safety important materials of DEMO, to be issued in conjunction with industrial codes & standards organisations, by 2028.

For the technology to be suitable for DEMO it needs to demonstrate that it is also viable for PROTO (or at least can be extrapolate to a first power plant without huge difficulty).

The technology required for DEMO to meet its goals needs to overcome the harsh environment present in a fusion reactor. As examples of these considerations we can underline: Neutron Damage, High heat fluxes, Erosion of materials and Cryogenic loads.

The past and current participation of TECFIR / UNED Group in DEMO encompasses two different aspects in the field of computational simulation for radiation transport and activation. On one hand, we develop simulation codes producing more reliable results in those areas of analysis showing a need for improvement of the simulation tools. As example, the R2SUNED is the code developed by TECFIR, under the Rigorous Two-Step (R2S) method for estimating the photon dose rates that result from neutron activation. On the other hand, TECFIR provides nuclear analysis on different relevant aspects for the design of DEMO, as activation and related responses for the characterization of the blanket concepts, calculation of residual doses for maintenance planning and ORE analysis, heat transfer by radiation to the magnets and coils, etc.


Source: EUROFusion consortium and own work