DEMO
The Future of Fusion

DEMO is the EU Demonstration Fusion Power Plant, the next step after ITER on the road to commercial fusion. RACE is leading the work on developing the maintenance systems for DEMO along with several other EU Research Units with support from industry. DEMO is at a very early stage of design and will demonstrate the technologies needed for a power plant. This includes breeding tritium, required for the fusion reaction and the transfer of heat to turbines for electric power generation.

A fusion power plant plasma produces a very large number of neutrons which progressively damage the plasma facing components. These components will require replacement several times during the life of the plant. This presents a significant maintenance challenge due to the mass of the components, the high temperature and radiation levels in the vessel, and the narrow access available through the bioshield and between the magnets. It is of utmost importance that maintenance is carried out as fast as possible, in order to minimise the time the plant is not generating electricity. It is therefore necessary to consider the maintenance strategies from the outset of the design to ensure a compatible plant architecture is adopted.


Challenges

One of the most significant maintenance challenges is the removal of the blankets which are 12m long and weigh up to 80 tonnes. The narrow port means the blankets must be handled through a complex path. The slender blanket and handling system cannot be made rigid, like an industrial robot, resulting in an unprecedented control problem. RACE is developing a novel control system that incorporates a structural simulator to predict the dynamic behaviour of the blanket and handling system in order to maximise accuracy and speed of motion whilst avoiding resonant states.

EU Demonstration Fusion Power Plant

Another significant challenge is the cutting and welding of the many pipe connections. Again, due to the narrow access, these pipes must be grouped close to each other, preventing cutting and welding from the outside of the pipe. Instead, RACE has designed and tested laser cutting and welding tools that can operate from the bore of the pipe. The pipes are grouped into modules so many can be removed at once. A design of pipe alignment cuff has also been tested to investigate the forces and pipe compliance required. This information is used to inform the developing plant design.


The narrow ports will contain many different systems. The layout needs to be considered from an early stage to ensure space is made available. Space is required for the deployment of the remote handling systems but also for the extraction of pipes, plasma facing components and other systems that require maintenance such as vacuum pumping and diagnostic systems.

In-bore laser cutting tool

A study of the operations required in the lower port has been conducted and it shows that there is sufficient space to use industrial robots deployed on a slideway, but that there are only a limited range of maintainable pipe configurations. These require complex operations with limited clearance. The addition of more systems in the ports will need to be done carefully. Many of the technologies that underpin the maintenance strategies will need to be verified through physical testing using test rigs and mock-ups.


The Future

The DEMO plant concept design review is planned for 2027. The remote maintenance systems will be reviewed two years earlier to ensure that plant concepts can be made compatible with the maintenance concept. This will require the continued development of maintenance concepts and technologies, concentrating progressively further from the machine core, to include the active maintenance facility, component transfer and maintenance of the ex-vessel systems such as the plasma heating systems and components such as pipework, pumps and heat exchangers.

DEMO

The Future of Fusion

DEMO is the EU Demonstration Fusion Power Plant, the next step after ITER on the road to commercial fusion. RACE is leading the work on developing the maintenance systems for DEMO along with several other EU Research Units with support from industry. DEMO is at a very early stage of design and will demonstrate the technologies needed for a power plant. This includes breeding tritium, required for the fusion reaction and the transfer of heat to turbines for electric power generation.


A fusion power plant plasma produces a very large number of neutrons which progressively damage the plasma facing components. These components will require replacement several times during the life of the plant. This presents a significant maintenance challenge due to the mass of the components, the high temperature and radiation levels in the vessel, and the narrow access available through the bioshield and between the magnets. It is of utmost importance that maintenance is carried out as fast as possible, in order to minimise the time the plant is not generating electricity. It is therefore necessary to consider the maintenance strategies from the outset of the design to ensure a compatible plant architecture is adopted.

EU Demonstration Fusion Power Plant

One of the most significant maintenance challenges is the removal of the blankets which are 12m long and weigh up to 80 tonnes. The narrow port means the blankets must be handled through a complex path. The slender blanket and handling system cannot be made rigid, like an industrial robot, resulting in an unprecedented control problem. RACE is developing a novel control system that incorporates a structural simulator to predict the dynamic behaviour of the blanket and handling system in order to maximise accuracy and speed of motion whilst avoiding resonant states.


Another significant challenge is the cutting and welding of the many pipe connections. Again, due to the narrow access, these pipes must be grouped close to each other, preventing cutting and welding from the outside of the pipe. Instead, RACE has designed and tested laser cutting and welding tools that can operate from the bore of the pipe. The pipes are grouped into modules so many can be removed at once. A design of pipe alignment cuff has also been tested to investigate the forces and pipe compliance required. This information is used to inform the developing plant design.


The narrow ports will contain many different systems. The layout needs to be considered from an early stage to ensure space is made available. Space is required for the deployment of the remote handling systems but also for the extraction of pipes, plasma facing components and other systems that require maintenance such as vacuum pumping and diagnostic systems.

In-bore laser cutting tool

A study of the operations required in the lower port has been conducted and it shows that there is sufficient space to use industrial robots deployed on a slideway, but that there are only a limited range of maintainable pipe configurations. These require complex operations with limited clearance. The addition of more systems in the ports will need to be done carefully. Many of the technologies that underpin the maintenance strategies will need to be verified through physical testing using test rigs and mock-ups.


The DEMO plant concept design review is planned for 2027. The remote maintenance systems will be reviewed two years earlier to ensure that plant concepts can be made compatible with the maintenance concept. This will require the continued development of maintenance concepts and technologies, concentrating progressively further from the machine core, to include the active maintenance facility, component transfer and maintenance of the exvessel systems such as the plasma heating systems and components such as pipework, pumps and heat ex-changers.