iX challenge: Magnetic Measurements for a Fusion Power Plant
UKAEA is searching for innovators who have expertise in magnetic measurement systems that can operate in harsh environments in a fusion reactor, accelerating the development of a prototype fusion reactor plant and the UK’s transition to net zero. Through its STEP Launch Pad, UKAEA is looking to make strategic investments in technologies that can address this challenge and widen its supply chain.
UKAEA is looking to make strategic investments in technologies that can address this challenge and widen its supply chain. Successful applicants will be provided with technical input and steer from fusion experts and may be given access to follow-on funding. It is anticipated that an aggregate budget of £50,000 will be available to each contract.
The Innovation Exchange programme is working alongside UKAEA to identify solutions for magnetic measurement systems that can operate in harsh environments in a fusion reactor, accelerating the development of a prototype fusion reactor plant and the UK’s transition to net zero.
Through initiating and maintaining the required current and magnetic forces, the magnet system in a tokamak is responsible for:
- Initiating and maintaining the plasma current
- Maintaining plasma in an ‘equilibrium’ position, both vertically and horizontally, relative to the vacuum vessel
- Applying the necessary corrections to alter the shape &/or position of the plasma
As such, a key requirement for plasma control during operation is to monitor the direction and strength of the magnetic field.
Magnetic measurement systems currently deployed on fusion-relevant applications are mostly oriented towards the measurement and control of fusion experiments. However, a Fusion Power Plant (FPP) like the STEP power plant will experience different, and more challenging, operational conditions to these experimental facilities due to longer pulse lengths; higher number of operational hours per year; increased temperature; and increased radiation levels.
The operational condition that poses the greatest challenge is neutron irradiation. Magnetic sensors under neutron irradiation can fail in various ways. The cables undergo radiation-induced conductivity (RIC), Radiation-Induced Electric Degradation (RIED) and Radiation-Induced Electromotive Force (RIEMF) – among other effects – all of which can degrade the signals. This challenge has been set up to begin to identify and develop measurement technologies that can either overcome or avoid these failure/degradation mechanisms.
To summarise, in addition to enabling plasma monitoring and control, the resilience of a measurement system and its sensitivity play a significant role in reducing FPP downtime and minimising human intervention during FPP operations. Therefore, there is a commercial drive and need to develop existing systems and/or identify alternative measurement technologies.
The Challenger is seeking a solution which will measure one or more of the following:
- The poloidal and radial components of the magnetic field at a large number (likely > 100 for spatial coverage and redundancy) of poloidal and toroidal positions outside the plasma (up to a few meters away), for basic position and shape control. Frequency: from DC up to a few kHz.
- The time derivative of the poloidal/radial magnetic field at several locations mainly above and below the plasma, for control of vertical stability. Measuring the derivative of the current in the passive stabilisers would be an acceptable alternative. Frequency: max 10s of kHz.
- The time derivative of the magnetic field at several locations for control of instabilities in the plasma. Frequency: max 10s of kHz.
- Higher frequency detection for Magnetohydrodynamic (MHD) mode monitoring. Frequency: up to 100s of kHz. The solution should be robust enough to operate in the required environment as shown in Figure 2.
The solution should:
- Survive the operating conditions listed for at least 4 hours a day for 2 years. If this cannot be achieved at the current TRL, then indicate how you intend to reach this capability, and how long this development would take, in your proposal.
- Measure poloidal/radial magnetic field components (ranging from 0 to 2 T) in the presence of large toroidal fields (ranging from around 1 T to 10 T depending on the distance from the machine centre column).
- Provide consideration on the required feedthroughs the sensing technology would need.
- Be capable of measuring fields with an accuracy of around 0.1 mT at 1 kHz.
Further information on technical requirements, with diagrams and full operating conditions, can be found at the link below.
Entrants to this competition must be established businesses, start-ups, SMEs or universities.