EPSRC Centre for Doctoral Training in the Science and Technology of Fusion Energy

Lead Research Organisation: University of York
Department Name: Physics


Fusion is the process that powers the sun. If we can harness fusion power on Earth, it would provide effectively limitless, carbon-free, safe energy. There are two approaches. In inertial fusion energy (IFE), high power lasers (or other 'drivers') compress a pellet of frozen deuterium-tritium fuel to very high density and temperature, confined for short times associated with the fuel's inertia (nanoseconds). The other approach, presently the more advanced, is magnetic fusion energy (MFE). Here the hot, low density fuel is held in a toroidal chamber using magnetic fields for confinement times of seconds.
When the fuel is heated to fusion temperatures (100,000,000K), the electrons are stripped from the nuclei, creating an ionised gas called a plasma. Plasmas are susceptible to a range of waves and instabilities that drive turbulence and degrade confinement. In MFE this determines the device size. For example, the 16Bn Euro ITER facility is large enough to give the required confinement despite the turbulence, providing a fusion yield of 10 times the applied heating power. Scheduled for completion in 2020, ITER will provide the first plasma with heating dominated by the energetic alpha particles produced by the fusion reactions, allowing the final physics questions to be answered to build a demonstration power plant, DEMO. For example, how do the alpha particles affect the plasma stability and turbulence, and how do we exhaust them from the plasma once they have cooled to avoid dilution extinguishing the fusion burn? The other fusion product is a 14MeV neutron to be captured in a blanket to extract its energy and react it with lithium to produce tritium. Understanding how materials behave under this energetic neutron irradiation, combined with exposure to hot plasma, is something we still know little about because ITER will be the first device to create these conditions. ITER will also address a range of fusion technologies, such as heating systems, tritium breeding blankets and exhaust handling: issues that integrate plasmas with materials.
The flagship IFE facility is NIF in the US. It tried to achieve fusion conditions during 2012, but did not succeed. The reasons require more research, but again plasma instabilities are a likely cause. Once the issues at NIF are resolved the priorities for future laser-based systems (e.g. HiPER) can be defined on the route to inertial fusion energy. Then the materials issues discussed above for MFE apply to IFE also. IFE creates extreme states of matter with high energy density that have important applications beyond energy. One is to create conditions suitable for benchmarking the computer codes that contribute to the UK's nuclear deterrent, avoiding the need for weapons testing: important in the strategy to avoid proliferation. AWE has recently commissioned a large laser facility, Orion, primarily for this purpose.
Fusion research interfaces with several fields. There are synergies with the nuclear industries where the next generation fission reactors will have high energy neutrons and so share some materials issues with fusion. Space plasmas share phenomena also found in MFE plasmas while energetic astrophysical phenomena can be simulated in the lab using high power lasers. In industry, low temperature plasmas with similar characteristics to those at the edge of a MFE plasma have applications in manufacturing, from advanced coating technologies to computer chips.
The focus of our CDT is fusion, training 5 cohorts, each of 15-16 PhD students, across the range of plasma, materials, IFE and MFE, as well as related fusion technologies. This will position the UK to take advantage of new high power laser and MFE facilities, advancing fusion energy. IFE, along with lab astrophysics, will develop skills relevant to the UK's national security strategy. Our training programme will seek to benefit other students in related fields, such as technological plasmas and nuclear materials.

Planned Impact

Identifying a solution to the energy problem is crucial to the UK economy and quality of life. In the near term a range of renewable options must be developed, eg wind and solar, but it is unlikely that these will provide the base-load supply required. Nuclear is an option for a carbon-free base-load and, in particular, fusion energy is safe and relatively clean. If it can be achieved, fusion would bring the largest economic benefits to those countries that lead the way to build the first fusion power plants, but ultimately most people in the world will benefit from fusion in some way.
ITER, the largest international science project on Earth, will operate from 2020 to answer the final physics questions and most technology questions required to construct the first demonstration magnetic fusion energy (MFE) power plant, DEMO. We will train the ITER generation of UK fusion scientists who will have the expertise to win time on this key facility against international competition. This is crucial to build experience that will feed into the design of DEMO, ensuring the UK remains at the forefront. EU design studies for DEMO are already under way, with manufacture of prototype components likely to follow soon. There are a number of beneficiaries from this training: (1) it will benefit Culham Centre for Fusion Energy (CCFE), providing well-trained new staff to replace those retiring, keeping the UK at the forefront of fusion energy research, competitive for ITER time and leading elements of DEMO design/prototype development; (2) it will provide expertise for the growing UK industry involvement in fusion, helping to win contracts for ITER and DEMO prototype components; (3) it will ensure the UK has a cadre of fusion experts to advise Government on future directions. We expect to train 60 students in MFE, approximately balanced across plasmas, materials (relevant for IFE also, see below) and related fusion technologies.
For inertial fusion energy (IFE), NIF in the US is the most advanced device in the world, and some expected it would achieve fusion conditions, i.e. ignition. In its 2012 ignition experiments, this did not happen, but the reason why is still uncertain. The immediate need is to understand this, which requires experts to win time on international facilities (including NIF), understand why ignition did not occur and so develop a roadmap to IFE based on the new knowledge. This will benefit the UK Government by providing experts to advise on an appropriate strategy, able to compare the relative merits of IFE and MFE because of our training across both areas. If IFE proves viable, then it will need to integrate fusion technologies in a similar way to ITER and DEMO, bringing benefits to industry. We expect to train 15 students in high energy density physics (HEDP), spanning IFE and lab astrophysics; the MFE materials students' expertise is also relevant for IFE reactor design.
Expertise in HEDP is required by AWE for its science-based approach to underpinning the UK's nuclear deterrent, and is a key element of the UK's strategy to comply with the Test Ban Treaty. The new Orion laser facility at AWE can replicate the conditions in a nuclear warhead, enabling advanced computer codes to be tested. Our students will have the expertise to work with Orion, which requires skilled scientists as it establishes its programme. Also the materials and computational scientists amongst the ~60 MFE students will be of value to AWE.
We will train students in the cooler exhaust plasma of a tokamak. Similar plasma conditions are used in manufacturing industries (coatings, computer chips, etc) so we will develop a skill base that will benefit a number of such companies. Materials research for fusion is also relevant for fission. The popularity of fusion amongst students is a good way to bring outstanding students into the field, providing expertise that benefits the growing nuclear industries and supporting the Government's nuclear policy.


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