Lecture Summaries/Abstracts

 

York Week – 19th – 22nd June 2023

Monday 19th June – University of York, Heslington East Campus

11:00-12:30 – Fusion Energy: the conditions & approaches Howard Wilson, University of  York

This presentation will introduce the background to fusion energy and the conditions required to produce it. The basic fusion process will be described, focussing mainly on the reaction between two heavy forms of hydrogen – deuterium (D) and tritium (T). The so-called “triple product” will be motivated and defined as the quantity that characterises the proximity of the DT fuel conditions to those required for a commercially viable fusion power plant. These include a temperature about ten times hotter than at the centre of the sun, and requires a sufficiently effective system to confine the DT fuel at this temperature. The fuel is then in a state called plasma, which will be defined and characterised. Two broad approaches are being explored to access fusion energy conditions – inertial confinement and magnetic confinement, which will be described. Some of the different fusion concepts in each scheme will be discussed. The presentation will close with a discussion of the large breadth of science and technology that must be brought together to realise a commercially viable fusion power plant, signposting the topics to be covered in the subsequent lectures of the school.

13:30 – 15:00 – Plasma Physics for Fusion Industry Nick Walkden, Frazer Nash
At the heart of all fusion power plant designs sits a plasma. Plasmas exhibit a wide range of complex phenomena that must be understood to design and predict the behaviour of fusion powerplants, ultimately providing the conditions for fusion to occur and setting the power output of the device. This talk will introduce the basics of plasma physics, and explain how key concepts such as plasma drifts, instabilities, turbulence, and equilibria, affect the performance and viability of fusion devices. It will describe techniques deployed to understand the physics of fusion plasmas and outline recent key developments in the field, to provide a comprehensive and understandable overview of fusion plasma physics.

15:30 – 17:00 –  Materials Science for Fusion Industry Amy Gandy, University of Sheffield
The core of a Tokamak is arguably one of the most extreme environments on Earth. Materials that are closest to the plasma will have to continue operating at high and fluctuating temperatures, under stresses exerted by the high magnetic fields, and levels of radiation damage orders of magnitude greater than in current fission reactors. In addition, commonly used materials will become radioactive due to the unique fusion radiation environment, generating gas (helium and hydrogen) during radioactive decay of the materials. The fusion plasma itself can result is surface erosion which contaminates the plasma, and the scare and radioactive fuel tritium can become trapped in the walls of the Tokamak. In this lecture, we will explore the unique and challenging environment of a magnetic fusion device, specifically looking at how radiation damages materials. We will discover the materials that are candidates for the different key components of a Tokamak, and the effects that the fusion environment has on these specific classes of materials. We will look at not only the plasma facing materials, but also superconducting magnets and the solid ceramic fuel candidates designed to breed tritium.

Tuesday 20th June – University of York, Heslington East Campus

09:00 – 10:30 – The Tokamak Garry Voss,UKAEA

The Tokamak configuration for magnetic confinement of plasma was first proposed in Russia in the 1950’s and has been adopted by most magnetically confined fusion research bodies as the preferred configuration. The geometry and terminology used to define the Tokamak will be introduced including the differences between the conventional Tokamaks (like JET and ITER) and the spherical Tokamak (like MAST-U and STEP). The main components of a Tokamak and their functions will be outlined including:
Toroidal field coils: These produce a magnetic field in the toroidal direction and are either formed from copper conductors or from superconductors which offer no resistive power loss.
Poloidal field coils: These produce a magnetic field in the poloidal direction. This combines with the toroidal field to form an efficient plasma confinement and shaping system.
The 1st wall: This faces the plasma and is subjected to high thermal loads due to radiation and particle flux as well as a volumetric heating due to neutron irradiation in fusion conditions. Materials such as graphite and tungsten are often used here.

The blanket: This is needed to breed the tritium fuel for the fusion reaction. It is located directly behind the 1st wall and contains lithium in the form of a ceramic, liquid metal or salt, which produces tritium when subjected to a neutron flux. A multiplier such as beryllium or lead is often included in the blanket to increase the number of neutrons and hence tritium breeding.
Divertor: The level of impurities and helium particles in the plasma needs to be controlled by allowing them to pass outwards to a scrape-off-layer which surrounds the plasma. This is then diverted to target plates at the top and/or at the bottom of the plasma. The heat loads and erosion rates on these target plates can be very high and their design often limits the size and power of the Tokamak.

Main support structure/cryostat: This reacts the loads induced on the coils, 1st wall and blanket structures and so holds the device together.

11:00-12:30 – Microwave Heating and Current Drive system for tokamak power plants Mark Henderson, UKAEA
This presentation reviews the steps required to develop microwave heating and current drive systems for tokamak power plants, highlighting the remaining R&D tasks to achieve a mature HCD system for a demonstration plant, and including the potential risks and opportunities associated with technology spin-offs. The UK Atomic Energy Authority is planning the construction of the STEP (Spherical Tokamak for Energy Production) aiming at generating ≥100MW net electric back to the grid in the 2040 period. We will use this STEP design to provide a specific case study. An assessment of the optimum Heating and Current Drive (HCD) system has been performed based on the functional requirements for maintaining a steady state plasma. The study concluded that a pure microwave HCD system is the optimal solution for STEP, which achieves a minimum technology advancement, while achieving the highest grid to plasma efficiency. A pre-concept design has been defined and the required R&D to raise the technology readiness level compatible with steady state operation on a burning plasma will be presented.

13:30 – 15:00 – Tokamak Operational Scenarios Fernanda Rimini, UKAEA
The talk will cover aspects of Tokamak Operations, focussing on different plasma scenarios and the implications they have for future reactor scenarios and design. We’ll touch on concepts like pulsed operation, thermal confinement and H-mode, plasma instabilities and disruptive events. We will, also, introduce some of the real-time machine protection and control issues, to be elaborated further in subsequent lectures

Wednesday 21st June – University of York, Heslington East Campus

09:00 – 10:30 – Diagnostics and Control Hartmut Zohm, IPP Garching
Diagnostics for magnetically confined fusion plasmas have to provide measurements of various quantities of interest in a harsh environment. In the last decades, enormous progress has been made in this field and to date, there are measurements available of a large number of plasma parameters with high temporal and spatial resolution. In present day experiments, diagnostics are used as instruments to understand the behavior of the hot plasma, but also as sensors, to feedback control the plasma discharge. In a fusion power plant, the emphasis will mainly be on the latter aspect, but also the environment will be significantly harsher than in present day machines, so the problem of diagnostics and control remains a challenging one.

In the talk, I will first review diagnostics principles for the main plasma parameters needed for both physics understanding as well as control. This will be followed by a brief discussion
of the available actuators (heating, current drive and fueling), which will be dealt with in more detail on the following day. From there, I move to describing the control challenge of tokamak plasmas, which turns out to be a multi-input multi-output problem. Strategies to cope with the challenges will be discussed as well, including the prospects for model-based control versus a pure heuristic approach.

11:00-12:30 – Inertial Confinement Fusion Nigel Woolsey, University of York & Hugo Doyle, First Light Fusion

Inertial confinement fusion (ICF) is an exciting avenue for energy production. The approach uses a powerful driver to rapidly compress deuterium and tritium fuel to immense pressures to ignite fusion reactions and release energy as an intense, short-lived pulse. A power station requires repeating this process continuously and possibly many times per second. The validity and the feasibility of this approach was unambiguously demonstrated in December using the National Ignition Facility which, for the first time, achieved fusion gain exceeding one. This experiment used 192 laser beams containing 2 million Joules to release 3.5 million Joules of fusion energy from a 2-millimetre diameter diamond spherical shell containing 0.2 milligrams of deuterium and tritium. The fusion reaction occurred in less than 0.1 billionths of a second.

In this discussion, we will introduce you to the basic concepts of inertial confinement fusion and explore the impact of the National Ignition Facility result. We will also examine current research by unpicking some of the experimental and computation tools used to explore the science that occurs in the extreme conditions of an inertial fusion plasma. Furthermore, we will highlight two approaches to inertial confinement fusion the first uses powerful lasers such as the National Ignition Facility, and the second is First Light Fusion Ltd., a unique approach that utilises hypervelocity projectiles. Hugo Doyle, the Head of Experimental Physics at First Light Fusion, will discuss a vision for a fusion reactor and highlight the engineering and materials challenges that projectile drive fusion and other  fusion approaches must overcome.

All fusion schemes hold promise as a sustainable and low-carbon-free energy source, and its implementation is uncertain. It will require overcoming significant scientific and engineering challenges, by understanding the underlying principles and exploring different approaches, we can pave the way for a brighter and cleaner energy future.

13:30 – 15:00 and 15:30 – 17:00 –Panel Session

Panelists will each give an overview on the fusion landscape in their area, followed by questions to the panel. Delegates are encouraged to pose questions directly.

Thursday 22nd June – University of York, Heslington East Campus

09:00 – 10:30 – Fuelling a tokamak Rachel Lawless, UKAEA
Tritium and deuterium are widely considered the most viable fuels for fusion power plants. Whilst deuterium is abundant on earth and can be treated like hydrogen, tritium does not occur naturally in significant amounts and must be handled carefully due to its radioactive nature. For fusion to be viable, technologies must be developed to safely breed, extract, process, handle, and store tritium gas. This talk will outline how fusion fuel cycles are designed, and the considerations needed when handling tritium and developing tritium technologies, as well as outlining the steps required to deliver safe and efficient fusion fuel cycles in the future.

11:00-12:30 – Nuclear/Neutronics Analysis of Fusion Systems Lee Packer, UKAEA & Gurdeep Kamal, Tokamak Energy

13:30 – 15:00 – Digital Approaches to Design in Fusion Andrew Davis, UKAEA
The process of designing fusion reactors and fusion reactor systems historically inherited much from traditional nuclear industry methods. Fusion however is a much more complex physics problem than fission systems. The fusion load case is multi-physics; large heat loads (even larger off-normal heat loads), high neutron flux, large magnetic field, complex chemistry, structural changes, and neutron flux dependent material parameters. We will cover the current set of technology issues that fusion faces, how computer based modelling will fill the gaps and what the state of the future might look like.

15:30 – 17:00 – Plasma Exhaust and divertor design in Tokamaks Rudolf Neu, IPP Garching

 


Oxfordshire Week – 25th – 28th September 2023

The Oxfordshire week will be hosted by University of Oxford Materials Department and UKAEA and will include one day at Culham Science Centre and three days at Keble College.

Monday 25th September – Keble College

09:30 – 11:00 – The UK fusion programme in the international landscape Ian Chapman, UKAEA
This talk will begin by explaining the UK government strategy to delivering fusion and setting this in the context of international energy strategies and other major fusion programmes internationally. It will then describe the major technical challenges required to deliver a magnetic fusion powerplant and give a brief overview of some of the key deliverables and discoveries that will be required on that pathway. An overview of recent major discoveries in the field will be presented to bring the delegates to the cutting edge of the field. Finally, a brief overview of the facilities at Culham will provide an introduction to the site tour later in the week.

11:30- 13:00 – Materials Technology for Fusion Aneeqa Khan, University of  Manchester
In this talk we will start with a short overview of the specific materials challenges that are faced in nuclear fusion, including radiation damage, high heat loads, plasma material interactions, helium, corrosion. We will then spend time discussing several case studies of specific materials requirements for enabling fusion such as structural and plasma facing materials for internal tokamak operations.

14:00 – 15:30 – Tritium and Fuelling Technologies Tamsin Jackson, UKAEA
Very few fusion facilities use tritium in their experiments due to the significant costs, hazards and complexity associated with designing and operating tritium systems. This talk will discuss the changing requirements and development journey for tritium technologies to progress from current-generation devices through ITER, and into fusion power plant concepts. Examples of the current technologies and engineering approaches used for tritium fuelling, recycling, confinement and recovery will be given. The key challenges to be addressed to develop those approaches and technologies to meet the potential requirements of future fusion power plants will be explored.

16:00 – 17:30 – Magnets and Magnet Technology Susie Speller, University of Oxford
Superconductors, with their ability to carry enormous electrical currents with no loss in energy, are an essential enable component for providing magnetic confinement in commercial fusion power plants. In this lecture, the diverse range of superconducting materials that can be used in high field magnets are introduced, with a key focus on understanding the specific materials and engineering challenges associated with the extremely harsh conditions of a fusion reactor.

Tuesday 26th September – Culham Science Centre

09:00 – 10:30 – Manufacturing for Fusion, Lee Aucott, UKAEA
This (somewhat interactive) lecture will delve into the details on how fusion reactors are manufactured and assembled. The prominent case study for this lecture will be the International Thermonuclear Experimental Reactor (ITER), currently under construction in the South of France. We will spend time looking at the method of manufacture and assembly for key ITER tokamak systems such as the Vacuum Vessel, In Vessel Components and Magnets. Some of the unique challenges propositioned by a fusion device, which tend to defy all traditional conventions will be explored in more technical detail. The general structure for the lecture will be an overview of the current MoM for a system, followed by open Q&A and discussion on challenges and potential solutions in relation to each system explored.

11:00-12:30 – Breeding blanket design, Samuel Murphy, University of Lancaster
The breeder blanket region of a future fusion power station performs several critical roles. Firstly, it is the region where neutrons ejected from the plasma are used to transmute lithium to ensure a sustainable fuel cycle. Secondly, it is where the neutron’s kinetic energy is converted into heat for electricity generation as well as providing shielding to protect external components from radiation damage. The design of the blanket will have major implications for other reactor systems, including the choice of coolant and engine cycle used for electricity generation, and the breeder blanket will determine the reactor’s efficiency and will require a delicate balancing of competing characteristics.

There are a number of different breeder blanket designs currently under consideration and many of these are being developed into Test Blanket Modules for testing on ITER. In this talk I will outline the general features of a breeder blanket as well as discussing the leading blanket concepts as well as outlining what the key challenges and opportunities are.

Wednesday 27th September – Keble College

09:00 – 10:30 –Plasma Heating and Current Drive Systems – neutral beam injection Ursel Fantz, IPP Garching

11:00-12:30 – System and Plant Maintenance Rob Skilton, UKAEA
No robotics, no fusion. Fusion energy has the potential to offer safe, sustainable and green electricity for future generations, however it is extremely challenging. Due to the extreme nature of the environments within fusion devices, regular maintenance will be required without human access. The commercial viability of fusion therefore depends on fast, robust, and reliable remote maintenance using robots. This talk will explore some of the biggest maintenance challenges that will need to be solved in order to make fusion energy a reality.

13:30 – 15:00 – Socio-economics of Fusion Energy Niek Lopes Cardozo, Technical University of Eindhoven
Will private companies bring fusion to the market soon?

Fusion holds the promise of unlimited, zero-CO2, safe energy, for all, forever. But the technology is extremely challenging. So much so, that after 60 years of research it is still not proven that a power-producing fusion reactor can be realised, the European roadmap projecting the first demonstrator (DEMO) in 2055.

But things have begun to shift, recently. The mainstream, government-funded fusion R&D programmes have achieved some major results: early February the EU programme announced a new fusion energy record achieved in the Joint European Torus (JET), a few weeks after the US inertial fusion programme achieved ‘ignition’ in the National Ignition Facility (NIF). In the meantime, the construction of the gigantic international fusion experiment ITER is well underway, with first operation expected in about 5 years from now.

The most surprising development, however, is the surge of private companies who aim at building a full power demonstrator within 10 years. As of last year, these companies are attracting billions (!) of private funding and feature highly competent, focused teams. Whereas the government-funded programme focuses on a single concept, the private initiatives explore a dozen different concepts in parallel. And they follow a completely different development philosophy.

In this talk I analyse these developments and discuss which innovation pathway could be the fastest route to fusion power. I compare the different approaches, ask the question how it is possible that private companies could be so much faster than the mainstream programme, and if it is likely they will succeed, and when, if even one of them is successful, fusion could start to play a role in the energy transition – for which thousands of power plants need to be build. The analysis is done in the context of the required energy transition, which dictates the pace but also the required investment level.

15:30 – 17:00 – Panel Session (tbc)

Thursday 28th September – Keble College

09:00 – 10:30 – Fusion Waste and Waste Management Mark Gilbert, UKAEA

The neutrons generated in fusion reactors will impinge on surrounding materials leading to the activation of those materials via nuclear reactions. Current predictions from numerical simulations indicate that future fusion reactors are likely to produce significant quantities of radioactive waste. This is a technological and societal challenge for fusion that must be addressed through careful engineering of materials, waste processing and handling, as well as through revised regulatory approaches to the handling of radioactive waste from fusion power plants.

In this presentation I will introduce the methodology behind the simulations of activation and waste that is performed by UKAEA’s FISPACT-II inventory solver. As well as waste assessment, FISPACT-II supports understanding of shielding requirements and the planning of maintenance, which is constrained by the short lived activation of materials. Inventory simulations also calculate transmutation and gas production, which must be accurately understood to inform lifetime predictions of materials whose properties can be altered by transmutation products.

In the second half of the presentation, I will discuss the current waste assessment predictions for the EU-DEMO fusion reactor design, with a particular focus on understanding the origin of long-lived radioactivity in critical fusion materials. These detailed assessments, facilitated by FISPACT-II can help to guide revised requirements on materials compositions, as well as the requirements for waste treatment.

11:00-12:30 – Fusion Powerplant Safety and Regulation Mike Webley, Environment Agency & Clare Lee, Health and Safety Executive
Designs for fusion energy prototype power plants are now being developed around the world by fusion research organisations and private companies, targeting deployment in the 2030s and 2040s. Fusion energy facilities will need to be regulated appropriately and proportionately in the UK to maintain public and environmental protections, provide public assurances and enable the growth of this low carbon energy industry. Fusion facilities must comply with health and safety regulations for workers and the public and with environmental and public protection regulations. This talk will introduce the UK regulators and fusion safety experts, provide an overview of fusion regulation and outline our work to build regulator capability and capacity to regulate fusion power plants.

13:30 – 15:00 – Engineering Delivery Rachel Packer, Atkins

15:30 – 17:00 – Systems Integration Chris Waldon, UKAEA
The quest for commercial fusion power is universally recognised as one of the most exacting that we face as engineers and scientists. Extremities of operation, complexity of design and an inability to prototype combine to make it a truly daunting prospect. The design space is an intimidating and hostile arena to operate with extensive uncertainties in the pathway heightened by many moving parts, causality breakdown, and multiple significant decisions to be made. Many strongly interacting elements (tensions) of the requirements/constraints and the design within the physics, technology and engineering spheres and between them makes the pathway seem opaque. With an unsolved, complex and highly interdependent design challenge, there is a need to balance exploration of the problem with progress. I will discuss the integration grand challenge and the iterative approach that is needed to reveal more about the interdependencies/trade offs as the design evolves towards an end.