Nuclear power currently constitutes approximately 11% of global electricity generation, with some 440 reactors in 31 countries with a total installed capacity of over 380GW.
Providing dispatchable carbon dioxide-free, affordable baseload energy, nuclear energy has demonstrated its role in significant emissions mitigation. As such it has a continuing role to play in the long term decarbonization of the sector through the move to emission free energies. Certainly that would seem the view in the large emerging economies such as India, China and Turkey, which account for the majority of new reactors currently under development, but it is also endorsed by the Global Sustainable Energy Partnership (GSEP) comprised of energy executives from leading energy companies worldwide, and by Engerati.
However, that doesn’t mean developers can rest on their laurels. There is a continuing need for innovation, particularly around performance and safety to reduce costs and improve the acceptability of these technologies.
The main technologies which are currently being focused on are fast neutron and molten salt reactors, as well as nuclear fusion. Advances individually and together ensure that these have the potential to provide power for generations far into the foreseeable future.
Travelling wave reactor
Among the dozen or so next generation fast neutron reactors under development, an example is the Travelling Wave Reactor (TWR), which is supported by Bill Gates through the company TerraPower, of which he is chairman. Perhaps with an eye to advancing the TWR, Gates is among the leaders of the Breakthrough Energy Coalition which was launched at COP 21 to support clean energy development.
Marketed as a “new class of nuclear reactor”, the TWR burns fuel made from depleted uranium – a byproduct of the enrichment process which is currently set aside as waste, and enabling it to operate for an extended period of time. The TWR also offers a claimed 50-fold gain in fuel efficiency over today’s light water reactor (LWR) designs.
The concept has been around since the late-1950s, but it has only been under serious development during the last decade. TerraPower aims to achieve startup of a 600MW prototype in the mid-2020s followed by global commercial deployment.
Key achievements reported to date include completion of the core concept design for the prototype TWR and definition of key equipment and system parameters. Experiments are also under way to test innovative material and fuel designs.
Integral molten salt reactor
While China is currently leading research on molten salt reactors, it is Canadian company Terrestrial Energy’s Integral Molten Salt Reactor (IMSR), which is also gaining momentum for a 2020s market entry, that provides the latest news.
The company has just announced the raising of CAD$10 million (US$7 million) in Series A funding, which will be used to support pre-construction and pre-licensing engineering as well as further engagement with industry and nuclear regulators.
The IMSR uses low enriched uranium in liquid form, so it serves both as fuel and coolant, and with recycling virtually all the fuel and waste is burnt. As such the concept is considered “a completely fresh narrative on civilian nuclear safety”.
The IMSR is a modular system and is planned in a variety of power outputs from as small as 30MW up to 300MW and larger. As such it can be built and shipped to a power plant located at point-of-demand via road or rail.
Nuclear fusion progress
Arguably the Holy Grail of nuclear power is the fusion process, which powers the Sun and the other stars in the universe and could lead to an almost inexhaustible source of energy in the future. However, despite decades of research effort across the world, the scientific and engineering challenges have so far proved insurmountable, primarily due to the difficulty in creating the sufficiently high temperatures and pressures required.
A 2012 document from the European EUROfusion consortium sets out a roadmap to realizing the supply of fusion energy to the grid by 2050. This is centred on the ITER tokamak facility, which is currently being built in southern France by a consortium of 35 nations, including those in Europe along with China, India, Japan, Korea, Russia, Switzerland and the United States.
ITER, which is on track for a 2020 completion, is expected to be the first fusion device to produce net energy, i.e. that the total energy created during a fusion plasma pulse surpasses the amount of energy required to power the machine’s systems.
A key milestone in the construction process was achieved just before Christmas – a few weeks ahead of schedule – with the arrival onsite of the first machine components. These are the first 12 segments, out of a total of 54, that are being manufactured in India that will make up the cryostat, which essentially will make up the outer shell of the device.
The goal of ITER is to operate at 500MW for at least 400 seconds continuously with less than 50MW of input power, i.e. a tenfold energy gain. However, ITER itself will not produce electricity. When the research findings from ITER start to come in these will feed into the development of a demonstration fusion power plant, which is envisaged to produce net electricity for the grid at the level of a few hundred megawatts starting in the early 2040s.