In the Spring Budget, the Chancellor classified nuclear energy as environmentally sustainable opening the way the sector to access the same incentives as renewables, again emphasising the Government’s commitment to nuclear energy.
It is increasingly clear, even to UK Greens that nuclear is a far better option than fossil alternatives such as gas and that with the anticipated electrification of both transport and heat that a very significant baseload generation capability is required. As such, the bar has been set for nuclear at 24 GW of generation - a long way from the approximately 4 GW of nuclear generation we have today.
Within a few years, existing generation will have dwindled to the 1.2 GW of Sizewell B, with Hinkley Point due to start generating 3.2 GW from 2026 onwards, and Sizewell C still on the starting blocks. There remains much to be done to get to 24 GW of generation, which is why the gentle push of the reclassification is in the right direction.
There is the need to ramp up the current generation of large, pressurised water and boiling water reactors which have demonstrated reliability and safety, but there is also a need to think longer term and recognise that the isotope of uranium, uranium-235, which is used in reactors is a reasonably rare commodity.
Professor Martin Freer, Director of the Birmingham Energy Institute - University of Birmingham
There is the need to ramp up the current generation of large, pressurised water and boiling water reactors which have demonstrated reliability and safety, but there is also a need to think longer term and recognise that the isotope of uranium, uranium-235, which is used in reactors is a reasonably rare commodity. This isotope forms less than one percent of natural uranium which is dominated by uranium-238. To operate, most current reactors need enriched uranium in which the fraction of uranium-235 is enhanced. Depending on the rate of usage, existing natural sources of uranium extractable by mining might only last another 100 years. Though the cost of the fuel represents only a reasonably small fraction - some 20% of the operating costs of the reactor - future cost rises could make nuclear generation less competitive.
Consequently, there is a need to look at next generation reactors, such as so-called ‘fast reactors’, which can use uranium-238 as a fuel. Current reactors use thermal neutrons, where the neutrons are slowed down, or moderated, to the point where their energy is representative of the thermal environment they are in. Fast neutrons are higher energy and can initiate reactions on the harder to fission uranium-238.
These next generation reactors also have the potential of being able to ‘burn’ elements such as plutonium, of which the UK has a significant stockpile arising from nuclear waste reprocessing, but also other nuclear waste elements. The UK has set its ambitions around developing a High Temperature Gas-cooled Reactor as a next generation reactor given the large amount of national expertise stemming from the UK’s fleet of AGR (Advanced Gas-cooled Reactors). These high temperature reactors have the potential for process heat production which can be exploited by co-located industry, but also hydrogen production.
So how environmentally sustainable is nuclear now and how sustainable will it be in the future? There are perhaps two aspects to consider. The first is the amount of CO2 generated per kWh of energy generated. Nuclear energy is in its generation intrinsically zero carbon, the nuclear fission process produces two atomic nuclei at high energy which are slowed down inside the uranium fuel generating heat. It is this heat which boils water and drives a steam turbine, generating electricity.
However, there are carbon emissions associated with the construction of the power station – there is a lot of concrete – decommissioning and fuel processing but given that nuclear power stations operate over a period of 60 years these contributions average over each kWh to be very low and around the same as wind and solar. In this way this is an environmentally sustainable technology.
The biggest push pack comes from the issue of what to do with the nuclear fuel post operation, or nuclear waste. At present the UK is engaged in developing a nuclear waste repository in which the waste will be safely disposed of deep underground. The ambition is to have a nuclear waste repository operating within the next 20 years, and certainly on a timescale that matches the need to manage the decommissioning of the Sellafield site. The cost of the management of Sellafield and the waste repository construction is eye watering - running to hundreds of billions of pounds. However, until this repository development is achieved, environmental sustainability remains an issue. This is high priority if the UK is going to be serious about the 24 GW of generation.
Finally, there is the need to address public concerns over safety. There remains a perception that nuclear energy is high risk with concerns over existing power plants in Ukraine, the history of well-publicised accidents such as Chernobyl and Fukushima, and the broader concerns over radiation. The facts are that nuclear energy is highly regulated. It has extraordinarily high levels of safeguards associated with operation and approval for plant design by the UK Office for Nuclear Regulation. Because of these measures, nuclear energy is in fact historically one of the safest energy technologies we have – perhaps remarkably even safer than wind compared to the integrated energy generated with the associated safety record.
So the bottom line is that, if the nuclear sector does sort out the waste disposal issue, it has a credible argument to make around being environmentally sustainable.
