Nuclear energy: An outlook on radioactive waste management

10 Sep 2020

By Brendan Comyn, University of York

A key part of the ‘circular economy’ strategy is designing waste, especially carbon dioxide emissions, out of the economic system.

While generating electricity at a nuclear power plant does not release greenhouse gasses into the atmosphere, it creates another kind of waste that is inherently difficult to re-use and recycle – radioactive waste. However, with the relatively low volumes of radioactive waste produced in the fuel cycle and with innovative approaches to waste management, should it threaten the role of nuclear energy in a circular economy?

The volume of radioactive waste produced in the UK is small when compared to waste from other industries. Estimates suggest 5.1 million tonnes of radioactive waste will be produced over the next 100 years in the UK, compared to the 5.3 million tonnes of hazardous waste produced annually by businesses and households. In the UK, radioactive waste is made up of low-level waste (94%), intermediate-level waste (6%) and high-level waste (0.1%).

Low-level waste management

Previously, low activity waste was often sent to the UK Low-Level Waste Repository (LLWR). However, with the application of the waste hierarchy in the Government’s Low-Level Waste strategy and the declining storage capacity of the LLWR, managers have been encouraged to opt for more sustainable disposal routes.

The Radioactive Waste Hierarchy. Source: UK NDA (2016)

The most promising of these disposal routes from a circular economy perspective is radioactive metals recycling. The recycling of active metals has increased in recent years after the purchase of Cyclife UK by EDF Energy, the UK’s main nuclear operator. Each year Cyclife’s Metals Recycling Facility receives around 1000 tonnes of low-level radioactive metals, of which 95% are recycled through techniques such as shot blasting – ‘blasting’ the metals with small steel balls to remove surface contamination.

While the facility mostly deals with smaller metal items, there is considerable scope for recycling larger pieces of plant. For instance, in Sweden,  Studsvik (Cyclife’s sister company) recycled the boilers from Berkeley’s Nuclear Site (UK) through various surface decontamination and volume-reduction techniques (such as melting). The facility has recycled other large items including steam generators, suggesting that, with more similar sites there is the potential to make the nuclear decommissioning process less wasteful.

High-level waste management

There have also been some innovative approaches to the re-processing and recycling of high activity waste, or ‘closing’ the fuel cycle. Indeed, fissile material (material that can be re-used as fuel) can be separated from the spent fuel and recycled. Globally, 100,000 tonnes out of the 290,000 tonnes of high activity waste produced has been reprocessed as such.

Looking to the future, proponents of Fourth-Generation reactors suggest the technology could actually use current stocks of high activity waste as a fuel source and thereby dramatically change the nature of radioactive waste management.

However, establishing a feasible, current-day strategy for spent fuel management remains one of the industry’s main challenges. At present, there are few permanent disposal facilities in operation, and most countries have not yet decided on a final destination for spent fuel.

Considering the alternatives

Even if long-term storage sites were developed across the world, this seems at odds with sustainable development goals of intergenerational fairness. Spent fuel remains radioactive for thousands of years and thus inevitably burdens future generations.

However, to decide which energy source is most appropriate for a circular economy, it is important to consider the alternatives. Greenhouse gas emissions from burning fossil fuels to generate electricity could, by many projections, contribute to devastating climate change for future generations.

Increasingly, policymakers may have to confront trade-offs between toxic waste production and climate change mitigation. Electric cars each contain a 250 kg battery pack, meaning, for every one million sold, there are 250,000 tonnes of toxic pack waste that must be dealt with. As with radioactive waste, recycling routes exist, and the large scale adoption of these will be essential in securing the role of the technology in the circular economy.

Must we accept that, at least for now, toxic wastes are an inevitable by-product of decarbonisation and building a ‘more circular’ economy? This may be the case, but the nuclear industry’s innovative approaches to radioactive waste management are certainly encouraging.

Brendan Comyn is studying towards a BSc in Environment, Economics, and Ecology at the University of York. He is currently undertaking an industry placement at a major nuclear power station.