There's a hidden radioactive waste problem at the heart of net zero

There's a hidden radioactive waste problem at the heart of net zero

The problems caused by the Sellafield plant highlight the need for more considered planning.

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Credit: Milos Dimic

Published: November 30, 2024 at 8:00 am

A dog hurtles past me, chasing a ball at top speed, across the wide-open flats of Seascale Beach in Cumbria. A small park and a row of shops and houses overlook the long, windswept sands. As I walk northward, tall chimneys and large cuboid buildings of a vast industrial site creep into view.

Right on the doorstep of this beach and the small coastal town of Seascale is Sellafield – a complex, 5km2 (2 sq miles) nuclear site that’s home to the vast majority of the UK’s radioactive nuclear waste, as well as the world’s largest stockpile of plutonium.

I visited Sellafield earlier this year to find out about the fate of the UK’s nuclear waste. What I discovered is that the site is now an eye-wateringly expensive lesson in what it means to not have a plan for dealing with this hazardous material.

Sellafield was at the centre of the race to produce plutonium for nuclear weapons at the height of the Cold War. Now, it’s effectively become a very complex clean-up operation – no longer producing or reprocessing nuclear material, but taking in spent nuclear fuel to be processed and stored. The fuel is cooled, stabilised and clad in layers of steel and concrete, before being put into storage silos.

In the site’s early days, not a lot of thought was given to safe long-term storage. Now, decades-old waste from that era is being slowly and very carefully moved from ageing silos – some of which are leaking – into safer, more modern stores.

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A recent report by the National Audit Office pointed out that Sellafield Ltd, the company that operates the site, is still in the early stages of delivering its clean-up mission, which is expected to take until 2125.

The report forecasts the total cost of decommissioning the site at £136 billion. But most importantly, the report revealed a great deal of uncertainty about what exactly needs to be done and when it needs to be done by.

The most hazardous nuclear waste can’t stay at this site permanently. And, while the plan is to bury it deep underground, it’s still unclear exactly where in the UK it’ll go.

The radioactivity of nuclear waste decreases over time, but as nuclear materials expert Prof Claire Corkhill from the University of Bristol told me, during the first 1,000 years of storage, the material currently being stored above ground in secure buildings at Sellafield is “really quite hazardous”.

“It remains hazardous for 100,000 years, some isotopes even longer,” she explained. “We need to isolate [this material] from future populations or even civilisations.”

The UK’s plan is to do exactly that – bury it in what’s known as a Geological Disposal Facility, or GDF. Layers of solid rock will create a permanent barrier before waste, contained in further layers of steel and concrete, is laid to rest there for millennia.

The government is in the process of finding the right place, but is looking for more than just suitable solid bedrock – the chosen site will also need to have a willing community. 

Six years ago, communities in England and Wales were asked to come forward if they were willing to consider having a GDF facility built near their town or village, with financial incentives offered to those taking part. Three communities are currently in discussions: Mid-Copeland in West Cumbria, very close to the Sellafield site; South Copeland, again on the Cumbrian coast; and a site on the east coast in Lincolnshire.

Many experts are convinced that a GDF is the best option. In Finland, a facility called Onkalo has already been built and could receive its first nuclear waste within the next year. Locations for three other sites have also been chosen in Switzerland, Sweden and France. 

The complexity and uncertainty of the site selection process has already seen the estimated opening date for a facility moved from 2040 to the 2050s, at the earliest. And while the waste piles up at Sellafield and the costs of cleaning up our nuclear past increase, new nuclear power is on the UK energy agenda. It’s part of the government’s strategy to cut greenhouse gases and, ultimately, reach net zero.

We’ve used nuclear energy in this country for 70 years and it’s now clear that it’ll be a part of the mission to keep the lights on and reduce our planet-warming emissions. That means we need a plan for the waste from the outset. A new generation of nuclear power means a new generation of nuclear waste. 

Meanwhile, we’re still dealing – at a huge cost and a great deal of uncertainty – with the mess of the previous generation.

About our expert, Prof Claire Corkhill

Claire is a Professor of Mineralogy and Radioactive Waste Management based at the University of Bristol's School of Earth Sciences.

Her work has been published in the journals Materials Advances, Nature and Ceramics.

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F is the best option. In Finland, a facility, called Onkalo, has already been built and could receive its first nuclear waste within the next year. Locations for three other sites have also been chosen in Switzerland, Sweden and France.

But what isn’t clear is whether a willing community and the right rocks will be located in the same place. The complexity and uncertainty of the site selection process has already seen the estimated opening date for a facility moved from 2040 to the 2050s at the earliest. That is more than a century after Sellafield first started producing plutonium and it could slip further.

And while the waste piles up at Sellafield and the costs of cleaning up our nuclear past increase, new nuclear power is on the UK energy agenda. It’s part of the government’s strategy to cut greenhouse gas emissions and, ultimately, reach net zero.

We have used nuclear energy in this country for 70 years and it’s now clear that it will be a part of the mission to keep the lights on and reduce our planet-warming emissions. That means that we need a plan for the waste from the outset.

A new generation of nuclear power means a new generation of nuclear waste. Meanwhile, we’re still dealing – at a huge cost and a great deal of uncertainty – with the mess of the previous generation.

In response to this column, Sellafield Ltd said: "A Geological Disposal Facility continues to be internationally recognised as the safest and most secure option for managing the most hazardous radioactive waste. We will continue to support Sellafield and the Nuclear Decommissioning Authority in its important mission to manage our nuclear legacy and clean-up sites safely."


About our expert, Prof Claire Corkhill

Claire is a Professor of Mineralogy and Radioactive Waste Management based at the University of Bristol's School of Earth Sciences.

Her work has been published in the journals Materials Advances, Nature and Ceramics.

Read more: