Comment: Nuclear GDF is vital for UK’s future

Martin Walsh, Head of Engineering at Nuclear Waste Services, ponders the unique engineering challenges of building a geological disposal facility for nuclear waste.

Sellafield in Cumbria is home to about 75 per cent of the UK's nuclear waste
Sellafield in Cumbria is home to about 75 per cent of the UK's nuclear waste - Adobe Stock

For the past 70 years, the UK has benefitted from a world-leading nuclear sector which provides around 15 per cent of the country's electricity. Today, nuclear power is viewed by the UK government as essential to the low-carbon energy mix and securing our energy supply in the future.

Critically, with nuclear technologies, comes nuclear waste. For now, the UK’s most hazardous radioactive waste is treated, packaged and safely managed at over 20 surface facilities across the country. While these facilities are safe for the short to medium term, they require ongoing upkeep and maintenance and would need to be rebuilt every 100 – 150 years.

For the disposal of the most hazardous radioactive waste, we’re proud to be delivering a Geological Disposal Facility (GDF) as the safe, secure, and long-term solution.

We have a varied inventory of nuclear waste to deal with, and all of it requires careful management, with safety the number one priority. As an indicator of the sheer scale of this challenge, we expect to have over 750,000m3 of packaged radioactive waste destined for a GDF - equivalent to 10,000 double-decker buses.

It is one of the largest environmental protection programmes in the UK and ensures we remove the costs and burden of having to keep the waste safe and secure in storage facilities for many thousands of years. Development of a GDF has been part of government’s policy to manage radioactive waste since 2006 and is a multi-generational programme, spanning 175 years. A GDF could offer unique opportunities for generations of engineers - it’s certainly a monumental, and unique engineering challenge!

Disposal deep underground in highly engineered vaults and tunnels will keep waste safe and secure over the hundreds of thousands of years it will take for the radioactivity to naturally decay. Geological disposal facilities use engineered barriers to work alongside the natural barrier of deep, stable rock hundreds of metres below the surface. This multi-barrier approach isolates and contains waste to prevent radiation from ever reaching the surface environment at levels that could do harm.

A GDF will be constructed between 200 and 1,000 metres below ground or the seabed. At this depth, the waste will be protected from natural events and processes such as earthquakes and long-term environmental changes such as future ice ages or sea level rises. It is possible that we could be building the disposal area at a scale few engineering projects have seen in the past – it is estimated 400km of underground tunnelling will be needed.

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For the construction industry, there will be unique challenges. The depth and extent of tunnelling, coupled with the longevity required to safely store waste is complex. With it being such a long-term project it means we must consider digital advances - every platform, every software tool, every construction method will evolve or change as the years go by, and we must consider this in our thinking.

A diversity of skills and high level of resource will be required from our engineering sector. As a multi-disciplined project, we need a team that spans management, science, technology, engineering, mathematics, sustainability, environment and more. This is not solely a challenge for the nuclear sector. The range of work on offer, coupled with resource issues, means that as an industry we must be open to the transfer of skills between sectors. We have taken inspiration from the mining, rail, highways and industrial sectors. As well as ensuring effective delivery, this promotes knowledge building, access to a breadth of solutions, and ultimately more inspiring careers for future engineers.

Positively, the GDF programme is making significant progress at a good pace with three communities across England, two in Cumbria, Mid Copeland and South Copeland, and one in Lincolnshire around Theddlethorpe who are engaging in the programme to learn what hosting a GDF could mean for them.

For a GDF, we require both a willing host community and a suitable site. This process can take time and this year we have started and progressed a range of studies and surveys. The emerging data is helping us to identify locations for further investigative work, such as drilling deep boreholes, to understand the geology and help us ensure a GDF can be constructed, operated, and closed safely and securely.

This isn’t something we can rush – the full programme lifecycle will take generations to complete, but it’s vital. It is a nationally significant programme and something that is essential for our national infrastructure and energy mix going forward.

A GDF is essential to managing our radioactive waste legacy in a responsible way and has the potential to unlock economic, environmental, and engineering opportunities for generations to come.

Martin Walsh is Head of Engineering at Nuclear Waste Services