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The University of Southampton
Ocean and Earth Science, National Oceanography Centre Southampton

A new radionuclide waste assessment tool for the nuclear sector

Scientists at the University of Southampton’s Geosciences Advisory Unit (GAU), led by Professor Ian Croudace and Dr Phil Warwick, have developed a better and faster way to extract and measure volatile radioactive isotopes, specifically tritium and carbon-14, which contaminate parts of nuclear sites. The information gained helps sites that are decommissioning nuclear power stations to make appropriate decisions on the proper disposal of their radioactive waste. In some cases, the new technology can help sites to develop simple remediation processes to safely recycle metal wastes. Over the last decade, the innovative analytical technique has been adopted by nuclear decommissioning companies and specialist laboratories in the UK and the international nuclear industry. Over 10 years, it is estimated that the Pyrolyser innovation will have generated £15-20m of turnover in the UK economy with clear benefits to society in terms of jobs and reduced amounts of waste requiring special disposal.

Research challenge

Tritium and C-14 pose particular problems to decommissioning teams as they can be found in many places throughout a nuclear site – for example in metal, wood, concrete and insulation materials. Former methods of identifying and removing these volatile radionuclides were quite inefficient. With the new method, six samples at a time can be heated in the specially designed furnace to release any tritium and C-14. The volatile products are then collected and analysed and decisions can be made on what to do with the material. Depending on the results, the materials can be processed for recycling under suitable circumstances or even disposed to special burial sites.


As policymakers debate how the country should generate power in future years and consider whether to embark on a major new nuclear energy programme, there is pressure to accelerate the current schedule of nuclear decommissioning to mitigate the legacy of the earlier generation of nuclear power plants. Any technology that potentially speeds up the process or leads to cost reduction is attractive to the sector.

In the UK alone, most Magnox nuclear power stations have reached the end of their working lives and the last stations are scheduled to be closed by 2035. The National Audit Office estimates that the total cost of decommissioning in the UK over the next 100 years could reach £100billion.

Our solution

Over the last 15 years the GAU at Southampton has become a world leader in the radioanalytical determination of tritium and carbon-14. This developed at the same time as the rising demand for accurate analysis of these radioactive isotopes linked to nuclear decommissioning. Its innovative analytical instrument that was commercialised and made available to the decommissioning sector was named the Pyrolyser-Trio system. It was designed to be cost-effective and efficient and able to extract tritium and C-14 from almost any sample type encountered on a nuclear site.

Professor Croudace and colleague Dr Phil Warwick jointly developed their pioneering method in 2000 but it continues to improve and evolve. The instruments have a strong reputation and are in demand throughout the world as government agencies start to dismantle ageing power plants or measure tritium in environmental materials.

In the UK, the GAU has worked closely with many nuclear decommissioning organisations from 2000 until the present day. Early work involved the UK Atomic Energy Authority, which was concerned with decommissioning its sites around the country. In one specific example, researchers found tritium was almost entirely confined to paint and surface corrosion layers in samples of contaminated steel at Winfrith in Dorset, a discovery that meant several hundred tonnes of reactor building steel could be safely recycled by simply removing the contaminated surface.

Our impact

The Pyrolyser-Trio innovation has made a major contribution to the accurate determination of the amounts of volatile radioactive isotopes which has led to the safe disposal of certain waste materials or has allowed for the safe recycling of potentially re-usable metals from nuclear sites. Overall the development and its associated techniques have contributed to cost savings throughout the international nuclear industry including decommissioning sites in Australia, China, Germany, France, Sweden, Switzerland, South Korea and the USA.

Magnox Ltd has praised the way Professor Croudace and Dr Phil Warwick shared their specific knowledge with companies and organisations in the radioanalytical community which has helped to improve the confidence of industry regulators in this aspect of the decommissioning process.

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Ventilation stack at DFR is removed for decommissioning - Image courtesy of Dounreay Site Restoration Ltd
Dounreay Fast Reactor (DFR)
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