Nuclear fusion and radioactive waste regulation: CoRWM members visit the Culham Center for Fusion Energy

By Claire Corkhill

Fusion will be ready when the world needs it.

This is what Ian Chapman, CEO of the UK Atomic Energy Authority (UKAEA), tells us in his introductory lecture. With COP26 just ended, it’s hard to argue that society doesn’t need it now. With this in mind, and following the recent release of the UK Government’s Fusion Strategy, which outlines the UK’s ambitions to become a superpower in the fusion industry, members of the Radioactive Waste Management Committee, the Culham Center for Fusion Energy (CCFE ) to visit. to see how plans to implement and regulate this revolutionary new technology are evolving.

The CCFE is located near the Harwell campus in Oxfordshire and has been developing quiet fusion energy for decades. Hidden behind huge doors several meters thick, the CoRWM members were shown a glimpse of the JET – Joint European Torus – reactor, which is the world’s first deuterium-tritium fusion reactor, which has been in operation since 1983. Only this glimpse was possible because JET is currently participating in a program of deuterium fusion experiments and testing the fuel for its successor, ITER – the International Thermonuclear Experimental Reactor. ITER – which means “the way” in Latin – is currently being built in France and will be the first fusion device to generate net energy. Its cousin STEP (Spherical Tokamak for Energy Production) will be a prototype for the UK’s first power-generating fusion reactor, due to go live in 2040.

Rapid advances in technology and the government’s ambitious merger strategy have resulted in the publication of a public consultation entitled Towards fusion energy: Regulatory Framework Proposals, to which the CoRWM has contributed. One of the core areas of CoRWM interests is the regulation of radioactive waste from fusion energy as well as its management and disposal, which are described in detail in the recently published CoRWM briefing led by member Professor Neil Hyatt. Although nuclear fusion does not produce long-lived fission products and actinides, neutron capture by the structural materials and components of the fusion reactor forms short, moderate and some long-lived activation products. In addition to tritium emissions and contaminated materials, it is clear that radioactive materials and waste generated by neutron activation must be treated within the framework of official controls over the entire life cycle of a fusion reactor.

Against this background, the CoRWM members spoke to the CCFE merger safety authority during the visit to the site. We saw the MAST (Mega Amp Spherical Tokamak) machine and learned the importance of reactor component design and material selection in minimizing radioactive waste. The safety team stated that changes can be made to the materials used in the front wall, ceiling, divertor, and vacuum vessel, but this does not preclude the fact that these must be treated as low-level waste or otherwise as low-risk intermediate level waste, at the end of reactor life.

Innovation was the focus of the visit. We were made familiar with novel robots that are able to penetrate the harsh reactor environment and thus reduce the radiological risk for the personnel. Hot cells (pictured) and state-of-the-art analytical equipment were demonstrated at the Materials Research Facility, which will be used to support the development of fusion reactor materials of the future. The STEP location process, which received a large number of submissions, is unique and makes the big leap from experimental physics to operational energy infrastructure. And refreshingly, the regulation of the technology, including the longer-lived radioactive wastes, is already being carefully scrutinized, although the first power-generating reactor will not be operational for more than 20 years.

In our work, CoRWM will work to ensure that innovations in the field of fusion energy and the resulting radioactive waste are duly taken into account, regulated and safely managed in the future. We look forward to seeing the progress on our next visit.

Left: the JET (Joint European Torus) fusion reactor in the Culham Center for Fusion Energy
Right: The operation of hot cells at the Materials Research Facility in Culham, showing equipment used to prepare activated fusion reactor materials for microscopy.