How can nuclear decommissioning be adapted to support a circular economy?

The current paradigm

The current view of the lifecycle of a nuclear facility is linear. Following site selection, facilities are constructed, commissioned, operated and decommissioned. As part of nuclear decommissioning, the standard practice is that everything must be removed before a site can be released from regulatory control and made available for other uses. The resulting wastes need to be stored, treated and disposed either at the site or elsewhere.

The waste hierarchy is fundamental in nuclear waste management, that is, that waste ideally should be avoided. And if that is not possible, it should – in descending order of priority – be minimized, reused, recycled or permanently disposed. For example, to limit the amount of material that might become radioactive waste in the first place, packaging is typically removed before taking any items into the areas of a facility where they could become contaminated. However, implementation of disposal facilities for radioactive waste has been fraught with challenges in most countries that have tried.

Some aspects of current practices are consistent with circularity principles. Refurbishing and extending the life of existing plants align with circularity thinking, as does recycling of metals and other materials that are conventional wastes. Other examples include reusing components from closed reactors in those that remain in service and repurposing buildings for processing and storage of waste, rather than constructing new waste buildings. After demolition, a common practice is to reuse the resulting rubble as fill material when grading and restoring the site, which reduces the amount of material that needs to be transported to and from the site.

The reprocessing of spent nuclear fuel enables circularity of the isotopes that can be reused. But at the same time, a lot of new materials go into reprocessing facilities, and additional waste forms are generated, which, in turn, need to be processed, stored and disposed of accordingly.

Different prerequisites

A cornerstone of circular economy is to ensure that both products and fixed assets (such as power plants) are designed to last for a long time and are easy to repair, reuse, repurpose and recycle.

Since circularity is enabled during the design stage, the reactors of the future have much better prerequisites than the existing ones, which were generally designed for a linear lifecycle. But there is greater potential than one might think for current nuclear sites to align their approach to decommissioning with circularity principles.

Several repurposed research reactor sites are good examples of this, such as the underground hall of Sweden’s first research reactor, which now is a venue for conferences, art installations, concerts, live theatre, film productions and more. Other innovative examples include using shutdown reactors for training of operators from other nuclear plants, and repurposing buildings for use by conventional industries. There are also good examples of the nuclear industry supporting circularity by reusing products no longer useable in other areas, such as using discarded hotel towels for workers instead of purchasing new ones.

The potential for achieving circularity on a nuclear site is greatly influenced by the interests and emphasis on a circular economy by governments, owners and operators. The same is true of local community stakeholders and the public, as local opinions and support are key for nuclear decommissioning projects. It is not uncommon that nearby voices are raised for preserving reactor buildings when they are about to be demolished, which may be a sign that support for repurposing of parts of a nuclear site generally is greater than many believe.

Given the shift worldwide toward renewable energy, it ought to be particularly relevant to explore more systematically if shutdown reactor sites can be repurposed to produce power from other sources – and whether that is something that local stakeholders would support.

The large increase in efforts and challenges associated with nuclear decommissioning over the coming years is also an important reminder for the wind and solar energy sectors. That is, when many facilities are built around the same time to tap into a new energy source, it is critical to consider how they will be decommissioned – and their associated wastes managed – already at the design stage. If not, the current wave of new renewable energy facilities risks creating a wave of decommissioning challenges eventually.

* Source: IAEA Power Reactor Information System (PRIS), https://www.iaea.org/pris/