The IAEA, the European Commission and the OECD Nuclear Energy Agency are working with the World Nuclear Association to consolidate the information gathered from different initiatives on assessing waste into a single publication, Status and Trends in Spent Fuel and Radioactive Waste Management. The publication is an attempt to systematically summarise the global status and trends of programmes and inventories for spent fuel and radioactive waste management. Previous reports were published in January 2018 (covering the situation to the end of 2013) and 2022 (covering the situation to the end of 2016). The third edition (up to the end of 2019) is now available in pre-print.
The basic information in this publication has been collected through submissions to the Spent Fuel and Radioactive Waste Information System (SRIS), complemented with openly available Joint Convention National Reports. Approximately 90% of states with operating nuclear power plants submitted their data to SRIS or their Joint Convention National Reports, representing almost 92% of all nuclear power reactors. Data are not available for every country, but available data provide a clear representation of the radioactive waste that exists and an indication of the challenges that will arise in the future as facilities still in operation, or planned, come to the end of their useful lives.
Due to the age of many nuclear power plants, decommissioning will become a more and more important activity as the first generation of nuclear power plants are reaching the end of their design lives. This change in waste management profile will be reinforced by changes in nuclear policy in some countries, such as Germany, that require the shutdown of nuclear reactors. In addition, the report says, many countries are now making concerted efforts to clean up past nuclear legacy sites.
The addition of more decommissioning waste accentuates some trends already existing within waste management. The report suggests that the availability of disposal routes for low level waste (LLW) and very low level waste (VLLW) will become more and more important. The rising importance of non-nuclear waste management and the move towards a ‘zero waste’ or ‘circular’ economy means that disposal of any waste should not be the preferred option so the challenge is increasingly in promoting and implementing waste minimisation techniques or recycling after decontamination, in an overall optimisation approach. This is reinforced by the fact that disposal facilities for radioactive waste or spent fuel are rare assets, and of high cost, and have to be used as efficiently as possible.
Assessing waste levels
The report finds that there is an estimated 301,000 tonnes of heavy metal (tHM) of spent fuel in storage worldwide, while about 7000 tHM is discharged annually. About 70% of spent fuel is currently stored in pools, but most new facilities are dry storage.
The current total global inventory of solid radioactive waste is approximately 32 million m3, of which 26.6 million m3 (83% of the total) has been disposed of permanently and a further 5.6 million m3 (17%) is in storage awaiting final disposal. More than 92% of the volume of solid waste is classified as being LLW or VLLW. Around 95% of the radioactivity is associated with intermediate and high level waste.
The report says significant progress has been made in formulating national policies and in legal and regulatory systems to manage Intermediate Level Waste (ILW) and LLW. The most important remaining challenge is development, public acceptance and funding of facilities for high level waste and spent fuel.
For countries with small inventories, the development of disposal facilities can be a challenge and there has been discussion about sharing efforts. But most nuclear states expect to dispose of their waste in facilities located on their territories. Where there is co-operation it involves technology development, rather than sharing of facilities, and significant progress has been made in the last two decades in treating, conditioning and storing waste.
Three deep geological repositories should start operation in the next 10 years in Europe but spent fuel, high level waste (HLW) and most ILW remain in safe storage, rather than final disposal. Disposal routes are also needed for waste generated by nuclear accidents.
Segregate or not?
The report explores whether it is more efficient to segregate classes of waste and send them to different repositories than allow for mixed or co-disposal. If the former route is taken, more work goes into segregating the waste. Sometimes, such as in France, the economic trade-off between direct disposal of the waste and waste treatment to reduce disposal volumes or to enable recycling can be difficult. In contrast, countries such as the UK have reduced costs by using routes such as licensed industrial landfill, where appropriate, using such concepts such as ‘below regulatory concern’ for waste that arises within a nuclear industry context but that has no radiological implications for the public.
This is important, in particular, for managing decommissioning waste, where large volumes of low or very low level waste will be generated.
There is a broad consensus that the preferred method of ensuring long-term safety for spent fuel and HLW is isolation in a deep geological repository.
A small number of countries are considering co-location of different waste classifications in geological facilities. This co-disposal can be simpler with fewer facilities required. But it can also introduce design complexity to avoid interferences between the waste types, as well as significant increases in the volume of material requiring handling at geological depths.
The report says that a set of evaluation tools will be required to support an integrated supply chain covering all aspects of waste production and management. Nuclear fuel cycle strategies need to be fully integrated with the overall spent fuel and radioactive waste management policy and infrastructure to ensure an optimal use of resources. Introducing efficiencies into individual steps in isolation can create additional challenges in subsequent steps.
Decommissioning issues and other trends
The amount of spent fuel in long-term storage is increasing. The report says that the number of nuclear states that send their spent fuel for reprocessing overseas is falling, as reprocessing plants are closed or are nearing the end of their lifetime.
In any case, after several decades in operation, the existing pool of nuclear reactors has generated a significant inventory of spent fuel, which increases yearly; accordingly, temporary storage is a need that goes beyond the choice of whether or not to reprocess fuel. Over recent years, many countries have had to extend their temporary storage capacity to accommodate these inventories by means of the extension of existing facilities or the construction of supplementary facilities.
When most of the storage systems were put into operation, they were designed to last between 20 and 50 years. As these systems reach the end of their lifespans, work is under way to develop additional monitoring and inspection techniques and on re-licensing of these activities.
The analysis highlights reports from several states of progress in decommissioning legacy facilities and the remediation of legacy sites, although the remediation of uranium mines has remained a major technical and financial challenge. Some states identified the need to establish a national strategy for dealing with legacy sites, including the need to build new facilities for the safe management of the waste arising.
Radioactive waste storage and disposal needs are increasing globally. Recent years have seen more progress in legislative and regulatory frameworks, political and social dialogue and in technical of facilities for final waste disposal. However, the long period required to move from framework to implementation means that in the vast majority of cases, storage capabilities are required until the final disposal route becomes available.
Many national programmes either do not have final disposal capabilities for each class of radioactive waste or their resources are insufficient.
The need to manage decommissioning waste is one of the drivers in adapting and improving existing facilities for the storage and disposal of radioactive waste. These improvements include the introduction of new techniques and technologies, such as facilities for the decontamination of waste, metal smelting plants and the use of new containers and configurations for the storage and disposal of this type of waste. The VLLW class was introduced only in the beginning of the 2000s, but the concept has matured rapidly. Many countries have established national systems and specific facilities to manage this type of waste and many of them have one or more disposal facilities to implement these programmes.
Radioactive waste from decommissioning is the main waste stream in many nuclear operating countries, generated both by nuclear power industry facilities and other facilities that use radioactive materials for different regulated activities, such as research and medicine. The report says, “Over recent decades, and very significantly in the last few years, the end of operation of a large number of these facilities is generating significant inventories of different classes and types of decommissioning radioactive waste that have become the most important stream from a quantitative perspective.” Countries such as Germany, Italy, Japan, Spain and the USA have driven the development of specific solutions on such aspects as characterisation, treatment and conditioning, and the associated logistics. The questions associated with managing this waste are consistent across jurisdictions, although the solutions adopted in each programme and project are more specific to their characteristics and contexts.
Waste hierarchy
The waste hierarchy and the circular economy are becoming more important in waste management. There are increasing efforts to reduce waste to the minimum, along with initiatives to recover radioactive materials that may be reused or recycled. These practices are common in operating facilities, and are similarly required in planning decommissioning projects where waste materials can be significant in mass as in volumes.
The option to clear radioactive waste that falls under the threshold for classification offers “very interesting opportunities to reduce the volume of the inventories to be managed,” the report says. More and more states have developed their regulatory frameworks to establish the limits and conditions for implementing this approach.
It says these developments “have a particular impact on the programmes and projects for the decommissioning of nuclear facilities since they facilitate the safe and significant reduction of the inventories of radioactive waste from decommissioning to be managed and disposed of at specific facilities”.
States with small nuclear inventories face particular challenges. The experience of more mature programmes shows that there are essential components to good waste management: suitable legislative and regulatory frameworks; access to knowledge and technology; availability of facilities and infrastructures; qualified personnel; financial resources; and a socio-political consensus. This requires “an effort at a demanding and continuous state level”. This is a complex challenge for states with small inventories of radioactive waste, who have to manage prioritisation, funding limitations and lack of awareness of social and environmental importance. But the report sees a growing number of states modernising their framework and infrastructure, establishing national policies and creating independent regulatory bodies.
Those states that have small inventories of spent fuel resulting from the operation of research reactors or small fleets of powerful reactors, face additional challenges to the large programmes. In these cases, difficulties often exist in the allocation of technical and financial resources while the management programme itself may be seen as a lower priority.
Overall, the report says many countries have now successfully established policies and strategies that have been stable over several decades and good progress has been made towards implementing them. However the report notes that maintaining a stable policy and strategy over time can be a challenge for various reasons: “As the possible management options can be changed, revisiting the decisions made in the past is important”.
