By Nicholas Watson, IAEA Department of Nuclear Energy

Operators and authorities in more and more countries are moving to immediately dismantle their retired nuclear facilities, and emerging digital technologies coupled with greater usage of robots and drones are offering significant potential for more effective project implementation and risk reduction, an IAEA survey on the global status of nuclear decommissioning has found.

Decommissioning activities including the use of cutting-edge technologies are set to ramp up in the coming years as several of the world’s 439 nuclear power reactors are phased out of operation. The conclusions of a 30-month IAEA project, discussed during a recent webinar, will provide additional insights for policymakers and other stakeholders interested in the future management of retired nuclear facilities.

“Previously, many programmes elected to defer dismantlement of retired facilities, but immediate dismantling is now becoming the predominant decommissioning strategy worldwide,” said Head of the IAEA’s Decommissioning and Environmental Remediation Section, Olena Mykolaichuk. “And our survey can help countries to keep abreast of important technical developments in this area.”

Decommissioning includes decontamination and dismantling of plant and building structures, leading to the removal of regulatory controls, so that a facility and site may be reused. It is a complex endeavour, requiring timely and effective management – skills and expertise that are crucial to further develop. Globally, 199 power reactors have been shut down for decommissioning, with 21 fully decommissioned. In addition, 130 fuel cycle facilities have been decommissioned as well as about 450 research reactors.

To improve understanding of the current status and future evolution of decommissioning activities, the IAEA sent out a Global Decommissioning Strategy questionnaire to more than 50 countries and evaluated the responses alongside data from the IAEA’s Power Reactor Information System (PRIS), Research Reactor Data base (RRDB) and Integrated Nuclear Fuel Cycle Information System (iNFCIS). At the same time, the IAEA hosted a series of technical meetings over three years that brought together dozens of experts from some 20 countries as well as the Nuclear Energy Agency of the OECD and the European Commission to share experiences and provide feedback.

While existing decommissioning technologies are mostly proving sufficient to the task at hand, the report showed that countries are increasingly looking at high-tech solutions to meet unique challenges and stand to benefit from further technological innovation to help reduce risks, enhance safety and cut schedules and costs.

Countries managing accident sites such as Japan are using innovative robotic technology and remote inspection tools to locate and characterize fuel debris as part of efforts to retrieve and dispose of this material. Technologies such as 3D modelling or building information modelling (BIM), virtual reality and remotely controlled technologies, including drones and robots, are also being applied increasingly to the decommissioning of facilities that have reached the end of normal life. These technologies enable more efficient collection, understanding, display and management of data, allowing different scenarios to be visualized during planning and preparation of dismantling and decontamination activities.

“Coupling BIM with GPS or location-aware Wi-Fi networks enables the deployment of semi or fully autonomous robotics systems and drones,” said Hannes Hanggi of the Swiss Federal Nuclear Safety Inspectorate, who helped lead the IAEA project. “They have the potential to significantly lower costs, further increase safety and enhance performance in decommissioning projects.”

Decommissioning strategies are informed by factors such as national policy, the availability of waste management systems and other enabling infrastructure as well as technological innovation and political and societal thinking on environmental issues such as sustainability and circular economy.

There is also a move towards earlier decommissioning licensing and a reduction of the time delay between final shutdown and the start of dismantling. One-fifth of the responses obtained from nuclear power plants envisaged that dismantling would proceed while spent fuel remained in the reactor or in the spent fuel pool.

The survey also analysed factors negatively impacting on the delivery of projects. Among them, the availability of waste facilities and funding had the biggest impact while end-state and future-use options had the smallest.

Most nuclear power plants are required to have a mechanism in place to ensure that sufficient funds will exist to pay for decommissioning. Such funds are typically built up through fractional charges in bills to ratepayers and set aside by electricity generators during the period of operation.

Significant financial resources have already been utilised globally to decommission nuclear power plants, research reactors and fuel cycle facilities, and significantly greater resources are expected to be needed for future activities over a period of several decades as ageing facilities are retired, said Senior Advisor on Nuclear Decommissioning at Vattenfall, Sweden, Simon Carroll,. “By the same token, human resource requirements for future decommissioning will be significantly larger than the level of resources already used,” Carroll added. “Simply put, the industry will need a lot more people and experts in this field.”

To attract new talent, the IAEA in 2020 held a global crowdsourcing challenge that sought original concepts or project outlines from young people for advancing the decommissioning of nuclear facilities or environmental remediation of radiologically contaminated sites. Entries included characterization toolkits, instruments for on‑field measurements and collecting 3D radiation data, as well as robots and artificial intelligence.

The IAEA assists countries in efforts to plan and implement decommissioning projects and develops related safety standards and Nuclear Energy Series publications and other reports on technical and safety related aspects, organizes meetings of experts, collaborative projects, scientific exchanges, peer reviews, training courses and workshops. These activities are supported by resources including an eLearning platform and the International Decommissioning Network (IDN), which provides a forum for interaction among experts who can also share knowledge via a wiki-based information resource. The Agency pays particular attention to introducing circular economy principles into decommissioning considerations.