Multi-Criteria Decision Making for Decommissioning Projects

Experts met in Vienna last month to discuss methodologies for selecting decommissioning strategies, sharing experience and examining factors that impact decision making. 

At the end of a nuclear facility’s life cycle, activities including radiological characterization, decontamination and materials management are necessary before the site can be released from regulatory controls and repurposed. These tasks, collectively known as decommissioning, support industry sustainability, responsible stewardship and environmental management. This complex work requires careful consideration at an early stage and assessing available options against factors such as technical feasibility, cost and environmental impact is crucial. 

Robotics and other advanced technologies have been used in decommissioning with much success in recent years in France, Japan, Slovakia and the United Kingdom, but may be more expensive than conventional techniques. Each situation demands rigorous evaluation based on site-specific factors, available resources and long-term site plans.  

 “For many nuclear installations, including research reactors, fuel cycle facilities and power reactors, dismantling was not taken into account at the design stage. Today, the right solution depends on many factors and can vary from country to country,” said Philippe Lefevre, a Senior Nuclear Engineer at the IAEA and scientific secretary of the meeting. “However, a common methodology can make it possible to arrive at a decision with international consensus.” 

Over 60 participants from 30 countries and three international organizations discussed how their countries have used multi-criteria decision making (MCDM) to plan decommissioning activities in line with national regulatory requirements, sustainability goals and long-term site objectives. Also used in spent fuel management, environmental remediation and advanced reactor technology assessment, MCDM assigns numerical weights to criteria based on input from regulators, industry representatives, operators and other stakeholders. Stakeholder groups may have differing views on the relative importance of these criteria, highlighting the need for constructive dialogue throughout the decision-making process.

“MCDM can help us make good decisions by structuring complex decisions, balancing competing criteria, managing quantitative and qualitative factors and providing a shared understanding of both the problem and the preferred options,” said Simon Boniface, Decommissioning Strategy Manager at the UK’s Nuclear Decommissioning Authority. “It’s important to build confidence in the decision-making process, and so the views of all stakeholders need to be considered.”  

Throughout the five-day meeting, participants presented decommissioning success stories as well as challenges and compared their approaches to decision making. They also collaborated on  hypothetical decommissioning planning scenarios using MCDM tools.

“In the past, decisions often relied on experience rather than systematic evaluation,” said Inhye Hahm, a Senior Researcher in the Decommissioning Technology Research Division at the Korea Atomic Energy Research Institute. “Cost is typically the dominant factor in technology selection, however in some national or facility-specific contexts where disposal capacity is constrained, waste volume reduction may become a higher priority than cost.” 

MCDM provides a structured and transparent way to integrate these competing factors, reducing reliance on experience-based or intuitive decision making, she added. The Kori-1 nuclear power reactor, which entered permanent shutdown in 2017, is set to become the Republic of Korea’s first decommissioned reactor after approval to begin this process was obtained last June.

“Amelioration factors, or technical solutions that were not available when the initial decision was made, are important to consider as part of a holistic approach to decommissioning,” said Alexia Mercier, a nuclear chemist and project lead at the Organisation for Economic Cooperation and Development’s Nuclear Energy Agency. “These can include developments in the maturity  of a particular technique, new reuse or recycle options for material and new proposals for site repurposing.”

Meeting recommendations included developing a publication on an adaptive MCDM framework for decommissioning; identifying additional case studies; and evaluating the demand for an IAEA Coordinated Research Project on the subject. Participants also called for workshops and other exercises to support capacity building in this area. 

The IAEA supports member countries s through the Decommissioning & Environmental Management Advisory Services (DEMAS), which provide tailored guidance for decommissioning and environmental management projects, and peer reviews including the Integrated Review Service for Radioactive Waste and Spent Fuel Management, Decommissioning and Remediation (ARTEMIS). 

Support is also provided via IAEA Collaborating Centres, technical cooperation projects, e-learning modules and the IAEA Decommissioning School, which offers specialized training for professionals in the field. In 2026, technical meetings and workshops are scheduled  on small facility decommissioning, cost estimation and stakeholder engagement. 

The IAEA also manages networking platforms such as the International Decommissioning Network and the Network of Environmental Remediation and NORM Management to foster knowledge sharing and promote coordination among various decommissioning and environmental remediation initiatives.