What types of facilities have to be decommissioned, and what is the outlook over the next five to 10 years?

Worldwide, there are 60 reactors currently under construction, of which 20 are in China and 7 in the Russian Federation. There are 449 reactors now in operation, many of them 30 years old or more. Some 50% are at least 30 years old, and the design life of older reactors reactor is usually 30 or 40 years, so many are coming to the end of their original design life. This can be extended, but it is very likely that some 200 reactors, especially the smaller units, will be shut down in the next 10-20 years. Since nuclear energy was first exploited commercially 160 reactors have been permanently shut down, of which only about 20 have now been decommissioned, so there are many reactors that are currently undergoing decommissioning or will be decommissioned in the near future.

For about 15 years until the current decade, few reactors were shut down, with most that were approaching the end of their design life applying for life extension. But then, around the time of the Fukushima accident, the economics of energy changed. This was not related to Fukushima, but because of the relative cost of energy from different sources, particularly in the USA. However, both factors had an impact. As a result of Fukushima many older plants required expensive safety upgrades. And the long-run energy costs were, in any case less attractive. So for a range of reasons several reactors have shut down in the past few years, especially in the USA, as well as one in Korea, some in Sweden and UK, and of course in Germany where the close out programme means that all nuclear power plants will be shut down by the early 2020s.

What are the main strategies for D&D?

An important early decision concerned with decommissioning is whether to proceed immediately with dismantling of the facility, or to delay it until the levels of radioactivity have diminished, after a period of ‘safe enclosure’. The current trend seems to be to proceed with direct dismantling. This makes it possible to take advantage of existing knowledge of the plant – and of any incidents that have occurred – because the people involved are still there or may easily be contacted. The full history of the plant is available. But, after 50 or 60 years in safe enclosure, it may well be necessary to undertake a full characterisation of the facility, because valuable information may have been lost. Another reason driving the trend towards direct dismantling is greater certainty about the costs – in the future these would depend on factors difficult to judge at present. A third reason is that some of these plants are important for socio-economic reasons in the local area. Direct decommissioning makes it possible to retain a certain level of employment in the surrounding area that otherwise would be lost. For example, the Ignalina plant in Lithuania, which is currently undergoing dismantling, is a very important provider of employment in that whole region. It still employs more than 2000 people.

What are the main requirements for a successful decommissioning programme and the main challenges?

In order to be able to proceed with decommissioning there are some important prerequisites. These include: a legal
and institutional framework setting out responsibilities; a regulatory framework; a waste management system; and a financing system. Availability of qualified people competent in dealing with the hazards involved in decommissioning, and access to appropriate technology, are also important factors. These three elements: people, technology and an appropriate institutional framework are fundamental requirements in order to make progress.

Assuming the above elements are in place, in order to proceed with decommissioning you need people with an appropriate capability and expertise to manage large, complex projects. Usually, decommissioning projects involve a greater use of contracting staff and it is necessary to properly manage diverse contractors and to maintain a good safety culture within the facility. A good relationship with the public is also necessary. The public needs to understand the reasons for selection of the adopted decommissioning strategy. All these elements are quite important, and will manifest as challenges if not properly managed. 

What modern technologies and/or approaches can be leveraged in decommissioning?

Decommissioning is a normal activity in the lifetime of a nuclear facility, being what has to be done at the end of the operating life in order to make the site available for other uses. So the whole process is planned in advance. The situation is quite different depending whether you are dealing with a plant that has had a normal life or one which has been in an accident.

Technologies important for decommissioning include those that assist in understanding the levels of radioactivity within the facility. The facility needs to be characterised in order to plan dismantling, including the extent and location of the contamination to ensure the safety of the workforce or to decide on the need for use of remotely-operated equipment.

New technological developments in recent years such as compact gamma cameras and drones, for instance, may make the process of characterisation much more efficient. Once the measurements have been made, an electronic representation of the facility may be created on which dose levels are superimposed, and to plan, using IT systems similar to those used in video gaming, how to undertake the dismantling. Virtual reality helps with planning so rather than physically building a model, as done in the past to test dismantling options, now this can be done using computer-aided modelling systems. Laser technology is very helpful for decontamination of surfaces and for cutting metal components. As to the dismantling itself, the existing technology is in most cases quite capable of doing this, e.g. using mechanical or thermal cutting devices.

The situation is more complicated in an accident situation, such as the Fukushima plant. This is where robots need to be used. Japan has a large programme of research on the development of robotics. Robots can go in to the plant and find out where the structure has become degraded to aid future access. Robotics can also be used for some of the dismantling work in situations where the level of radiation is too high for human entry. And of course similar issues apply to Chernobyl following the installation of a new safe confinement around the shelter constructed following the accident. Unstable elements of the original shelter will now be removed safely using remotely operated tools suspended from the crane system inside the new confinement structure.

What is the IAEA’s role in nuclear decommissioning?

We have three main roles – safety, knowledge transfer and competence building. The IAEA, through its Nuclear Safety and Security Department, is tasked with developing international safety standards, which can be used by member states in developing their own regulations and guidance. Our second role is to try to ensure a good flow of information among member states on current good international practice. We also have networks and communities of practice where experts involved in decommissioning activities can come together and share their experiences, lessons learned and so on. These networks also manage a number of collaborative projects to help to ensure good transfer of knowledge and good practice.
And finally our third role is to assist member states in building competence, e.g. how to undertake planning and implementation of a decommissioning project. This is done mainly through our technical cooperation programme.

What initiatives does the IAEA have related to decommissioning?

I am jointly responsible for the International Decommissioning Network (IDN) –a focal point for people involved in decommissioning across the globe, and we have an annual meeting, usually towards the end of the year. We also have a website and a wiki-based information platform where IDN participants share information on decommissioning technologies and case studies on their use. The website is not open to the public because it is specifically designed to be a tool for decommissioning professionals. IDN also has a number of collaborative projects, including the CIDER project (Constraints
to Implementing Decommissioning and Environmental Remediation). The GRAPA project (Irradiated Graphite Processing Approaches) considers how to deal with irradiated graphite and DACCORD (Data Analysis and Collection for Costing
of Research Reactor Decommissioning) focusses on costing the decommissioning of research reactors. We have recently completed a project on managing risk in decommissioning – DRiMa (International Project on Decommissioning Risk Management). Member states unfamiliar with decommissioning often need some assistance in developing processes for identifying risks to the delivery of projects, so those risks are recognised and managed. The IDN also provides a mechanism for IAEA to get feedback on topical issues in the field of decommissioning and on its programme
of work to address these issues. Environet does something similar. Beyond the network activities, IAEA has also established the DAROD project, a collaborative project concerned with exchanging good practices on the decommissioning and remediation of accident-damaged nuclear sites. We have also recently launched the ARTEMIS Peer Review Service on waste management, decommissioning and environmental remediation. One of the first reviews under this service will take place in Italy this year [2017], concerned with the programme for decommissioning Italy’s shutdown reactors and associated fuel cycle facilities.

What do you see as the key achievements of IDN over the past decade?

IDN has been established for 10 years and is unique in the world due to the extent of its scope. It is well known as a focal point where people involved in decommissioning can share information. That is one achievement. The collaborative projects are really important forums for developing common positions on topical issues. The Wiki platform is also an important source of information. It is useful for those seeking to find if a particular issue has been addressed before and how it was managed. IDN has also been supportive of the IAEA’s training programmes, e.g. host organisations for regional or interregional training events are generally also actively engaged in IDN activities. Every year we have a few hundred people involved in some type of training activity related to decommissioning, mostly organised through the technical cooperation programme.

This involves a combination of training courses, workshops, and fellowships where people will spend several weeks in another organisation working with their experts. In recent years, we have put a lot of effort into developing our e-learning materials so it is not necessary to physically come to a training event. It is possible to gain information
on decommissioning from the e-learning materials available on the open web. It is linked to the face-to-face training, and can act as a first step.

What collaboration do you have with other industry organisation and what benefits does this offer?

The European Commission (EC) and the OECD Nuclear Energy Agency (NEA) in Paris also undertake a number of activities in this area, and we try to collaborate to get the best synergy and to avoid unnecessary overlap. We have a number of joint activities and also arrange meetings to decide on the coordination of this work. Decommissioning costing is one area where we have collaborated closely in developing a standardised approach to presenting decommissioning cost estimates to facilitate comparison – the International Structure for Decommissioning Costing (ISDC). We have also worked with the NEA on identification of uncertainties in decommissioning and how to represent them in cost estimates to ensure the money set aside by the operators will be sufficient to deliver the project. Another organisation we work with is the World Nuclear Association.

How have IDN and other IAEA programmes adapted to meet the evolving needs of member states over the last few years? What are the plans for the future?

Over the past six years I have seen an evolution in the assistance we are being asked for by member states. A few years ago the focus was on designing and planning a decommissioning project. Operating nuclear facilities are expected
to have a plan for decommissioning and to set aside money for this. More recently we are being asked for assistance on delivery of projects, particularly by countries with less advanced nuclear programmes. With many member states now at the point of implementing facility dismantling, there is more interest in issues related to project implementation and technology. In many smaller countries there is still a need there to develop regulations and institutional infrastructure and devise integrated plans with waste management. We are also adapting our organisation to respond to the growing requests for assistance coming from the member states.

As to the future, I think this evolution will continue. Decommissioning now is mainly focused in the advanced nuclear programmes in the USA, UK, France, Germany, Japan and the Russian Federation. This is where most work is taking place. I think we will see more decommissioning in the less advanced programmes, which raises some issues because the levels of expertise will not be quite so advanced. There are a number of member states in Europe following shutdowns agreed as part of the process of accession to the European Union. Lithuania, for example, agreed to shut down the RBMK reactors at Ignalina. The EC has provided substantial support, through the EBRD, to proceed with dismantling that facility. There is also a lot of decommissioning work taking place in Slovakia and Bulgaria, and we are assisting all those programmes.

And there is Chernobyl of course. These are decommissioning programmes that are not supported by a big nuclear industry, so transferring the experience from these programmes will be an important element in future.

Are you looking at the future decommissioning of more advance reactors?

We are looking at dismantling all types of reactors. We have done quite a lot of work in dealing with thermal reactors, which is one of our principal areas of work. With fast reactors, one issue is the different type of coolant used – liquid metals such as sodium or sodium potassium for example, which raises different problems. There have been quite a few. The UK has Dounreay; France has the Phénix and Superphénix, and there are also some in the USA at Idaho, in the Russian Federation at Beloyarsk and in Kazakhstan at Aktau, where the IAEA had an extensive engagement. So there is experience, and we have been involved in several of those projects and have published a number of reports on the decommissioning of fast reactors.  

*Patrick O’Sulllivan works as a decommissioning specialist at the International Atomic Energy Agency in Vienna. In his previous career he has worked at the OECD Nuclear Energy Agency, also in the field of decommissioning, and at the Nuclear Research Group in the Netherlands. He began his career in the UK nuclear energy industry, where he worked for the Central Electricity Generating Board and Nirex.