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Key principles

IRESNE: a decisive player in the dismantling field.​

Nuclear reactors have a limited lifetime. This means that when a reactor (or any facility hosting or having hosted radioactive material) is decommissioned, it must undergo clean-up and then dismantling. Radioactive waste is generated during these operations and we must manage the impact of this waste.
As nuclear operator, the French Alternative Energies & Atomic Energy Commission (CEA) - under which IRESNE works - is responsible for the clean-up and dismantling of its facilities, as well as for the management of the resulting waste.
As a key R&D player, we lead research on the treatment, conditioning and long-term behaviour of radioactive waste. Each nuclear waste package has its own chemical, physical and radiological characteristics, which calls for a distinct management process. To choose and apply the optimal management method for waste, it is classified into categories according to the level of radioactivity and the half-lives of the radioelements present. This classification is possible thanks to the precise characterisation of the waste and more specifically its composition.

Yet there are many technical challenges to overcome in order to characterise waste in safe conditions. The CEA benefits from the clean-up and dismantling knowledge and skills that its teams at IRESNE have accumulated over the years.​​

What is nuclear waste?

Definition

Nuclear waste refers to any radioactive by-products generated during nuclear-related operations (e.g. electricity production, research, medical activities, industrial processes, etc.) that cannot be reused or recycled for technical or economic reasons.

Types of radioactive waste

The notion of radioactive waste encompasses several types of waste categories

Radioactive waste can come in any shape, e.g. an article of clothing, metal part or tool, etc. It can be described as conventional waste that has been contaminated with a radioactive substance. For this reason, it also emits radiation and can represent a risk to people.​​

Six waste categories as defined by ANDRA

The French national radioactive waste management agency (ANDRA)

In France, there are six different categories of radioactive waste:

• Very short-lived waste (VSL-W)
  




• Very low-level waste (VLLW)




• Short-lived low- and intermediate-level waste (SL-LILW)




• Long-lived low-level waste (LL-LLW)




• Long-lived intermediate level waste (LL-ILW)




• High-level waste (HLW).​​
  

What does ANDRA do?

ANDRA is tasked with managing nuclear waste in France

The French national radioactive waste management agency (ANDRA) is a state-owned industrial and commercial entity (EPIC) tasked with managing nuclear waste in France. More specifically, ANDRA is responsible for all nuclear waste disposal facilities, from their design, construction and operation, through to their monitoring after site closure. It accepts waste packages that have already been categorised and conditioned by the operators having produced them. Once ANDRA has assessed and validated their content, they are placed in their assigned disposal spaces.​​

What is the difference between clean-up and dismantling?

Clean-up versus dismantling

Dismantling refers to all the technical operations carried out after the final shutdown of a nuclear facility in order to achieve the intended final state necessary for its classification downgrade. Dismantling includes several phases, such as the disassembly and removal of equipment, the cleaning of rooms and floors, and the possible demolition of engineered structures, etc.

Clean-up covers all the actions carried out to remove most of the residual radioactivity. It can therefore be considered as one of the phases of dismantling.​

Main dismantling phases

Four key phases of dismantling:

1. Authorisation procedure

In France, the dismantling of a reactor or nuclear facility can only begin once two prior phases have been completed:

• The first involves the final shutdown and dismantling decree (MAD-DEM), which must be issued by the government for the facility in question.
  

• The second involves the examination of all the facility’s safety case files by the French Nuclear Safety Authority (ASN), who must issue its authorisation to proceed with clean-up and dismantling. During this examination process, a public enquiry must be held for the relevant populations and stakeholders. The ASN is supported by the Institute for radiation protection & nuclear safety (IRSN), its technical expert.
  

However, the operators hold the responsibility for the dismantling of their facilities and the management of the waste resulting from these activities.

2. Material and waste removal

Any equipment and waste remaining inside the facility must be removed in two phases:

• First, the staff must remove any material and spent fuel.

• Then, the staff must dismantle all the remaining tools and large components, e.g. gloveboxes, dissolvers, reactor vessel, etc.

3. Clean-up

During this third phase, the operators in charge of the dismantling project must decontaminate all the engineered structures. The objective is to eliminate all the radioactivity in the buildings. It may also be necessary to demolish all or part of the buildings to do this.

4. Classification downgrade

An inspection phase is initiated once all the clean-up and dismantling operations have been completed. Carried out by the ASN, this inspection is designed to make sure that all the operations have been done correctly and that the initial objectives have been reached. If the inspection is successful, the facility’s classification is downgraded and it is ready to host other activities, nuclear or other.

The operator has to deal with any operational issues that arise during each phase. This can, in turn, generate numerous scientific and technical questions that can only be resolved through research and development (R&D).​​​​​​​

Learn more about dismantling at IRESNE​.