What is radioactive waste?

Radioactive waste is all material that contains radioactive elements, for which no practical application is known. It can come from medicine, industry and power generation, as well as other sources. Radioactive waste is divided into three categories: A, B and C. The classification is based mainly on the type and intensity of ionising radiation.


More information on the types of radioactive waste can be found on website of the NIRAS (National Institute for Radioactive Waste and Enriched Fissile Materials).

Who keeps radioactive waste?

In Belgium, NIRAS (National Institute for Radioactive Waste and Enriched Fissile Materials) and its subsidiary Belgoprocess manage radioactive waste from nuclear power stations, industrial and medical applications and research centres. Management focuses on isolating waste from the environment until such time as the radioactivity has naturally decayed to a sufficiently low level. Financing is based on the 'polluter pays' principle. Like other producers of radioactive waste, ENGIE Electrabel pays for long-term waste management costs.


Nearly all radioactive waste in Belgium is processed at the NIRAS facilities in Dessel. Spent nuclear fuel from Belgium's Doel and Tihange nuclear power stations is an exception to this rule. Pending future political decisions on processing and final storage, such waste is temporarily stored in specific buildings on the power station sites.

Why can the quantity of high-level waste not be limited?

During the production process, any uranium 235 in the fuel assemblies is split. This releases a great deal of heat. A fuel assembly is spent, meaning that all usable energy is gone, after three or four years in the reactor core. These spent fuel assemblies are cooled in water and then transported to a storage building located on the nuclear power station sites. This is done pending a future political decision which could make final, controlled storage in stable clay layers possible.

How do we limit the quantity of medium-level and low-level waste?

ENGIE Electrabel has a number of its own facilities which enable it to process a large proportion of its own waste. Low-level and medium-level liquid and solid radioactive waste is processed at special facilities. Water filters, low-level resins and sludge are mixed with concrete in special waste drums. As a result, the waste forms a single whole with the concrete. This manner of immobilising waste is also called 'conditioning'. The drums are temporarily stored on the nuclear power station sites before being transferred to Belgoprocess (a subsidiary of NIRAS).


Solid compactible waste is compressed and transferred to Belgoprocess for subsequent processing. Fragmentation is another possibility. In this case, the waste is incinerated in a specially equipped incinerator at Belgoprocess. If possible, low-level liquid waste is processed and re-used, discharged after processing or conditioned via evaporation for further processing. Limiting the quantity of low-level and medium-level radioactive waste, including through prevention and recycling, is an ongoing objective.

How much radioactive waste is produced?

Radioactive waste accounts for a minute fraction of the total volume of waste produced in Belgium. The total quantity of nuclear waste per person per year (categories A, B and C combined) is 0.5 kg, i.e. the volume of just one large can of soda.


The quantity of highly radioactive waste is 5 grams per person per year, i.e. about a thimbleful. Total quantity of nuclear waste in Belgium over a period of 100 years: category A = 69,900 m3, category B = 11,100 m3, category C = 4,500 m3.

How is radioactive waste kept?

Short-lived waste accounts for 90% of the total volume of radioactive waste. Such waste consists of, among other things, shoe coverings and clothing, cleaning equipment such as cloths and mops, residue from treated reactor water, filters, resins, etc. The radioactivity from this waste falls over time, dropping by 50% every 30 years. Surface storage is used for such short-lived waste. In this case, the drums are encapsulated in concrete containers for temporary storage which are then encased underground in a concrete layer.


Long-lived high-level radioactive waste consists mainly of spent fuel assemblies. Such waste releases a lot of heat and must be closed off for tens of thousands of years until the level of radioactivity has dropped to the same level as natural background radiation. This type of waste accounts for just 1% of the total volume of radioactive waste in Belgium. The storage of this kind of waste has been studied for years now, with the various options weighed up against each other. The Belgian Nuclear Research Centre (SCK┬ĚCEN) has been conducting extensive research since 1973 into the Boom clay layer under its site, which is suitable for 'deep storage'. It is researching whether this is safe and feasible and is using a special instrument for that purpose: an underground laboratory dug 225 metres deep into the clay. This type of storage is also the solution recommended by the International Atomic Energy Agency, an autonomous organisation of the United Nations.

What happens if nuclear power stations are ever demolished?

At some point, the time will come to demolish our power stations. Years ago, a reserve was established to cover this cost. This is called the 'nuclear provision'. It is funded by nuclear power station operators and managed by Synatom. Its management team consists of directors from ENGIE Electrabel appointed as representatives by the federal energy minister.


The size of the provision is defined on the basis of periodic studies conducted by specialist consultants under the supervision of the Nuclear Provisions Committee.