Radioactive waste

Radioactive waste is any material that contains, or is contaminated with, radionuclides at concentrations above the limits set by regulation and for which no further use is foreseen. It is treated as a distinct, highly regulated category of hazardous waste.

It is generated mainly in nuclear power plants, but also in hospitals, research laboratories, industry and defence. Its management poses unique challenges because of its hazard, its persistence over time and the need for long-term isolation.

What is radioactive waste?

A radioactive waste is any material, in solid, liquid or gaseous form, that contains radioactive isotopes above the exemption limits and requires specific treatment, conditioning and storage to protect human health and the environment. Its defining features are:

• Emission of ionising radiation.
• A long half-life in some cases (thousands of years).
• The need for prolonged isolation and control.

Classification of radioactive waste

Under international standards (IAEA and Euratom), several categories are distinguished:

Very low-level waste (VLLW)

• Comes from contaminated construction materials and rubble.
• Low radiation level.
• Stored in surface facilities.

Low and intermediate-level waste (LILW)

• Clothing, filters, contaminated tools.
• Emits radiation for decades or centuries.
• Stored in surface or near-surface engineered structures.

High-level waste (HLW)

• Mainly spent nuclear fuel from reactors.
• High radioactivity and heat generation.
• Requires initial cooling followed by deep geological disposal.

Sources of generation

1. Nuclear power plants: spent fuel, maintenance waste, activated metal components.
2. Nuclear medicine: radiopharmaceuticals used in diagnosis and treatment.
3. Research and teaching: laboratories using radioactive isotopes.
4. Industry: industrial radiography, detectors, gauges.
5. Defence: military programmes involving depleted uranium or plutonium.

Regulation in Spain and the EU

• Euratom Treaty (1957): the basis of European nuclear policy.
• Directive 2011/70/Euratom: establishes a Community framework for the responsible and safe management of spent fuel and radioactive waste.
• Law 25/1964 on Nuclear Energy (Spain).
• Royal Decree 102/2014 on the responsible and safe management of spent nuclear fuel and radioactive waste.
• Nuclear Safety Council (CSN): the regulatory authority in Spain.

Management of radioactive waste in Spain

ENRESA, the state-owned company, is responsible for every stage of management. Spain's policy is set out in the 7th General Radioactive Waste Plan (PGRR), approved in December 2023, which redefined the country's storage strategy:

1. Collection and transport: from hospitals, laboratories and power plants.
2. Treatment and conditioning: compaction, solidification and encapsulation.
3. Disposal of low and intermediate-level waste: at the El Cabril facility (Cordoba).
4. Decentralised temporary storage (ATD): the 7th PGRR cancelled the previously planned centralised store (ATC) at Villar de Cañas and instead foresees individual temporary stores at each nuclear site for spent fuel and high-level waste.
5. Deep geological repository (AGP): planned for the long term (around 2073) to permanently isolate high-level waste; currently in the research and siting phase.

Associated risks

1. Radiological risks: exposure of workers and the public.
2. Transport accidents: possible releases of radioactivity.
3. Long-term environmental impact: the need to isolate waste for thousands of years.
4. Social and political risks: public opposition to nuclear storage sites.

Relationship with the circular economy

Although radioactive waste is not recyclable in the classic sense, there are active lines of work in:

• Recycling of lightly contaminated metallic materials.
• Reprocessing of spent nuclear fuel to recover reusable uranium and plutonium (France, Japan).
• Innovation in Generation IV reactors that could use fuel more efficiently and reduce the amount of high-level waste.

Radioactive waste is one of the greatest environmental and technological challenges of the 21st century. Although its volume is small compared with other industrial waste, its hazard and long half-life demand extremely rigorous management. Within the energy transition, safe management of this waste will be a decisive factor in guaranteeing the sustainability of and trust in national and European energy policy.

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