Challenges and solutions for radioactive waste disposal industries

Introduction

Radioactive waste disposal is an urgent environmental and public safety issue. As the world increasingly relies on nuclear technology for energy, various industries, medicine and research, the safe management of radioactive waste has become essential. Improper disposal can have serious consequences, including contamination of ecosystems and health hazards for present and future generations.

This article explores the types of radioactive waste, the risks associated with its disposal and strategies for its management, with a focus on international commitments and standards that guide safe practices.

What is radioactive waste?

Radioactive waste is material that no longer serves a useful purpose and contains radioactive elements, which makes it hazardous due to the emission of ionizing radiation. These wastes are mainly produced in nuclear power plants, medical institutions, industrial processes and research facilities. The potential hazard of these radioactive materials depends on their type and level of radioactivity, ranging from short-lived isotopes used in medical diagnostics to long-lived isotopes generated in nuclear reactors.

What is radioactive waste management?

Radioactive waste management refers to the safe treatment, storage and disposal of liquid, solid and gaseous wastes from operations involving the handling of radioactive material with the objective of protecting people and the environment.

Radioactive waste of various types results from any activity using nuclear materials, including medical and industrial uses. However, nuclear power is the most important source of such waste due to the larger volumes generated and its long-lived nature. Whatever its origin, radioactive waste must be managed in a safe and economical manner¹.

Types of radioactive waste

The approach to classification will depend on the purpose of the radioactive waste classification system². A generally accepted way of classifying radioactive waste is on the basis of its level of radioactivity and longevity. According to this approach, the types of radioactive waste are:

1. Exempt waste (EW): These are wastes with such a low radioactivity content that they no longer require control by the regulatory authority. Once the material is approved by the regulatory authority, it is no longer considered radioactive waste.
2. Very short-lived waste (VSLW): Waste that can be stored for a limited period of up to a few years to allow its radioactivity content to be reduced by radioactive decay. Subsequently, they may be released from regulatory control in accordance with provisions approved by the regulatory authority for disposal as ordinary waste, for use or for controlled discharge. This class includes waste containing radionuclides with very short half-lives that are often used for medical and research purposes.
3. Very low level waste (VLLW): This waste typically has a higher radioactivity content than EW, but nevertheless may not require a high level of containment and isolation. It is suitable for disposal in near-surface landfill-type facilities with limited regulatory control. Typical wastes in this class include soil and debris with low levels of radioactivity, originating from sites previously contaminated by radioactivity. May contain small amounts of longer-lived radionuclides.
4. Low-level waste (LLW): This waste has a high radioactivity content, but contains limited amounts of long-lived radionuclides. It requires robust isolation and containment for periods of up to a few hundred years, and is suitable for disposal in facilities designed near the surface. It covers a very wide range of wastes and may include short-lived radionuclides with higher levels of activity concentration, and also long-lived radionuclides, but only with relatively low levels of activity concentration.
5. Intermediate level waste (ILW): This is waste that, because of its radioactivity content, particularly of long-lived radionuclides, requires a greater degree of containment and isolation than that provided by near surface disposal. However, ILW needs no or only limited provision for heat dissipation during storage and disposal. ILW may contain long-lived radionuclides that will not decay to a level of activity concentration acceptable for near-surface disposal for as long as institutional controls can be relied upon. Therefore, wastes of this class require disposal at greater depths, on the order of tens of meters to a few hundred meters.
6. High-level waste (HLW): These are wastes with activity concentration levels high enough to generate significant amounts of heat through the radioactive decay process or wastes with large amounts of long-lived radionuclides that must be considered in the design of a disposal facility for such wastes. The generally recognized option for disposal of HLW is disposal in deep, stable geologic formations, generally several hundred meters or more below the surface. Each type of waste requires customized disposal methods to mitigate its potential risks.

What are the main risks associated with improper disposal of radioactive waste?

Improper management and disposal of radioactive waste present several risks:

• Environmental contamination: Improper disposal can lead to the seepage of radioactive materials into soil and water bodies, affecting ecosystems and fauna.
• Human health risks: Exposure to radioactive materials can cause cancer, genetic mutations and other serious health problems. Contaminated water sources, food chains and air increase the risk of exposure.
• Long-term impact: Some radioactive materials remain hazardous for thousands of years, posing a risk to future generations if not properly contained.

The dangers of inadequate management highlight the need for strict regulations and safety standards to protect current and future populations.

The importance of managing radioactive waste

Effective radioactive waste management is essential for both environmental protection and public safety. It ensures that radioactive materials are contained and disposed of in adequate physical spaces, and that an administrative protocol for their control is followed, preventing their entry into ecosystems or human contact.

Good management also helps sustain the growth of the nuclear industry, as safe disposal practices can help gain public confidence and regulatory approval. In addition, well-managed disposal systems help meet international commitments aimed at preventing environmental contamination and limiting the risk of radiological incidents.

Radioactive waste management responsibilities

Responsibility for radioactive waste management relies on a number of stakeholders, including:

• Governmental agencies: Regulatory agencies such as the U.S. Nuclear Regulatory Commission (USNRC) and the European Atomic Energy Community (EURATOM) apply safety standards and guidelines for the management of radioactive materials.
• International organizations: Key institutions, such as the International Atomic Energy Agency (IAEA), establish international guidelines and provide support to member countries to develop safe disposal methods for radioactive waste. They work closely with other entities such as the World Health Organization (WHO) and the United Nations Environment Programme (UNEP) to ensure safe radioactive practices.
• Private sector and facility operators: Companies that generate radioactive waste, including nuclear power plants and medical facilities, are responsible for its safe storage, handling and disposal. They must comply with national and international guidelines to minimize the risks associated with radioactive materials.

The following animation explains how radioactive waste is managed to protect people and the environment from radiation now and in the future. Source: IAEA

Stages of radioactive waste management

Radioactive waste management involves several key stages, including collection, transport, treatment, and storage:

1. Collection and classification: Waste is collected and sorted according to its level of radioactivity. Low-level and high-level waste are handled differently to ensure safety.
2. Treatment and conditioning: Waste is treated to reduce its volume, toxicity or radioactivity. Conditioning involves stabilizing the waste by processes such as solidification or encapsulation to make it suitable for safe storage or disposal.
3. Storage: Radioactive waste is stored to allow the radioactivity to decay, safely and out of reach of the public. Storage facilities are built to contain waste for extended periods of time, with safe containment to prevent leakage, for which administrative control of the waste must be maintained, including recording of the material, radiation monitoring and installation of alarms, access control, and maintenance to ensure safe containment of the radioactive material until disposal.
4. Final disposal: This involves placing the waste in engineered facilities where it will remain permanently. It consists primarily of placing radioactive waste in a disposal facility with reasonable assurances of safety, with no intention of retrieval and no reliance on long-term monitoring and maintenance. An example of a radioactive waste disposal facility is shown in figure1.

International commitments and agreements in radioactive waste management

Global cooperation is essential in radioactive waste management, as radiological incidents can have transboundary impacts. Several international commitments and agreements establish protocols and responsibilities for managing radioactive waste, such as the Joint Convention, which is the first legal instrument to address the issue of safety in spent fuel and radioactive waste management on a global scale. It does so by establishing fundamental safety principles and creating a “peer review” process similar to the one used in the Convention on Nuclear Safety³.

The joint convention is an international legal resource, ratified by the participating countries and organizations called Contracting Parties (CPs), which include more than 80. The International Atomic Energy Agency (IAEA) acts as the Secretariat of the CPs. This agreement applies to spent fuel from civilian nuclear reactors and radioactive waste from different civilian applications, such as industrial radiography, radiological activities for health, industrial process control, soil studies, among others. The agreement also applies to radioactive waste from military or defense programs.

Conclusion

The disposal of radioactive waste poses significant challenges, requiring stringent safety measures to protect human health and the environment. Proper disposal of radioactive waste requires strong regulations, international cooperation and multi-stakeholder engagement. Key organizations, such as the IAEA and USNRC, provide the necessary framework and guidance for responsible waste management practices, promoting safe and sustainable solutions.

With continued advances in nuclear science and technology, as well as strengthening global commitments, responsible management of radioactive waste remains a priority for a safer future.

References

1. NUCLEAR ENERGY AGENCY. Radioactive waste management; Consultado 26 de Octubre de 2024. https://www.oecd-nea.org/jcms/c_12892/radioactive-waste-management#:~:text=Radioactive%20waste%20of,safely%20and%20economicallyIAEA.
2. IAEA. Clasificación de desechos radiactivos; Consultado 25 de Octubre de 2024. https://www-pub.iaea.org/MTCD/Publications/PDF/P1419S_web.pdf
3. IAEA. Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management; Consultado el 24 de Octubre de 2024. https://www.iaea.org/topics/nuclear-safety-conventions/joint-convention-safety-spent-fuel-management-and-safety-radioactive-waste