The world’s first nuclear waste vault will be started in Finland

The world’s first facility for the permanent disposal of spent nuclear fuel is set to begin in Olkiluoto Island, Finland.

Built deep beneath Olkiluoto Island, this facility is designed to store 6,500 tonnes of spent nuclear fuel. However, it presents a workable model that other countries can also adopt.

The Onkalo facility is located about 400 to 450 meters below the ground surface, in bedrock that is approximately 1.9 billion years old.

Finland’s solution may offer a viable model for safely isolating radioactive waste from people and the environment over geological timescales.

Since the 1950s, nuclear reactors around the world have produced large amounts of spent fuel. Globally, this amount has reached about 400,000 tonnes, most of which is currently stored in temporary facilities such as cooling pools and dry containers.

Olkiluoto Island nuclear waste vault

Onkalo (which means "cave" in the Finnish language) began construction in 2004 on the western coast. This €1 billion facility is expected to remain operational until the 2120s.

Its design is based on a multi-barrier safety system. The spent fuel is first sealed in metal canisters, which are then enclosed in corrosion-resistant copper capsules.

These are surrounded by bentonite clay; a material that swells when wet and helps prevent water flow. The entire structure is embedded in solid rock, creating multiple barriers between the waste and the biosphere.

Nuclear waste

Nuclear waste includes argon-41, radioiodine, cobalt-60, strontium-90, tritium and cesium-137. It has two main classifications: high-level (HLW) and low-level waste.

High-level waste mainly consists of uranium fuel that has been used in a nuclear reactor and is now "spent" or no longer efficient in generating electricity.

Some uranium atoms absorb neutrons produced during nuclear fission. These atoms form heavier elements such as plutonium, known as transuranic elements, which take a very long time to decay.

Low-level waste includes materials contaminated with radioactive substances, such as shoe covers, clothing, wiping cloths, filters, etc.

What is vitrification?

It is a major and developed method for stabilizing high-level nuclear waste (HLW). In this process, waste is mixed with glass-forming materials (such as silica) and then melted at very high temperatures (around 1,150°C/2,100°F) to form a durable, chemically inert borosilicate glass.

This technique reduces the volume of waste, prevents radioactive leakage and facilitates safe storage in stainless steel containers for thousands of years.

India’s major nuclear waste management facilities

Bhabha Atomic Research Centre (BARC), Trombay: Conducts research and development in waste management, including HLW disposal technologies.

Tarapur Waste Immobilization Plant: Uses advanced vitrification technologies such as Induction Heated Metallic Melter (IHMM) and Joule Heated Ceramic Melter (JHCM).

Kalpakkam Waste Immobilization Plant: Known for using JHCM for vitrification of HLW and managing waste from the Fast Breeder Test Reactor (FBTR). Solid Storage Surveillance Facility (SSSF): Used for interim storage of vitrified HLW, allowing it to cool down.