Nuclear Energy

- Overview

Nuclear energy provides efficient and reliable electricity around the world. Today, more than 400 commercial reactors operate in more than 30 countries. 

A common definition of nuclear energy is the energy released by a chain reaction, especially fission or fusion. In fact, nuclear energy uses fuel made from mined and processed uranium to create steam and generate electricity. 

Nuclear power generation is the only source of electricity that can reliably generate a steady supply of electricity, known as baseload electricity, without emitting greenhouse gases. Of any source of electricity, nuclear energy has the least environmental impact on land and natural resources. 

What is the role of nuclear power in clean energy transitions? Nuclear power accounts for about 10% of electricity generation globally, rising to almost 20% in advanced economies (2023). It has historically been one of the largest global contributors of carbon-free electricity and while it faces challenges in some countries, it has significant potential to contribute to power sector decarbonisation.

- Nuclear Fusion and Nuclear Fission

There are two types of nuclear reactions known as nuclear fission and nuclear fusion. Nuclear fission and fusion involve the disintegration and binding of elemental nuclei. In the case of nuclear fission, one atom splits into two or more smaller or lighter atoms. Nuclear fusion occurs when two or more atoms combine or fuse together to form a larger or heavier atom. 

When each atom split, a tremendous amount of energy is released. Fission reactions do not occur in nature naturally. Little energy is needed to split an atom in a fission reaction. Atomic bomb works on the principle of nuclear fission.

The energy released during nuclear fusion is several times greater than the energy released during nuclear fusion. Fusion reactions occur in stars and the sun. High energy is needed to bring fuse two or more atoms together in a fusion reaction. Hydrogen bomb works on the principle of a nuclear fusion bomb.

- Clean Source of Power

Over the past two decades, nuclear energy has reliably and economically contributed nearly 20 percent of U.S. electricity generation. It remains the largest contributor (over 70%) of non-greenhouse gas-emitting electricity generation in the United States. 

Nuclear technology uses the energy released by splitting the atoms of certain elements. It was originally developed in the 1940s, and during World War II, the initial research focus was on bomb production. In the 1950s, attention turned to the peaceful use of nuclear fission, controlling it for power generation. Nuclear energy is harnessed by splitting (fission) or merging (fusion) the nuclei of two or more atoms. 

As the global demand for electricity continues to surge, nuclear energy is becoming increasingly important as a clean energy source with the potential to address global climate change. Fluctuations in fossil fuel prices and countries' growing focus on securing energy supplies are other drivers of nuclear energy. Nuclear power is often excluded from discussions of "clean energy", even though it is the world's second-largest source of low-carbon electricity after hydropower.

- The Major Challenges of Nuclear Energy

The major challenges facing the nuclear industry include ensuring power plant safety, protecting reactors from natural disasters and external aggression, and finding effective solutions for long-term waste management. Nuclear power's role in a decarbonized energy mix that can help limit global warming will depend on how these challenges are met.

There are currently 439 nuclear power reactors operational in 30 countries worldwide. This accounts for 14% of the total power generation of the world. The International Atomic Energy Agency (IAEA) expects the global nuclear power generation capacity to increase from the current 372 gigawatts (GW) to 437–542 GW by 2020 and to 473–748 GW by 2030. 

However, for nuclear power to emerge as a reliable and clean source of energy, several challenges need to be addressed. Some of these include improvement in economic competitiveness, designing safe and reliable nuclear power plants, management of spent fuel and disposal of radioactive waste, developing adequate skilled workforce, ensuring public confidence in nuclear power, and ensuring nuclear non-proliferation and security.  

- The Nuclear Fuel Cycle

(The Nuclear Fuel Cycle - World Nuclear Association)

• The nuclear fuel cycle is a series of industrial processes that involve the production of electricity from uranium in nuclear power reactors.

• Uranium is a relatively common element found all over the world. It is mined in many countries and must be processed to be used as fuel for nuclear reactors.

• Fuel taken from the reactor, at the end of its useful life, can be reprocessed so that most of the fuel can be recycled for new fuel.

The various activities associated with generating electricity from nuclear reactions are collectively referred to as the nuclear fuel cycle. The nuclear fuel cycle begins with the mining of uranium and ends with the disposal of nuclear waste. With the reprocessing of spent fuel as an option for nuclear energy, these stages form a true cycle. 

To prepare uranium for use in nuclear reactors, it goes through the steps of mining and grinding, conversion, enrichment, and fuel fabrication. These steps constitute the "front end" of the nuclear fuel cycle. 

After the uranium is used in the reactor to generate electricity for about three years, the spent fuel may go through a series of further steps, including interim storage, reprocessing and recycling, before disposal of waste. These steps are collectively referred to as the "back end" of the fuel cycle.

- Nuclear Waste Storage

Next to climate change, nuclear waste storage is one of the biggest generation-spanning issues facing the world. The stakes are high; world powers like the US and the U.K get a fifth of their power from nuclear plants, while in France the share is 40 percent. This reliance makes the need for safe and sustinable storage obvious.

The Onkalo spent nuclear fuel repository is a deep geological repository for the final disposal of spent nuclear fuel, the first such repository in the world. It is currently under construction at the Olkiluoto Nuclear Power Plant in the municipality of Eurajoki, on the west coast of Finland, by the company Posiva. It is based on the KBS-3 method of nuclear waste burial developed in Sweden by Svensk Kärnbränslehantering AB (SKB).