Nuclear waste recycling: converting radioactive materials into clean fuel
Nuclear waste recycling: converting radioactive materials into clean fuel
The energy challenges of the past century imposed themselves as an obstacle in the path of many countries towards achieving a huge industrial and economic leap, which necessarily led to the search for new methods of generating energy. To work alongside fossil fuels, one of the most prominent methods that have been discovered and developed – and thus relied upon – is the generation of nuclear energy.
Nuclear energy, of course, brought with it a bundle of conflicting effects. On the one hand, nuclear power plants can secure a large proportion of any country’s electricity needs, and on the other hand, they pose great dangers, both during their operations and when disposing of their radioactive waste. In this article, we try to search for solutions to deal with this highly hazardous waste. To advance towards a sustainable future and clean energy.
Nuclear waste problem
When electricity is generated, a wide range of wastes are generated, regardless of the fuel used. Just as nuclear power plants produce radioactive waste (radioactive waste), various other wastes are also produced by fossil fuel power plants. In all cases, all of this waste must be managed to protect public health and reduce negative environmental impacts, but given the devastating effects it can cause; Radioactive waste occupies a special place.
What is striking here is that nuclear energy represents – in itself – a unique type of energy, as we can generate large quantities of this energy using small quantities of nuclear fuel, such as enriched uranium. The amount of waste generated by this industry is also small. But the problem here is that the vast majority of this waste is radioactively contaminated. Which makes dealing with it more difficult.
Radioactive waste is produced at all stages of nuclear energy production, and requires special treatment processes and specific disposal methods. This is to ensure that radioactive contamination does not leak into the surrounding environments.
Nuclear waste recycling
Nuclear energy is produced for peaceful purposes through chemical fission reactions, where strikes are directed to the nuclei of nuclear fuel atoms using neutrons. This leads to the fission of these nuclei, generating huge amounts ofthermal energy, which is then used in producing steam to generate electricity.
Recycling of spent nuclear fuel constitutes a fundamental pillar in nuclear waste management, as nuclear fuel waste can be treated to recover fissile and fertile materials; To be used again in nuclear fission reactions. While many countries have not yet embraced the idea that spent nuclear fuel is a resource that can be utilized, and not just waste that must be disposed of; European countries, China and Japan, for example, each have procedures in place to reprocess used nuclear materials.
Perhaps the main motivation behind these countries’ adoption of reprocessing spent nuclear fuel was to obtain the plutonium and uranium that were wasted during energy production processes. This could lead to the production of 25-30% additional energy, in addition to reducing the amount of hazardous waste disposed of by approximately one-fifth.
It is worth noting that reprocessing spent nuclear fuel has been applied in this industry for a long time. To recover fissile elements and recycle them, as well as reduce the amount of highly radioactive waste produced, but the matter needs to be transformed into a standard method, widely used in this industry in various countries of the world.
To know the extent of the impact of recycling nuclear waste, we find – for example – that in fast neutron nuclear reactors – which are reactors that use neutrons loaded with energy exceeding 5 MeV – recycling waste can reduce the half-life of the nuclides of these wastes from 10,000 to 200 years; Which reduces the radiological toxicity of nuclear waste over a long period.
For those who do not know, the half-life of radioactive materials is the time required for half of the atomic nuclei to decay into a radioactive mass, or – more simply – the time required for half the amount of a radioactive mass to disappear, and this half-life changes from one radioactive isotope to another; Which means that the lower the half-life of the radioactive substance or residue, the less harmful its impact on the environment.
The most prominent nuclear waste recycling techniques
Nuclear energy has long been promoted as a practical way to combat climate change and provide a reliable supply of electricity, but disposing of nuclear waste remains a major challenge. On the other hand, recent developments in fourth-generation nuclear reactors and small modular reactors (SMRs) have provided viable options; To deal with radioactive waste and recycle it, we highlight in the following the most prominent of these options:
1- Molten salt reactors: Molten salt reactors (MSRs) use liquid salts of fluoride or chloride, as both coolants and fuels, as these salts are considered inherently safer; Because they operate at higher temperatures and lower pressures. By effectively burning nuclear waste resulting from this type of reactor, the amount of radioactive elements, which have longer half-lives, can be reduced.
2- Fast Neutron Reactors (FNRs): These reactors, as we indicated, use neutrons with an energy exceeding 5 MeV, to convert enriched radioactive materials into nuclear fuel; Which enables it to exploit uranium resources more efficiently and reduce radioactive waste.
3- High-temperature gas-cooled reactors (HTGRs): These reactors are characterized by their operation at very high temperatures, compared to other reactors, and they also use inert gases in the cooling process. This type of reactor can produce hydrogen, as well as use the large amounts of waste heat – as a result of its operations – to provide the heat needs of other industries, while the resulting nuclear waste can be burned or recycled.
4- Sodium-cooled fast reactors (SFRs): Reactors that use liquid sodium as a coolant instead of water are known as sodium-cooled fast reactors, or SFRs. In these reactors, spent nuclear fuel can be recycled. This reduces waste and extends the productive life of uranium supplies.
Successful experimentsfor recycling nuclear waste
France represents a unique model in recycling nuclear waste, and one of its most notable successes in this field is its innovative nuclear fuel recycling plant in the English Channel, where spent nuclear fuel is processed, to recover valuable fissile materials – such as uranium and plutonium – that are reused in nuclear reactors.
This treatment not only reduces the volume of nuclear waste, but also improves sustainable energy reserves in France; This country relies – largely and fundamentally – on nuclear energy to provide its electricity needs at a rate of up to 68%, which is the highest percentage of any country around the world.
This French approach to recycling industrial waste leads to increasing the life of nuclear fuel and reducing dependence on fossil fuels. It is an example of the optimal application in the use of nuclear energy, as a solution to meet energy needs in a clean manner and with a small carbon footprint.
The United Kingdom has another great example of recycling at the Sellafield nuclear complex in Cumbria, northwest of England, through the Thermal Oxide Reprocessing Plant known as “THORB”, as this facility helps recycle nuclear fuel and reduce radioactive waste.
Future opportunities and challenges
We must be aware that reprocessing and recycling spent nuclear fuel will lead to the generation of waste that can decompose at natural levels, which range between 300 and 400 years, and this is instead of 250,000 years if this waste is disposed of directly without recycling. Which necessarily means that the process of reprocessing and recycling is an essential process to significantly reduce the burden on future generations when dealing with these highly hazardous wastes.
However, enforcing nuclear waste recycling on a large scale is quite a difficult task. Therefore, it is necessary – before imposing this application on all countries as standard industry practice – that reprocessing and recycling techniques are improved; To avoid any problems that may result.
To sum up the above –As we mentioned in a previous article– nuclear energy can be the key to achieving net zero emissions; This pioneering technology can meet global energy needs with a low carbon footprint, but the dangers related to this industry – most notably radioactive waste – represent a stumbling block in the path of nuclear energy, and perhaps we have tried in this article to review the latest findings of the industry to deal with this issue.
