Nuclear Power & Waste

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Nuclear energy, like all industries and energy-producing systems, generates waste products. Nuclear waste is divided into three categories based on its radioactivity: low-level, intermediate-level, and high-level. Only highly contaminated objects, such as tools and work apparel, make up the great majority of the waste (90 per cent of total volume) yet contain only 1% of the total radioactivity. High-level waste, on the other hand, accounts for only 3% of the total waste volume but contains 95% of total radioactivity. It is largely made up of used nuclear (also referred to as spent) fuel that has been categorized as waste from nuclear reactions.

It is possible to recycle used nuclear fuel to create new fuel and byproducts. Even after five years of operation in a reactor, the fuel retains more than 90% of its potential energy.

Nuclear waste has never harmed anybody since the beginning of the civil nuclear power sector. The common belief is that because certain portions of nuclear waste are radioactive for billions of years, the hazard must continue for that long. This is not the case, however. The radioactivity from the major component of the waste, which could cause health problems, will have reduced to acceptable levels by a few hundred years, albeit remaining mildly radioactive for a few hundred thousand years.

The fact that the number of elements that would be found in the environment in the case of a leak would be very minimal is also an important component in understanding why nuclear waste dumps do not constitute a health danger. The number of radioactive materials that would be released into the environment would have no effect on the natural ecosystem or on future humanity. After all, both the environment in which we live and the human body are radioactive by nature. Radiation is an unavoidable element of life on our planet; life evolved and thrived in this radioactive environment, and the doses from a nuclear waste repository would be over 50 times lower than background radiation.

Recycling:

Even though certain countries, most notably the United States, treat used nuclear fuel as waste, most of the material in old fuel may be recycled. Approximately 97 per cent of it might be utilized as a fuel in certain types of reactors, with uranium accounting for the vast bulk (94 per cent). Too far, most recycling efforts have concentrated on plutonium and uranium extraction, as these materials can be reused in conventional reactors. The plutonium and uranium that have been separated can then be combined with fresh uranium to create new fuel rods.

France, Japan, Germany, Belgium, and Russia have all employed plutonium recycling to generate electricity while also minimizing their waste’s radioactive footprint. Some by-products (about 4%), primarily fission products, will still need to be disposed of in a repository and will be immobilized by combining them with glass in a process known as vitrification.

Nuclear waste for Energy Solution:

A new generation of nuclear power technology aims to turn one of the industry’s most persistent issues, radioactive waste, into a source of energy.

The plan is to reprocess the spent fuel to generate more electricity. Proponents claim that the technology is now available to address nuclear proliferation problems that have plagued earlier recycling programs. They also claim that advanced reactors powered by recycled fuel would represent a significant step forward in terms of safety. Nuclear sceptics remain unconvinced, especially since the industry is requesting that the government cover the high cost of constructing the first facilities to demonstrate the technology. However, given the urgency of climate change and nuclear technology’s ability to create vast amounts of power without generating greenhouse gases, the nuclear industry and its allies argue that the Integral Fast Reactor (IFR), which has been studied for decades, deserves a new look.

Pyroprocessing:

The pyrometallurgical process (“pyro” for short) extracts from used fuel a mix of transuranic elements instead of pure plutonium, as in the PUREX route. It is based on electroplating— using electricity to collect, on a conducting metal electrode, metal extracted as ions from a chemical bath. Its name derives from the high temperatures to which the metals must be subjected during the procedure. Two similar approaches have been developed, one in the U.S., and the other in Russia. The major difference is that the Russians process ceramic (oxide) fuel, whereas the fuel in an ALMR is metallic.

The pyroprocess, unlike the current PUREX technology, captures practically all transuranic elements (including plutonium), with significant uranium and fission product carryover. Only a small percentage of the transuranic component gets up in the final waste stream, resulting in a significant reduction in the required isolation time. The combination of fission and transuranic products is unsuitable for weapons or even thermal reactor fuel. This mixture, on the other hand, is not only palatable but also beneficial for powering rapid reactors.

Researchers have shown the basic concepts of pyrometallurgical recycling technology, which is not yet ready for commercial usage. It has been successfully demonstrated in operating power plants in both the United States and Russia on a trial scale. However, it has not yet been put into full production.

Most of the used fuel will most likely be dumped underground, though where and when is yet unknown. As it turns out, having nuclear waste buried in their backyards does not sit well with many individuals. However, some spent nuclear fuel may be repurposed to feed newer nuclear reactors that are smaller and safer than their predecessors. INL scientists have been recycling spent uranium for the past year to meet the fuel requirements of a new generation of compact commercial reactors.

Re-Processing:

The reprocessing of irradiated nuclear fuel, the final step in the nuclear fuel cycle, is responsible for more than 99 per cent of all waste radioactivity generated by nuclear power plants. Fission products accumulate in the reactor’s fuel components, eventually absorbing neutrons to the point where the fission process is disrupted. As a result, the fuel elements are removed from the reactor and shipped to reprocessing plants before all the useable fuel has been burnt. The primary goal of reprocessing is to recover plutonium (which is created in the reactor) and unburned uranium in sufficient purity for re-use in the fuel cycle in a safe and efficient manner.

Nuclear Powered Battery:

Traditional batteries have a short lifespan, which means they can’t be utilized or have substantial limitations in situations where charging or replacing batteries is still not possible. Pacemakers, satellites, high-altitude drones, and even spacecraft are examples of low-power electrical equipment that require a long life from the energy source.

A team of physicists and chemists from the University of Bristol have created a man-made diamond that can generate a small electrical current when placed in a radioactive field. Unlike most electricity-generating technologies, which rely on energy to move a magnet through a coil of wire to generate a current, the man-made diamond can generate a charge simply by being near a radioactive source.

According to the professor “There are no moving components, no pollutants, and no maintenance issues; only direct electrical generation is necessary. We turn a long-term problem of nuclear waste into a nuclear-powered battery and a long-term supply of clean energy by encapsulating radioactive particles inside diamonds “.

The researchers have developed a prototype ‘diamond battery’ that uses Nickel-63 as a radiation source. However, they are presently aiming to dramatically enhance efficiency by utilizing carbon-14, a radioactive form of carbon produced in graphite blocks used to control nuclear reactor reactions. The radioactive carbon-14 is concentrated at the surface of these blocks, according to research conducted by Bristol scientists, making it easy to process them to remove most of the radioactive material. The carbon-14 is then removed and integrated into a diamond to make a nuclear-powered battery.

The advancement may be able to address some of the issues around nuclear waste, renewable electricity generation, and battery life.

Aspects of nuclear energy are being discussed.

Nuclear power stations emit no greenhouse gases when in operation, and over the length of their lives, they emit about the same amount of carbon dioxide-equivalent emissions per unit of energy as wind and one-third of the emissions per unit of electricity as solar. 

Figure 1: Average Greenhouse Gas Emission

Nuclear energy is not intermittent, as nuclear power plants may operate continuously for up to a year without interruption or maintenance, making it a more reliable source of energy. While other sources may stop generating power for example there will be no electrical energy when the wind stops blowing. Renewable energy sources such as wind and solar have long been criticized for producing power only when the wind blows or the sun shines.

Nuclear power stations are less expensive to operate than coal or gas-fired counterparts. Nuclear facilities are predicted to cost between 33 and 50 per cent of a coal plant and 20 to 25 per cent of a gas combined-cycle plant, even after factoring in expenditures such as maintaining radioactive fuel and disposal.

As the amount of concrete needed for building a nuclear power plant is very high and as concrete with its main ingredient cement is very emission-intensive it should be considered to continue to use the already build nuclear power plants and make efficient use of nuclear waste. Building new plants on the other hand is due to the CO2e of the complete life cycle of the nuclear powerplant, including the excavation of nuclear material, the building and the dismantling neither sustainable nor close to zero emissions.

References

  • Environmental life cycle risk modelling of nuclear waste recycling systems
    https://ideas.repec.org/a/eee/energy/v112y2016icp836-851.html
  • Recycling Gives New Purpose to Spent Nuclear Fuel
    https://www.pnnl.gov/news-media/recycling-gives-new-purpose-spent-nuclear-fuel
  • Smarter Use of Nuclear Waste
    https://www.scientificamerican.com/article/smarter-use-of-nuclear-waste/
  • Nuclear waste could be recycled for diamond battery power
    https://www.bristol.ac.uk/news/2020/january/recycling-nuclear-waste-for-diamond-battery.html
  • Are Radioactive Diamond Batteries the Solution to Nuclear Waste?
    https://interestingengineering.com/are-radioactive-diamond-batteries-the-solution-to-nuclear-waste
  • Recycled Nuclear Waste Will Power a New Reactor
    https://www.wired.com/story/recycled-nuclear-waste-will-power-a-new-reactor/
  • Destroying nuclear waste to create clean energy? It can be done
    https://www.weforum.org/agenda/2018/11/destroying-nuclear-waste-to-create-clean-energy-it-can-be-done/
  • Nuclear waste recycling is a critical avenue of energy innovation
    https://techcrunch.com/2021/06/13/nuclear-waste-recycling-is-a-critical-avenue-of-energy-innovation/
  • Constructing a lot of nuclear power plants is not material constrained
    https://www.nextbigfuture.com/2007/07/constructing-lot-of-nuclear-power.html
  • Metal And Concrete Inputs For Several Nuclear Power Plants
    https://fhr.nuc.berkeley.edu/wp-content/uploads/2014/10/05-001-A_Material_input.pdf
  • Irradiated Concrete in Nuclear Power Plants: Bridging the Gap in Operational Experience
    https://inis.iaea.org/collection/NCLCollectionStore/_Public/43/070/43070885.pdf
  • Cement, Concrete, and CO2
    https://www.cement.org/docs/default-source/th-paving-pdfs/sustainability/carbon-foot-print.pdf

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