Today, nuclear power is an important energy source. Compared to fossil fuels, it can produce a lot more energy with less fuel, and it does not generate carbon dioxide. Not emitting carbon dioxide is a huge advantage now that we are facing a serious climate crisis.

However, nuclear power also has a significant disadvantage: radioactive substances. Waste from nuclear power generation is contaminated with radioactive substances emitting radiation that is harmful to living things. Improper disposal of such substances poses a great threat not only to humans but also to the ecosystem. That is why many people are against nuclear power generation.

Radioactive waste from nuclear power plants can be divided into low, intermediate, and high-level radioactive waste according to the degree of risk. Low-level waste includes clothes, gloves, rags, and tools used in nuclear power plants. They account for about 90% of radioactive waste but emit only 1% of the total radiation.

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Intermediate-level waste includes parts contaminated in nuclear reactors or nuclear protection suits. It is more dangerous than low-level waste, but it emits only 4% of the total radiation. High-level radioactive waste takes up only a low percent of the total, but it is a very dangerous material emitting 95% of the total radiation. Spent nuclear fuel falls under the category of high-level radioactive waste.

We use the term “half-life” when talking about how long a radioactive material can remain dangerous. A half-life is the time required for a quantity to reduce to half of its initial value; the radioactivity of a radioactive substance halves every half-life. Radioactive materials in waste from nuclear power plants have different half-lives. Plutonium-239 has a half-life of about 24,000 years, and it takes hundreds of thousands of years for radioactivity to decay to levels that exist in nature.

Therefore, dealing with radioactive waste is very difficult. It should be located far from where people live, not adversely affect the ecosystem, be safe from natural disasters such as earthquakes, and be surrounded by huge rocks that can block radiation. Even if there is a place that satisfies all these conditions, you cannot just bury the waste there. Radioactive waste emits intense heat as well as radiation. The effect of the heat on the rocks or soil around the waste should be investigated over a long period of time.

While low- and intermediate-level waste can be treated in this way, there seems to be no proper way to treat high-level radioactive waste. There is no high-level radioactive waste treatment plant yet around the world, and Korea is still storing it in nuclear power plants. We need to find a solution before we run out of space inside the nuclear power plants. Even if we created a safe site for the disposal of radioactive waste, there would be more to consider. It takes hundreds of thousands of years for high-level radioactive waste to become completely safe, which is dozens of times longer than the human history.

Will humanity be able to properly manage radioactive waste treatment plants after 100,000 or 200,000 years? After the fall of the current civilization, if a new civilization rises and the people dig where the waste was buried without knowing what it is there, they could suffer great damage. To prevent such a disaster, we need to come up with a way to communicate beyond language and time to warn our descendants.

Some people suggest throwing it out of the Earth altogether. They say we put it on a rocket and launch it to distant space or the sun. This could be a good solution that does not require a long-term storage, but if the rocket crashes by accident or explodes in mid-air, it leads to the contamination of larger areas.

Recycling radioactive waste is an alternative solution. Spent nuclear fuel can be reprocessed and used as a fuel for nuclear power generation once again. Radioactive waste cannot be completely eliminated, but at least it can be reduced. However, this process is not easy and can be suspected of manufacturing nuclear weapons from the international community.

Disposing of radioactive waste is indeed a vexing problem. Although the new trend is to reduce nuclear power generation and transition to renewable energy, the radioactive waste accumulated so far must be disposed of in a safe way. As we learned the lessons from the Chernobyl and Fukushima nuclear disasters, the aftermath of a nuclear accident lingers forever. It is the responsibility of us, who have benefited from nuclear power generation, to find a smart way to deal with it so that our descendants hundreds of thousands of years from now do not need to live in fear.