Japan Approves to Release Radioactive Wastewater into the Pacific Ocean

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Issue 16, Volume 111

By Hellen Luo 

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Whether we are studying low-carbon electricity generation in an environmental science class or participating in discussions around climate change, the use of nuclear power tends to be at the center of controversy. In some cases, nuclear power is considered one of the cleanest and most sustainable energy sources to generate electricity, primarily because it does not emit carbon dioxide while operating. Though building these power sources involves trace amounts of carbon dioxide emissions, such emissions are minuscule in comparison to those released by fossil fuel plants. However, because of limited supplies of their fuel, uranium, and the potential disposal of highly radioactive wastes into the environment, the future of nuclear power remains uncertain on a larger scale. In fact, several accidents involving explosions and partial or complete meltdowns of nuclear plants have occurred over the past few decades, resulting in prolonged environmental effects due to pollution and an increased risk of exposure to radiation.

A well-known nuclear accident took place at the Fukushima Daiichi Power Plant on March 11, 2011, when an immense offshore earthquake of 9.0 magnitude caused a devastating tsunami across the northwest coast of Japan, destroying coastal habitats while triggering a series of equipment failures and explosions at the site. Systems at the nuclear plant detected the earthquake and automatically shut down the nuclear reactors, while emergency diesel generators turned on to keep coolant pumping around the cores. The large tsunami, however, knocked out the nuclear plant’s protective seawalls, flooding the diesel generators and circuits of three operating reactors’ emergency core cooling systems inside the plant. Shortly after, the buildup of hydrogen gas produced by the exposed nuclear rods blew off three of the reactor buildings’ roots and released radioactive materials into the Pacific Ocean and the atmosphere. The overheating of these three reactors fully melted the cores, resulting in a nuclear meltdown.

There were no reported immediate deaths during the nuclear accident, but over 16 workers were injured and about 130,000 people were evacuated as a preventative measure. Though scientists believe that the risk of radiation remains relatively low, the long-term effects of radiation are unknown. The Japanese government confirmed the first acknowledged death caused by lung cancer from prolonged radiation exposure in 2018, where the employee who died was in charge of measuring the radiation of the first reactor after its meltdown.

Since the accident, the accumulating radioactive water has been pumped nonstop through the three reactors to cool the melted fuel and prevent debris from overheating again or causing further damage. The contaminated water has then been collected and stored in more than 1,000 large steel tanks crammed onto the Fukushima campus, along with other leftover materials such as radioactive sludge and debris. Tokyo Electric Power Co. (TEPCO) estimates that it will take at least three to four decades to completely dispose of the radioactive water from the wrecked power plant, retrieve undamaged fuel, clean up the remaining resolidified fuel debris, and decommission the reactors.

Japan has recently approved a long speculated plan to release more than a million metric tons of contaminated water into the Pacific Ocean two years from now. It claims to have no environmental impact since it will be greatly diluted and processed to remove its radioactive elements to keep the water far above safety standards. However, about 70 percent of the water has exceeded permitted discharge limits for contamination. It is said that the plan cannot be postponed any further, as the storage tanks will likely run out of capacity next year and it is an unavoidable step to make the environment surrounding the plant safe for residents to live in. Meanwhile, the area filled with these tanks must be cleared before building new facilities to remove other remaining wastes.

Environmental groups and neighboring countries, however, are opposed to this plan. Chinese scientists have described the proposal as irresponsible and called for Japan to reexamine the issue. South Korea has expressed deep concerns that the water release plan could significantly affect the safety of its country’s population. An environmental group called Greenpeace has also raised attention to this large-scale opposition from a majority of residents living in Fukushima and broader Japan.

Japanese fishing industries and marine scientists have also turned against the decision due to its potential impact on fisheries. They are worried that certain isotopes can be ingested by fish populations and consumed, or biomagnified, at successive trophic levels. This is because the treatment process involves putting the water through a complex chain of filters known as the Advanced Liquid Processing System (ALPS). Though this system can capture 62 kinds of radionuclides, it is not able to filter out tritium, which is known to be harmless at trace amounts since it emits one of the lowest radiation doses of any radionuclide. Besides tritium, however, several more dangerous isotopes with longer radiative lifetimes—including ruthenium, cobalt, strontium, and plutonium—may sometimes slip through the ALPS treatment and can incorporate into the marine ecosystem.

The safety concerns and long-term effects of the discharge are still a matter of debate. Some argue that there are alternative approaches to this controversial problem, such as dumping the water into concrete pits and expanding capacity to store the water on land or underground. Others still insist that discharging to the sea is the only realistic solution left. Despite these controversies, the Fukushima disaster has increased public fear throughout the world over the reliability of nuclear power. Overall, the human population still has a long way to go in developing more sustainable energy generation methods, as well as understanding the lessons learned from the Fukushima disaster that could help prevent future nuclear accidents.