New Delhi: On 24 August, Japan started the process of releasing treated radioactive water from the Fukushima nuclear plant into the Pacific Ocean. Promptly, China issued a blanket ban on all seafood imports from Japan, citing “risk of radioactive contamination”, while North Korea criticized Japan’s decision, saying it was a crime against humanity.
Hong Kong, Japan’s second-biggest seafood market after China, too banned seafood imports from Tokyo, Fukushima, Chiba, Tochigi, and six other regions. “The release was irresponsible and posed impossible risks to food safety and irreparable pollution and destruction of marine environment,” the Hong Kong Chief Executive said in a statement.
The Fukushima nuclear plant was wrecked in a 2011 tsunami, after which it was left with about 350 million gallons of radioactive water stored in more than 1,000 tanks. After treating it to remove most radioactive elements, Japan decided to release 1.3 million tonnes of water in 2021. The plant, managed by Tokyo Electric Power (TEPCO), also got approval from the International Atomic Energy Agency (IAEA) on 4 July.
Then why are certain countries still protesting Japan’s decision and what are the actual properties of the wastewater stored at the plant in Fukushima? ThePrint explains the concerns over Fukushima wastewater, as well as the science behind the treatment.
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Fukushima nuclear disaster
The Fukushima Daiichi Nuclear Power Station is a defunct nuclear plant wrecked by the tsunami triggered by a 9.1 magnitude earthquake that struck off the northeast coast of Honshu on 11 March, 2011.
The tsunami caused a level-7 nuclear accident at the Fukushima Daiichi plant, as categorized on the International Nuclear and Radiological Event scale. For context, the Chernobyl nuclear disaster in the USSR was also a level-7 nuclear accident.
Due to the tsunami, several reactors at the plant melted down. These reactors were then flooded with water to reduce further damage. Additionally, even though the plant is no longer functional, water is constantly being used to cool the reactors. This water, which has been stored at Fukushima itself, is highly contaminated with radioactive elements.
Groundwater too seeped into the reactors, leading to a large amount of radioactive water getting stored in the plant. On 18 August, the Japanese government said in a statement that the tanks were “97 percent full” and that there was no additional storage space for more water.
The water, therefore, is planned to be released off the coast of Japan into the Pacific Ocean.
According to TEPCO, the water will be treated properly to remove all radioactive elements. The treated water will then be mixed with saltwater, to reduce its concentration before it is released using an undersea tunnel, around 1 km off the coast. Also, the water is scheduled to be released gradually, and the entire process is bound to take at least 30 years.
The current release plan, which started on 24 August, will take 17 days.
Treatment process
Apart from a gradual release of treated wastewater, the treatment process itself is rigorous.
This contaminated water is basically water that has radioactive isotopes present in it. The Japanese government and TEPCO have worked to treat this water, with a machine called Advanced Liquid Processing System (ALPS).
Most of the isotopes, especially the harmful ones like Cesium-137 and Strontium-90 have been removed with this method. However, the main hazardous element that remains is tritium. Tritium is an isotope of hydrogen, and since hydrogen is part of water (H2O), it is difficult to separate it from water.
Tritium, which is a long-lived radioactive element, emits beta radiation as it decays. It is most commonly found in the form of tritiated water since it replaces the hydrogen atom of water. It is a relatively weak source of radiation, but when consumed in heavy amounts it can increase the risk of cancer.
Tritiated water coming into contact with marine life has a possibility of getting into the food chain of humans. But, the half-life of tritium in biological life is only 10 days, which means it takes 10 days for tritium to decay to half its original amount once it comes in contact with a biological being. Comparatively, Uranium-238, one of the most radioactive elements on Earth, has a half-life of almost 4.5 billion years.
A report by the Japanese government, published on the IAEA website, states the water will be diluted before release. “Tritium levels in the treated water and diluted water will be below those considered safe for drinking,” it says.
Clarifying the treatment process, Japan said that the ALPS system was approved by Japan’s independent regulator, the Nuclear Regulation Authority (NRA). “No discharges of ALPS treated water will be made from any tank to the sea unless the water from that tank meets the discharge standards instituted by the NRA and reviewed by the IAEA as part of its safety review,” the report says.
In its independent report, the IAEA said that the treated water met international safety standards. Prepared over a period of two years, the IAEA report also states that the water discharge “would have a negligible radiological impact on the people and the environment”.
IAEA head Rafael Grossi said the organisation would be present and help Japan before, during, and after the release.
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Why concerns persist
China has been against the plan to discharge Fukushima wastewater ever since it was announced two years ago. The Chinese foreign ministry called the move “selfish” in a statement, and said Japan should not cause “secondary harm to the world”.
Japan, on its part, has reiterated its commitment to safety standards and international protocol. It has also offered “individual briefing sessions to Chinese nuclear experts” to promote Beijing’s understanding of the matter. It has claimed utmost transparency in the process of treatment as well as monitoring undertaken by the IAEA.
Further, media reports have shown, and Japan has stated that multiple active nuclear plants also release tritium water into the ocean. The wastewater released by Japan will contain 190 becquerels (one of three units used to measure radioactivity) of tritium per litre, while the WHO’s tritium limit for drinking water is 10,000 becquerels per litre.
One report by Al Jazeera shows that while Fukushima is releasing 22 trillion becquerels of tritium per year, active nuclear plants such as China’s Hongyanhe and UK’s Heysham release 87 and 390 trillion becquerels of tritium per year, respectively. This essentially means that Fukushima’s contribution to radioactive matter in the oceans is relatively lesser than that of many other nuclear plants.
(Edited by Tony Rai)
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