- Alvin Bellamy
Japan’s Controversial Plan to Dump Radioactive Wastewater into The Ocean. Is It Safe?
After numerous recovery efforts following the 2011 Fukushima Daiichi Nuclear Power Plant disaster, the Japanese government recently announced controversial plans to dispose of more than one million tons of radioactive wastewater from the remains of the Fukushima Daiichi nuclear power plant. It is reported that these wastewater contain tritium, a non-neutralizable radioactive compound.
A look back on history : March 11, 2011
On March 11, 2011, the world watched in horror as the Great East Japan Earthquake struck, triggering a massive tsunami and causing catastrophic damages to not only the general public area, but also the Fukushima Daiichi Nuclear power plant, as it caused the destruction of three reactors and sent large amounts of radioactive radiation into the atmosphere. The accident was rated level 7 on the International Scale of Nuclear and Radiological Events and became the worst nuclear disaster since Chernobyl in 1986. More than a decade later, the aftermath of the disaster is still being felt, with lasting implications for Japan and the global community.
The Fukushima Daiichi Nuclear Power Plant (DW, 2023)
What's the current treatment system for the wastewater?
The high levels of tritium found in the wastewater at the Fukushima Daiichi nuclear power plant after the 2011 disaster were primarily caused by the use of water to cool the damaged reactor cores. This water became contaminated with tritium and other radioactive isotopes, and had to be treated and stored on site.
Currently, there are about 1,3 million tons of wastewater stored in more than 1000 tanks installed by Tokyo Electric Power (TEPCO), the plant operator. The stored water is being decontaminated through a filtration process called the Advanced Liquid Processing System (ALPS), which will remove most of the worst radioactive contaminants. This filtration process is able to remove 62 radionuclides and can be done repeatedly until the contamination concentration has reached an amount far below the regulation standards.
The Multi-nuclide Removal Facility (ALPS) Structure (TEPCO, 2015)
Even so, tritium is still able to be found in the processed water, as there are currently no ways to remove the high levels of tritium present in the large volumes of water stored in Fukushima.
This obviously poses a concern, as the Japanese government plans to dump more than one million tons of water from the remnants of the Fukushima Daiichi nuclear power plant into the Pacific Ocean.
What is tritium anyways?
Tritium (abbreviated as 3H) is a hydrogen atom that has two neutrons in the nucleus and one proton. Tritium is produced naturally in the upper atmosphere when cosmic rays strike nitrogen molecules in the air. Tritium is also produced during nuclear weapons explosions, and as a byproduct in nuclear reactors. Although tritium can be a gas, its most common form is in water because radioactive tritium reacts with oxygen to form water.
Tritium Atomic Structure (Wikipedia, 2014)
While tritium is less harmful than some other radioactive isotopes, such as cesium-137 or strontium-90, it can still pose risks to human health and the environment. Tritium can accumulate in water and food, and exposure to high levels can increase the risk of cancer and other health effects.
Other ways to manage radioactive wastewater
Though currently no way to remove tritium from radioactive wastewater exists, in recent decades, various membrane separation processes have been developed and utilized in the field of potable water purification. The best known and most utilized processes in the field of water and wastewater treatment are those utilizing pressure gradient as the process driving force.
It has been demonstrated that pressure driven membrane separation processes can be successfully employed for the removal of radioactive substances, with some distinct advantages over the more conventional processes. After development of suitable membrane materials and their long term verification in conventional water purification fields, these membrane processes have been adopted by the nuclear industry as a viable alternative for the treatment of Liquid Radioactive Wastes (LRWs). Membrane separation processes are governed by both the chemical nature of the membrane materials and the physical structure of the membranes. The types of membranes suitable for use in pressure driven separation processes are polymeric membranes and inorganic membranes.
Structure of an anisotropic membrane (IAEA, 2004)
CARBOSEP Tubular Inorganic Membranes (IAEA, 2004)
Public backlash on the government plan
While dumping the wastewater into the pacific ocean is considered safe and reasonable according to the Japanese Government, the plan has also received numerous opposition from the general public. Countries in East Asia like South Korea, China, and Taiwan, are in opposition to Japan’s Unilateral Decision to dump nuclear-contaminated wastewater into the Pacific Ocean.
Even the Japanese people themselves are opposed to the plan. Many local fishermen and fishery groups have expressed their concerns on the impacts the radioactive wastewater will have on the local aquatic life.
References
A.K. Pabby, B. Swain, N.L. Sonar, V.K. Mittal, T.P. Valsala, S.Ramsubramanian, D.B. Sathe, R.B. Bhatt & S. Pradhan (2021): Radioactive waste processing using membranes: State of the art technology, challenges and perspectives, Separation & Purification Reviews, DOI: 10.1080/15422119.2021.1878221.
International Atomic Energy Agency. (2004) Application of Membrane Technologies for Liquid Radioactive Waste Processing.
(2023) Fukushima Daiichi Accident, World Nuclear Association, January 2023. Available at: https://www.world-nuclear.org/information-library/safety-and-security/safety-of-plants/fukushima-daiichi-accident.aspx (Accessed: March 30, 2023).
(2023) Radionuclide Basics: Tritium . United States Environmental Protection Agency, February 2023. Available at: https://www.epa.gov/radiation/radionuclide-basics-tritium (Accessed: March 30, 2023).
Glossary
Liquid Radioactive Wastes (LRWs) : Wastegenerated during nuclear reactor operations and during industrial and institutional application of radioisotopes.
Radionuclides : An unstable form of a chemical element that releases radiation as it breaks down and becomes more stable