Over a decade since the Fukushima nuclear disaster, there has been waning public interest in the aftermath of the accident (Hidaka et al., 2022). However, recent news of the Japanese government’s approval of nuclear plant operator TEPCO’s release of water into the Pacific Ocean has led to objections from various local communities and countries (McCurry, 2023). This is despite TEPCO’s assurances of radionuclide concentration, with the exception of tritium, being below government regulations. The question that arises is whether these oppositions stem from genuine environmental concern, or if they are a product of overreaction.

 

TEPCO wastewater treatment technology

Figure 1: Membrane separation treatment (Kim et al., 2020)

The main method used by TEPCO for radioactive wastewater treatment is membrane separation, running the wastewater through multiple filters in its Advanced Liquid Processing System (ALPS) (Normile, 2021). The common membrane separation method uses reverse osmosis to drive wastewater liquid through microfiltration membranes (Ma et al., 2023). These semi-permeable membranes can have pore sizes as small as 1 to 2nm, only allowing certain low molecular weight solutes, low-valent ions or solvent molecules to pass through (Fig.1). A study by Chen et al. (2021) also highlighted that that the reverse osmosis method has a good purification effect on the radioactive waste liquid. Additionally, the ALPS can remove 62 different radioactive materials from the contaminated water, leaving only tritium due to its chemical bonds with water (METI, 2023). Even so, the ALPS treated water will be diluted by seawater to a tritium concentration of 1500Bq/L, 1% of WHO standard for drinking water (METI, n.d.).

However, many still have doubts over the safety of the treated wastewater, where its tritium concentrations are still many times higher than the natural level of 0.119Bq/L in the north Pacific Ocean (Kaizer et al., 2020). Moreover, as tritium has a shorter half-life of 12.33 years compared to other radionuclides, there are views that Japan could store the contaminated water to decay for 40 to 60 years to a point of negligeable radiation (Normile, 2023).

 

Overall, it could be said that the various stakeholders all share valid concerns. Japan has limitations in storing nuclear wastewater while fishing communities and neighbouring countries worry about the possible radionuclide pollution in their shared marine environment. Hence, more research into nuclear disposal and transparent communication between involved parties is needed for the safe and sustainable use of nuclear energy.

 

References:

Chen, B., Yu, S., & Zhao, X. (2021). The separation of radionuclides and silicon from boron-containing radioactive wastewater with modified reverse osmosis membranes. Process Safety and Environmental Protection, 146, 639–646.

Hidaka, T., Endo, S., Kasuga, H., Masuishi, Y., Kakamu, T., & Fukushima, T. (2022). Visualizing the decline of public interest in the Great East Japan Earthquake and Fukushima Daiichi nuclear power plant accident by analyzing letters to the editor in Japanese newspapers. FUKUSHIMA JOURNAL OF MEDICAL SCIENCE, 68(1), 63–66.

Kaizer, J., Kumamoto, Y., Molnár, M., Palcsu, L., & Povinec, P. P. (2020). Temporal changes in tritium and radiocarbon concentrations in the western North Pacific Ocean (1993–2012). Journal of Environmental Radioactivity, 218(C), 106238–106238.

Kim, H-J., Kim, S-J., Hyeon, S., Kang, H., H & Lee, K., Y. (2020). Application of Desalination Membranes to Nuclide (Cs, Sr, and Co) Separation. ACS Omega. 5 (32), 20261-20269. DOI: 10.1021/acsomega.0c02106

Ma, H., Shen, M., Tong, Y., & Wang, X. (2023). Radioactive Wastewater Treatment Technologies: A Review. Molecules (Basel, Switzerland), 28(4), 1935.

Normile, D. (2023). Fukushima wastewater release set to start soon. Science (American Association for the Advancement of Science), 379(6630), 321–321.

McCurry, J. (2023, February 15). Fukushima: Japan insists release of 1.3m tonnes of ‘treated’ water is safe. The Guardian. Retrieved from: https://www.theguardian.com/environment/2023/feb/15/fukushima-japan-insists-release-of-treated-water-is-safe-nuclear-disaster

METI. (n.d.). What is “ALPS treated water”? Ministry of Environment, Technology and Industry. Retrieved from: https://www.meti.go.jp/english/earthquake/nuclear/decommissioning/pdf/alps_8pages_en.pdf

METI. (2022, August 30). ALPS Treated Water Q&A. Ministry of Environment, Technology and Industry. Retrieved from: https://www.meti.go.jp/english/earthquake/nuclear/decommissioning/qa.html#q1