An earthquake and a tsunami hit Japan’s Fukushima Tokyo Electric Power Company (TEPCO) nuclear power plant in 2011, which resulted in a triple meltdown when the supply of cooling water to the reactor core was interrupted. Eight years later, the storage space to store 1 million tons of radioactive water used to cool the destroyed reactors is running out.

When a nuclear reactor melts down the destroyed core will stay “hot” for a long time due to the isotopes of strontium-90 and cesium-137, which are radioactive isotopes with half-lives of 30 years. The damaged cores continue to produce heat; so, continued cooling is required.

Normally, the water is not directly exposed to radioactive materials and is recycled. However, in the case of a meltdown, the water is contaminated and must be safely treated and stored.

TEPCO used a decontamination method used called “Advanced Liquid Processing System” (ALPS). The process can remove almost all radioactive elements with the exception of tritium, which is a radioactive isotope of hydrogen regarded by the government as relatively “low risk” to humans. Despite this, ALPS is not yet advanced enough to remove tritium.

The one obvious and most practical solution is to use the vast quantities of water in the ocean to dilute the contaminated water as to where it becomes harmless to humans and other life forms. In other words, dump it into the ocean.

The mayor of Osaka, Ichiro Matsui, is willing to go along with putting the water into the Osaka Bay but only if the government can prove that it is scientifically safe for humans. As expected, there has been a strong backlash from the local fisheries and fishermen whose livelihood depends on healthy fish stocks and clean water. The reputation of Japan’s fishing industry is at stake and it prompted the Osaka Prefectural Fisheries Cooperative Association to submit a letter of protest to the city.

A further complication is coming from South Korea. The two countries have been at odds since World War 2 over Japan's abusive treatment of Korean citizens during the war. South Korea seems to be using this situation to whip up some hysteria over the radioactive water.

South Korean Vice Science Minister Mun Miock stressed, at a meeting at the International Atomic Energy Agency in Vienna, that “anxiety is spreading all over the world” and it was “not only a Japanese issue but an international one that could affect the global marine environment.”

Other environmental groups, like Greenpeace, warn that the accumulation of radioactive elements could be absorbed by shellfish and in the bones of small fish. While a controlled release of water is the most pragmatic solution other options under consideration include geological injections, evaporation ponds and adding additional long-term storage.