FEATURE: Future Power Technology – Something in the water: controversy courts the Fukushima clean-up

The Japanese government has announced plans to release more than a million tonnes of water from the Fukushima site into the sea.

In the decade since the Fukushima Daiichi nuclear power plant disaster devastated the region, local fisheries have worked hard to win back consumer trust in their catch. As a confidence-building measure, all docked fish are routinely screened for radioactive caesium, and must meet standards more stringent than those in the EU, before they can be sold to market.

It was perhaps unsurprising, then, that when the Japanese Government announced in April that it will release around 1.25 million tonnes of water from the power plant site into the sea, those fishermen felt devastated once again.

Water has been steadily accumulating at the Fukushima site since it was evacuated 10 years ago. Currently, it’s stored in up to a thousand large tanks, but the government and Tepco [Tokyo Electric Power Company], the plant operator, say this strategy is not viable for the long-term future. Instead, the water must be released into the sea, possibly over a decade or so, though arrangements are yet to be confirmed.

The plans, which are expected to start in two years, have the backing of the International Atomic Energy Agency and the US Government. However, alongside local fishermen, China has called the move “extremely irresponsible” and South Korea and Taiwan are also strongly opposed.

Why is there so much water at Fukushima?

Water is an important part of all nuclear power plants because it’s used to cool the reactors’ hot radioactive cores. As a matter of routine, this water goes through a filtration process to reduce pollution to permitted levels and is then either stored in large tanks or released into nearby bodies of water.

When a core meltdown happens, radioactivity – primarily Caesium-137 and strontium – is released from the broken fuel pins into the cooling water, contaminating it. After this happened at Fukushima, a few cubic metres per hour were routinely added to the site to maintain cooling.

Furthermore, to stop any water from leaking out of the facility and into the sea, groundwater levels in the building were kept lower than outside, meaning the site is always gaining water. Hence why quantities increase by around 140 tonnes every day.

An advanced liquid processing system (ALPS) is used to remove Caesium, strontium, and other isotopes from the water; however, tritium, which cannot be chemically separated from water, still remains at low levels.