The leak of radioactive water from storage tanks at Fukushima nuclear station late last month is the latest in a line of incidents that has led to a loss of confidence in the plant’s managers, according to a UK nuclear expert.
University of Cambridge nuclear engineering lecturer Tony Roulstone said the leak was just the latest example of the troubled clean-up of the power station by operator Tokyo Electric Power Co.
The Japanese government last week declared it would be taking a greater role in containing radiation at the plant, which was badly damaged in the earthquake and tsunami of March 2011.
According to news agency Bloomberg, trade minister Toshimitsu Motegi told reporters Tokyo Electric had turned the contaminated water containment campaign “into a game of Whack-a-Mole”.
Roulstone told NCE the company had recognised in May that radiation that leaked into the ground due to the original accident was flowing into the sea. Yet latest readings showed the rate was still not falling, he said.
“There have also been three small water leaks, less than 1t each, and electricity has been cut off to the cooling system causing a minor scare,” said Roulstone.
“This has destroyed confidence in Tokyo Electric’s management at the site and now the government seems to be bringing its own managers in.”
In the latest incident, 300t of contaminated water was found to have escaped from a storage tank in August. Reports last weekend suggested radiation levels near the tank in question were far higher than originally thought.
Roulstone said that the job of making the Fukushima plant safe should not be particularly taxing.
“The individual pieces of technology are not too complicated but the multiplicity and the scale is what makes it a difficult job.”
He said the site needed to be cleaning more water than it was pumping in to cool the damaged reactors before work could begin getting the plant back to normal. Full decommissioning could take another decade, he added.
The latest leak was discovered at 9.50am local time on 19 August when a Tokyo Electric employee conducting a patrol found water leaking from a drain valve of a tank dike in the H4 area of the plant.
A 9m2 puddle, 10mm deep, was found outside the drain valve, containing radioactive material. A further 3m2 puddle of similar depth was found nearby.
However, Roulstone said the tank was found to be 300t emptier than it should have been, leading to fears that the material had seeped into the ground and could be washed out to sea.
Fuel rods melted at three of the plant’s reactors after the March 2011 earthquake set off a tsunami that knocked out cooling systems. Leaking radiation prompted the evacuation of thousands of residents.
Tokyo Electric Co and the Japanese government were this week unavailable for comment.