The plant's operator, Tokyo Electric Power Company (TEPCO), admitted yesterday that at least 300 tonnes of water had seeped from a storage tank into the ground, marking the worst leak in almost two and a half years since the earthquake and tsunami in March 2011.

The radiation level of the water, which continues to leak, is about 100 millisieverts per hour - a person standing 50 centimetres away would, within an hour, receive a radiation dose five times the average annual global limit for nuclear workers.

After 10 hours, a worker in that proximity to the leak would develop radiation sickness with symptoms including nausea and a drop in white blood cells.

However, Tokyo 2020's acting communications director Masa Takaya seems unconcerned by the problem as the Fukushima site is located at a safe distance from the city.

"I have seen news reports about activity at the Fukushima plant," he told insidethegames.

"There is no threat in Tokyo with the plant over 250km away and the city's safety is not affected.

"Japanese Government officials are taking all necessary steps to control the situation, and experts are acting quickly and efficiently.

"Tokyo 2020's bid effort remains focused on providing the best possible stage for athletes, and we will work closely with all relevant Government authorities to ensure the safety of all Games participants."

Before the 2011 Fukushima meltdown, the worst nuclear accident since the Chernobyl disaster of 1986, Japan depended on nuclear power for about 30 per cent of its electricity.

Now almost all of the nation's 50 operable reactors have been taken offline for safety inspections.

Tokyo is currently tied in a bidding race against Madrid and Istanbul for the 2020 Olympics and Paralympics.

The winning host city will be named at the 125th International Olympic Committee (IOC) Session in Buenos Aires on September 7.

Contact the writer of this story at [email protected]


Related stories
March 2013: No safety fears over Tokyo 2020, IOC Evaluation Commission assured
July 2011: Tokyo Governor says he expects to "win" as he officially launches bid for 2020 Olympics