Highly Radioactive Water Leaks Outside Japan's Nuclear Plant Building

Japan's stricken nuclear plant hit a further setback on Monday after highly radioactive water was found leaking outside a building.

The water seeping into a trench outside the Number two reactor at Fukushima Daiichi nuclear plant in northeast Japan had a radiation level of more than 1,000 millisieverts per hour.

Such a high level can cause temporary radiation sickness including nausea and vomiting and far exceeds the 100 millisievert per hour which is generally regarded the lowest amount at which cancer risks are apparent.

Officials at Tokyo Electric Power Co (TEPCO) are now attempting to locate the source of the leak, which is near the turbine building of the Number 2 reactor and around 180 feet from the sea.

"The trench is located outside the building and the water contains radioactive materials," Hiro Hasegawa, a spokesman for TEPCO, told The Daily Telegraph.

"There is normally no water found in this area so it is difficult to compare this to normal levels.

"But we do not believe it is leaking into the ocean. We are now working out where the cause of the leak is and finding ways to remove the water as soon as possible."

It is the latest in a series of setbacks at Fukushima Daiichi, where staff have been working around the clock to restore crucial cooling functions following the March 11 earthquake and tsunami.

The discovery of the contaminated trench came one day after officials evacuated the turbine building of the Number 2 reactor when puddles of water inside were found to contain 1,000 millisieverts per hour of radioactivity – 100,000 times the normal level.

A temporary meltdown inside the core of the Number 2 reactor was possibly the cause of the building's contaminated water, according to Yukio Edano, the chief government spokesman.