The operator of Japan’s Fukushima nuclear power plant says that seawater radioactivity fifteen kilometres offshore has risen significantly. Plant operator TEPCO reports it is 600 times the maximum allowed by law.

The company has released a new video of the inside of reactor number one. A US-made robot recorded the images on April 29. Experts confirmed that electricity cables were safe and there were no water leaks, but said radiation levels were higher than expected.

Following the March 11 earthquake and tsunami disaster, hundreds of tons of highly contaminated water from the plant was released into the north Pacific Ocean.

As cleanup in the surrounding danger area proceeds, new filtering equipment and fencing were being set up. Tokyo Electric Power has said it may take the rest of this year to bring the nuclear plant back under control.