Again, not so good news from Fukushima Daiichi...

A radioactive substance about 10,000 times the limit was detected from groundwater around the No. 1 reactor of the Fukushima Daiichi nuclear power plant, plant operator Tokyo Electric Power Co. said Thursday.

Meanwhile, UN nuclear monitors have advised Japan to consider doubling the radius of its 20 km exclusion zone, after finding radioactive contamination exceeding safe limits in a town 40 km from the crippled plant.

UPDATE: TEPCO officials have identified the radioactive substance as iodine-131.