POSTED: Friday, March 15, 2013 - 9:00am
UPDATED: Friday, March 15, 2013 - 9:04am
NBC News — A study says dangerous levels of radioactive cesium continues to leak from the damaged nuclear plant in Fukushima, Japan.
The study by the Tokyo University of Marine Science and Technology Research Group found the leak contained radioactive cesium 73 times higher than the safety limit set before the nuclear accident.
The radioactive cesium leaked into an artificial harbor.
Water from the Pacific Ocean can flow in and out of the harbor, which is partly secluded by a man-made wall.
The research group said further work was needed to identify how the leak was continuing.
According to the study, 44% of the sea water in the secluded harbor appeared to be replaced due to the ocean current and tide.
The research was conducted because the density of cesium in the secluded water next to the plant hasn't changed.
Tokyo Electric Power Company, the operator of the Fukushima Daiichi nuclear plant, said the contaminated water had stopped leaking in June 2011.
The company says it believes there is no radioactive leak but plans to investigate why the cesium level in the secluded water has not declined.