link to original article: http://www.fukushimaminponews.com/news.html?id=476
Highly radioactive rainwater that accumulated on the rooftop of the No. 2 reactor building at the crippled Fukushima Daiichi nuclear power plant was found to have leaked into the Pacific Ocean through the complex’s drainage ditch, Tokyo Electric Power Co. said on Feb. 24. TEPCO discovered the leakage of contaminated water into the ocean no later than in April last year and had been investigating the cause, but did not make the issue public until now.
The drainage runs through the inland side of the complex next to the Nos. 1 to 4 reactor buildings and into the open sea outside the bay south of the No. 4 reactor. The level of radioactive cesium in rainwater that had accumulated on the rooftop of an entrance for heavy duty trucks and other vehicles transporting large items at the No. 2 reactor building measured 29,400 becquerels per liter, while that of beta ray-emitting substances such as strontium-90 was 52,000 becquerels per liter, according to TEPCO.
At the drainage outlet outside the bay, where no measures have been taken to prevent radioactive substances from being released into the ocean, the level of radioactive cesium measured a high of 1,050 becquerels and that of beta ray-emitting substances measured 1,500 becquerels.
TEPCO said it believes radioactive substances scattered from the nuclear accident had remained on the entrance rooftop and that every time it rained, rainwater mixed with such substances flowed into the ditch via the drainage on the rooftop. “According to test results so far, no major changes in radiation levels have been observed in the ocean outside the bay adjacent to the plant,” TEPCO said.
(Translated by Kyodo News)