Via Japan Today :
" TOKYO : Highly contaminated radioactive water that leaked into the sea in earlier May from a pit near a seawater intake of the No. 3 reactor at the Fukushima Daiichi nuclear power plant totaled 250 tons and contained an estimated 20 terabecquerels of radioactive substances, Tokyo Electric Power Co said Saturday.
The estimated amount of radioactive substances from the plant, crippled by the March 11 earthquake and ensuing tsunami, is about 100 times the annual allowable limit for release outside the plant, said TEPCO.
The leak is estimated to have lasted for 41 hours from 2 a.m. on May 10 through 7 p.m. on the following day, TEPCO said based on its analysis of data showing changes in water levels in the pit.
The leak raised the concentration of radioactive substances within the port of the power plant, but the level outside the port did not change significantly, TEPCO said.
The leak from near the No. 3 reactor compares with about 500 tons of radioactive water with 4,700 terabecquerels of radioactive substances that leaked from near the No. 2 reactor from April 1 to 6.
TEPCO reported the latest finding to the government’s Nuclear and Industrial Safety Agency, which is expected to ask the utility to take steps to prevent a recurrence.
The utility found out about the leak on May 11 and stopped it by filling the pit with concrete and other substances that day."