Tokyo Electric Power Co. (TEPCO), the operator of the crippled Fukushima Daiichi nuclear power plant, said Thursday that it had found another leak at the site and that levels of radioactivity near a ditch had spiked.
The embattled utility said that one of its workers Thursday morning found radioactive water spewing from the top of one of its storage tanks situated on an embankment, Xinhua reported.
The tank lies close to the numbers one and two reactors that were severely damaged by the March 11 earthquake-triggered tsunami and faces the ocean, the utility said.
It added that it believes the overflowing water, which has been contained within barriers around the faulty tank, was caused by a generator used to pump water from the tank to a storage facility inside the reactor building stopping due to power failure.
The tank contains huge volumes of radioactive water drawn from groundwater that flows into the complex from surrounding mountains and becomes irradiated once inside the complex.
Heavy rain from Wednesday's massive typhoon may have caused the generator to fail and led to other problems at the crisis-hit facility, the utility said, although it could not confirm the exact cause of the generator failing and the tank overflowing.
TEPCO said it is trying to confirm the exact amount of toxic water that has leaked from the tank, its level of radioactivity and the environmental impact of the leak.
Following the typhoon, high levels of radiation were also detected in a ditch leading to the Pacific Ocean, TEPCO said.
Officials from the utility said that due to the high volume of rainfall Wednesday, contaminated soil flowed into the ditch causing radioactivity to spike to 70 times higher than that measured on Tuesday.
TEPCO detected 1,400 becquerels per litre of beta ray-emitting radioactive material at the ditch which is located just 150 metres from the Pacific Ocean. The utility said that the radioactive materials had likely flowed into the ocean.
Tests are under way to determine the exact extent of the toxicity in the surrounding sea after the mishap at the facility -- the latest in a string of other leaks and accidents caused by faulty equipment and human error.
TEPCO was urged by Japan's Nuclear Regulatory Authority (NRA) to take pre-emptive measures to guard against the typhoon well in advance of it lashing Japan's eastern seaboard Wednesday.
The NRA blasted TEPCO's efforts to prevent radioactive water from flowing freely into the ocean, stating that they have been "ineffective" with "little effect being seen".
Masaya Yasui, an emergency response official at the NRA secretariat, said that the amount of radioactive material flowing into the sea is rising. His comments were based on sea water samples collected and tested from near the plant.
Thursday's leak and massive spike in radioactivity at the plant and the likely contamination of the sea off the coast of Japan's northeast where the plant is located, comes just one day after Prime Minister Shinzo Abe told a lower house session that the situation at the Fukushima plant was "under control".
Abe's comments were dismissed as unfounded by Banri Kaieda, head of the main opposition Democratic Party of Japan (DPJ), who claimed Abe's consistent mantra that the situation is "under control" was "facetious".