Officials of Tokyo Electric Power Co (TEPCO) say they have confirmed the source of radioactive water leaking from a storage tank at the crippled Fukushima Daiichi nuclear plant’s No. 3 reactor.
The source of the leakage, which began in January, was discovered on Thursday as TEPCO personnel were inspecting the damaged areas of the storage container with a video camera. Fuji TV quoted a TEPCO official as saying workers found a pipe joint that was showing signs of radioactive water leakage. This is the first time officials have been able to confirm the source of the water leaks at the No. 3 reactor.
TEPCO said the contaminated water is seeping out of the pipe joint at a slow rate.
The utility also said that it plans to start releasing uncontaminated groundwater around the facility into the ocean some time next week.
TEPCO has lobbied local fishermen to allow a groundwater bypass for nearly two years and finally got their approval in March.
TEPCO has built a thousand tanks at the Fukushima plant that hold more than 431,000 tons of radioactive water. Nearly 90% of available capacity in the tanks are already filled with radioactive water.
Contaminated water accumulates at a rate of 400 tons a day at Fukushima as groundwater flows downhill into the destroyed basements of the reactor buildings and mixes with highly radioactive water used to cool melted fuel. Radioactive water poses a long-term risk to the shutdown of the plant, a task expected to span more than three decades.
TEPCO’s bypass will release 100 tons of groundwater a day that flows downhill toward the devastated plant and funnel it to the sea before it reaches the reactor buildings.
Both Japan’s Nuclear Regulation Authority and the International Atomic Energy Agency have said controlled release of low-level water should be considered to make storage space at the facility for irradiated water.
Local fisheries unions had been bitterly opposed to TEPCO’s proposed bypass after irradiated water leaked from tanks that were just uphill of the proposed groundwater drains last year. The leaks sparked international alarm and led to a boycott of Fukushima fish by South Korea.
As part of its approval of the bypass, local media reported that fishermen requested a third party organization to check radiation levels of groundwater before it is released and any released water to have less than 1 becquerels per liter of Cesium-134, a radioactive element that has a half life of around two years.
The legal limit of releasing Cesium-134 into the ocean is 60 becquerels per liter.