(April 4) — Tokyo Electric Power Co. began disposing of a total of 10,000 tons of water containing low-level radioactive substances in the Pacific Ocean on Monday from the crippled Fukushima Daiichi nuclear power plant to make room to store more highly polluted water filling the No. 2 reactor turbine building, as the water is hampering the plant’s restoration work, it said.
Separately from the contaminated water kept in a waste processing building, the company also said it plans to release 1,500 tons of groundwater, also containing radioactive materials, near the No. 5 and No. 6 reactors. The government said the water disposal will pose ”no major health risk” and is inevitable in order to secure safety.
”We’ve placed priority on not letting the highly radioactive flow into the sea,” top government spokesman Yukio Edano told a press conference.
Removal of contaminated water at the turbine buildings of several reactors is necessary to reduce the risk to workers being exposed to radioactive substances as it hinders efforts to restore the vital cooling functions to stably cool down the reactors and spent nuclear fuel pools.
The contaminated underground water also threatens the cooling functions at the No. 5 and No. 6 reactors of the plant.
The latest move shows that the operator, known as TEPCO, is struggling to find places to store water containing radioactive materials spotted in various areas in the premises of the nuclear complex, located on the Pacific coast in Fukushima Prefecture.
TEPCO is also stepping up efforts to stop highly radioactive water from leaking into the sea, and the company used colored powder Monday to try to locate the point from where radioactive water is leaking into the sea.
The company poured 13 kilograms of white bath agent into an underground tunnel-like trench that is connected to the No. 2 reactor turbine building, but colored water did not come out from a seaside pit where a 20-centimeter crack has been found to be leaking radioactive water into the Pacific Ocean, company officials said.
Highly radioactive water has been filling up the basement of the No. 2 reactor turbine building and the tunnel-like trench connected to it. Meanwhile, the water in the pit is believed to have come from the No. 2 reactor core, where fuel rods have partially melted.
TEPCO has revealed that radioactive iodine-131 more than 10,000 times the legal concentration limit was detected in the water found in the pit.
”We must prevent radioactive water from spreading in the sea as soon as possible,” Chief Cabinet Secretary Edano said earlier in the day, adding that the longer the contamination continued, the larger the impact on the sea would be, even if radioactive materials were diluted in the sea.
While efforts are continuing to track down the water flow, TEPCO is considering installing ”silt fence” barriers in areas where radioactive water is suspected to be flowing into the sea, Hidehiko Nishiyama, a spokesman for the government’s Nuclear and Industrial Safety Agency, said.
Nishiyama said it would likely take ”several days” to complete the work.
The barriers basically consist of curtains attached with weights, which TEPCO hopes will contain the contaminated water. One of the barriers would be placed in front of the No. 2 reactor’s water intake, close to the pit in question, and another barrier is expected to be set up around a damaged portion of the levee near the No. 4 reactor.
TOKYO, April 4, Kyodo
Source: Kyodo News