![]() ![]() The emergency prompted hundreds of thousands of people in the region to leave their homes amid fears of radiation contamination and a nuclear explosion. The nuclear accident was assigned the maximum severity. The plant suffered a triple meltdown after it was hit by a powerful earthquake and ensuing tsunami in March 2011. Hydrogen explosions destroyed two reactor buildings and there was meltdown of the reactor cores. In February, a remote-controlled robot with tongs removed pebbles of nuclear debris from the Unit 2 reactor but was unable to remove larger chunks, indicating a robot would need to be developed that can break the chunks into smaller pieces. Robotic probes have photographed and detected traces of damaged nuclear fuel in all three reactors that had meltdowns, but the exact location and other details of the melted fuel are largely unknown. On March 11th 2011, the control rods were inserted into the FDNPP reactors to stop the fission reactions immediately after the earthquake, but the later tsunami destroyed the reactor cooling. The work is carried out remotely from a control room about 500 metres away because of still-high radiation levels inside the reactor building that houses the pool. The whole process occurs underwater to prevent radiation leaks. Workers are remotely operating a crane built underneath a jelly roll-shaped roof cover to raise the fuel from a storage rack in the pool and place it into a protective cask. Removing the fuel in the cooling pools was delayed for five years by mishaps, high radiation and radioactive debris from an explosion that occurred at the time of the reactor meltdown, underscoring the difficulties that remain. ![]() It will be sent through a pipe from the sampling tanks to a coastal pool to be diluted with seawater and released through an undersea tunnel to a point 1 kilometer offshore.The step comes ahead of the real challenge of removing melted fuel from inside the reactors, but details of how that might be done are still largely unknown. They also want to release the water in a controlled way to avoid the risk that contaminated water would leak in case of another major quake or tsunami. The tanks are 96 percent full and expected to reach their capacity of 1.37 million tons in the fall. The government and TEPCO say the tanks must make way for facilities to decommission the plant, such as storage space for melted fuel debris and other highly contaminated waste. WHY RELEASE THE WATER? Fukushima Daiichi has struggled to handle the contaminated water since the 2011 disaster. The water release will be gradual and tritium concentrations will not exceed the plant’s pre-accident levels, TEPCO says. It will be also diluted, along with other radioactive isotopes, they say. Tritium cannot be removed from the water but is unharmful in small amounts and is routinely released by any nuclear plant, officials say. TEPCO says the radioactivity can be reduced to safe levels and it will ensure that water is treated until it meets the legal limit. About 70 percent of the treated water still contains cesium and other radionuclides that exceed releasable limits. The 130 tons of contaminated water created daily is collected, treated and then stored in tanks, which now number about 1,000 and cover much of the plant’s grounds. Water used to cool the reactors’ cores leaked into the basements of the reactor buildings and mixed with rainwater and groundwater. WHAT IS TREATED WATER? A magnitude-9.0 quake on March 11, 2011, triggered a massive tsunami that destroyed the plant’s power supply and cooling systems, causing three reactors to melt and spew large amounts of radiation. The International Atomic Energy Agency, collaborating with Japan to ensure that the project meets international standards, will send a mission to Japan and issue a report before the discharge begins. TEPCO needs a safety approval from the Nuclear Regulation Authority. The plant’s operator, the Tokyo Electric Power Co., aims to have the facilities ready by spring. From there, the water will be released via an undersea tunnel. A concrete facility for diluting the water after it is treated and tested is in the final stages of construction. HOW ARE WATER-DISCHARGE PREPARATIONS PROCEEDING? During a recent visit, Associated Press journalists saw 30 giant tanks for sampling and analyzing the water for safety checks. That process has barely progressed, and the removal of melted nuclear fuel hasn’t even started. Japanese officials say the release is unavoidable and should start soon.ĭealing with the wastewater is less of a challenge than the daunting task of decommissioning the plant. OKUMA, Japan - Twelve years after the triple reactor meltdowns at the Fukushima Daiichi nuclear power plant, Japan is preparing to release a massive amount of treated radioactive wastewater into the sea. ![]()
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