The Japanese government said it planned to begin the discharge (排放) of slightly radioactive wastewater from the Fukushima Daiichi nuclear plant on Thursday, rejecting calls for a delay from some people in neighboring countries.
An earthquake and tsunami knocked out power at the Fukushima nuclear plant on March 11, 2011, causing meltdowns at three reactors. Tritium (氚) and carbon-14 are, respectively, radioactive forms of hydrogen(氢) and carbon, and are difficult to separate from water. They are widely present in the natural environment, water and even in humans, as they are formed in the Earth's atmosphere and can enter the water cycle. Both emit very low levels of radiation but can pose a risk if absorbed in large quantities. Water which was used to cool reactor cores as well as rainwater and groundwater that flowed into or near the plant have been contaminated with radioactive substances. Plant operator Tokyo Electric Power, or Tepco, has stored the water in more than 1,000 tanks at the facility but says it is running out of room.
Tepco says it will reduce the concentration(浓度) of nearly all radioactive substances in the wastewater to a safe level with the exception of tritium, an isotope(同位素) of hydrogen. The water will then get diluted(稀释)with seawater so the concentration of tritium is reduced to a safe level before the discharge, according to Tepco. As the water is diluted further in the ocean, the concentration of tritium will almost equal the natural level by 6 miles from the discharge point, which is at the end of an undersea tunnel about six-tenths of a mile from the shoreline, a Tepco official said.
But that hasn't reassured many of Japan's neighbors, with officials from China and the Pacific Islands voicing alarm and opposition to the plan. Beijing will take "necessary measures" to safeguard food safety and its people's health, said Chinese foreign ministry spokesperson Wang Wenbin on Tuesday, adding they "strongly urge the Japanese side to correct its wrongful decision." Meanwhile, fishing communities in Japan and South Korea worry the wastewater release could mean the end of their livelihoods—with consumers across the region already beginning to quit seafood from Japan and its nearby waters, and some governments even banning imported food from parts of Japan, including Fukushima.
0.6 miles offshore.
D . The concentration of tritium will be nearly at the natural level after being diluted further in the ocean.