TOKYO | Workers began pumping more than 3 million gallons of contaminated water from Japan’s tsunami-ravaged nuclear plant into the Pacific Ocean on Monday, freeing storage space for even more highly radioactive water that has hampered efforts to stabilize the reactors.
It will take about two days to pump most of the less-radioactive water out of the Fukushima Dai-ichi nuclear complex, whose cooling systems were knocked out by the magnitude 9.0 earthquake and tsunami March 11.
Radioactivity is quickly diluted in the ocean, and government officials said the dump should not affect the safety of seafood in the area.
Since the disaster, water with different levels of radioactivity has been pooling throughout the plant. People who live within 12 miles have been evacuated and have not been allowed to return.
The pooling water has damaged systems, and the radiation hazard has prevented workers from getting close enough to power up cooling systems needed to stabilize dangerously vulnerable fuel rods.
On Saturday, they discovered that some radioactive water was pouring into the ocean.
The less-radioactive water that officials are dumping purposely into the sea is up to 500 times the legal limit for radiation.
“We think releasing water with low levels of radiation is preferable to allowing water with high levels of radiation to be released into the environment,” said Junichi Matsumoto, an official with plant operator Tokyo Electric Power Co. (Tepco).
Workers need to get rid of the highly radioactive water, but first they need somewhere safe to put it. Much of the less-radioactive water being dumped into the sea is from the tsunami and had accumulated in a nuclear waste storage building.
The building is not meant to hold water, but it’s also not leaking, so engineers decided to empty it so they can pump in the more-radioactive water. The rest of the water going into the sea is coming from a trench beneath two of the plant’s six reactors.
More water keeps pooling because Tepco has been forced to rely on makeshift methods of bringing down temperatures and pressure by pumping water into the reactors and allowing it to gush out wherever it can. It is a messy process, but it is preventing a full meltdown of the fuel rods that would release even more radioactivity into the environment.
“We must keep putting water into the reactors to cool to prevent further fuel damage, even though we know that there is a side effect, which is the leakage,” said Hidehiko Nishiyama, a spokesman for Japan’s Nuclear and Industrial Safety Agency. “We want to get rid of the stagnant water and decontaminate the place so that we can return to our primary task to restore the sustainable cooling capacity as quickly as possible.”