August 23, 2013

The discovery that highly radioactive water is leaking from a storage tank at Japan’s crippled Fukushima Daiichi Nuclear Power Station has further alarmed scientists already gravely concerned about conditions at the site. The tank is 1 of 1,000 built to store the massive amounts of water being used to cool the fuel rods from nuclear reactors damaged by a magnitude-9 earthquake and subsequent tsunami that hit Japan’s main island, Honshu, on March 11, 2011. Three of the six reactors at Fukushima went into full meltdown after the plant’s cooling system was knocked out.

The storage tanks at Fukushima, which are about 85 percent filled, currently hold a total of about 80 million gallons (300 million liters) of contaminated water. The leaking tank has released about 80,000 gallons (300,000 liters), most of which has seeped into the ground. Inspectors said the leak resulted from deteriorating plastic seams on the tanks. The leaking tank is one of 350 temporary steel-plated vessels constructed to expand the storage capacity for contaminated water. The other tanks are welded steel vessels. The problem with the storage tank led Japan’s nuclear energy watchdog agency to raise the threat level at the plant from one to three on the International Nuclear and Radiological Event Scale. Conditions at the plant were rated seven–the highest rating–after the tsunami.

A huge wave strikes Japan's coast on March 11, 2011. An earthquake that day caused a tsunami (series of powerful ocean waves) that crippled the Fukushima Daiichi nuclear plant. (© Mainichi Shimbun, Reuters)

News of the leak has strengthened the belief of many scientists that conditions at the plant are much worse than the Japanese government and and Tokyo Electric Power Company (TEPCO), the plant’s operator, are admitting. The leak has also intensified criticism of TEPCO for failing to contain leaks from the plant.

The tanks are only one focus of concern. One nuclear safety expert was quoted by the BBC as saying that contaminated water was leaking everywhere at the site, “not just from the tanks. It is leaking out from the basements, it is leaking out from the cracks all over the place.” According to a Japanese government official, as much as 75,000 gallons (284,000 liters) of groundwater is believed to be flowing daily downhill through the ruined plant and into a containment pond. Despite efforts to hold the contaminated water in the pond, some appears to be flowing into the Pacific Ocean. At a recent news conference, the head of Japan’s nuclear regulation agency expressed concerns about future leaks. Shunichi Tanaka told reporters, “We should assume that what has happened once could happen again, and prepare for more.”

Additional World Book articles:

• Japan 2011 (a Back in Time article)
• Reconsidering Nuclear Power (a special report)

August 9, 2013

Prime Minister Shinzo Abe of Japan has directed his government to step in and do whatever is necessary to stabilize the damaged Fukushima Daiichi nuclear plant. His move throws a glaring light on the fact that the plant’s operator, Tokyo Electric Power Company (TEPCO), has failed to contain nuclear radiation leaks more than two years after a catastrophic triple meltdown caused by an earthquake and tsunami. A magnitude-9 earthquake and subsequent tsunami that hit Japan’s main island, Honshu, on March 11, 2011, knocked out the plant’s cooling systems, triggering blasts at three of six reactors. The earthquake and disaster also left 15,800 people dead and more than 2,600 others missing. Hundreds of thousands of people were left homeless.

A huge wave strikes Japan's coast on March 11, 2011. An earthquake that day caused a tsunami (series of powerful ocean waves) that crippled the Fukushima Daiichi nuclear plant. (© Mainichi Shimbun, Reuters)

According to a government official, as much as 75,000 gallons (284 cubic meters) of  groundwater is believed to be flowing daily downhill through the ruined plant and into a containment pond. In June, TEPCO created a “chemical wall” to line the pond by treating the soil to make it impermeable to water. For a time, the pond contained the contaminated water, but now the water has filled the pond and appears to be flowing over the top of the barrier and into the Pacific Ocean. Nuclear scientists suggest that one solution would be to build a wall of ice around the damaged reactor buildings. This would freeze the surrounding soil, shutting off the flow of groundwater into the plant.

Additional World Book articles:

• Japan 2011 (a Back in Time article)
• Reconsidering Nuclear Power (a special report)

June 19, 2013

Dangerously high levels of toxic radioactive isotopes have been found in groundwater at Japan’s Fukushima nuclear plant, according to the Tokyo Electric Power Company (Tepco) that operates the utility. Tests have shown that strontium 90 is present at 30 times the legal limit and that the radioactive isotope tritium is at 8 times an acceptable level. Tepco officials informed the Japanese media that levels of strontium in groundwater at the Fukushima plant had increased 100-fold since the end of last year.

Three of six nuclear reactors at Fukushima went into full meltdown after a massive earthquake and tsunami on March 11, 2011, crippled the plant’s cooling system. More recently, Fukushima has undergone a series of water leaks and power failures. Radioactive water was found leaking from a storage tank earlier this month. Scientists note that the detection of increasing levels of highly radioactive strontium 90 indicates that Tepco has yet to fully contain the Fukushima reactors.

The tsunami (series of powerful ocean waves) that struck Japan's coast on March 11, 2011, flooded the Fukushima nuclear power plant, causing the meltdown of three of the six reactors. (© Mainichi Shimbun, Reuters)

At the current levels found in the groundwater at Fukushima, strontium 90 has a half-life of 29 years. In humans, this means that the element will continue to irradiate them for years to come. It concentrates in human bone, where it is believed to cause cancer. Tritium, once used on glow-in-the-dark watch and clock faces, is also known to cause cancer.

Additional World Book articles:

• Alkaline earth metal
• Earthquake
• Nuclear energy
• Tsunami
• Japan 2011 (a Back in Time article)
• Reconsidering Nuclear Power (a special report)

March 28, 2012

Damage to one of the reactors at Japan’s crippled Fukushima Daiichi nuclear power plant is much worse than previously thought, Tokyo Electric Power Co. announced today. On March 27, workers were able to insert a probe into reactor #2. Radiation was found to be 10 times as great as a fatal dose, the highest level yet recorded at the plant. The probe also revealed that cooling water in the reactor vessel was only 24 inches (60 centimeters) from the bottom, far below the level estimated when the government declared the plant stable in December. The instrument used to assess damage inside the reactor chamber was equipped with a tiny video camera, a thermometer, a water gauge, and a dosimeter (a small device for measuring the doses of atomic radiation).

The Fukushima Daiichi plant was severely damaged on March 9, 2011, by one of the worst natural disaster in Japanese history–a magnitude 9 earthquake off Honshu, Japan’s main island. The earthquake, in turn, triggered a massive tsunami that resulted in the deaths of thousands of people.

Nuclear energy experts suggest that the other two reactors at Fukushima that underwent meltdowns could be in even more serious states. Because of extreme radiation levels, neither has been examined closely. Before the disaster, the Fukushima plant generated one-third of Japan’s electric power.

Public reaction to the meltdown at Fukushima has persuaded the Japanese government to shut down all but 1 of the nation’s 54 nuclear reactors in operation before the disaster. The last is to be switched off in May.

Additional World Book articles

• Energy supply
• Japan earthquake and tsunami of 2011
• Three Mile Island
• Japan 1923 (Back in Time article)
• Japan 2011 (Back in Time article)
• Big Waves: Tracking Deadly Tsunamis (a special report)
• When the Earth Moves (a special report)