POWER PLANT ON FIRE: Black smoke rising from the No.3 reactor of the Fukushima Daiichi nuclear power plant on March 21 (XINHUA/AFP)
It started with an earthquake that led to a tsunami that caused one of the worst nuclear power disasters in history. As Japan reels from this trio of disasters, the catastrophe continues as its Fukushima nuclear power station leaks radioactive materials. Now people wonder: How did the leaks happen? How many countries will be affected? Is nuclear power safe enough for future use?
Japanese Prime Minister Naoto Kan announced on March 29 that Japan is undergoing the worst crisis in history. As it stands, no timetable is available about when the nuclear leaks will be stopped or how bad the situation will be.
Even as the fate of the nuclear reactors remains uncertain, experts are pointing out the cause lies within more than just the earthquake and ensuing tsunami. Man-made flaws also contributed to the radiation leaks.
The main problem was the design of the reactors at the Fukushima Daiichi nuclear power plant, said Qu Jingyuan, a professor with the Institute of Nuclear and New Energy Technology at Tsinghua University. All six of the plant's reactors are boiling water reactors. Boiling water reactors are less expensive than pressurized water reactors, but the steam released from boiling water reactors can potentially contain radioactive substances.
After the earthquake on March 11, reactors operational at the time began shutting down according to protective protocols set in motion when the power station sensed shock waves from the quake. The problem began when the plant's cooling systems malfunctioned after being drowned out by the tsunami. Growing pressure and increasing temperatures inside the reactors' cores caused nuclear fuel rods to begin melting.
In a country prone to earthquakes, boiling water reactors were not an ideal choice, said Qu. The Japanese Ministry of Economy, Trade and Industry said on March 29 the power plant was designed to withstand a hit from a 3.122-meter-high tsunami. The tsunami on March 11reached a height of about 14 meters.
Japan has 55 nuclear power stations, and more than 70 percent are located in areas with high earthquake risks. Many of the plants were designed using U.S. nuclear power technologies from more than 40 years ago, which means their service lives are close to exceeding the expectancy or safe operating threshold of 25 to 30 years.
Located in northeast Japan, the Fukushima Daiichi plant began operating its first reactor in 1971. Now 40 years has passed.
The owner and operator of the plant, the Tokyo Electric Power Co., issued an analysis report on the No.1 reactor on February 7 this year. The report said the reactor showed signs of aging in the reactor core and the heat exchange system.
Liu Junhong, a researcher with the China Institutes of Contemporary International Relations, pointed out poor supervision was another reason for the leaks. While the Japan Nuclear and Industrial Safety Agency, which is under the country's Ministry of Economy, Trade and Industry, is in charge of safety inspections for all nuclear power plants in Japan, the plants are privately owned.
Liu said this type of management system led to loopholes and corner-cutting in supervision. For example, the Fukushima Daiichi plant actually had a near critical accident in 1978 that was covered up until 2007.
"This nuclear crisis has gone far beyond Japan's control. Now it's a security issue that will affect the whole region and even the world," said Teng Jianqun, a researcher with the China Institute of International Studies. Inevitably, he said, a nuclear disaster on this scale will jeopardize the security of neighboring countries.
In a worst-case scenario, nuclear fuel rods will continue to melt down and reactor containment structures could be breached, said Vladimir Chupkov, a Greenpeace representative during a recent press conference at the Beijing News Center of Russia's RIA Novosti News Agency. Then reactors will collapse causing the radiation level to skyrocket.
"Radioactive substances will cover the ground for dozens of kilometers," said Chupkov. "The polluted ground might have to be abandoned forever."
He said besides melting reactor cores, the plant's nuclear fuel storage and spent nuclear fuel storage also present dangers. Each of the six reactors usually has about 10 to 15 tons of fuel storage. The plant has been in use for 40 years—so there could be tons of spent nuclear fuel. "It is hard to say whether or not this fuel will cause more radiation leaks," Chupkov said.
Shi Yongkang, a researcher with the China Nuclear Science Institute, said Japan would not consider burying the nuclear reactors in sand and concrete, thus forming a sarcophagus of sorts, until the situation was completely out of control. If this option is undertaken, it will take weeks to bury the reactors with enough sand and concrete and could take years to complete the whole process. Radioactive materials would continue to permeate the area during this process, said Shi.