TOKYO— Japanese authorities warned on Sunday that a second nuclear reactor at the Fukushima Daiichi power plant could explode; heightening fears among many that Japan is headed for a major nuclear emergency.
On Saturday, after a strong aftershock, the No. 1 reactor at the Fukushima Daiichi plant near the epicenter of Japan’s massive earthquake Friday exploded. Seawater is frantically being pumped in a bid to avoid a meltdown of the fuel rods. The rods need to be complete submerged in water at all times to avoid overheating. Using seawater is considered a measure of last resort since it will make the plant inoperable going forward.
Japan’s Chief Cabinet Secretary Yukio Edano warned on Sunday that the Fukushima Daiichi No. 3 Reactor could also explode. He said the situation at the No. 3 reactor is less severe, however, with little radioactive material having escaped so far.
“It is estimated that a large amount of hydrogen has accumulated near the upper area of the building at the No.1 Reactor, and there is a possibility of hydrogen explosion,” said Edano at a televised press conference.
Fukushima Prefecture authorities said on Sunday that so far 22 people have tested positive for radiation exposure, but 160 more may also have been irradiated at a hospital roughly six miles from the plant.
Everyone within a 20-km (12.4-mile) radius of the reactor has been evacuated.
This is the first severe reactor explosion for Japan, despite relying on 55 nuclear reactors for 30 percent of the nation’s energy needs. After the United States and France, Japan is the third largest producer of nuclear power.
On Saturday, after a strong aftershock, the No. 1 reactor at the Fukushima Daiichi plant near the epicenter of Japan’s massive earthquake Friday exploded. Seawater is frantically being pumped in a bid to avoid a meltdown of the fuel rods. The rods need to be complete submerged in water at all times to avoid overheating. Using seawater is considered a measure of last resort since it will make the plant inoperable going forward.
Japan’s Chief Cabinet Secretary Yukio Edano warned on Sunday that the Fukushima Daiichi No. 3 Reactor could also explode. He said the situation at the No. 3 reactor is less severe, however, with little radioactive material having escaped so far.
“It is estimated that a large amount of hydrogen has accumulated near the upper area of the building at the No.1 Reactor, and there is a possibility of hydrogen explosion,” said Edano at a televised press conference.
Fukushima Prefecture authorities said on Sunday that so far 22 people have tested positive for radiation exposure, but 160 more may also have been irradiated at a hospital roughly six miles from the plant.
Everyone within a 20-km (12.4-mile) radius of the reactor has been evacuated.
This is the first severe reactor explosion for Japan, despite relying on 55 nuclear reactors for 30 percent of the nation’s energy needs. After the United States and France, Japan is the third largest producer of nuclear power.
With few natural resources, Japan relies mostly on imported fossil fuels. Since the 1970s, Japan has been working to become more self-sufficient in meeting energy needs; nuclear power has been a focus of that effort.
Japan’s first commercial facilities were built in 1970. Nuclear facility construction took off in the 1970s as Japan’s domestic nuclear facility industry matured. Facilities in use today were mostly built in the ’70s, ’80s, and ’90s.
Japan plans to continue increasing nuclear energy production. As of February 2011, in addition to the 55 nuclear power plants on line, two more are under construction and 12 more are planned.
The oldest reactors are just now reaching 40 years in operation; the end of their expected life cycle. In 2008, Japan announced a plan to reduce greenhouse gas emissions by 90 percent by 2100. The plan relies on increasing nuclear energy production to meet 60 percent of energy needs.
Japan’s first commercial facilities were built in 1970. Nuclear facility construction took off in the 1970s as Japan’s domestic nuclear facility industry matured. Facilities in use today were mostly built in the ’70s, ’80s, and ’90s.
Japan plans to continue increasing nuclear energy production. As of February 2011, in addition to the 55 nuclear power plants on line, two more are under construction and 12 more are planned.
The oldest reactors are just now reaching 40 years in operation; the end of their expected life cycle. In 2008, Japan announced a plan to reduce greenhouse gas emissions by 90 percent by 2100. The plan relies on increasing nuclear energy production to meet 60 percent of energy needs.
Earthquake Frequency
Located at the intersection of four continental plates, Japan frequently experiences earthquakes. According to the U.S. Geological Survey Japan, experienced 30 major earthquakes of more than 5.9 on the Richter scale since 1995, including the 1995 Kobe earthquake that killed more than 5,500 people.
The closest nuclear facilities to Kobe, 68 miles north, were not affected in 1995. But after the Kobe earthquake Japan put together a panel to review the safety and design guidelines of nuclear facilities.
Because powerful earthquakes are frequent in Japan, nuclear facilities are built with special attention to exact location, design, and construction, for which codes are far stricter than non-nuclear facilities. Reactors are built on hard rock foundations rather than sediment to reduce the impact of tremors on the building.
After the Kobe quake, the Japanese Nuclear Safety Commission reviewed the structural criteria required for a nuclear plant to withstand a large earthquake. The commission concluded that current structural guidelines would enable a nuclear power plant to survive near the epicenter of magnitude 7.75 quake.
Originally written in 1978, nuclear facility seismic building codes were partially revised in 2001. A 2000 quake of magnitude 7.3 in an area not lying on a fault ilne prompted a full review of seismic building codes that was completed in 2006. The Nuclear Safety Commission then required plant owners to review each plant’s structural integrity in light of revised guidelines.
The closest nuclear facilities to Kobe, 68 miles north, were not affected in 1995. But after the Kobe earthquake Japan put together a panel to review the safety and design guidelines of nuclear facilities.
Because powerful earthquakes are frequent in Japan, nuclear facilities are built with special attention to exact location, design, and construction, for which codes are far stricter than non-nuclear facilities. Reactors are built on hard rock foundations rather than sediment to reduce the impact of tremors on the building.
After the Kobe quake, the Japanese Nuclear Safety Commission reviewed the structural criteria required for a nuclear plant to withstand a large earthquake. The commission concluded that current structural guidelines would enable a nuclear power plant to survive near the epicenter of magnitude 7.75 quake.
Originally written in 1978, nuclear facility seismic building codes were partially revised in 2001. A 2000 quake of magnitude 7.3 in an area not lying on a fault ilne prompted a full review of seismic building codes that was completed in 2006. The Nuclear Safety Commission then required plant owners to review each plant’s structural integrity in light of revised guidelines.
Nuclear plants are also set up with seismic detectors that safely shut down the reactors when earthquakes cause ground motion of a certain magnitude.
Earthquakes in Japan in 2004, 2005, 2007, and 2009 shut down nuclear reactors when tremors set off their trip switches.
A severe earthquake in Taiwan in 1999 also tripped kill switches at three reactors in Japan. The reactors were restarted days later.
Japan will likely be reviewing safety precautions of nuclear facilities again after Saturday’s explosion.
Nicholas Zifcak is reporting from New York.
Earthquakes in Japan in 2004, 2005, 2007, and 2009 shut down nuclear reactors when tremors set off their trip switches.
A severe earthquake in Taiwan in 1999 also tripped kill switches at three reactors in Japan. The reactors were restarted days later.
Japan will likely be reviewing safety precautions of nuclear facilities again after Saturday’s explosion.
Nicholas Zifcak is reporting from New York.
