Washington Post, 20:12 ET, March 15:
New assessments of the explosion at Unit 2 of Japan’s stricken Fukushima Daiichi nuclear plant Tuesday heightened fears that it will begin spewing large amounts of radiation.
The explosion probably damaged the main protective shield around the uranium-filled core inside one of the plant’s six reactors. Such a breach would be the first at a nuclear power plant since the Chernobyl catastrophe in the Soviet Union 25 years ago.
The latest explosion — compounded by a fire in a different unit Wednesday morning — marked yet another setback in the five-day battle to stabilize the Daiichi facility, which suffered heavy damage to its cooling systems after Friday’s earthquake and tsunami. Other explosions occurred earlier at two of the plant’s reactors.
Tepco said a skeleton crew of 50 to 70 employees — far fewer than the 1,400 or more at the plant during normal operations — were working in shifts to keep seawater flowing to the three reactors now in trouble.
The removal of most of the plant’s workers “is a sign to me that they have given up trying to prevent a disaster and gone into the mode of trying to clean up afterward,” Gunderson said.
Also on Tuesday, and again on Wednesday morning, fires temporarily flared up in Unit 4, causing fear that spent uranium fuel sitting in a pool above the reactor was burning. Such a conflagration would generate intense concentrations of cesium-137 and other dangerous radioactive isotopes.
A spokesperson for the Nuclear Energy Institute, an industry lobbying group, said that Tepco concluded that the first fire in Unit 4 was not in the spent fuel pool, “but rather in a corner of the reactor building’s fourth floor.”
With the outer containment building at Unit 2 primed for a possible explosion, any fire crews would be in grave peril.
If the fuel pools are exposed to the air, the radiation doses coming from them could be life-threatening up to 50 yards, Alvarez said.
Satellite photos show steam rising from the facility. The amount of radioactivity carried by the plume is unknown, but small increases in radiation — not enough to affect human health — were reported in Tokyo, about 150 miles to the southwest of the facility, and in other parts of Japan.
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UPDATE, March 15:
Stars and Stripes reports:
The U.S. Navy in Japan has said very low levels of airborne radiation were detected Tuesday morning at greater Tokyo-area bases in Yokosuka and Atsugi, prompting commanders to direct base residents to remain indoors as a precaution.
At 7 a.m., the aircraft carrier USS George Washington at Yokosuka Naval Base detected elevated radiation levels, according to a U.S. Navy 7th Fleet statement. The Navy said the elevated levels were associated with the disaster at the Fukushima Dai-Ichi nuclear power plant, located about 200 miles to the north.
A level of 0.5 millirems of radiation was detected at Atsugi with similar levels at Yokosuka, said Atsugi public affairs officer Tim McGough. The radiation was detected coming from winds blowing from the northeast, he said.
A Hiroshima radiation expert said that the levels of radiation detected so far at Yokosuka and Atsugi are not a health hazard.
For perspective, the U.S. Nuclear Regulatory Commission estimates that a passenger on a round-trip flight from Washington D.C. to Los Angeles would be exposed to four millirems of radiation. Hoshi said that male reproductive functions would be threatened at 10,000 millirems.
The radiation readings in Tokyo were 0.809 microsieverts (.0809 millirems) at 10 a.m. Tuesday, said Keiichi Nakaya, chief of Tokyo Metropolitan Government’s Office in Charge of Health and Safety. The reading had dropped to 0.147 microsieverts by 11 a.m., he said.
“Even the highest reading at this time has no health impact,” Nakaya said.
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New York Times
10:11 PM ET. March 14
Japan faced the likelihood of a catastrophic nuclear accident Tuesday morning, as an explosion at the most crippled of three reactors at the Fukushima Daichi Nuclear Power Station damaged its crucial steel containment structure, emergency workers were withdrawn from the plant, and much larger emissions of radioactive materials appeared imminent, according to official statements and industry executives informed about the developments.
Prime Minsiter Naoto Kan of Japan was preparing to make a televised address to the nation at 11 a.m. Tokyo time.
The sharp deterioration came after government officials said the containment structure of the No. 2 reactor, the most seriously damaged of three reactors at the Daichi plant, had suffered damage during an explosion shortly after 6 a.m. on Tuesday.
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At 20:00 ET, March 14, The New York Times reports that a new blast has occurred at Japan’s Fukushima Daiichi Nuclear Power Station, that may have damaged the inner
steel containment vessel of the No. 2 reactor, leading to the wide release of radioactive materials there and forcing the evacuation of emergency workers,
The blast appeared to be different — and more severe — than those that at two other troubled reactor at the same nuclear complex because this one, reported to have occurred at 6:14 a.m., happened in the “pressure suppression room” in the cooling area of the reactor, raising the possibility to damage to the reactor’s containment vessel.
The BBC reports at 14:32 ET, March 14:
The fuel rods inside reactor 2 at the Fukushima Daiichi were fully exposed on two occasions, although the IAEA has said there are no signs of a meltdown.
Sea water is being pumped into the reactor to try to prevent overheating.
A cooling system breakdown preceded explosions at the plant’s reactor 3 on Monday and reactor 1 on Saturday.
The latest hydrogen blast injured 11 people, one of them seriously. It was felt 40km (25 miles) away and sent a huge column of smoke into the air.
The outer building around the reactor was largely destroyed.
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BBC Reports at 22:16 ET, March 12:
A second nuclear reactor is experiencing serious problems at Japan’s earthquake-damaged Fukushima power station in northern Japan, which was hit by a big explosion on Saturday.
The plant’s operator says pressure is rising inside reactor No. 3 after it lost its emergency cooling system.
A similar problem led to a blast at the plant’s No. 1 reactor on Saturday.
An estimated 170,000 people have been evacuated from the area around the plant, the UN nuclear watchdog says.
The Japanese government has sought to play down fears of a meltdown at Fukushima 1, but media reports say radiation has now risen above safety limits at the plant.
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While some had feared that a second explosion at the Fukushima Daiichi nuclear reactor would create a radioactive cloud and while, according to the Guardian, Japanese authorities said there was a possibility that fuel rods may have melted” and “…[t]he nation was one short step away from enduring genpatsu-shinsai – an atomic disaster triggered by earthquake…” now it has been announced that “although the outer structure of the 40-year-old reactor building had been blown off by the blast, the actual reactor inside had not been breached.”
Government spokesman Yukio Edano said that the explosion had destroyed the exterior walls of the building where the stricken reactor is located, but not the actual metal housing that enveloped the reactor.
According to the Guardian, “Disaster had been avoided – but by the narrowest of margins.”
The operators of the Fukushima plant announced they had started to fill the containment vessels in which the reactor rests with sea water in a bid to cool it down, a process that would take from five to 10 hours, an official told reporters.
Finally, “[t]he danger to the Fukushima Daiichi appears to be receding…”
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The BBC reports that “a massive explosion has rocked a Japanese nuclear power plant after Friday’s devastating earthquake.”
A huge pall of smoke was seen coming from the plant at Fukushima and several workers were injured.
Japanese officials fear a meltdown at one of the plant’s reactors but say the container housing it was not damaged.
It appears that the reactor was shut down well before any melting occurred, which should reduce considerably the risk of radioactive materials entering the environment.
However, the detection of caesium isotopes outside the power station buildings could imply that the core has been exposed to the air.
Television pictures showed a massive blast at one of the buildings of the Fukushima-Daiichi plant, about 250km (160 miles) north-east of Tokyo.
A huge cloud of smoke billows out and large bits of debris are flung far from the building.
Officials ordered the evacuation zone around the plant expanded from a 10km radius to 20km. BBC correspondent Nick Ravenscroft said police stopped him 60km from the Fukushima-Daiichi plant.
Analysts say a meltdown would not necessarily lead to a major disaster because light-water reactors would not explode even if they overheated.
But Walt Patterson, of the London research institute Chatham House, said “this is starting to look a lot like Chernobyl”.
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CNN reports that Tokyo Electric Power Co. has been cited as saying that reactors at the two Fukushima Daiichi nuclear power plants can no longer cool radioactive substances inside, and that, according to a news agency report, atomic material may have leaked out of one of the plants.” (Apparently there are two separate facilities with nuclear reactors named Fukushima Daiichi.)
There are also reports that the cooling system at three of the four units of one Fukushima Daini plant in northeastern Japan’s Fukushima prefecture had failed:
Temperatures of that plant’s coolant water was hotter than 100 degrees Celsius (212 degrees Fahrenheit), the news agency said, an indication that the cooling system wasn’t working.
Japan’s Kyodo News Agency also confirmed earlier reports that “Japan’s nuclear safety agency has ordered the power company to release valves in that plant [Fukushima Daini], as well as the other Fukushima Daiichi plant’s ‘No. 1′ reactor. The goal was to release some of the growing pressure inside the reactors tied to both atomic plants.”
The International Atomic Energy Agency said Friday on its website that the quake and tsunami knocked out the reactor’s off-site power source, which is used to cool down the radioactive material inside. Then, the tsunami waves disabled the backup source — diesel generators — and authorities were working to get these operating.
Using Air Force planes, the U.S. government has sent over coolant for the Fukushima plant, Secretary of State Hillary Clinton said Friday.
“We’re really deeply involved in trying to do as much as we can on behalf of the Japanese and on behalf of U.S. citizens,” she said.
The problems at the Fukushima Daiichi reactor are just one of many affecting power stations around the country, especially in northeast Japan.
The Tokyo Electric Power Co. said that its Fukishima Daini reactor was also shut down because of the quake, and seven thermal power stations and 24 hydro power stations that it operates also have been shut down. The Goi Thermal Power Station has since been restarted, as have hydro power stations in Niigata prefecture, the company said.
All these shutdowns had left more than 1.2 million people without power as of Saturday morning, according to the electric company.
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Kathy has already mentioned the potentially grave situation surrounding the Fukushima Daiichi nuclear power plant that has been damaged both by the earthquake and by the subsequent tsunami in Japan.
MSNBC has just announced that “slightly radioactive” steam is being vented from that plant because of the failure of power sources to operate the pumps that pump the necessary water to cool the hot reactor cores.
Japanese authorities had already warned that there could be a small radiation leak from this nuclear reactor and that technicians at the Fukushima Daiichi plant were set to release steam from the unit in question to lower the pressure and prevent a meltdown.
Japanese officials have said that a “small” amount of radioactive material could leak and that wind direction would be taken into account when releasing such radioactive steam and that the amount of steam would not be in quantities big enough to affect human health.
The reactor at the Fukushima Daiichi power station that triggered the emergency alert was the 40-year-old Reactor 1, one of six on the site.
Other affected power plants are, according to the BBC:
• Onagawa – all three reactors shut down automatically
• Fukushima Daiichi – reactors 1,2 and 3 shut down automatically; reactors 4,5 and 6 were not in operation; reactor 1 was not cooling as expected
• Fukushima Daini – all four reactors shut down automatically
• Tokai – single operational reactor shut down automatically
In total, the country has 55 reactors providing about one-third of the nation’s electricity.
The Los Angeles Times also has a report on the problems at the Japanese power plants and an extensive report on other consequences of the disaster.