Update 3/17/11 10:00 EST (Reuters) – A water cannon began dousing an overheating nuclear reactor at Japan’s quake-stricken power plant on Thursday, after earlier being forced to withdraw because of high radiation levels, broadcaster NHK said.The water cannon had been called in to spray the Fukushima Daiichi complex’s No.3 reactor, which contains plutonium fuel and has been the top priority for authorities. [more below]
Update 3/17 @04:00 EST – The Latest Developments a Reactor by Reactor Roundup – “Because we cannot get near it, the only way to monitor the situation is visually from far away.” The not so reassuring words from Japanese officials.
ZAO, Japan — Japanese military helicopters dumped loads of seawater onto a stricken nuclear reactor Thursday, trying to avoid full meltdowns as plant operators said they were close to finishing a new power line that could restore cooling systems and ease the crisis.
U.S. officials in Washington, meanwhile, warned that the Fukushima Dai-ichi plant in northeastern Japan may be on the verge of spewing more radioactive material because water was gone from a storage pool for spent nuclear fuel rods.
The troubles at several of the plant’s reactors were set off when last week’s earthquake and tsunami knocked out power and ruined backup generators needed for their cooling systems, adding a major nuclear crisis for Japan as it dealt with twin natural disasters that killed more than 10,000 people and left hundreds of thousands homeless.
After a third explosion Tuesday at the Fukushima Daiichi nuclear power plant, the government is telling people living within 20 miles to stay indoors with the windows closed because of the possibility of high levels of radiation being released from the plant.
A Japanese military CH-47 Chinook helicopter began dumping seawater on the damaged reactor of Unit 3 at the Fukushima complex at 9:48 a.m., said defense ministry spokeswoman Kazumi Toyama. The aircraft dumped at least four loads on the reactor, though much of the water appeared to be dispersed in the air.
The dumping was intended both to help cool the reactor and to replenish water in a pool holding spent fuel rods, Toyama said. The plant’s owner, Tokyo Electric Power Co., said earlier that the pool was nearly empty, which might cause the rods to overheat.
Emergency workers were forced to retreat from the plant Wednesday when radiation levels soared, losing precious time. They resumed work after radiation levels dropped, but much of the monitoring equipment in the plant is inoperable, complicating efforts to assess the situation. “We are afraid that the water level at unit 4 is the lowest,” said Hikaru Kuroda, facilities management official at Tokyo Electric Power Co. But he added, “Because we cannot get near it, the only way to monitor the situation is visually from far away.”
Japanese officials raised hopes of easing the crisis, saying early Thursday that they may be close to bringing power back to the plant and restoring the reactors’ cooling systems. The new power line would revive electric-powered pumps, allowing the company to control the rising temperatures and pressure that have led to at least partial meltdowns in three reactors. The company is also trying to repair its existing disabled power line. Tokyo Electric Power spokesman Naoki Tsunoda said the new power line to the plant is almost finished and that officials plan to try it “as soon as possible,” but he could not say exactly when. (read more)
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Helicopters are dumping water on a stricken reactor in northeastern Japan to cool overheated fuel rods inside the core. The crisis at several reactors of the Fukushima Dai-ichi plant were set off when last week’s earthquake and tsunami knocked out power needed for their cooling systems and ruined backup generators. Japanese officials struggling to avoid full meltdowns have raised hopes of easing the crisis, saying they may be close to bringing power back to the plant and restoring the cooling systems.
Check back soon for further information. AP’s earlier story is FUKUSHIMA, Japan (AP) — Nuclear plant operators trying to avoid complete reactor meltdowns said Thursday that they were close to finishing a new power line that could end Japan’s crisis, but several ominous signs have also emerged: a surge in radiation levels, unexplained white smoke and spent fuel rods that U.S. officials said might be on the verge of spewing more radioactive material.
Surging radiation levels temporarily halted work to cool the troubled reactors at the Fukushima Daiichi nuclear power plant, raising worries that officials are running out of options to stabilize the escalating catastrophe. “We’re very close now to the point of no return,” Dr. Michio Kaku, a theoretical physicist, said. “It’s gotten worse. We’re talking about workers coming into the reactor perhaps as a suicide mission and we may have to abandon ship.” A group of 180 workers rotate shifts working at the plant in teams of 50 men. The men have been nicknamed the “Fukushima Fifty.”
Reactor by Reactor Roundup:
REACTOR No 1:
What is happening? An explosion occurred at the reactor on Saturday. Kyodo reported on Wednesday an estimated 70% of the nuclear fuel rods have been damaged. Authorities are pumping sea water into the reactor to prevent overheating, and pressure levels were stable, Edano said on Tuesday. The Japan nuclear agency said on Wednesday the pumping was proceeding smoothly.
What are the risks?
The IAEA said on Tuesday the primary containment vessel appeared intact. If the fuel rods in the reactor are not covered by coolant, they can heat up and start to melt
REACTOR No 2:
What is happening? An explosion rocked the plant on Tuesday, damaging a suppression pool, into which steam is vented from the reactor to relieve pressure. The roof of the reactor building is damaged, Jiji news agency reported. Tepco said on Tuesday the fuel rods were fully exposed. Kyodo reported an estimated 33% of the nuclear fuel rods have been damaged at the No 2 reactor. However, on Wednesday, Japan’s nuclear agency said the pumping of sea water into the reactor was proceeding smoothly.
What are the risks?
When fuel rods are no longer covered in coolant they can heat up and start to melt, raising the risk of a radiation leak. The suppression pool is part of the primary containment vessel, which is designed to prevent a leak, but the IAEA said the blast “may have affected the integrity of its primary containment vessel.” Still, beyond the primary containment vessel is the containment building, which is also designed to prevent radiation from escaping.
REACTOR No 3:
What is happening? Tepco said on Wednesday that resolving problems at this reactor was the top priority because it had the highest radiation levels. This reactor is the only one that includes plutonium in its fuel mix. The operator has been pumping sea water into the reactor to prevent overheating. The building housing the reactor was hit by an explosion on Monday. An attempt by a military helicopter to drop water on the reactor failed on Wednesday probably because radiation levels were too high, Kyodo reported. The Japan nuclear agency had said earlier in the day that the pumping of sea water was proceeding smoothly. Tepco said the spent fuel pool may have heated up, producing steam. The temperature has risen to around 60C from the usual 30C-40C but the change was not critical, it said.
What are the risks?
The International Atomic Energy Agency (IAEA) said on Tuesday that the primary containment vessel, the first line of defence against a radiation leak, appeared intact.
However, government spokesman Yukio Edano said on Wednesday there is a “possibility” the vessel had been damaged, Kyodo reported. If that is the case, authorities will be worried that radiation may leak through the first containment wall into the secondary containment building. The spent fuel pools present a radiation risk if the spent fuel is exposed to the atmosphere. When a rod is exposed to the air, zirconium metal on the rods will catch fire, which could release radiation contained in the fuel, said Arnie Gundersen, a 39-year veteran of the nuclear industry who is now chief engineer at Fairwinds Associates Inc.
REACTOR No 4:
What is happening? TV on Wednesday showed smoke or steam rising from the facility after flames were seen earlier. The reactor had been shut down for maintenance when the earthquake and tsunami struck. On Tuesday, a pool where spent fuel is stored caught fire and caused an explosion. Japan’s nuclear safety agency says the blast punctured two holes around 8-metres square in the wall of the outer building of the reactor. Tepco has said it may pour water through the two holes within two or three days to cool spent nuclear fuel that is inside. Workers cannot prepare to pour water into the pool sooner because of high radiation levels, Kyodo said. Instead, Tepco plans to bulldoze a road to the reactor building so water-pump trucks can approach and hose water inside, said Kazuya Aoki, a director of Japan’s Nuclear and Industrial Safety Agency.
What are the risks?
Exposure of spent fuel to the atmosphere is serious because there is more radiation in the spent fuel than in the reactor, said Gundersen. The spent fuel pool is not inside a containment facility either. “They need to keep water in those pools because the roof over the building housing the pools is already damaged and radiation will escape,” he said.
The pools contain racks that hold spent fuel taken from the reactor. Operators need to constantly add water to the pool to keep the fuel submerged so that radiation cannot escape. Exposing the spent fuel to the atmosphere will release radiation.
REACTOR No 5:
What is happening? The reactor had been shut down for maintenance at the time of the quake and tsunami. Tepco said on Wednesday water was being poured into the reactor and that temperatures in the spent fuel pool were rising slightly.
What is the risk?
Reactor 5 and reactor 6 are seen less at risk than reactors 1 to 4.
REACTOR No 6:
What is happening? Tepco said on Wednesday water was being poured into the reactor and that temperatures in the spent fuel pool were rising slightly.
When radiation levels surged following a fire at Unit 4 and a rising cloud of radioactive vapor from unit 3, officials deemed it too risky for the plant workers to continue their critical work of pumping sea water on the damaged reactors and fuel ponds.
“The workers cannot carry out even minimal work at the plant now,” Chief Cabinet Secretary Yukio Edano told the Associated Press. “Because of the radiation risk we are on standby.” Radiation levels were as high as 10 millisieverts per hour today, the equivalent of getting a CT scan for every hour of exposure. Radiation levels have since dropped and the plant workers are planning to return to work, officials said.
The Japanese government has actually amended its national safety standard on how much radiation workers can be exposed to so that workers can return to the plant. The limit is now 250 millisieverts, 2.5 times the previous limit.
In the aftermath of the 9.0 magnitude earthquake and tsunami, the growing fear of a nuclear meltdown has spread throughout Japan. Emperor Akihito, a figure deeply respected in Japan, spoke for the first time since the Mar. 11 earthquake that has left at least 4,340 people dead. He tried to ease worries about the country’s nuclear crisis. “With the help of those involved I hope things will not get worse,” Akihito, 77, said. He offered his condolences to a grieving nation where at least 9,083 people are still missing and 434,00 are homeless. “It is important that each of us shares the difficult days that lie ahead,” Akihito said. “I pray that we will all take care of each other and overcome this tragedy.”
In another sign of escalating nuclear danger, Cabinet Secretary Edano acknowledged that the containment vessels of some of the reactors are likely damaged. The Japan Atomic Industrial Forum confirmed damage to Units 2 and 3. The last step in a nuclear meltdown is the breaching of the containment vessels. The fact that at least two containment vessels are damaged makes nuclear experts nervous. “We have cracks now, cracks in the containment vessels…and if those cracks grow or if there’s an explosion, we’re talking a full blown Chernobyl, something beyond Chernobyl,” Kaku said.
“I think the last ace in the hole is the Japanese Air Force, the military at some point may have to take over, may have to bury these reactors in concrete just like we did at Chernobyl, sandbagging the reactor with 5,000 tons of concrete, boric acid and sand,” Kaku said. Earlier today, government officials called off a plan for helicopters to dump seawater on the troubled reactors because of the heightened radiation levels.
The Japanese government has asked for the United States’ help in the crisis. Already, seven additional experts from the U.S. Nuclear Regulatory Commission arrived in Japan today. The United States government may be sending in a special nuclear team, made up of hundreds of U.S. military and civilians trained specifically for nuclear emergencies, a team put together after the Sept. 11, 2001 terrorist attacks. They would be help respond to the disaster and offer aid to the local population if they suffered decontamination.
At least 140,000 people in the 12 mile radius around the plant have been evacuated. Those in a 12 to 19 mile radius of the plant have been ordered to stay indoors. The mayor of Minami Soma, a town within that radius, said that residents are being stigmatized, Japanese broadcaster NHK reported. “We are being labeled as contaminated lepers,” he said. The mayor said that drivers are refusing to transport supplies to them, NHK reported.
As Japan continues its rescue efforts, strong aftershocks continue to jolt the nation. Two aftershocks of magnitude 6.0 have hit Japan in the last 24 hours. The Japanese are also bracing for a cold snap. Rain and snow is expected in the north. The worry for some is whether the snow will be radioactive. Foreign Countries Begin Evacuation – Japan requests “Calm Consideration” Japan’s Foreign Ministry has urged calm as some foreign governments have issued warnings against travel to Japan, or advised citizens already in the country to leave. The moves come amid the threat of seismic aftershocks and continuing leaks from the Fukushima nuclear power plant.
The governments of Iraq, Bahrain and Angola have notified the Foreign Ministry that they will temporarily close their embassies in Japan. Their staff are reportedly moving out of Tokyo. The Foreign Ministry says the Panamanian government has transferred its embassy functions to Kobe, western Japan, and Austria has evacuated its ambassador and embassy officials to Kyoto, also in western Japan. The ministry on Wednesday asked foreign diplomats and government officials in Japan to accurately convey information provided by Japanese authorities concerning the plant.
