Tag Archives: Nuclear reactor

TEPCO Plans to Flood Reactors and Extract Fukushima’s Nuclear Fuel

Tokyo Electric Power Co. said Wednesday that it plans to remove the melted nuclear fuel from inside the crippled reactors at the Fukushima No. 1 power plant after repairing the reactor containers and filling them with water. But the utility did not give further details, only saying the plan, unveiled during a meeting of a government panel on nuclear energy policy, is just "at a concept stage at the moment."The process is expected to start with the removal of radioactive substances inside the buildings housing the reactors, which would be followed by repair work on the primary containment vessels.

Read the rest of the story: Tepco plans to flood reactors, extract fuel.

http://www.youtube.com/watch?v=fbwCDnIHBpE

‘Fukushima 50’ risk lives to prevent meltdown

We do not know their names, their faces, their families or their personal stories. Nobody really does. They are strangers, in a faraway land, doing the unthinkable.

In Japan they have a name: The Fukushima 50. A coterie of nuclear plant employees — some reports indicate 50, others suggest four working rotations of 50 — who stayed behind while 700 of their co-workers were evacuated from the stricken Fukushima-Daiichi facility on the Japanese coast.

Five have been killed. Two are missing. Twenty-one have been injured in a struggle where, in the words of Japan’s Prime Minister Naoto Kan, “retreat is unthinkable.”

The men understand the stakes. They know there is no turning back. One worker told a departing colleague he was prepared to die — that it was his job. Another informed his wife he wouldn’t be coming home anytime soon.

Read the rest of the story: ‘Fukushima 50’ risk lives to prevent meltdown.

http://www.youtube.com/watch?feature=player_embedded&v=n_wCwgGV_RQ

U.S. Calls Radiation ‘Extremely High,’ Sees Japan Nuclear Crisis Worsening

The chairman of the United States Nuclear Regulatory Commission gave a far bleaker appraisal on Wednesday of the threat posed by Japan’s nuclear crisis than the Japanese government had offered. He said American officials believed that the damage to at least one crippled reactor was much more serious than Tokyo had acknowledged, and he advised Americans to stay much farther away from the plant than the perimeter established by Japanese authorities.

The announcement opened a new and ominous chapter in the five-day-long effort by Japanese engineers to bring the six side-by-side reactors under control after their cooling systems were knocked out by an earthquake and a tsunami last Friday. It also suggested a serious split between Washington and its closest Asian ally at an especially delicate moment.

The Congressional testimony by Gregory Jaczko, the chairman of the commission, was the first time the Obama administration had given its own assessment of the condition of the plant, apparently mixing information it had received from Japan with data it had collected independently.

Read the rest of the story: U.S. Calls Radiation ‘Extremely High,’ Sees Japan Nuclear Crisis Worsening.

Too dangerous: Japan suspends work at stricken nuclear plant

Japan may seek direct U.S. military help to end a crisis at a quake-damaged nuclear power plant in northeastern Japan, the chief government spokesman said on Wednesday.

Japan suspended operations to prevent a stricken nuclear plant from melting down Wednesday after a surge in radiation made it too dangerous for workers to remain at the facility.

Chief Cabinet Secretary Yukio Edano said work on dousing reactors with water was disrupted by the need to withdraw.

The level of radiation at the plant surged to 1,000 millisieverts early Wednesday before coming down to 800-600 millisieverts. Still, that was far more than the average

"So the workers cannot carry out even minimal work at the plant now," Edano said. "Because of the radiation risk, we are on standby."

Experts say exposure of around 1,000 millisieverts is enough to cause radiation sickness.

Earlier officials said 70 percent of fuel rods at one of the six reactors at the plant were significantly damaged in the aftermath of Friday’s calamitous earthquake and tsunami.

Read the rest of the story: Japan suspends work at stricken nuclear plant.

Japan Faces Potential Nuclear Disaster as Radiation Levels Rise

Japan’s nuclear crisis verged toward catastrophe on Tuesday after an explosion damaged the vessel containing the nuclear core at one reactor and a fire at another spewed large amounts of radioactive material into the air, according to the statements of Japanese government and industry officials.

In a brief address to the nation at 11 a.m. Tokyo time, Prime Minister Naoto Kan pleaded for calm, but warned that radiation had already spread from the crippled reactors and there was “a very high risk” of further leakage. Fortunately, the prevailing winds were sweeping most of the plume of radioactivity out into the Pacific Ocean, rather than over populated areas.

The sudden turn of events, after an explosion Monday at one reactor and then an early-morning explosion Tuesday at yet another — the third in four days at the plant — already made the crisis at the Fukushima Daiichi Nuclear Power Station the worst nuclear accident since the Chernobyl reactor disaster a quarter century ago.

It diminished hopes earlier in the day that engineers at the plant, working at tremendous personal risk, might yet succeed in cooling down the most damaged of the reactors, No. 2, by pumping in sea water. According to government statements, most of the 800 workers at the plant had been withdrawn, leaving 50 or so workers in a desperate effort to keep the cores of three stricken reactors cooled with seawater pumped by firefighting equipment, while the same crews battled to put out the fire at No. 4 reactor, which they claimed to have done just after noon on Tuesday.

Read the rest of the story: Japan Faces Potential Nuclear Disaster as Radiation Levels Rise.

An overview of Japan’s nuclear issues

Japan’s electric power companies run 54 nuclear reactors, with two under construction, at 17 power plants, according to figures from the International Atomic Energy, the U.N. nuclear watchdog. They produced more than 280,000 gigawatt-hours of electricity in 2010 — about 30 percent of Japan’s total electricity generation.

Most Japanese plants — including the three facing emergencies since the earthquake — use boiling-water reactors, in which water circulated through the reactor is converted to steam and used to drive a generator.

Most U.S. reactors and about 40 percent of Japan’s are pressurized-water reactors, in which reactor coolant is kept separate from the steam used to drive generators.

Both types are far different than the Soviet design involved in the 1986 Chernobyl disaster, a reactor model now considered unsafe by the international nuclear industry. In addition, the Chernobyl plant lacked the kind of reinforced steel-and-concrete containment structure that U.S. and Japanese regulators require.

Read the rest of the story: An overview of Japan’s nuclear issues .

Nuclear Plant Engineer and Designer ‘very concerned’

A local man is keeping a closer eye than most on what’s happening with Japan’s stricken nuclear reactors.

That’s because he helped develop one of them.

Ron Karzmar, a physicist and engineer, helped develop and manufacture all of the control panels and nuclear sensors inside the plant 40 years ago.

Now, he watches with the rest of the world as Japanese officials warn there could be a second explosion at the same quake-damaged plant where a nuclear reactor unit blew up on Saturday.

Read the rest of the story: Seattleite who helped design stricken nuke plant ‘very concerned’.