Japanese nuclear disaster

[Brotherhood]

6th reactor at Fukushima Nuke plant loses cooling functions: TEPOC - People's Daily Online March 13, 2011


The Fukushima nuclear plant in Fukushima prefecture in northeastern Japan is pictured in a 2008 file photo. (Xinhua/Kyodo file photo)

A sixth reactor at the Fukushima nuclear power plants has lost its ability to cool the reactor core since the massive earthquake and ensuing tsunami struck Japan Friday, said Tokyo Electric Power Co.(TEPOC), operator and owner of the plants, early on Sunday.

The No. 3 reactor at Fukushima No. 1 nuclear power plant lost the function after No. 1 and No. 2 reactors at the No. 1 plant and No. 1, No. 2 and No. 4 at the No. 2 plant had suffered the same trouble.

At an emergency press conference early Sunday, Chief Cabinet Secretary Yukio Edano said that the reactor is releasing radioactive steam after the malfunction occurred.

An explosion occurred at the Fukushima No. 1 nuclear power plant Saturday, destroying the roof and the walls of the building of the No. 1 reactor's outer container.

Four people were injured at the power plant, but radiation levels dropped quickly after surging for a while following the blast.

Edano said that the TEPOC has begun new cooling operations to fill the reactor with sea water and pour in boric acid to prevent an occurrence of criticality.

He said that there had been no major changes in the results of monitoring radioactivity near the No. 1 reactor.

The top government spokesman warned that there are still 114 people staying within a 10-km radius of Fukushima No.1 nuclear power plants and 180,000 in the 20-km evacuation zone.

All inhabitants have been evacuated from a three-km radius of the No. 2 plant, and authorities have begun evacuating more than 30,000 from a 10-km zone around the plant, he added.

On Saturday authorities expanded the evacuation zone from a 10- km radius for the Fukushima nuclear plants to a 20-km radius.

Separately, the Fire Disaster Management Agency said Sunday that 15 people have been exposed to radioactivity within a 10-km radius of Fukushima No. 1 nuclear power plant.

Source: Xinhua

 

[CardSharp]

I have a bad feeling about this.... Hope everyone has been evacuated and there is no human radiation exposure. Dumping sea water is the last resort that the Japanese have and they are fast running out of options.

They've evacuated the area and have handed out iodine tablets.

 

[jbond197]

^^^
Brotherhood, where are you located in Japan mate? Hope everything is fine at your end..

 

[CardSharp]

^^^
Brotherhood, where are you located in Japan mate? Hope everything is fine at your end..

He's in the states for the moment and his family in Japan is fine. He told us in another thread.

 

[Solomon2]

As I understand it a crack in the inner core caused an explosion of the "wet" part of the reactor core. I am wondering if there is an update on the status of the inner core containment.

Not sure what you mean. These are boiling-water reactors, not pressurized-water reactors, so there is no "inner core".

The science talking heads on TV say using sea water as emergency coolant is unprecedented and may be a sign that the situation isn't under control.

Most reactors are designed with a large body of water nearby as an ultimate heat sink. It's unprecedented, but in the plan. What isn't known is the condition of the core.

 

[CardSharp]

Not sure what you mean. These are boiling-water reactors, not pressurized-water reactors, so there is no "inner core".

Most reactors are designed with a large body of water nearby as an ultimate heat sink. It's unprecedented, but in the plan. What isn't known is the condition of the core.

Thanks the diagram they showed on TV wasn't exactly too clear.

 

[StingRoy]

They've evacuated the area and have handed out iodine tablets.

I hope everyone is out of the 20 km radius, but I also fear about the engineers in the control room trying to fight the disaster. There are 6 reactors out there and if one explodes, it would lead to a breach of the other reactors and might result in a cascading effect.

 

[Thomas]

a couple different news organizations are reporting that at least 3 plant workers have come down with radiation sickness. Sounds like the Government is playing down how bad the radiation leak is.

Japan earthquake and tsunami: Thousands undergo radioactive screening after explosion | Mail Online

 

[casual]

a couple different news organizations are reporting that at least 3 plant workers have come down with radiation sickness. Sounds like the Government is playing down how bad the radiation leak is.

Japan earthquake and tsunami: Thousands undergo radioactive screening after explosion | Mail Online

understandable. news of a radiation leak would cause unnecessary panic.

 

[Aramsogo]

Most reactors are designed with a large body of water nearby as an ultimate heat sink. It's unprecedented, but in the plan.

I don't think dumping sea water into the core is in the formal safety plan. What safety regulator would approve of this type of contamination even as the 10th level backup system. I think they are in new territory now and writing the playbook as they go.

 

[Thomas]

I don't think dumping sea water into the core is in the formal safety plan. What safety regulator would approve of this type of contamination even as the 10th level backup system. I think they are in new territory now and writing the playbook as they go.

When they use sea water on a reactor they are effectivly putting the reactor of of commision for good. It can not be salvaged after that. It is used after they have exhuasted all options.

 

[hembo]

Radiation to impact northeast Japan
English.news.cn 2011-03-13 13:22:32

BEIJING, March 13 (Xinhuanet) --Scientists fear that radiation leaked from the Fukushima Number One Nuclear Power Plant will most likely impact the northeast region of Japan, although the government insists the levels are low.

They worry the resulting cloud will drift in the wind, affecting neighboring areas. Meteorological officials say a westerly wind will dominate the zone around the facility throughout Sunday.

Its direction will later change, and blow toward the north. Cities located north of the site will be affected. China is not predicted to be impacted by the radiation in the next three days.

Meanwhile, the Fukushima Number Two Nuclear Power Plant has also lost cooling ability. Operators are releasing steam from reactors to reduce pressure. Authorities have ordered an evacuation radius of 10 kilometers.

(Source: CNTV.cn)

 

[Kyusuibu Honbu]

a couple different news organizations are reporting that at least 3 plant workers have come down with radiation sickness. Sounds like the Government is playing down how bad the radiation leak is.

nation-wide Panic is the last they"d want at this time

 

[hembo]

Partial meltdown likely underway at reactor: Japanese official
Eric Talmadge and Yuri Kageyama
Tokyo— The Associated Press
Published Saturday, Mar. 12, 2011 12:45AM EST
Last updated Saturday, Mar. 12, 2011 11:07PM EST

A partial meltdown was likely underway at a second nuclear reactor, a top Japanese official said Sunday, as authorities frantically tried to prevent a similar threat from nearby unit following a catastrophic earthquake and tsunami.

Some 170,000 people have been ordered to evacuate the area covering a radius of 20 kilometres around the plant in Fukushima near Iwaki. A meltdown refers to a very serious collapse of a power plant's systems and its ability to manage temperatures. A complete meltdown would release uranium and dangerous byproducts into the environment that can pose serious health risks.

Read the rest on the link..

 

[hembo]

Japan nuclear plant faces new threat
Justin McCurry in Tokyo guardian.co.uk, Sunday 13 March 2011 05.28 GMT

Officials in protective gear at the the Fukushima nuclear plant in Japan. Photograph: Kim Kyung-Hoon/Reuters​

Japan is struggling to contain a growing crisis at two nuclear power plants damaged in Friday's huge earthquake and tsunami, as officials revealed that the emergency cooling system at another reactor had failed, raising fears of a serious accident.

Government officials said the negligible radioactivity levels near the plants in Fukushima prefecture posed no threat to human health. Screening centres were being set up for people worried about exposure.

Tokyo Electric Power [Tepco] decribed the situation at the Fukushima No. 1 power plant as an emergency after the cooling system failed at a second reactor at the plant.

Tepco said radioation levels at the plant had exceeded the legal limit on Sunday morning. Hourly radiation at the site was measured at 882 micro sievert, in excess of the allowable level of 500, Japan's nuclear safety agency said. The government's chief spokesman, Yukio Edano, said the level had briefly risen 1,204 micro sievert.

"There was no sudden rise in radiation because of the ventilation activities," Edano said, adding that there was no immediate threat to human health.

"We are doing the two things at the same time - venting air out of the reactor and supplying water into the reactor," he told reporters.

As authorities released steam to relieve pressure from the second overheating reactor, efforts were under way to evacuate 210,000 people living within 20 kilometres of the two plants.

Among those waiting to leave was Reiko Takagi, who lives in Iwaki, about 30 kilometres from the No. 1 plant.

"Everyone wants to get out of the town. But the roads are terrible," she said. "It is too dangerous to go anywhere. But we are afraid that winds may change and bring radiation toward us."

Edano said: "There is no confusion at this point, although we appreciate that people will have to leave their homes and livelihoods behind, but there is no panic."

Efforts were also under way to cool off three reactors at the firm's No. 2 nuclear plant in Fukushima, about 150 miles south of Tokyo.

The complete failure of more cooling systems has added an additional level of danger to what was already one of the worst nuclear accidents in Japan's history. The government has classed the accident as level four on an international scale of zero to seven.

At least 22 people are known to have been exposed to radiation and were being treated in hospital, but Japan's nuclear and industrial safety agency said that as many as 160 people may have been exposed.

Tepco confirmed that the No. 3 reactor of the quake-hit Fukushima plant had lost its cooling functions. Yesterday a small amount of radiation leaked after similar problems hit the facility's No. 1 reactor.

Nineteen people were found to have been exposed to radioactivity on Sunday; three more were exposed when the roof of a building housing the No. 1 reactor exploded the previous day.

Tepco said the No. 1 reactor had partially melted – the first time this has happened in Japan – and was continuing effort to cool the reactor with seawater, a procedure a British nuclear expert described as "an act of desperation".

The company notified the government on Sunday morning that the No. 3 reactor had lost the ability to cool the reactor core, and that radiactive steam was being released. Kyodo News quoted Tepco as saying that the up to three metres of MOX fuel rods were exposed above water at the Fukushima plant.

Shaun Burnie, an independent nuclear energy consultant and forner head of nuclear campaigns at Greenpeace, said the presence of a percentage of fuel core loaded with plutonium MOX fuel in the No. 3 reactor posed a grave threat to the surrounding area.

"Plutonium MOX fuel increases the risk of nuclear accident due the neutronic effects of plutonium on the reactor," Burnie told the Guardian. "In the event of an accident - in particular loss of coolant - the reactor core is more difficult to control due to both neutronics and higher risk of fuel cladding failure.

"In the event of the fuel melting and the release of plutonium fuel into the environment, the health hazards are greater, including higher levels of latent cancer."

The MOX fuel was delivered in 1999 and was loaded into the reactor by Tepco only last year after sitting in Fukushima storage ponds amid opposition and delays from the prefecture's governor, Burnie said.

The No. 3 reactor is the sixth facing risks because of loss of cooling water since Friday's devastating quake and tsunami.

Tepco last night filled the No. 1 reactor with seawater and boric acid to prevent criticality - or an uncontrolled nuclear reaction – hours after an explosion blew away the roof and walls of a building housing the rector.

The blast is thought to have occurred when hydrogen being released from the reactor mixed with oxygen either in the air or in cooling water.