Japan weighs need to bury nuclear plant; tries to restore power

UPDATED @ 02:55:34 PM 18-03-2011

March 18, 2011

 

Fire trucks spray water on nuclear reactor No. 3 at Fukushima Daiichi nuclear power plant in this still image taken from video footage today March 18, 2011. — Reuters pic

 

TOKYO, March 18 — Japanese engineers conceded today that burying a crippled nuclear reactor in sand and concrete may be the only way to prevent a catastrophic radiation leak, the method used to seal huge leakages from Chernobyl in 1986.

Officials said they still hoped to fix a power cable to at least two reactors to restart water pumps needed to cool overheating nuclear fuel rods. Workers also sprayed water on the No. 3 reactor, one of the most critical of the plant’s six.

It was the first time the facility operator had acknowledged that burying the sprawling complex was an option, a sign that piecemeal actions such as dumping water from military helicopters were having little success.

“It is not impossible to encase the reactors in concrete. But our priority right now is to try and cool them down first,” an official from the plant operator, Tokyo Electric Power Co, told a news conference.

As Japan entered its second week after a 9.0-magnitude earthquake and 10-metre tsunami flattened coastal cities and killed thousands of people, the world’s worst nuclear crisis since Chernobyl looked far from over.

Millions in Tokyo remained indoors today, fearing a blast of radioactive material from the complex, 240km to the north, although prevailing winds would likely carry contaminated smoke or steam away from the densely populated city to dissipate over the Pacific Ocean.

Radiation did not pose an immediate risk to human health outside the vicinity of the plant, said Michael O’Leary, the World Health Organisation’s representative in China.

“At this point, there is still no evidence that there’s been significant radiation spread beyond the immediate zone of the reactors themselves,” O’Leary told reporters in Beijing.

Japan’s nuclear disaster has triggered global alarm and reviews of safety at atomic power plants around the world.

President Barack Obama, who stressed the United States did not expect harmful radiation to reach its shores, said he had ordered a comprehensive review of domestic nuclear plants and pledged Washington’s support for Japan.

The Group of Seven rich nations, stepping in together to calm global financial markets after a tumultuous week, agreed to join in rare concerted intervention to restrain a soaring yen.

The top US nuclear regulator said it could take weeks to reverse the overheating of fuel rods at the Fukushima Daiichi plant.

“This is something that will take some time to work through, possibly weeks, as you eventually remove the majority of the heat from the reactors and then the spent-fuel pools,” Nuclear Regulatory Commission chairman Gregory Jaczko told a news conference at the White House.

Yukiya Amano, head of the Vienna-based International Atomic Energy Agency (IAEA), arrived in his homeland today with an international team of experts after earlier complaining about a lack of information from Japan.

Graham Andrew, his senior aide, called the situation at the plant “reasonably stable “ but the government said white smoke or steam was still rising from three reactors and helicopters used to dump water on the plant had shown exposure to small amounts of radiation.

“The situation remains very serious, but there has been no significant worsening since yesterday,” Andrew said.

The nuclear agency said the radiation level at the plant was as high as 20 millisieverts per hour. The limit for the workers was 100 per hour.

Even if engineers restore power at the plant, it was not clear the pumps would work as they may have been damaged in the earthquake or subsequent explosions, and there are fears of the electricity shorting and causing another blast.

Japan’s nuclear agency spokesman, Hidehiko Nishiyama, said it was also unclear how effective spraying water on the reactors from helicopters had been yesterday. The priority was to get water into the spent-fuel pools, he said.

“We have to reduce the heat somehow and may use sea water,” he told a news conference. “We need to get the reactors back online as soon as possible and that’s why we’re trying to restore power to them.”

Asked about burying the reactors in sand and concrete, he said: “That solution is in the back of our minds, but we are focused on cooling the reactors down.”

Jaczko said the cooling pool for spent-fuel rods at the complex’s reactor No. 4 might have run dry and another was leaking.

Plutonium-uranium mixed oxide (MOX) fuel rods are placed in a storage pool at the No. 3 reactor of the Fukushima Daiichi nuclear power plant, in this picture taken August 21, 2010. — Reuters pic

An official at the plant operator said he expected power to be restored at its most troubled and damaged reactors — No. 3 and No. 4 — by Sunday. Engineers are trying to reconnect power to the least damaged reactors first.

Dollar gains as financial leaders intervene

The US dollar surged more than two yen to 81.80 after the G7’s pledge to intervene, leaving behind a record low of 76.25 hit yesterday.

Japan’s Nikkei share index ended up 2.7 per cent, recouping some of the week’s stinging losses. It has lost 10.2 per cent this week.

US markets, which had tanked earlier in the week on the back of the crisis, rebounded yesterday but investors were not convinced the advance would last.

The yen has seen steady buying since the earthquake, as Japanese and international investors closed long positions in higher-yielding, riskier assets such as the Australian dollar, funded by cheap borrowing in the Japanese currency.

Expectations that Japanese insurers and companies would repatriate billions of dollars in overseas funds to pay for a reconstruction bill that is expected to be much costlier than the one that followed the Kobe earthquake in 1995 also have helped boost the yen.

Radiation levels in Tokyo barely above average

The government had warned Tokyo’s 13 million residents yesterday to prepare for a possible large-scale blackout but later said there was no need for one. Still, many companies voluntarily reduced power, plunging parts of the usually neon-lit city in darkness.

The US embassy in Tokyo has urged citizens living within 80km of the Daiichi plant to evacuate or remain indoors “as a precaution”, while Britain’s foreign office urged citizens “to consider leaving the area”. Other nations have urged nationals in Japan to leave the country or head south.

Japan’s government has told everyone living within 20 km of the plant to evacuate, and advised people within 30km to stay indoors.

At its worst, radiation in Tokyo has reached 0.809 microsieverts per hour this week, 10 times below what a person would receive if exposed to a dental x-ray. Yesterday and today, radiation levels were within average levels.

The plight of hundreds of thousands left homeless by the earthquake and tsunami worsened following a cold snap that brought heavy snow to worst-affected areas.

Supplies of water, heating oil and fuel are low at evacuation centres, where many survivors wait bundled in blankets.

About 30,000 households in the north were still without electricity in near-freezing weather, Tohuku Electric Power Co said, and the government said at least 1.6 million households lacked running water.

The National Police Agency said today that it had confirmed 5,692 deaths from the quake and tsunami disaster, while 9,522 people were unaccounted for in six prefectures. — Reuters

China suspends nuclear building plans

17 March 2011 Last updated at 08:11 GMT

By Michael Bristow BBC News, Beijing

 China has suspended approval for new nuclear power stations following the accident at Japan's Fukushima Daiichi plant.

It will also carry out checks at existing reactors and those under construction.
China is currently building 27 new reactors - about 40% of the total number being built around the world.
The news comes as China grows increasingly worried about the nuclear accident in Japan.
'Top priority' The decision to temporarily halt approval for nuclear plants came at a meeting of China's State Council, or Cabinet, chaired by Premier Wen Jiabao.
"We will temporarily suspend approval for nuclear power projects, including those that have already begun preliminary work, before nuclear safety regulations are approved," read a statement from the State Council.
"Safety is our top priority in developing nuclear power plants."
It went on to say that China's medium and long-term nuclear plans would be "adjusted and improved".

“If there is an accident it will be worse than in Japan because many of the new plants are near high-population areas so we need to be careful”

China currently gets only about 2% of its electricity from nuclear power from 13 reactors, but it has launched an ambitious project to drastically increase those figures.

It is currently building more reactors than any other country in the world.
According to the World Nuclear Association, China wants to build a total of 110 nuclear reactors over the next few years.
This is part of a plan to develop other energy sources - such as wind and solar power - to reduce the country's dependence on coal, which currently supplies about three-quarters of its energy needs.
China also recently announced that it had developed its own technology to reprocess spent nuclear fuel, which could be used to run these new power plants.
Yang Fuqiang, an energy and climate change expert, said the government's latest move showed it was being responsible.
"There are many nuclear power stations under construction at the moment - that's risky. We have to go back and check each one," he said.
"If there is an accident it will be worse than in Japan because many of the new plants are near high-population areas so we need to be careful."
China's State Council has assured people that the country will not be affected by the radioactive leaks.
But shoppers have been buying up vast quantities of salt in many parts of the country, partly in the belief that it could protect them against radiation.
Potassium iodide, a salt, protects the thyroid gland against radioactive iodine.
Some people also seem to believe future supplies of salt could be contaminated by radiation leaking from the Daiichi nuclear plant, so they are buying up stocks now.
"We need to dispel rumours. Don't let Japan's nuclear crisis become China's salt crisis," said on online commentator.
Pharmacies are also reporting massive demand for medicine that protects against radiation.

Japanese emperor 'deeply worried'

By Richard Warry BBC News
 

Click to play

 

Prof Malcolm Sperrin, a medical physicist, on the Japan quake health risks

The Japanese authorities say radiation levels from the Fukushima Daiichi nuclear plant climbed to potentially harmful levels for a brief interval on Tuesday.

Residents living within 30km (18 miles) of the plant have been advised to leave the area, or to stay indoors, and try to make their homes airtight.
Experts have stressed that swift action should be able to minimise any impact on human health.

What are the immediate health effects of exposure to radiation?

Exposure to moderate levels of radiation - above one gray - can result in radiation sickness, which produces a range of symptoms.
Nausea and vomiting often begin within hours of exposure, followed by diarrhoea, headaches and fever.
After the first round of symptoms, there may be a brief period with no apparent illness, but this may be followed within weeks by new, more serious symptoms.
At higher levels of radiation, all of these symptoms may be immediately apparent, along with widespread - and potentially fatal - damage to internal organs.
Exposure to a radiation dose of four gray will typically kill about half of all healthy adults.
For comparison, radiation therapy for cancer typically involves several doses of between one and seven gray at a time - but these doses are highly controlled, and usually specifically targeted at small areas of the body.

 How is radiation sickness treated?

The first thing to do is to try to minimise further contamination by removing clothes and shoes, and gently washing the skin with soap and water.
Drugs are available that increase white blood-cell production to counter any damage that may have occurred to the bone marrow, and to reduce the risk of further infections due to immune-system damage.
There are also specific drugs that can help to reduce the damage to internal organs caused by radioactive particles.

How does radiation have an impact on health?

Radioactive materials that decay spontaneously produce ionising radiation, which has the capacity to cause significant damage to the body's internal chemistry, breaking the chemical bonds between the atoms and molecules that make up our tissues. The body responds by trying to repair this damage, but sometimes it is too severe or widespread to make repair possible. There is also a danger of mistakes in the natural repair process.
Regions of the body that are most vulnerable to radiation damage include the cells lining the intestine and stomach, and the blood-cell producing cells in the bone marrow.
The extent of the damage caused is dependent on how long people are exposed to radiation, and at what level.

What are the most likely long-term health effects?

Cancer is the biggest long-term risk. Usually when the body's cells reach their "sell-by date" they commit suicide. Cancer results when cells lose this ability, and effectively become immortal, continuing to divide and divide in an uncontrolled fashion.
The body has various processes for ensuring that cells do not become cancerous, and for replacing damaged tissue.
But the damage caused by exposure to radiation can completely disrupt these control processes, making it much more likely that cancer will result.
Failure to properly repair the damage caused by radiation can also result in changes - or mutations - to the body's genetic material, which are not only associated with cancer, but may also be potentially passed down to offspring, leading to deformities in future generations. These can include smaller head or brain size, poorly formed eyes, slow growth and severe learning difficulties.

Are children at greater risk?

Potentially yes. Because they are growing more rapidly, more cells are dividing, and so the potential for things to go wrong is greater. Following the Chernobyl nuclear reactor accident in the Ukraine in 1986, the World Health Organization recorded a dramatic increase in thyroid cancer among children in the vicinity.
This was because the radioactive materials released during the accident contained high levels of radioactive iodine, a material that accumulates in the thyroid.

What risk does Fukushima pose currently?

The Japanese authorities have recorded a radiation level of up 400 millisieverts per hour at the nuclear plant itself. A sievert is essentially equivalent to a gray, but tends to be used to measure lower levels of radiation, and for assessing long-term risk, rather than the short-term acute impact of exposure.
Professor Richard Wakeford, an expert in radiation exposure at the University of Manchester, said exposure to a dose of 400 millisieverts was unlikely to cause radiation sickness - that would require a dose of around twice that level (one sievert/one gray). However, it could start to depress the production of blood cells in the bone marrow, and was likely to raise the lifetime risk of fatal cancer by 2-4%. Typically, a Japanese person has a lifetime risk of fatal cancer of 20-25%.

Prof Wakeford stressed only emergency workers at the plant were at risk of exposure to such a dose - but it was likely that they would only be exposed for short periods of time to minimise their risk.
The level of exposure for the general population, even those living close to the plant, was unlikely to be anywhere near as high.

How can the Japanese authorities minimise the cost to human health?

Prof Wakeford said that provided the Japanese authorities acted quickly, most of the general population should be spared significant health problems.
He said in those circumstances the only people likely to be at risk of serious health effects were nuclear workers at the plant or emergency workers exposed to high levels of radiation.
He said the top priority would be to evacuate people from the area and to make sure they did not eat contaminated food. The biggest risk was that radioactive iodine could get into their system, raising the risk of thyroid cancer.

To counter that risk, people - in particular children - could be given tablets containing stable iodine which would prevent the body absorbing the radioactive version.
The Japanese already have a lot of iodine in their natural diet, so that should help too.

How does Fukushima compare to Chernobyl?

Professor Gerry Thomas, who has studied the aftermath of the Chernobyl disaster, said: "It is very unlikely that this will turn into anything that resembles Chernobyl.
"In Chernobyl you had a steam explosion which exposed the reactor core, which meant you had a lot of radiation shooting up into the atmosphere."
Prof Thomas said although the Chernobyl disaster had led to a rise in thyroid cancer cases, the only people affected were those living in the immediate area of the explosion and who were young at the time.

Radiation & Cancer

Nuclear power plants shut down in Germany

 

15 March 2011 Last updated at 16:21 GMT

Germany has temporarily shut down seven of its nuclear power plants while it reconsiders its nuclear strategy.

Chancellor Angela Merkel said that all reactors operational before 1980 would be taken offline, and safety checks carried out on the remaining plants.

The move comes after concerns about radiation leaks at a Japanese plant after last Friday's earthquake.
The EU has also reached agreement on "stress tests" of all European nuclear facilities.
"We want to look at the risk and safety issues in the light of events in Japan," the European energy commissioner Guenther Oettinger said.

'Out of service' Chancellor Merkel also pointed to the safety concerns behind the German move.
"In light of the situation, we will carry out a safety check of all nuclear plants," she said.
"Those nuclear power plants which began operation before 1980 will be provisionally shut down for the duration of the moratorium. They will be out of service.

"Safety is the priority. Those are the criteria by which we acted today."
All safety questions would be answered by 15 June, she said. Last year, Germany decided to extend the life of its 17 nuclear power plants by 12 years, but that decision was suspended for three months on Monday.

The government had faced growing pressure for the extension to be scrapped. More than a quarter of all German electricity comes from nuclear power. The Swiss government has also suspended decisions on its nuclear programme.

Concerns are growing about radiation leaks at a nuclear plant in Japan that has been hit by a third explosion in four days following last week's earthquake and resulting tsunami.

The blast occurred at reactor 2 at the Fukushima Daiichi plant - 250km (155 miles) north-east of Tokyo - which engineers had been trying to stabilise after two other reactors exploded.

bbc uk

Japan's nuclear explosions 'are a catastrophe'