1.30pm (10.30pm JST): Good afternoon, welcome to the Guardian's live coverage of the Japanese humanitarian crisis and latest updates on conditions at the Fukushima Daiichi nuclear power plant. Here's a summary of the days events so far: 
 
 • Authorities are struggling to control the situation at the Fukushima Daiichi nuclear plant, where the situation in reactors No 3 and No 4 remains fast-moving and perilous. 
 
 Reactor 3 is a particular worry – Japan's government said today that there a "possibility" that the reactor's primary containment vessel for radiation had been damaged after steam was seen rising into the air. Attempts to drop water from helicopters was abandoned due to radiation levels. The latest mooted plan involves a police water cannon truck. 
 
 Staff dousing reactors with seawater were forced to evacuate part of the building for a period this morning after radiation levels surged. These later receded and staff returned. 
 
 French government ministers have urged the country's nationals in Tokyo to leave Japan or else head south in case radiation is blown onto the capital, saying Japanese authorities had "visibly lost control". 
 
 • The country faces an increasingly desperate humanitarian crisis caused by the direct effects of Friday's huge earthquake and resultant tsunami, one made worse by freezing weather. 
 
 The official death toll has now hit 4,255 deaths, with 8,194 people registered as unaccounted for. Survivors, many of them homeless, are struggling with a wave of cold weather forecast to last well into this week, with night time temperatures dipping to -5C in some places. 
 
 • Japan's emperor, Akihito, has made a rare TV appearance to express his condolences to his people and his worry at the nuclear situation. 
 
 
 
 • Following its precipitous plunge yesterday, Tokyo's stock market bounced back nearly 6%. Japan's central bank has injected a further $40bn into the financial markets. 
 
 You can read our previous live blog following Wednesday's developments here. 
 
 1.41pm (10.41pm JST: Ian Sample, the Guardian's science correspondent, has been talking to Andrew Sherry, director of the Dalton Nuclear Institute at Manchester University, about steam seen rising from the reactor 3. Ian says the fact steam is escaping does not necessarily mean any of the "serious containment structures" within reactor 3 have been damaged: 
 
 Specifically, I wondered how the steam could be radioactive, given all the containment systems that surround the reactor core. This is different to the steam that is released regularly when the engineers vent the pressure vessel after pumping it full of seawater. One likely scenario is this: high pressures in the reactor vessel can cause it to dump steam into what's called a torus beneath it. This is a metal donut half-filled with water. That torus was thought to be damaged in yesterday's explosion, so steam might be leaking from that. Crucially, the torus is outside any of the serious containment structures - only the outer building can hold the radioactive steam in, but the outer building was torn apart in an explosion. Another source of the steam is water boiling at the spent fuel rod pools. 
 
 1.46pm (10.46pm JST: My colleague Martin Shuttleworth has updated the Guardian's before and after pictures showing the devastation caused by the Japanese tsunami. 
 
 The images show a lot of is yet to recede from the worst hit areas. 
 
 1.58pm (10.58pm JST): James Randerson has sent through some more interesting nuclear context, from the UK's Institution of Mechanical Engineers. He particularly highlights this snippet: 
 
 A concern for the people not just of Japan but the Pan Pacific area is whether Fukushima will turn into the next Chernobyl with radiation spread over a big area. The answer is that this scenario is highly unlikely, because of the wildly different design of the two reactors. 
 
 The reason why radiation was disseminated so widely from Chernobyl with such devastating effects was a carbon fire. Some 1,200 tonnes of carbon were in the reactor at Chernobyl and this caused the fire which projected radioactive material up into the upper atmosphere causing it to be carried across most of Europe. 
 
 There is no carbon in the reactors at Fukushima, and this means that even if a large amount of radioactive material were to leak from the plant, it would only affect the local area. 
 
 The Japanese authorities acted swiftly and decisively in evacuating people living within 20km of the plant, and ensuring people living within 30km of the plant remained in their homes, with windows and doors closed. The radiation measured so far at Fukushima is 100,000 times less than that at Chernobyl. 
 
 2.23pm (11.23pm JST): The New York Times has gone big today on comments by Yukio Edano, variously described as the chief cabinet secretary or the government's chief spokesman, that a cloud of steam rising from the No 3 reactor at the Fukushima nuclear plant indicated that the reactor's containment vessel, designed to keep in radiation, might have been ruptured. At a subsequent press conference he said that there was little chance of serious damage. But as the NYT notes, the "rapid and at times confusing pronouncements" by Japan's government are far from reassuring. 
 
 2.31pm (11.31pm JST): It seems that a small number of people are benefiting from the nuclear scare: Adam Gabbatt reports here how sales of potassium iodide supplements, intended to limit the risk from radiation, have soared in the US and Canada. 
 
 2.45pm (11.45pm BST): A man from the University of Canterbury in New Zealand who put together an interactive map of the various tremors which hit Christchurch has done the same for Japan (see screengrab below). It's fascinating – and frightening – to watch the sheer number of aftershocks. 
 
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 2.51pm (11.51pm JST): The main focus on this new blog so far has been on the nuclear situation, which is in some ways understandable as it's the most fast-moving and unpredictable element of the story, four days after the main quake and tsunami. But it's worth reiterating – as I tried to in this morning's blog – that a far greater humanitarian crisis remains. 
 
 As well as an official death toll now over 4,200, which will inevitably rise much higher, hundreds of thousands of people have been left homeless, in many cases losing just about every possession. Their plight has been made worse by the severe weather affecting much of Japan's north-east at the moment, with some areas experiencing blizzards and temperatures of -5C. There are temporary evacuation shelters but these are generally basic and often very chilly. Food and fuel are in short supply. 
 
 As we reach midnight in Japan it's perhaps worth looking through today's photo gallery of the quake aftermath and reflecting that worries about Chernobyl-style clouds of radioactivity sweeping across the Pacific, while understandable, are not the only issue. 
 
 3.20pm (12.20am JST): John Vidal reports that David Cameron has said nuclear power should remain part of the UK's energy mix, while stressing there were lessons to be learned from the Japanese nuclear crisis. 
 
 "I do think that nuclear power should be part of the mix in future as it is part of the mix right now," Cameron told parliament. 
 
 "Obviously I'm sure that everyone watching the dreadful events in Japan will want to make sure we learn any lessons." 
 
 Cameron's comments have provoked an immediate response from environment groups, John says. Here's a statement from Friends of the Earth: 
 
 The events in Japan must lead to an urgent review of UK plans to build more nuclear reactors. The UK can meet its energy needs and tackle climate change by harnessing its vast renewable energy potential and slashing energy waste – new nuclear stations will inevitably starve these programmes of vital funds. We must invest in a cleaner, safer future – nuclear power is a gamble we don't need to take. 
 
 3.34pm (12.34am JST): Japanese authorities have "reported concerns" about the condition of the spent nuclear fuel pool at Fukushima Daiichi Unit 3 and Unit 4, the International Atomic Energy Agency has said. 
 
 Japanese Defence Minister Toshimi Kitazawa announced Wednesday that Special Defence Forces helicopters planned to drop water onto Unit 3, and officials are also preparing to spray water into Unit 4 from ground positions, and possibly later into Unit 3. Some debris on the ground from the 14 March explosion at Unit 3 may need to be removed before the spraying can begin. 
 
 The IAEA quote above is already a little out of date – while Japan had indeed planned to use helicopters, we heard earlier that this plan had to be abandoned due to radiation levels. 
 
 With the helicopters abandoned, plans are apparently now reliant on water cannon being deployed from ground level. 
 
 3.44pm (12.44am JST): Right on cue, Kyodo news is reporting that a "water cannon vehicle" has arrived at reactor 4. 
 
 3.49pm (12.49am JST): Suzy Goldenberg has just been on a conference call with US energy secretary and Nobel prize winner (in atomic physics) Stephen Chu. Suzy was tweeting as Chu spoke – here's a sample: 
 
 • @suzyji Chu - There are several reactors now at risk. We do not want to speculate as to what will happen #eg 
 
 • @suzyji Chu - We think there is a partial meltdown in #Japan, but doesn't mean containment vessel will fail #eg 
 
 3.55pm (12.55am JST): Reuters is reporting that the head of the International Atomic Energy Agency has said the situation at the Fukushima Daiichi nuclear power plant is "very serious". 
 
 4.03pm (1.03am JST): "The magnitude of the Japanese earthquakes and the main resulting tsunami are apparent from the immense scale of devastation and from the fact that all countries around the Pacific were affected," says Dr Philippe Blondel, deputy director of the Centre for Space, Atmospheric & Oceanic Science at University of Bath. 
 
 Blondel adds that the "current fears about nuclear safety should not shadow the huge plight of the refugees": 
 
 For example, the tsunami waves were still more than 1m high when they reached New Zealand, having travelled the 8,000 km in about 12 hours. And they even reached Antarctica, albeit much reduced in height. The current fears about nuclear safety should not shadow the huge plight of the refugees and the difficulties of on-going search and rescue operations. They are taking place in the background of regular earthquakes, some of them associated to tsunami alerts. The Japanese Meteorological Agency estimated on Monday that the next 3 days would see a 40% probability of large aftershocks (more than magnitude 5), reducing to 20% from 17-20 March. Current activity supports their predictions." 
 
 4.13pm (1.13am JST): The US is to fly a spy plane over the stricken Fukushima plant in a bid to get a closer look at the damage, according to Kyodo news. 
 
 The Japanese news agency said the military will operate an unmanned Global Hawk high-altitude reconnaissance aircraft over the plant, perhaps as soon as Thursday, to examine the plant's reactors, Kyodo said, quoting a government source. 
 
 "Photographs taken by the plane equipped with infrared sensors could provide a useful clue to what is occurring inside the reactor buildings, around which high-level radiation has been detected," it added. 
 
 4.21pm (1.21am JST): The director general of the International Atomic Energy Agency, Yukiya Amano, has said he will travel to Japan as soon as possible, perhaps arriving as soon as Thursday. 
 
 Amano, who is from Japan originally, will meet with senior officials and stay one night, he told reporters this afternoon. He said he hopes to come back with "firsthand information" on the situation and address the issue of improving the flow of information to the IAEA. 
 
 Earlier today Amano urged the Japanese government to provide better information to the agency about the nuclear crisis. 
 
 4.58pm (1.58am JST): Australia has advised its citizens to consider leaving Tokyo and earthquake-affected areas, but has said its advice is not due to the threat of nuclear contamination. 
 
 The country's Department of Foreign Affairs and Trade said its advice to Australians had nothing to do with the threat from the damaged plant. 
 
 "We are providing this advice because of the continuing disruption to major infrastructure, its impact on the welfare of people on the ground and continuing aftershocks," its notice said. 
 
 5.36pm: Reuters reports that the US government is now advising its citizens who live within 80km of the Fukushima nuclear plant evacuate or take shelter indoors. The Japanese government has not altered its 20km exclusion zone. 
 
 6pm: It's 3am JST in Japan, here's a summary of events today so far: 
 
 • Tens of thousands of people are still missing since Friday's earthquake and tsunami. Around 850,000 households in the north of the country are still without power in near-freezing weather conditions, and water supplies are disrupted in the worst hit areas. The official death toll has reached 4,000 but the total number of dead is expected to exceed 10,000. 
 
 • A massive international rescue effort to help Japan find and aid survivors is gathering pace. Japan's foreign ministry said today that 113 countries and regions as well as 24 international organisations had offered help, as well as offering assistance to tackle the deepening crisis at the Fukushima nuclear site. 
 
 • Yukiya Amano, the head of the International Atomic Energy Agency, said the situation at the Fukushima Daiichi nuclear power plant is "very serious" and confirmed core damage at reactors 1, 2 and 3. Amano is to visit Japan as early as Thursday. 
 
 • Earlier on Wednesday, a fire broke out at reactor No 4, a day after a blast blew a hole in the building housing the reactor's spent fuel rods. White smoke seen from No 3 reactor – thought to be most at risk – is most likely to be steam from water being poured in to cool exposed fuel rods. 
 
 • Japanese authorities are resorting to desperate measures to cool down the damaged reactors. Plans for military helicopters to pour water onto a damaged reactor are being reconsidered, after an earlier attempt was aborted due to safety concerns. Police will attempt to add coolant to the No 4 reactor's spent fuel pool using a water cannon. 
 
 • Japan's government says radiation levels around the Daiichi site are not at levels to cause an immediate health risk, while the Japanese Red Cross says Tokyo is safe for international travellers. The World Health Organisation says there is no evidence of a significant spread of radiation from the crippled Fukushima plant. 
 
 • In a rare bright spot, the Nikkei share index gained 4.5% during trading on Wednesday as several major companies announced plans to reopen businesses. The country's central bank, the Bank of Japan, continued to inject trillions of yen to keep the economy functioning. 
 
 This is Richard Adams in the Guardian's Washington bureau taking over live blogging duties. 
 
 6.20pm: Tepco, the operator of the Fukushima Daiichi plant, is holding a press briefing and saying that a new power line that could solve the cooling problem at the plant is almost ready. 
 
 No details yet but presumably that could mean the company could reconnect the reactors to the grip and so operate their usual cooling functions. Let's wait and see. 
 
 6.33pm: The UK's Foreign Office is now advising that British nationals currently in Tokyo and to the north of Tokyo should consider leaving the area: 
 
 We advise against all non essential travel to Tokyo and north eastern Japan given the damage caused by the 11 March earthquake and resulting aftershocks and tsunami. Regarding the situation at the Fukushima nuclear facility, the most recent advice from the UK's Chief Scientific Adviser remains that for those outside the exclusion zone set up by the Japanese authorities there is no real human health issue that people should be concerned about. This advice is kept under constant review. However, due to the evolving situation at the Fukushima nuclear facility and potential disruptions to the supply of goods, transport, communications, power and other infrastructure, British nationals currently in Tokyo and to the north of Tokyo should consider leaving the area. 
 
 More FCO information here. 
 
 6.48pm: Some more details on the new power lines being laid to the Fukushima plant, from the Associated Press: 
 
 The operator of Japan's tsunami-crippled nuclear plant says it has almost completed a new power line that could restore electricity to the complex and solve the crisis that has threatened a meltdown. Tokyo Electric Power Co spokesman Naoki Tsunoda said early Thursday the power line to Fukushima Dai-ichi is almost complete. Officials plan to try it "as soon as possible" but he could not say when. The new line would revive electric-powered pumps, allowing the company to maintain a steady water supply to troubled reactors and spent fuel storage ponds, keeping them cool. The nuclear crisis has triggered international alarm and partly overshadowed the human tragedy caused by Friday's earthquake and tsunami that pulverized Japan's northeastern coastline. 
 
 7pm: The latest estimates from Japan's National Police Agency puts the tally of dead and missing at 12,000, with the death toll to date above 4,000. 
 
 According to a statement by the agency: 
 
 As of 10pm [JST], the death toll from the disaster stood at 4,277. The number of deaths stood at 2,207 in Miyagi Prefecture, the highest figure among the 12 prefectures where deaths have been reported. In Iwate Prefecture, 1,482 were killed. In Fukushima Prefecture, the death toll reached 533. Only 40% of the victims have been identified as of Wednesday morning, according to the NPA. At least 8,194 people are missing in six prefectures. The number stood at 3,318 in Iwate, 2,507 in Fukushima and 2,362 in Miyagi. 
 
 7.15pm: Tepco's delay in reconnecting the Fukushima plant to Japan's national grid is the subject of criticism from outside experts, writes my colleague Suzanne Goldenberg: 
 
 Kenneth Bergeron, who has done research on nuclear accident simulation at Sandia national labs in New Mexico, said the experience of Three Mile Island accident had demonstrated the importance of bringing in outside experts. "I am concerned that the management of this accident was left to very local hands for a very long time," he said. "Experience has shown in particular at Three Mile Island that sometimes the managers and operators in place when the accident has taken place are not well qualified. They may have the inability to see the big picture." In particular, he faulted the rescue effort for not immediately working to restore the power to the reactors' cooling systems. "What was really needed at Fukushima was restoration of the AC power to the emergency cooling system, and instead we saw them running fire hoses from the ocean. Time will tell whether that was the only option or not but a jerry-rigged arrangement like that sounds to me like a move or real desperation." 
 
 7.30pm: AP is reporting a very worrying comment by Greg Jaczko, chairman of the US Nuclear Regulatory Commission: 
 
 US nuclear agency chief says no more water in spent fuel pool at troubled Japan plant. 
 
 That presumably refers to No 4 reactor. Jaczko is currently giving a briefing on the nuclear plant crisis in Japan to the US Senate's committee on the environment and public works. (There's a live webcast of the briefing here.) 
 
 If Jaczko's statement is correct, then there is nothing to stop the exposed fuel rods from getting hotter and melting down. And Jaczko should know: the NRC has experts on the ground in Japan. 
 
 7.49pm: Jaczko's worrying comments below (see 7.30pm) are at odds with reports from the Japanese media saying that coolant continues to be added into the Fukushima reactors. 
 
 According to the last report from the Jiji Press agency, posted nearly three hours ago, states: 
 
 [Tepco] kept working to pump seawater into the pressure vessels of the No 1, 2 and 3 reactors of the Fukushima No 1 nuclear plant. But the water levels have not reached the top of the nuclear fuel rods, and portions of the fuel rods thus remained exposed. 
 
 On the other hand, the discrepancy between the US and official Japanese position might explain why the US has told its citizens to maintain a 50 mile (80km) exclusion zone around Fukushima, compared with the 20 mile (30km) zone imposed by the Japanese government 
 
 8pm: According to the Kyodo news agency, Japan's nuclear agency has said that the water level has been dropping in the No 5 reactor as well: 
 
 The agency said it will closely monitor data on the reactor to prevent the problems that occurred at other reactors. 
 
 Given what has happened elsewhere this isn't a surprise and we should expect the same thing in No 6 as well. Reactors 4, 5 and 6 were actually out of commission at the time of the earthquake and tsunami, but the danger remains because of the highly radioactive used fuel stored in the reactors. In the case of No 4, it may have had more spent fuel, and it was harmed by the nearby explosions in the 1, 2 and 3 reactors, which was most likely to cause of the first fire in No 4. 
 
 8.21pm: More on the comments on the Fukushima nuclear plant by Greg Jaczko, chairman of the US Nuclear Regulatory Commission, to a congressional committee in Washington: 
 
 We believe at this point that Unit 4 may have lost a significant inventory, if not lost all, of its water.... There is no water in the spent fuel pool and we believe that radiation levels are extremely high, which could possibly impact the ability to take corrective measures. 
 
 Jaczko also said there was the possibility of a leak in the spent fuel pool in reactor No 3, "which could lead to a loss of water in that pool", as well as a falling water level in the spent fuel level at the No 2 reactor. 
 
 According to Reuters, Jaczko said radiation levels around the site could give emergency workers "lethal doses" of radiation, forcing them to stay away: 
 
 "We believe that around the reactor site there are high levels of radiation," Jaczko said. "It would be very difficult for emergency workers to get near the reactors. The doses they could experience would potentially be lethal doses in a very short period of time." 
 
 8.40pm: Fukushima cannot possibly become a second Chernobyl disaster, explains Sir John Beddington, the UK's chief scientific officer, speaking to the British embassy in Tokyo: 
 
 [Even] if you then couple that with the worst possible weather situation ie prevailing weather taking radioactive material in the direction of greater Tokyo and you had maybe rainfall which would bring the radioactive material down - do we have a problem? The answer is unequivocally no. Absolutely no issue. The problems are within 30 km of the reactor. And to give you a flavour for that, when Chernobyl had a massive fire at the graphite core, material was going up not just 500m but to 30,000ft. It was lasting not for the odd hour or so but lasted months, and that was putting nuclear radioactive material up into the upper atmosphere for a very long period of time. But even in the case of Chernobyl, the exclusion zone that they had was about 30km. And in that exclusion zone, outside that, there is no evidence whatsoever to indicate people had problems from the radiation. The problems with Chernobyl were people were continuing to drink the water, continuing to eat vegetables and so on and that was where the problems came from. That's not going to be the case here. So what I would really re-emphasise is that this is very problematic for the area and the immediate vicinity and one has to have concerns for the people working there. Beyond that 20km or 30km kilometres, it's really not an issue for health." 
 
 9pm: Facebook user Jun Shiomitsu has been collating and translating into English Japanese Twitter messages sent out about people's experiences following last week's earthquake. You can read them on his Facebook page but here are a few translations: 
 
 I went out last night to help some friends who were volunteering as security personnel between Machida City and Sagami Ohno City. I saw total strangers, both young and old, helping each other along everywhere I turned and was heartened with an overwhelming feeling of encouragement. I was so touched I hid behind the toilets and cried. While most of the convenience stores near the station were closed because of the quake, there was just one Seven Eleven that was open. The employees had lit lots of candles and put them on the stores shelves. The cash register was not working and they could not take inventory, so the employees worked in threes, one reading up the item description and price, another punching the numbers into a calculator, and the last one using a flashlight to help them work. The store managed to operate both "cash registers" efficiently this way. Impressed! A goth youth with white hair and body piercings walked into my store and shoved several tens of thousands of yen [several hundred dollars ] into the disaster relief fund donation box. As he walked out, I and people around me heard him saying to his buddies, "I mean, we can buy those games anytime!" At that, we all opened our wallets and put our money into the donation box. Really, you cannot judge people by their appearances. 
 
 9.14pm: Japanese authorities have denied the claim by Greg Jaczko, chairman of the US Nuclear Regulatory Commission, that the No 4 reactor at Fukushima may have lost all its coolant. 
 
 AP reports Hajime Motojuku, spokesman for plant operator Tepco, as saying the "condition is stable" at the No 4 reactor. 
 
 9.29pm: A useful post from the journal Nature explaining the types of radiation and their effects, to help readers know their millisieverts from their microsieverts: 
 
 One of the most important and misunderstood aspects of radiation is that the effects are cumulative. That means that when thinking about health effects, the time of exposure is just as important as the dose. For example, the average person receives about 1-2 mSv per year without any bad effects, but if they received a does of 1-2 mSv/minute they would become sick in less than a day. The peak doses recorded at Fukushima Daiichi have been around 400 mSv per hour, enough to induce radiation sickness in about two hours' time. (Radiation levels at the site have since fallen, but continue to fluctuate). 
 
 9.51pm: The Guardian's Jon Watts is in Kitakami, Iwate Prefecture, finds that many of those hit by the disaster still lack blankets, food or fuel, raising fears of a full-blown humanitarian crisis: 
 
 Masaki Ohata, a pharmacist whose home in Kesennuma was destroyed by the tsunami, said the radiation threat was a lesser concern. "The nuclear meltdown is frightening. It's something you can't see that can hurt you. But frankly it is not as terrifying as the disaster I saw with my own eyes." Ohata has been sleeping in a room outside the city hall on a concrete floor with no blankets. The Guardian has spoken to dozens of refugees, all of whom were waiting for help that was yet to come on anything like an adequate scale. Some needed medicine. Others were desperate for sanitary wear. Many were cold because they lacked blankets and stoves. All were uncomfortable and unhappy about the lack of running water which meant they were having to relieve themselves in plastic bags. 
 
 10.10pm: Nuclear plant operator Tepco says it plans to try again on Thursday with its plan to drop water into the No 3 reactor by military helicopter. The frist attempt today was called off because of high radiation around the Fukushima Daiichi site, although the IAEA also had concerns about the method. 
 
 The damaged No 3 reactor remains the highest priority, because of the presence of Mox (Mixed oxide) fuel which contains highly dangerous plutonium. 
 
 10.24pm: Japan's giant car manufacturers remain closed in the wake of the traumatic earthquake and tsunami – but there was a sliver of good news from Toyota. 
 
 The company said it will keep its car production lines closed for another week, but said it will reopen its replacement parts factories on Thursday and the factories making parts for overseas production on Monday. 
 
 Nissan also said it is restarting car assembly on Thursday for as long as supplies lasts. 
 
 10.39pm: Greg Jaczko of the US Nuclear Regulatory Commission was buttonholed by journalists in Congress and pressed on his claims of no water remaining in a No 4 reactor's spent fuel pool, subsequently denied by Japanese officials. Jaczko says: 
 
 The information I have is coming from staff people in Tokyo who are interfacing with their Japanese counterparts. They believe the information they have is reliable. 
 
 The NRC has 11 staff currently working in Japan. Jaczko did also say: "It is my great hope that the information is not accurate." 
 
 10.54pm: NHK has more details on Tepco's attempts to lay new power lines to the Fukushima Daiichi nuclear plant and restart cooling systems: 
 
 The operator of the quake-damaged Fukushima Daiichi nuclear power plant says it is trying to install new power lines to reactivate its cooling systems in a desperate effort to stop the ongoing radioactive leakage. Tokyo Electric Power Company says it wants to start the work to install the new lines as early as Thursday morning. ... The top priority at the moment is restoring the functions of the cooling systems now that radiation is continuing to leak from the plant. Tokyo Power Electric Company says it is considering laying new power lines into the plant directly from cables of another power company. The company says it hopes to reactivate the cooling systems by connecting the cables to a makeshift switchboard and using them as an emergency power source for the systems. But the company says it was unable to carry out the work on Wednesday because of high readings of radiation in the compound. The company says it will try to complete the installation as soon as possible after reviewing the procedures in order to keep the workers' radiation exposure to a minimum. 
 
 11.08pm: Asahi Shimbun's English language site on Facebook has a description of the grim conditions facing refugees in the icy north of Japan, at the centre of the earthquake's devastation: 
 
 In Morioka, the mercury hit a low of minus 1.4 degrees. Throughout wide areas of the Tohoku region heavy snow forced evacuees inside evacuation centers. Many had fled their homes with little more than the clothes on their backs after the March 11 M9.0 earthquake and tsunami. Evacuees in many shelters were crammed into cold, uncomfortably tight quarters, raising fears of flu outbreaks. At municipal Daiichi Junior High School in Rikuzentakata, Iwate Prefecture, about 20 residents huddled around a large drum where a bonfire was burning. Here, at least, fuel was not a problem. "We have all the lumber we need," said one evacuee who had been at the shelter since the the first day of the disaster. He said that the fires were kept burning around the clock. With the school surrounded by homes flattened by the quake, wood was plentiful. 
 
 11.22pm: The New York Times gives its take on the differing Japanese and American views on the facts inside the Fukushima reactors: 
 
 The chairman of the United States Nuclear Regulatory Commission gave a significantly bleaker appraisal of the threat posed by Japan's nuclear crisis than the Japanese government, saying on Wednesday that the damage at one crippled reactor was much more serious than Japanese officials had acknowledged and advising Americans to evacuate a wider area around the plant than the perimeter established by Japan. 
 
 11.45pm: The Japanese yen has strengthened remarkably against the US dollar and other currencies such as the Australian dollar in overnight foreign exchange trading. 
 
 The yen now stands at its highest level against the US dollar since 1945, with just over 76 yen to the dollar, on a wave of buying in anticipation of Japanese companies selling dollar-denominated assets and moving funds back into yen. 
 
 The strengthening yen helped push Japanese share prices down, with the stronger yen making Japan's exports more expensive. The government may intervene in the foreign exchange market and sell yen to push its value down. 
 
 Meanwhile, the Bank of Japan injected trillions of yen in the country's financial system for the fourth day in a row. 
 
 12.17am: Kyodo news agency is reporting that Japanese Self-Defense Forces helicopters are in the air monitoring radiation levels above the Fukushima Daiichi reactor. 
 
 12.28am: The International Atomic Energy Agency has more bad news that temperatures within Fukushima Daiichi reactors number 4, 5 and 6 have been rising. 
 
 Until today there had been little to say about the 5 and 6 reactors, which along with reactor No 4 had been shut down at the time of the earthquake. But all three contain spent fuel. 
 
 12.42am: The search for bodies continues along Japan's northeast coast as survivors and rescue teams hunt for the missing. This AP story is filed from Miyagi prefecture: 
 
 Line after line, a list on the wall of city hall reveals the dead. Some are named. Others are identified only by a short description. Female. About 50. Peanuts in left chest pocket. Large mole. Seiko watch. Male. 70-80 years old. Wearing an apron that says "Rentacom." One set catches the eye of Hideki Kano, a man who appears to be in his 30s. "I think that's my mom!" he says. He rushes out into the snow, headed for a makeshift morgue. The list in Natori, and others along Japan's northeast coast, will only get longer. Five days after the 9-magnitude earthquake and tsunami, the official death toll is more than 4,300. More than 8,000 people are still missing, and hundreds of national and international rescue teams are looking for them. In the industrial town of Kamaishi, 70 British firefighters in bright orange uniforms clamber over piles of upturned cars to search a narrow row of pulverized homes. They wear personal radiation detectors amid fears of leaks from damaged nuclear plants far to the south. One woman's body is found wedged beneath a refrigerator in a two-story home pushed onto its side. "Today and tomorrow there is still hope that we will find survivors," says Pete Stevenson, head of the British rescue crews. "We'll just keep on carrying out the searches." 
 
 1am: Broadcaster NHK is reporting that water tankers are near the Fukushima power plant, preparing to spray water into the No 4 reactor: 
 
 High-pressure water spray vehicles will aim at the fuel storage pool through a hole in the wall of the No 4 reactor housing structure. The police unit will wear protection gear provided by the Self-Defense Forces and maintain safety measures, such as checking radiation levels during the operation. 
 
 1.14am: The Guardian's Suzanne Goldenberg looks at criticism of how Japan authorities have tackled the nuclear crisis emerging at Fukushima – and talks to the man who had to clean up Chernobyl, who has a chilling logic: 
 
 Yuli Andreyev, former head of the agency tasked with cleaning up after Chernobyl, told the Guardian that the Japanese had failed to grasp the scale of the disaster. He also said the authorities had to be willing to sacrifice nuclear response workers for the good of the greater public, and should not only be deploying a skeleton staff. "They don't know what to do," he said. "The personnel have been removed and those that remain are stretched." 
 
 Further down: 
 
 The decision to evacuate personnel when radiation levels spiked also attracted criticism. Arjun Makhijani, president of the Institute for Energy and Environmental Research, said: "How long can 50 workers last in trying to manage a disaster in four reactors?" 
 
 1.26am: Reuters has a round-up of the aftermath of Japan's earthquake disaster in numbers: 
 
 Death toll 
 
 The death toll is expected to exceed 10,000, with northeastern prefectures of Miyagi, Iwate and Fukushima most severely hit. At least 4,314 people were confirmed dead, but more than 8,600 people are still missing, Japan's Asahi newspaper quoted police as saying on early Thursday. 
 
 People evacuated 
 
 More than 440,000 people have been evacuated, NHK says. Hundreds of people are waiting for help in isolated areas and have no access to food. 
 
 People without power or water 
 
 About 850,000 households in the north are still without electricity in near-freezing weather, Tohuku Electric Power Company says. The government says at least 1.5m households lack running water. 
 
 Buildings damaged 
 
 More than 100,000 buildings have been damaged, including at least 7,400 completely destroyed, public broadcaster NHK says. 
 
 Economic impact 
 
 Citigroup expects 5tn-10tn yen in damage to housing and infrastructure, while Barclays Capital estimates economic losses of 15tn yen ($183bn) or 3% of Japan's GDP. 
 
 International aid 
 
 According to Japanese foreign ministry, 114 countries and 24 international organisations have offered assistance. 
 
 1.34am: Helicopters are now dumping water on the Fukushima Daiichi No 3 reactor in a desperate attempt to add coolant, Kyodo reports: 
 
 A Self-Defense Forces helicopter dropped water on the troubled No 3 reactor of the Fukushima nuclear power plant on Wednesday as it is feared the reactor may have released radioactive steam due to damage to its containment vessel. 
 
 According to AP, it's more than one helicopter. 
 
 1.45am: A UN forecast of the movement of a radioactive plume coming from the Fukushima reactors shows it possibly reaching California on Friday, the New York Times is reporting: 
 
 On Wednesday, the agency declined to release its Japanese forecast, which The New York Times obtained from other sources. The forecast was distributed widely to the agency's member states. But in interviews, the technical specialists of the agency did address how and why the forecast had been drawn up. "It's simply an indication," said Lassina Zerbo, head of the agency's International Data Center. "We have global coverage. So when something happens, it's important for us to know which station can pick up the event." 
 
 The report makes clear that any likely plume would have "extremely minor health consequences in the United States". 
 
 1.51am: News of a radioactive plume that could reach California may only serve to increase sales of iodide pills in the US. But Twitter warns: 
 
 Potassium Iodide Pills (KI) are NOT antiradiation pills! Americans should NOT be taking KI as it can have negative side effects for some! Nuclear Fissionary 
 
 Fissionary 
 
 
 
 That tweet comes from a pro-nuclear blog Nuclear Fissionary. 
 
 2.04am: How difficult has the tsunami damage made rescue efforts? Australian emergency crews in Japan are digging through ice to rescue bodies trapped in Minamisanriku, where more more than half of the coastal town's 17,000 residents are still missing. 
 
 ABC News reports that until yesterday the crews were having to walk 20km there and back each day to the rescue site, until the Japanese military were able to help. 
 
 2.14am: So far there have been four attempts by helicopters to dump giants buckets of water on the No 3 reactor at Fukushima Daiichi, and only one has succeeded in hitting the target. 
 
 From Asahi: 
 
 A Ground Self-Defense Force helicopter dropped water on the No 3 reactor at the Fukushima No 1 nuclear power plant at 9.48am [JST]. Two helicopters flew over the reactor four times to drop water. The helicopters scooped up seawater in an attached bucket with a capacity of 7.5 tons. The four water drops ended the helicopter operation. Workers on the ground were planning to begin spraying water from a police water cannon. A GSDF helicopter tried to drop water over the crippled reactor Wednesday, but had to abandon the plan because of the high radiation levels over the reactor. 
 
 2.19am: Power supply to the Fukushima plant may partially resume later in the afternoon, thanks to a new power line being laid by Tepco, Kyodo news agency is reporting. 
 
 2.26am: The disturbing news of some of those who died in the panic and chaos following the earthquak and tsunami last Friday. 
 
 Fukushima Prefecture is looking into the deaths of 14 hospital patients at an emergency shelter where they had evacuated. According to broadcaster NHK, officials say 128 hospital patients were taken on Monday to a relief shelter in a high school in Iwaki city. Two of them reportedly died en route, and 12 others died shortly after arriving at the shelter. 
 
 2.35am: Keiji Takeuchi, a senior staff writer at Asahi Shimbun newspaper, has a column which raises the question of the likely cost in human lives from the deadly effort required to tame Fukushima's reactors: 
 
 During the Chernobyl accident in 1986, sand was poured from the air by helicopter over the exposed reactor core. On the ground, many people worked at close range to the crippled reactor. However, the massive discharge of radioactive materials was stopped in one week. Without that death-defying effort, the world would have been contaminated to a greater degree. In the wake of that accident, the topic of working under very high radiation levels was also discussed in Japan. However, that debate faded because it would have involved the fundamental social issue of whether a democratic state can order people to do work harmful to their health. There was also the myth that major accidents just do not happen in Japan. Now, however, we face an emergency situation. A quick decision and response is required. 
 
 2.46am: Japanese prime minister Naoto Kan and US president Barack Obama held a 30 minute phone conversation this evening, with Obama promising to send more US nuclear experts to Japan, and offered further aid to help with the country's massive relief effort. 
 
 3.04am: Mizhuo Bank says all its automated teller machines have stopped working across Japan. 
 
 3.18am: 
 
 Public distrust in the government is "growing day by day" over its handling of the crisis, writes Takuya Karube of Kyodo News agency. 
 
 The commentary offers more details of the in-fighting between the government and Tepco which led to Japan's prime minister Naoto Kan and chief cabinet secretary Yukio Edano summoning executives of the power company and urging them to share information. (You'll recall that Kan was heard shouting "What the hell is going on?" at the company.) 
 
 Kiyoshi Sasamori, a former head of the Japanese Trade Union Confederation, quoted Kan as saying during their talks Wednesday, ''I went into the head office because the utility company lacks a sense of crisis as the plant's operator.'' 
 
 This is Tania Branigan in Beijing taking over from Richard Adams. 
 
 If you're just joining us, it's 3.45am in London, 12.45pm in Japan, and this is a quick summary of events: 
 
 • The official death toll following Friday's earthquake and tsunami has reached 5,000 but the total number of dead is expected to exceed 10,000. Around 850,000 households in the north of the country are still without power in near-freezing weather conditions, and water supplies are disrupted in the worst hit areas. 
 
 • A massive international rescue effort to help Japan find and aid survivors is gathering pace, but supplies remain short in many places. President Obama has just offered to send more nuclear experts and assist long term recovery efforts in a 30 minute phone conversation with Japanese prime minister Naoto Kan. 
 
 •Japanese self-defence force helicopters have been dropping water on unit 3 at the damaged nuclear plant. They appear to have been struggling to hit their target. The airdrop has finished and police water cannons will now be used. 
 
 • The move follows reports that Greg Jaczko, chairman of the US Nuclear Regulatory Commission, said there was "no water" in the spent fuel pool at troubled Japan plant. There is a lot of concern about the state of the pool at unit 4 and Kyodo news agency says the water level has dropped in unit 5 too, citing Japan's nuclear agency. 
 
 • Tepco officials are running a new powerline to the plant and say power could resume as early as this afternoon. Experts have said powering the cooling system is essential to get the plant back under control and have criticised the company's failure to deal with the issue earlier. 
 
 • The UK – which last night urged citizens in or north of Tokyo to consider leaving – is now echoing US advice to remain outside an 80km radius of the facility "as an additional precautionary measure". The embassy in Tokyo adds: "The most recent advice from the UK's Chief Scientific Adviser remains that for those outside the exclusion zone set up by the Japanese authorities there is currently no real human health issue that people should be concerned about." 
 
 • Chief government spokesman Yukio Edano says it still believes its measures are appropriate (they are: a 20km evacuation zone and a 20-30km zone in which people should remain indoors). 
 
 3.57am (12.57pm JST): On NHK, Professor Akira Yamaguchi of Osaka University has offered a somewhat gloomy analysis of the attempts to douse the fuel pool with water using helicopters. The images suggested it was "highly likely" the effort was insufficient, he said, because the spent fuel pool is believed to have been almost empty and when water is dropped from above a lot of it gets lost en route. He added: 
 
 
 
 "7.5 tonnes of water has been dumped [it seems]. We do not know the size of the pool, but judging from other examples it probably holds 2000 tonnes. It does not mean the pool needs to be completely full, but maybe a third of the tank's capacity is needed. 
 
 It [the water dumping] needs to be done continuously." 
 
 4.08am (1.08pm JST): Reuters is reporting that the US government has authorised the voluntary departure of the family members of embassy staff. The State Department is also chartering aircraft to Tokyo to help Americans leave Japan, it says. 
 
 Given the growing concern, it is worth a reminder that we have a piece looking at what the radiation levels actually mean. 
 
 And, as we have said, the bigger issue for many survivors right now is the inadequate supply of food, fuel and medicine. 
 
 4.31am (1.31pm JST): Further bad news for survivors in the quakezone: more snow is expected in Miyagi and Iwate prefectures today, though forecasters say the cold front should move away by Friday evening. 
 
 If you missed his terrific report earlier, the Guardian's Jonathan Watts has reported from Iwate on the impact of mid-winter temperatures and a shortage of supplies: 
 
 "What we urgently need now is fuel, heavy and light oil, water and food. More than anything else, we need fuel because we can't do anything without it. We can't stay warm or work the water pumps," said Masao Hara, the mayor of Koriyama city, in Fukushima prefecture... As far as the refugees are concerned, the balance of priorities is wrong. Masaki Ohata, a pharmacist whose home in Kesennuma was destroyed by the tsunami, said the radiation threat was a lesser concern. "The nuclear meltdown is frightening. It's something you can't see that can hurt you. But frankly it is not as terrifying as the disaster I saw with my own eyes." 
 
 4.42am (1.42pm JST): The office of the Japanese prime minister is using its English language Twitter account (@JPN_PMO) to reassure people in light of the US warning to stay more than 80km away from the Fukushima plant or take cover: 
 
 We believe they made a more conservative assessment of the radiation level from perspective of protecting US citizens. Mr. Edano: Japan Gov't has asked residents living btw 20 & 30 km from the plant to take shelter as a precaution. No impact on human body at present even if u staying outside for 24 hrs. 
 
 4.48am (1.48pm JST): Reuters reports that finance leaders and central bank governors from the G7 nations will hold a teleconference on Friday at 7am JST tomorrow (10pm GMT tonight for those in the UK). 
 
 "Japan will explain the damage from the earthquake, financial market movements and government efforts," Finance Minister Yoshihiko Noda told reporters. 
 
 5.01am (2.01pm JST): The BBC is carrying a disturbing report from Minamasoma, just 20km away from Fukushima No 1 plant, where residents say they are running short of supplies and complain that no one is helping them. Relief teams are reluctant to go in - remember that people 20km to 30km away from the plant have been told to stay inside - and inhabitants say there is too little fuel for everyone to leave. The footage appears to have been shot by a Japanese crew. 
 
 The town's mayor, Katsunobu Sakurai, is scathing: 
 
 
 
 "We were not told when the first reactor exploded. We just heard about it on TV. The government doesn't tell us anything. We are isolated. They are leaving us here to die." 
 
 5.27am (2.27pm JST): A quick response to some of the queries people have raised in the comments section: @kansaimon, we did indeed report on Naoto Kan shouting at Tepco executives earlier this week; I have revised that entry accordingly. 
 
 @erudition comments on the danger posed by spent fuel rods - as you say this is a big issue; we have reported on it in several places - notably in this piece by Suzanne Goldenberg. There is also a very clear explanation of the issues from the All Things Nuclear blog run by the Union of Concerned Scientists. 
 
 @gluino says Britons were advised to consider leaving Tokyo (and areas north of the capital) for reasons other than possible radiation. In fact, the Foreign Office advice specifically mentioned the "evolving situation" in Fukushima as well as potential disruptions to transport, supplies, communication and power. 
 
 As we mentioned earlier, it updated its advice this morning, urging Britons to remain outside an 80km radius of the plant "as an additional precautionary measure" or take shelter if they stayed within 30-80km. It said people within 80km of Fukushima should contact its Japan emergency hotline on +44 20 7008 0000 for further advice. 
 
 5.35am (2.35pm JST): The New York Times has a useful graphic explaining how many people are affected by the Japanese exclusion and take-shelter zones and the US evacuation recommendation. It says the US recommendation to its nationals (an 80km radius) would affect 1.9 million people if Japanese residents followed suit. 
 
 5.53am (2.53pm Japan): The Guardian's Justin McCurry in Japan has filed an update on the situation at Fukushima. His full story will be up shortly. 
 
 
 
 Attempts to cool down a stricken reactor at the Fukushima Daiichi nuclear plant suffered an early setback on Thursday after seawater dumped from the air failed to bring down radiation levels. Radiation readings taken 20 minutes after self-defence force helicopters doused the plant's No. 3 reactor remained unchanged, Tokyo Electric Power [Tepco] said, according to Kyodo news agcncy. 
 
 6.00am (3pm JST): NHK has another worrying report of shortages, this time from Minamisanriku, one of the towns worst hit by the tsunami. The mayor told the broadcaster it needs more fuel "for the very survival of its people...It is going to be a long battle." 
 
 6.19am (3.19pm JST): Kyodo points out that the yen briefly spiked to a new record high of 76.25 against the US dollar in Sydney today , having previously risen to 79 yen in New York (the previous postwar high was 79.75 yen). Although this might sound counter-intuitive, the assumption is that Japanese companies will want to repatriate funds overseas to pay for the impact of the earthquake, tsunami and nuclear crisis. 
 
 6.40am (3.40pm JST): Justin McCurry's story on this morning's water drop on to the overheating fuel pool at unit 3 is here . 
 
 Attempts to cool down a stricken reactor at the Fukushima Daiichi nuclear plant suffered an early setback on Thursday after seawater dumped from the air failed to bring down radiation levels. Radiation readings taken 20 minutes after self-defence force helicopters doused the plant's No 3 reactor remained unchanged, Tokyo Electric Power [Tepco] said, according to Kyodo news agcncy. The use of Japanese military helicopters to drop seawater onto the plant's reactor marked the opening of a new front in the battle to avert nuclear meltdown. 
 
 7.07am (4.07pm): Some good news on the recovery efforts: NHK reports that telecoms firms are sending mobile receivers, power services and phone chargers into the disaster zone. That should help with logistics, but could also be an important boost to morale, allowing more survivors to make contact with friends and loved ones. 
 
 7.20am (4.20pm JST): Kyodo says Japanese officials are "baffled" by the warning from the chair of the US nuclear regulatory commission that there was no water in the spent fuel pool in reactor 4, which we reported earlier. The NRC has dispatched experts to assist Japan as it battles the crisis at the nuclear plant. 
 
 ''There was a slight delay conveying to the U.S. side the information about whether or not there is water'' in a pool holding spent nuclear fuel rods at the quake-hit Fukushima No. 1 nuclear plant, Chief Cabinet Secretary Yukio Edano told a news conference... A Ground Self-Defense Force chopper, which doused the overheating spent nuclear fuel pool with water Thursday morning at the No. 3 reactor, found that water is left in the pond at the No. 4 unit, according to the plant operator Tokyo Electric Power Co... Based on the NRC's finding, the U.S. Embassy in Japan has asked American citizens living within an 80-kilometer radius of the Fukushima No. 1 power station to evacuate as a precautionary measure... Japan's Nuclear and Industrial Safety Agency said it believes the U.S. evacuation recommendation is ''not appropriate'' and will bolster information sharing with U.S. authorities so as not to cause misunderstandings. 
 
 7.46am (4.46pm JST): The Daily Yomiuri helps to explain why many emergency shelters are still low on food, fuel and other essentials. It says the supplies are reaching distribution depots, but officials are struggling to get them to the people who need them because of fuel shortages and because many routes are inaccessible due to quake and tsunami damage. ||||| Japan said radiation levels in spinach and milk from farms near its tsunami-crippled nuclear complex exceeded government safety limits, as emergency teams scrambled Saturday to restore power to the plant so it could cool dangerously overheated fuel. 
 
 In this image taken from a footage released by the Japan Defense Ministry, part of buildings at the Fukushima Dai-ichi nuclear complex is seen damaged just before military fire trucks sprayed the reactor... (Associated Press) 
 
 In this image taken from footage released by the Japan Defense Ministry, Japanese military personnel stand on fire engines before spraying water on reactors of the troubled Fukushima Dai-ichi nuclear... (Associated Press) 
 
 In this image taken from footage released by the Japan Defense Ministry, a fire engine from the Japan Self-Defense Forces sprays water toward Unit 3 of the troubled Fukushima Dai-ichi nuclear complex... (Associated Press) 
 
 Tayo Kitamura, 40, looks down at the wrapped body of her mother Kuniko Kitamura, 69, after Japanese firemen discovered the dead woman inside the ruins of her home in Onagawa, northeastern Japan, Saturday,... (Associated Press) 
 
 Tayo Kitamura, 40, stands on the rubble of the home of her mother, Kuniko Kitamura, 69, as Japanese firemen discover her mother's body in Onagawa, northeastern Japan Saturday, March 19, 2011. (AP Photo/David... (Associated Press) 
 
 A U.S. Marine photographs the damage at Sendai airport in Sendai, Miyagi Prefecture, Japan, Saturday, March 19, 2011. The U.S. military have been asked to help clear the debris from last week's tsunami... (Associated Press) 
 
 A man walks past a store building tangled with fishing nets and buoys washed away by the March 11 tsunami in Minamisanrikucho, Miyagi Prefecture, Japan, Saturday, March 19, 2011. (AP Photo/Kyodo News)... (Associated Press) 
 
 In this image taken from a footage released by the Japan Defense Ministry, Unit 3 reactor, left, is seen damaged by explosions at the Fukushima Dai-ichi nuclear complex just before military fire trucks... (Associated Press) 
 
 Japanese firemen carry away a body they found where it had been washed into a ravine in Onagawa, northeastern Japan, Saturday, March 19, 2011. (AP Photo/David Guttenfelder) (Associated Press) 
 
 Mizue Yamamura, 76, searches the area around her damaged apartment building for her husband in Onagawa, northeastern Japan, Saturday, March 19, 2011. Yamamura said that when the tsunami approached, she... (Associated Press) 
 
 People wait for their flights at Narita International Airport Saturday, March 19, 2011, in Narita, Japan. Tokyo's two main airports continue to fill with passengers trying to flee Japan, many fearing... (Associated Press) 
 
 Two covered bodies lay on the ground as Japanese firemen search a destroyed area of Onagawa, northeastern Japan, Saturday, March 19, 2011. (AP Photo/David Guttenfelder) (Associated Press) 
 
 Computer laptops lie damaged on the floor of a airport building at Sendai Airport in Sendai, Miyagi Prefecture, Japan, Saturday, March 19, 2011.The U.S. military have been asked to help clear the debris... (Associated Press) 
 
 A Japan Ground Self Defense Force personnel officer conducts a search of the debris at Sendai airport in Sendai, Miyagi Prefecture, Japan, Saturday, March 19, 2011. The U.S. military have been asked to... (Associated Press) 
 
 A Japan Ground Self-Defense Force officer conducts a search of the debris at Sendai Airport in Sendai, Miyagi Prefecture, Japan, Saturday, March 19, 2011.The U.S. military have been asked to help clear... (Associated Press) 
 
 In this image taken from footage released by the Japan Defense Ministry, a fire engine from the Japan Self-Defense Forces sprays water toward Unit 3 of the troubled Fukushima Dai-ichi nuclear complex... (Associated Press) 
 
 In this image taken from footage released by the Japan Defense Ministry, a fire engine from the Japan Self-Defense Forces sprays water toward Unit 3 of the troubled Fukushima Dai-ichi nuclear complex... (Associated Press) 
 
 Tayo Kitamura, 40, kneels in the street to caress and talk to the wrapped body of her mother Kuniko Kitamura, 69, after Japanese firemen discovered the dead woman inside the ruins of her home in Onagawa,... (Associated Press) 
 
 Tayo Kitamura, 40, kneels in the street to caress and talk to the wrapped body of her mother Kuniko Kitamura, 69, after Japanese firemen discovered the dead woman inside the ruins of her home in Onagawa,... (Associated Press) 
 
 Residents walk down an empty street in the tsunami and earthquake destroyed town of Onagawa, northeastern Japan Saturday, March 19, 2011. (AP Photo/David Guttenfelder) (Associated Press) 
 
 In this image taken from a footage released by the Japan Defense Ministry, Unit 3 reactor, left, is seen damaged by explosions at the Fukushima Dai-ichi nuclear complex just before military fire trucks... (Associated Press) 
 
 The food was taken from farms as far as 65 miles (100 kilometers) from the stricken plants, suggesting a wide area of nuclear contamination. 
 
 While the radiation levels exceeded the limits allowed by the government, Chief Cabinet Secretary Yukio Edano insisted the products "pose no immediate health risk." 
 
 Firefighters also pumped tons of water directly from the ocean into one of the most troubled areas of the Fukushima Dai-ichi nuclear complex _ the cooling pool for used fuel rods at the plant's Unit 3. The rods are at risk of burning up and sending radioactive material into the environment. 
 
 The first word on contaminated food in the crisis came as Japan continued to grapple with overwhelming consequences of the cascade of disasters unleashed by a 9.0-magnitude earthquake on March 11. The quake spawned a tsunami that ravaged Japan's northeastern coast, killing more than 7,200 people and knocking out backup cooling systems at the nuclear plant, which has been leaking radiation. 
 
 The tainted milk was found 20 miles (30 kilometers) from the plant, while the spinach was collected between 50 miles (80 kilometers) and 65 miles (100 kilometers) to the south, Edano told reporters in Tokyo. 
 
 More testing was being done on other foods, he said, and if tests show further contamination then food shipments would be halted from the area. 
 
 "It's not like if you ate it right away you would be harmed," Edano said. "It would not be good to continue to eat it for some time." 
 
 Edano said someone drinking the tainted milk for one year would consume as much radiation as in a CT scan; for the spinach, it would be one-fifth of a CT scan. A CT scan is a compressed series of X-rays used for medical tests. 
 
 Just outside the bustling disaster response center in the city of Fukushima, 40 miles (60 kilometers) northwest of the plant, government nuclear specialist Kazuya Konno was able to take only a three-minute break for his first meeting since the quake with his wife, Junko, and their children. 
 
 "It's very nerve-racking. We really don't know what is going to become of our city," said Junko Konno, 35. "Like most other people, we have been staying indoors unless we have to go out." 
 
 She brought her husband a small backpack with a change of clothes and snacks. The girls _ aged 4 and 6 and wearing pink surgical masks decorated with Mickey Mouse _ gave their father hugs. 
 
 Low levels of radiation have been detected well beyond Tokyo, which is 140 miles (220 kilometers) south of the plant, but hazardous levels have been limited to the plant itself. 
 
 Nuclear reactors at the Fukushima plant began overheating and leaking radiation into the atmosphere in the days after the March 11 quake and the subsequent tsunami overwhelmed its cooling systems. The government admitted it was slow to respond to the nuclear troubles, which added another crisis on top of natural disasters, which officials estimate killed more than 10,000 people and displaced more than 400,000 others. 
 
 The complex is deeply troubled, Edano said Saturday, but it's not getting worse. 
 
 "The situation at the nuclear complex still remains unpredictable. But at least we are preventing things from deteriorating," he said. 
 
 A fire truck with a high-pressure cannon was parked outside the plant's Unit 3, about 300 meters (yards) from the Pacific coast, and began shooting a stream of water nonstop into the pool for seven straight hours, said Kenji Kawasaki, a spokesman for the nuclear safety agency. 
 
 A separate pumping vehicle will keep the fire truck's water tank refilled. Because of high radiation levels, firefighters will only go to the truck every three hours when it needs to be refueled. They expect to pump about 1,400 tons of water, nearly the capacity of the pool. 
 
 Emergency workers are also funneling water into the complex's most troubled reactors _ Units 1, 2 and 3, officials said. 
 
 A power company official said holes had to punched in the roofs of the buildings housing Units 5 and 6, as workers tried to prevent dangerous buildups of hydrogen gas _ a sign that temperatures continued to rise in those units' fuel storage pools. Firefighters had started pumping water into Unit 5's pool, and the temperature had gone down, but a pump broke, delaying the refilling, the official said. 
 
 Meanwhile, Hidehiko Nishiyama of Japan's Nuclear and Industrial Safety Agency said backup power systems at the plant had been improperly protected, leaving them vulnerable to the tsunami that savaged the northeastern coast. 
 
 The failure of Fukushima's backup power systems, which were supposed to keep cooling systems going in the aftermath of the massive 9.0-magnitude earthquake, let uranium fuel overheat and were a "main cause" of the crisis, Nishiyama said. 
 
 "I cannot say whether it was a human error, but we should examine the case closely," he told reporters. 
 
 A spokesman for Tokyo Electric Power Co., which owns and runs the plants, said that while the generators themselves were not directly exposed to the waves, some electrical support equipment was outside. The complex was protected against tsunamis of up to 5 meters (16 feet), he said. Media reports say the tsunami was at least 6 meters (20 feet) high when it struck Fukushima. 
 
 Spokesman Motoyasu Tamaki also acknowledged that the complex was old, and might not have been as well-equipped as newer facilities. 
 
 Plant operators also said they would reconnect four of the plant's six reactor units to a power grid Saturday. Although a replacement power line reached the complex Friday, workers had to methodically work through badly damaged and deeply complex electrical systems to make the final linkups without setting off a spark and potentially an explosion. 
 
 "Most of the motors and switchboards were submerged by the tsunami and they cannot be used," Nishiyama said. 
 
 Even once the power is reconnected, it is not clear if the cooling systems will still work. 
 
 The storage pools need a constant source of cooling water. When removed from reactors, uranium rods are still very hot and must be cooled for months, possibly longer, to prevent them from heating up again and emitting radioactivity. 
 
 People evacuated from around the plant, along with some emergency workers, have also tested positive for radiation exposure. Three firefighters needed to be decontaminated with showers, while among the 18 plant workers who tested positive, one absorbed about one-tenth tenth of the amount that might induce radiation poisoning. 
 
 As Japan crossed the one-week mark since the cascade of disasters began, the government conceded Friday it was slow to respond and welcomed ever-growing help from the U.S. in hopes of preventing a complete meltdown. 
 
 The United States has loaned military firefighting trucks to the Japanese, and has conducted overflights of the reactor site, strapping sophisticated pods onto aircraft to measure radiation aloft. Two tests conducted Thursday gave readings that U.S. Deputy Energy Secretary Daniel B. Poneman said reinforced the U.S. recommendation that people stay 50 miles (80 kilometers) away from the Fukushima plant. Japan has ordered only a 12-mile (20-kilometer) evacuation zone around the plant. 
 
 Emergency crews at the plant faced two continuing challenges: cooling the nuclear fuel in reactors where energy is generated, and cooling the adjacent pools where thousands of used nuclear fuel rods are stored in water. 
 
 The tsunami knocked out power to cooling systems at the nuclear plant and its six reactors. Since then, four have been hit by fires, explosions or partial meltdowns. 
 
 The government on Friday raised the accident classification for the nuclear crisis, putting it on a par with the Three Mile Island accident in Pennsylvania in 1979, and signifying that its consequences went beyond the local area. 
 
 This crisis has led to power shortages and factory closures, hurt global manufacturing and triggered a plunge in Japanese stock prices. 
 
 Police said more than 452,000 people made homeless by the quake and tsunami were staying in schools and other shelters, as supplies of fuel, medicine and other necessities ran short. 
 
 On Saturday evening, Japan was rattled by 6.1-magnitude aftershock, with an epicenter just south of the troubled nuclear plants. The temblor, centered 150 kilometers (90 miles) northeast of Tokyo, caused buildings in the capital to shake. 
 
 ___ 
 
 Yuasa reported from Tokyo, as did Associated Press writers Mari Yamaguchi, Elaine Kurtenbach, Tim Sullivan, and Jeff Donn. ||||| His statement was quickly but not definitively rebutted by officials of Tokyo Electric Power, the Daiichi’s plant’s operator, and Japan’s nuclear regulatory agency. 
 
 “We can’t get inside to check, but we’ve been carefully watching the building’s environs, and there has not been any particular problem,” Hajime Motojuku, a spokesman for Tokyo Electric, said Thursday morning in Japan. 
 
 Later Thursday, a spokesman for Japan’s Nuclear and Industrial Safety Agency, Yoshitaka Nagayama, was more equivocal, saying, “Because we have been unable to go the scene, we cannot confirm whether there is water left or not in the spent fuel pool at Reactor No. 4.” 
 
 At the same time, officials did raise concern about two other reactors where spent fuel rods were stored, Nos. 5 and 6, saying they had experienced a slight rise in temperature. 
 
 On Wednesday night, Mr. Jaczko reiterated his earlier statement and added that commission representatives in Tokyo had confirmed that the pool at No. 4 was empty. He said Tokyo Electric and other officials in Japan had confirmed that, and also stressed that high radiation fields were going to make it very difficult to continue having people work at the plant. 
 
 Photo 
 
 If the American analysis is accurate and emergency crews at the plant have been unable to keep the spent fuel at that inoperative reactor properly cooled — it needs to remain covered with water at all times — radiation levels could make it difficult not only to fix the problem at reactor No. 4, but to keep servicing any of the other problem reactors at the plant. In the worst case, experts say, workers could be forced to vacate the plant altogether, and the fuel rods in reactors and spent fuel pools would be left to meltdown, leading to much larger releases of radioactive materials. 
 
 While radiation levels at the plant have varied tremendously, Mr. Jaczko said that the peak levels reported there “would be lethal within a fairly short period of time.” He added that another spent fuel pool, at Reactor No. 3, might also be losing water and could soon be in the same condition. 
 
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 On Thursday morning, Japan’s Self-Defense Forces started dumping water from a helicopter on reactor No. 3, making several passes. They planned to do the same for No. 4 sometime Thursday. Tokyo Electric was also working busily to complete a high power line to the plant to restore the electricity needed to run the cooling systems, according to a senior nuclear industry executive. 
 
 On Wednesday, the American Embassy in Tokyo, on advice from the Nuclear Regulatory Commission, told Americans to evacuate a radius of “approximately 50 miles” from the Fukushima plant. 
 
 The advice to Americans in Japan represents a graver assessment of the risk in the immediate vicinity of Daiichi than the warnings made by the Japanese themselves, who have told everyone within 20 kilometers, about 12 miles, to evacuate, and those 20 to 30 kilometers to take shelter. While maps of the plume of radiation being given off by the plant show that an elongated cloud will stretch across the Pacific, American officials said it would be so dissipated by the time it reached the West Coast of the United States that it would not pose a health threat. 
 
 “We would recommend an evacuation to a much larger radius than has currently been provided by Japan,” Mr. Jaczko said. That assessment seems bound to embarrass, if not anger, Japanese officials, suggesting they have miscalculated the danger or deliberately played down the risks. 
 
 Late Wednesday night, after President Obama spoke with Prime Minister Naoto Kan , the State Department announced what it described as a “voluntary” evacuation of dependents of American government personnel in northeastern Japan, down to Tokyo and Yokohama . The undersecretary of state for administration, Patrick Kennedy, said that no one would be ordered to leave the country, and embassy staff and military officials would be expected to stay and perform their jobs. But the government is providing charter flights for dependents who want to leave. 
 
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 In the same call with reporters, Daniel B. Poneman, the deputy secretary of energy, said the United States was also providing sophisticated nuclear detection devices. Some are flown aboard American aircraft. “We are dealing with this as a day to day, minute to minute situation,” he said. 
 
 It was not immediately clear how many people live within the zone around the plant that American officials believed should be evacuated. But the zone gets far closer to the city of Sendai, with its population of one million, which took the brunt of the earthquake last week. 
 
 At a hearing on Wednesday, Senator Barbara Boxer , chairman of the Senate Environment and Public Works Committee, pointed out that 50 miles could take in a huge number of people; San Onofre, in her home state, California , has seven million people living within that radius, she said. 
 
 American officials who have been dealing with their Japanese counterparts report that the country’s political and bureaucratic leadership has appeared frozen in place, unwilling to communicate clearly about the scope of the problem and, in some cases, unwilling to accept outside assistance. Two American officials said they believed that the Japanese government itself was not getting a clear picture from the Tokyo Electric Power Company. 
 
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 “Everything in their system is built to build consensus slowly,” said one American official who would not be quoted by name because of the delicacy of discussions with Japan. “And everything in this crisis is about moving quickly. It’s not working.” 
 
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 United States Air Force officials announced Wednesday that a Global Hawk remotely piloted surveillance plane would be sent on missions over Japan to help the government assess damage from the earthquake and the tsunami. A Pentagon official said the drone was expected to fly over the stricken nuclear plant. 
 
 American officials were careful to offer no public comparisons to past nuclear accidents when discussing the Fukushima disaster. But clearly the crisis in Japan already far outstrips what happened at Three Mile Island in Pennsylvania , where very little radiation escaped a crippled reactor. The effort now is to keep the Japanese crisis, involving at least three reactors that had been in active use before the quake, and three others that were inactive but had storage pools for spent fuel, from escalating to the levels of the worst nuclear disaster in history: Chernobyl. 
 
 Though the plant’s reactors shut down automatically when the quake struck on Friday, the subsequent tsunami wiped out the backup electronic pumping and cooling system necessary to keep the fuel rods in the reactors and the storage pools for spent nuclear fuel covered with cool water. 
 
 The spent fuel pools can be even more dangerous than the active fuel rods, as they are not contained in thick steel containers like the reactor core. As they are exposed to air, the zirconium metal cladding on the rods can catch fire, and a deadly mix of radioactive elements can spew into the atmosphere. The most concern surrounds Cesium-137, which has a half-life of 30 years and can get into food supplies or be inhaled. 
 
 Mr. Jaczko (pronounced YAZZ-koe) said radiation levels might make it impossible to continue what he called the “backup backup” cooling functions that have so far helped check the fuel melting inside the reactors. Those efforts consist of using fire hoses to dump water on overheated fuel and then letting the radioactive steam vent into the atmosphere. 
 
 Those emergency measures, carried out by a small squad of workers and firefighters, represent Japan’s central effort to forestall a full-blown fuel meltdown that would lead to much higher releases of radioactive material into the air. 
 
 Mr. Jaczko’s testimony, the most extended comments by a senior American official on Japan’s nuclear disaster, described what amounts to an agonizing choice for Japanese authorities: keep sending workers into an increasingly contaminated area in a last-ditch effort to cover nuclear fuel with water, or do more to protect the workers but risk letting the pools boil away — and thus risk a broader meltdown. 
 
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 According to Tokyo Electric’s data, the spent fuel pool at the No. 4 reactor contains 548 fuel assemblies that were in use at the reactor until last November, when they were move to the storage pool on the site. That means that the fuel rods were only recently taken out of active use and that their potential to burn and release radioactivity is higher than spent fuel in storage for a longer period. 
 
 Experts say workers at the plant probably could not approach a fuel pool that was dry, because radiation levels would be too high. In a normally operating pool, the water not only provides cooling but also shields workers from gamma radiation. 
 
 Earlier in the day, Japanese authorities announced a different escalation of the crisis at Daiichi when they said that a second reactor unit at the plant, No. 3, might have suffered damage to its primary containment structure and appeared to be releasing radioactive steam.
– Japan is considering burying its troubled nuclear plant in sand and concrete—the same move made in Chernobyl 25 years ago, Reuters reports. “It is not impossible to encase the reactors in concrete. But our priority right now is to try and cool them down first,” said an official, as authorities work to restore power. Smoke has been rising from the No. 2 reactor at the plant, and authorities aren’t sure of the cause—though it may be linked to the explosion there Tuesday, notes the AP. New damage has been discovered in the fuel pool at the plant’s No. 4 reactor, hampering cooling efforts to refill it with water (click for more on the alarming situation). US data-collecting flights suggest that radiation hasn’t expanded outside a 19-mile area—but Japan has raised its threat level from 4 to 5 out of 7, pointing to danger that extends beyond the local. The crisis could continue for weeks, said a US official. Meanwhile, the Huffington Post notes, authorities are using every cooling method available, from fire trucks to water cannons.