Radiation levels inside a damaged reactor at the Fukushima Daiichi nuclear power station are at their highest since the plant suffered a triple meltdown almost six years ago.The facility’s operator, Tokyo Electric Power (Tepco), said atmospheric readings as high as 530 sieverts an hour had been recorded inside the containment vessel of reactor No 2, one of three reactors that experienced a meltdown when the plant was crippled by a huge tsunami that struck the north-east coast of Japan in March 2011. </s> The level of nuclear radiation detected at the troubled Fukushima nuclear plant in Japan spiked on Thursday to its highest level since the triple core meltdown in 2011.

In March 2011, multiple reactors at the Fukushima Daiichi power plant spiraled out of control after a 42-foot tsunami overwhelmed the plant’s sea walls, rendering the vital systems used to cool the plant’s six reactors inoperable. Ultimately, fuel meltdowns occurred at three reactors, releasing vast amounts of radioactive matter and resulting in the world’s worst nuclear disaster since Chernobyl.

On Thursday, the Tokyo Electric Power Company (TEPCO), the investor owned utility that operates the Fukushima reactors, reported that it detected a radiation level of 530 sieverts per hour in the containment vessel of reactor 2 at the Fukushima No. 1 power plant.

A sievert is a measure of the health effect of low levels of ionizing radiation on the human body.

Even a brief exposure to 530 sieverts of radiation would kill a person. Exposure to only one sievert is enough to result in infertility, loss of hair and cataracts. According to the National Institute of Radiological Sciences, exposure to a mere four sieverts of radiation would typically be lethal for one out of every two people. The highest level of radiation detected previously at the Fukushima reactor was 73 sieverts per hour.

According to the Japan Times, the reading was taken near the entrance to the space just below the pressure vessel, which contains the reactor core. The extremely high radiation levels suggest that some of the melted fuel that escaped the pressure vessel is nearby.

TEPCO had planned to deploy a remote-controlled robot to assess conditions inside the containment vessel. But, considering the extreme radiation levels, it is unclear whether it will be able to do so.

The robot is designed to withstand exposure of up to 1,000 sieverts. Based on the calculation of 73 sieverts per hour, the robot could run for more than 10 hours, but 530 sieverts per hour means it would be rendered inoperable in less than two hours.

William Pentland is a Partner at Brookside Strategies, LLC, a consulting firm in Portland, Maine that focuses on issues in utility regulation, market strategy and energy policy. </s> An area of the Fukushima Daiichi nuclear plant is showing record levels of radiation, the highest since the complex suffered a nuclear meltdown initiated by a tsunami in 2011. The plant operator Tokyo Electric Power Company (Tepco) announced that the containment vessel of the No 2 reactor showed radiation levels of up to 530 sieverts per hour, which can kill a human in under a minute.

Previous analysis of the area back in 2012 showed records of 73 sieverts per hour in the same area. The new discovery, which was made on 30 January, is based on images captured by three manned cameras which were mounted on a robot to gather information about the state of the reactor.

Images also indicated a hole below the pressure vessel, Nekkei Asian Review reported. According to Tepco, the hole may have been the result of nuclear fuel that entered the vessel as it overheated. Loss of reactor cooling functions in the days following the tsunami could have led to the melting of the walkway.

"It may have been caused by nuclear fuel that would have melted and made a hole in the vessel, but it is only a hypothesis at this stage," Tepco spokesman Tatsuhiro Yamagishi told AFP on 3 February.

"We believe the captured images offer very useful information, but we still need to investigate given that it is very difficult to assume the actual condition inside."

The radiation levels could effectively shut down TEPCO's robots that are being used for the investigation in under two hours, AFP reported. However, the operators plan to extend the probe and check conditions by sending a robot to the bottom of the reactor containment vessel.

The Fukushima plant suffered three meltdowns as a result of the tsunami on 11 March, 2011 which destroyed the emergency generators which provided power to cool the reactors. The accident led to one of the worst nuclear disasters since Chernobyl in 1986, and last year, researchers were able to detect radiation from the site all the way in Oregon, USA. </s> A record radiation level has been detected inside the No. 2 reactor at the damaged Fukushima Daiichi nuclear complex, with the estimated reading of up to 530 sieverts per hour, the plant operator said Thursday.

The reading means a person could die from even brief exposure, highlighting the difficulties ahead as the government and Tokyo Electric Power Company Holdings Inc grope their way toward dismantling all three reactors that melted down in the March 2011 nuclear disaster.

The plant operator also announced that based on an image analysis, a 1-square-meter hole has been found on a metal grating beneath the reactor pressure vessel, likely caused by melted nuclear fuel that fell through the vessel.

The new radiation level, described by some experts as “unimaginable,” far exceeds 73 sieverts per hour, the previously highest radiation reading monitored in the interior of the reactor.

An official of the National Institute of Radiological Sciences said medical professionals have never considered dealing with this level of radiation in their work.

According to TEPCO, the extremely high radiation level was detected inside the containment vessel, in the space around 2.3 meters away from the base of the reactor pressure vessel.

According to the institute, 4 sieverts of radiation exposure would kill one in two people.

Experts say 1,000 millisieverts, which equals 1 sievert, could lead to infertility, loss of hair and cataracts, while exposure to radiation doses above 100 sieverts increases the risk of cancer.

The latest discovery spells difficulty in removing the fuel debris as part of decommissioning work at the plant. The government and TEPCO hope to locate the fuel and start removing it from a first reactor in 2021.

The debris is believed to have been created as nuclear fuel inside the reactor pressure vessel overheated and melted due to the loss of reactor cooling functions.

In the coming weeks, the plant operator plans to deploy a remote-controlled robot to check conditions inside the containment vessel, but the utility is likely to have to change its plan.

For one thing, it will have to reconsider the route the robot is to take to probe the interior because of the hole found on the grating.

Also, given the extraordinary level of radiation inside the containment vessel, the robot would only be able to operate for less than two hours before it is destroyed.

That is because the robot is designed to withstand exposure to a total of up to 1,000 sieverts of radiation. Based on the calculation of 73 sieverts per hour, the robot could have operated for more than 10 hours, but 530 sieverts per hour means the robot would be rendered inoperable in less than two hours.

The latest analysis follows TEPCO’s discovery Monday of a black mass deposited on the grating directly beneath the pressure vessel, possibly melted fuel after the unit suffered a meltdown along with two other reactors at the six-reactor plant.

Images captured using a camera attached to a telescopic arm on Monday also showed part of the grating has gone.

If the deposits are confirmed as fuel debris, it would be the first time the utility has found any at the three units that suffered meltdowns.

Following the world’s worst nuclear disaster since the 1986 Chernobyl catastrophe, the plant’s No. 1 to 3 reactors suffered fuel meltdowns.

Portions of the fuel in the reactors are believed to have accumulated at the bottom of the containment vessels. But the actual condition of the melted fuel remains unknown due to high radiation levels. </s> This article is more than 2 years old

This article is more than 2 years old

Extremely high radiation levels have been recorded inside a damaged reactor at the Fukushima Daiichi nuclear power station, almost six years after the plant suffered a triple meltdown.



The facility’s operator, Tokyo Electric Power (Tepco), said atmospheric readings as high as 530 sieverts an hour had been recorded inside the containment vessel of reactor No 2, one of three reactors that experienced a meltdown when the plant was crippled by a huge tsunami that struck the north-east coast of Japan in March 2011.

The extraordinary radiation readings highlight the scale of the task confronting thousands of workers, as pressure builds on Tepco to begin decommissioning the plant – a process that is expected to take about four decades.

Even if a 30-percent margin of error is taken into account, the recent reading, described by some experts as “unimaginable”, is far higher than the previous record of 73 sieverts an hour detected by sensors in 2012.

Tepco pointed out, however, that the camera had probed deeper inside the reactor than before and had focused on a single point. Radiation levels at other spots filmed by the camera are estimated to be much lower, it added.



A single dose of one sievert is enough to cause radiation sickness and nausea; 5 sieverts would kill half those exposed to it within a month, and a single dose of 10 sieverts would prove fatal within weeks.

Tepco also said image analysis had revealed a hole in metal grating beneath the same reactor’s pressure vessel. The one-metre-wide hole was probably created by nuclear fuel that melted and then penetrated the vessel after the tsunami knocked out Fukushima Daiichi’s back-up cooling system.

“It may have been caused by nuclear fuel that would have melted and made a hole in the vessel, but it is only a hypothesis at this stage,” Tepco’s spokesman Tatsuhiro Yamagishi told AFP.

“We believe the captured images offer very useful information, but we still need to investigate given that it is very difficult to assume the actual condition inside.”

The presence of dangerously high radiation will complicate efforts to safely dismantle the plant.

A remote-controlled robot that Tepco intends to send into the No 2 reactor’s containment vessel is designed to withstand exposure to a total of 1,000 sieverts, meaning it would survive for less than two hours before malfunctioning.

The firm said radiation was not leaking outside the reactor, adding that the robot would still prove useful since it would move from one spot to the other and encounter radiation of varying levels.

Tepco and its network of partner companies at Fukushima Daiichi have yet to identify the location and condition of melted fuel in the three most seriously damaged reactors. Removing it safely represents a challenge unprecedented in the history of nuclear power.

Quantities of melted fuel are believed to have accumulated at the bottom of the damaged reactors’ containment vessels, but dangerously high radiation has prevented engineers from accurately gauging the state of the fuel deposits.

Earlier this week, the utility released images of dark lumps found beneath reactor No 2 that it believes could be melted uranium fuel rods – the first such discovery since the disaster.

In December, the government said the estimated cost of decommissioning the plant and decontaminating the surrounding area, as well as paying compensation and storing radioactive waste, had risen to 21.5tn yen (£150bn), nearly double an estimate released in 2013.

This article was amended on 9 February to explain that the camera had probed deeper inside the No 2 reactor – and closer to the damaged nuclear fuel – than before, hence the high radiation estimate. </s> The Fukushima nuclear power plant’s (NPP) operator has detected extremely high radiation levels at a damaged reactor at the Fukushima power plant in Japan.

Radiation levels that are lethal after brief exposure were found inside the second reactor on Thursday

Tokyo Electric Power Company also found a hole which was likely caused by melted nuclear fuel was also discovered at the reactor.

Radiation levels of up to 530 Sieverts per hour were detected inside an inactive Reactor 2 at the Fukushima Daiichi nuclear complex damaged during the 2011 earthquake and tsunami catastrophe, Japanese media reported on Thursday citing the plant operator, Tokyo Electric Power Company (TEPCO).

A dose of about 8 Sieverts is considered incurable and fatal.

A hole of no less than one square meter in size has also been discovered beneath the reactor’s pressure vessel, TEPCO said. According to researchers, the apparent opening in the metal grating of one of three reactors that had melted down in 2011, is believed to be have been caused by melted nuclear fuel that fell through the vessel.

The iron scaffolding has a melting point of 1500 degrees, TEPCO said, explaining that there is a possibility the fuel debris has fallen onto it and burnt the hole. Such fuel debris have been discovered on equipment at the bottom of the pressure vessel just above the hole, it added.

The latest findings were released after a recent camera probe inside the reactor, TEPCO said. Using a remote-controlled camera fitted on a long pipe, scientists managed to get images of hard-to-reach places where residual nuclear material remained. The substance there is so toxic that even specially-made robots designed to probe the underwater depths beneath the power plant have previously crumbled and shut down.

However, TEPCO still plans to launch further more detailed assessments at the damaged nuclear facility with the help of self-propelled robots.

Earlier this week, hopes for a more efficient cleanup at Fukushima were high, as the plant operator announced a portion of nuclear fuel debris responsible for a lot of the lingering contamination from six years ago may have finally been found. </s> Local residents look out to sea from higher ground after evacuating their homes following a 6.9 magnitude earthquake and tsunami alert in Iwaki, Fukushima prefecture, on November 22, 2016 (AFP Photo/JIJI PRESS)

Tokyo (AFP) - A powerful 6.9-magnitude earthquake hit northeast Japan on Tuesday, sparking panic and triggering a tsunami including a one-metre (three-foot) wave that crashed ashore at the stricken Fukushima nuclear power plant.

National broadcaster NHK urged residents to "flee immediately" to higher ground, reminding viewers to heed the lessons of the "Great East Japan Earthquake".

A massive undersea quake with a magnitude of 9.0 that struck in March 2011 unleashed a tsunami that left more than 18,500 people dead or missing. It sent three reactors into meltdown at the Fukushima Daiichi power plant in one of the world's worst nuclear disasters.

An official from plant operator TEPCO told a news conference that a one-metre wave had hit the coast at the facility, but a company spokesman told AFP there were no reports of damage.

About a dozen other waves were recorded elsewhere on the northeast coast, according to the Meterological Agency, but they were smaller than initial warnings of waves as high as 3.0 metres.

The biggest, measuring 1.4 metres, hit the port at Sendai north of Fukushima, but officials said there were no reports of damage there.

NHK aired rolling coverage of the earthquake, with the words "Tsunami! Flee!" in white lettering over a bright red band on the screen.

The Meterological Agency lifted its final tsunami warning nearly seven hours after the earthquake struck.

TEPCO earlier reported that a water cooling system at a reactor in the separate Fukushima Daini facility had briefly stopped, in an automatic response, but that it was back up and operating.

"The biggest risk now is a case whereby contaminated water is carried away with the tsunami, which pollutes the environment," TEPCO's chief decommissioning officer Naohiro Masuda told reporters, of the situation at Fukushima Daiichi.

The 2011 disaster sent radiation levels across the Pacific Ocean soaring and decimated some fishing grounds off Japan's coast.

The global Scientific Committee on Oceanic Research said in July that levels were returning to normal but that the seabed and harbour near Fukushima were still highly contaminated.

Residents along the coast heeding evacuation advice clogged some roads, with a Fukushima newspaper reporting unusual early morning traffic jams in the small city of Soma.

There were no immediate signs of widespread damage and only minor injuries were initially reported.

Fourteen injuries have been reported throughout the region, including three elderly women who broke bones when falling or trying to evacuate.

Still, people along the coast were badly shaken.

"It was huge and lasted so long," Akemi Anzai, from the city of Minamisoma north of the Fukushima plant, said of the quake.

"The tsunami siren warning can be heard from the coastline," she told AFP. "The ground is still shaking. I'm so scared. But my concern is rather the situation at the nuclear plant."

The United States Geological Survey said the 6.9 magnitude quake, at a shallow depth of 11.3 kilometres (seven miles), struck shortly before 6:00 am (2100 GMT on Monday) in the Pacific off Fukushima.

It shook buildings in Tokyo, 230 kilometres to the south.

Shinkansen bullet train services were suspended in the region but gradually resumed, though delays were still being reported.

Sendai airport, which suffered significant damage during the 2011 tsunami, temporarily closed but flights resumed in the morning.

Fishing boats had rushed out to sea to avoid the direct impact of the tsunami, the Sankei Shimbun said.

NHK showed footage of what appeared to be seawater flowing up a river in Miyagi prefecture though none of it surged beyond the banks.

"The fear that I felt almost six years ago came back," Junko Murata, another Minamisoma resident, told AFP.

"Maybe there won't be major damage this time but we will have to remain on edge for years and years," she added, referring to the Fukushima plant.

Japan sits at the junction of four tectonic plates and suffers several relatively violent quakes every year, although high building standards and frequent drills limit the number of casualties.

In April two strong quakes hit Kumamoto prefecture, leaving at least 50 dead and causing widespread damage. </s> An aerial view of Fukushima Dai-ichi nuclear power plant in Okuma, Japan, following a strong earthquake hit off Fukushima on Tuesday.

The magnitude 7.4 earthquake, which was felt in Tokyo, sent thousands of residents fleeing for higher ground as dawn broke along the northeastern coast.

A powerful earthquake hit northern Japan early on Tuesday, briefly disrupting the cooling functions of a nuclear plant and generating a small tsunami in the Fukushima region that was devastated by a 2011 quake, tsunami and nuclear disaster.

The magnitude 7.4 earthquake, which was felt in Tokyo, sent thousands of residents fleeing for higher ground as dawn broke along the northeastern coast.

There were no reports of deaths or serious injuries hours after the quake hit at 5:59 a.m. It was centred off the coast of Fukushima prefecture at a depth of about 10 km, the Japan Meteorological Agency (JMA) said.

A wave of up to 1.4 metres (4.5 feet) high was recorded at Sendai, about 70 km (45 miles) north of Fukushima, with smaller waves hitting ports elsewhere along the coast, public broadcaster NHK said.

Television footage showed ships moving out to sea from harbours as tsunami warnings wailed after alerts of waves of up to 3 metres (10 feet) were issued.

“We saw high waves but nothing that went over the tidal barriers,” a man in the city of Iwaki told NTV television network.

Aerial footage showed tsunami waves flowing up rivers in some areas, and some fishing boats were overturned in the port of Higashi-Matsushima before the JMA lifted its warnings.

The U.S. Geological Survey measured Tuesday's quake at magnitude 6.9, down from an initial 7.3.

All Japan's nuclear power plants in the area were shut down in the wake of the March 2011 disaster, which knocked out the cooling systems of the Tokyo Electric Power Co's Fukushima Daiichi nuclear plant, causing reactors to melt down and spew radiation into the air, soil and sea.

The cooling system of a storage pool for spent nuclear fuel at the reactor at the Fukushima Daini Plant was initially halted on Tuesday, said a spokeswoman of the Tokyo Electric Power Company, known as Tepco, but was restarted soon after.

Only two reactors are operating in Japan, both in the southwest. Nuclear plants need cooling systems operating even when in shutdown to keep spent fuel cool.

Tohoku Electric Power Co said there was no damage to its Onagawa nuclear plant, while the Kyodo news agency reported there were no irregularities at the Tokai Daini nuclear plant in the Ibaraki prefecture.

Japanese Minister for Disaster Management Jun Matsumoto told reporters there were no reports of significant injuries. One woman suffered cuts to her head from falling dishes, Kyodo reported, citing fire department officials.

Japan accounts for about 20 per cent of the world's earthquakes of magnitude 6 or greater.

The March 11, 2011 quake was magnitude 9, the strongest quake ever recorded in Japan. The massive tsunami it generated knocked out the Fukushima Daiichi plant, causing the worst nuclear crisis since Chernobyl a quarter of a century earlier. </s> Media playback is unsupported on your device Media caption Japan tsunami waves push river upstream

Japan has lifted the tsunami advisories issued after a 7.4 magnitude earthquake hit its eastern coast.

The quake struck near Fukushima at about 06:00 local time (21:00 GMT Monday), triggering initial warnings of 3m (9.8ft) high waves. The waves which eventually hit the coast were much smaller.

Thousands were asked to evacuate the area and minor injuries were reported.

An earthquake and tsunami struck the area in 2011 killing 18,000 people.

That quake, one of the most powerful ever recorded, also caused a meltdown at the Fukushima nuclear power plant, where a massive clean-up operation is still going on.

How the 2011 quake is still felt in Japan

Officials have said there is no sign of damage to the plant this time.

Image copyright AP Image caption Miyagi prefecture police released a video showing water flowing up the Sunaoshi River as a result of the waves hitting the coast

The US Geological Survey initially put the magnitude at 7.3 but later downgraded this to 6.9, lower than the number given by the Japanese authorities.

The Japan Meteorological Agency (JMA) said in its latest update that no tsunami damage is expected, although there may be slight changes to the sea level.

The agency has also said the latest tremor was an aftershock of the 2011 quake.

A spokesman quoted by Japan Times said the area was still generating at least one earthquake of 7.0 magnitude or more each year.

Heading for higher ground

The depth of Tuesday's quake was estimated to be 30km (18.6 miles), the JMA said.

Image copyright EPA Image caption The agency said seismic activities had continued for years after the 2011 earthquake in Fukushima

Strong tremors could be felt as far away as the capital, Tokyo, 100 miles south of Fukushima prefecture. Buildings in the capital shook for at least 30 seconds.

Media playback is unsupported on your device Media caption Japanese broadcaster NHK World reported that people should evacuate immediately

The BBC's Rupert Wingfield-Hayes in Tokyo says tens of thousands of people have heeded evacuation warnings and headed for higher ground.

Ships could be seen moving away from harbours in Fukushima prefecture and car manufacturer Nissan suspended work at its Fukushima engine factory.

A 1m wave hit the coastline near the Fukushima nuclear power plant, but Cabinet Chief Secretary Yoshihide Suga said at a televised news conference that "there was no problem".

All reactors were shut down in 2011, but cooling is still needed for the used nuclear fuel stored on the site.

Mr Suga said the water cooling system on the third reactor had stopped working, but there were no signs of further damage or abnormalities.

Tokyo Electric Power, which operates the plant, later said it had restarted the cooling system, and reported only small temperature increases, within safety limits.

Image copyright Reuters Image caption The evacuation order caused early morning traffic jams

A wave of 60cm (2ft) arrived in Onahama Port in Fukushima, Japanese broadcaster NHK reported, and another of 90cm in Soma.

There so far appears to have been only minimal damage, and our correspondent says tsunami defences rebuilt since 2011 have ensured that waves have not caused flooding nor damage.

Japan lies in a particularly seismically active region and accounts for around 20% of quakes worldwide of magnitude 6.0 or more.

At least 50 people died in two quakes in the southern Kumamoto prefecture in April.

Image copyright Reuters Image caption The tsunami warning was issued for an area including the site of the Fukushima nuclear plant

Meanwhile, an earthquake of 5.6 magnitude and 30km depth hit an area 200km north east of the New Zealand capital, Wellington. There were no immediate reports of deaths or injuries.

Geoscience Australia senior seismologist Hugh Glanville told New Zealand's Stuff news website that the quakes "are not directly related".

"One did not cause the other, but are both a result of shifts in the Pacific plate," he said.

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According to Tokyo Electric Power Company, radiations levels within one of the reactors of Fukushima Daiichi Nuclear Power Plant, damaged by an earthquake and tsunami in 2011, are at its highest level since experiencing a meltdown, with a reading of 530 sieverts an hour.