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9714 |
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Date: February 03, 2017 at 22:21:10
From: Shirley/PA, [DNS_Address]
Subject: Unimaginable’ – Understanding Radiation Levels Inside Fukushima Reacto |
URL: https://sputniknews.com/science/201702041050336701-unimaginable-fukushima-reactor-radiation-levels/ |
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Complete quote: "06:06 04.02.2017(updated 06:07 04.02.2017
Radiation levels inside the damaged Fukushima nuclear power plant have been labeled “unimaginable” by its owner Tepco. But how strong is a 530 sieverts/hour (Sv/hr) level of radiation? Strong enough to kill a machine designed to withstand just such an occurrence, and in less than an hour.
Reuters reporter measures a radiation level of 9.76 microsieverts per hour in front of Kumamachi Elementary School inside the exclusion zone in Okuma, near Tokyo Electric Power Co's (TEPCO) tsunami-crippled Fukushima Daiichi nuclear power plant, Fukushima Prefecture, Japan, February 13, 2016
© REUTERS/ Toru Hanai
Japanese Experts Record Dangerous Radiation Level at Fukushima Reactor
Tokyo Electric Power, or Tepco, assisted in the 1970s design and construction, and ran the Fukushima-1 nuclear power plant. In March 2011 the plant suffered the simultaneous meltdown of three of its six reactors after it was hit by an estimated 42-foot tsunami, following a six-minute magnitude-9.0 submarine earthquake about 43 miles off the coast. The reactor failure is the world's worst nuclear catastrophe since the 1986 Chernobyl reactor explosion and fire.
Tepco is charged with decommissioning the damaged nuclear power plant, and the process has already proven itself to be a highly-complicated and staggeringly expensive task, especially now, considering the recent measurements. To assess what is occurring inside one of the reactors, Tepco sent in robots which returned the eyebrow-raising figure of 530 Sv/hr.
To better understand this figure, a dose of one Sv/hr in a human is enough to cause radiation sickness and nausea. A 10-Sv/hr dose causes death within several weeks. Current radiation levels inside the Chernobyl reactor amount to about 34 Sv/hr, which is lethal to a person in about 10-20 minutes.
Contrary to popular belief, radiation does affect robots, and 530 Sv/hr is enough to kill not one, but five Tepco robots, very quickly.
The Tepco robots are purposefully designed to withstand large amounts of deadly radiation. According to media reports, after losing five robots, Tepco will now deploy what it considers to be a particularly tough variant, designed to withstand 1000 Sv/hr. Even so, that robot will only be able to survive for about two hours before it breaks down.
Men wearing protective suits and masks work in front of welding storage tanks for radioactive water, under construction in the J1 area at the Tokyo Electric Power Co's (TEPCO) tsunami-crippled Fukushima Daiichi nuclear power plant in Okuma in Fukushima prefecture. (File)
© AFP 2016/ TORU HANAI
TEPCO Finds Possible Nuclear Fuel Debris Under Fukushima's Reactor Number 2
This latest Fukushima radiation reading is far higher than the previous highest recording of 73 Sv/hr. According to the Japan Times, the reading was taken in a space just below the pressure vessel, which contains the reactor core. The extremely high radiation levels suggest that melted fuel escaped the pressure vessel.
Tepco robots identified a hole, about one meter in diameter, in a metal grating beneath the reactor's pressure vessel.
For Tepco, the decommissioning process has suddenly become much more difficult. The company has been under intense pressure, not only for its culpability in the environmental disaster, but also for its inability to keep to the stated cleanup timeline. The nuclear fuel is supposed to be removed from the reactor by 2018, so that crews can proceed with dismantling operations, but Tepco is far behind that original projection. Costs are also skyrocketing as, combined with decontamination and compensation payments, some $187 billion is expected to be spent, most of which will come from the Japanese treasury.
Total cleanup is expected to take 40 years.
But for now, Tepco must first understand how to approach the deadly environment.
The removal of the melted fuel represents "a challenge unprecedented in the history of nuclear power," according to The Guardian.
Russia offered assistance in overcoming the consequences of the Fukushima incident, just days after the disaster occurred. It was not until Russian President Vladimir Putin's December 2016 visit to Japan, however, that Tokyo and Moscow signed a memorandum of understanding regarding nuclear power."
Did you read that: "The extremely high radiation levels suggest that melted fuel escaped the pressure vessel."
Escaped it to where?
It's all unimaginable!
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Responses:
[9715] [9716] [9717] |
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9715 |
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Date: February 03, 2017 at 22:27:08
From: Shirley/PA, [DNS_Address]
Subject: Highest radiation reading since 3/11 detected at Fukushima No. 1 react |
URL: http://www.japantimes.co.jp/news/2017/02/03/national/fukushima-radiation-level-highest-since-march-11/#.WJVy-cIzWLh |
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Complete quote: "Feb 3, 2017
The radiation level in the containment vessel of reactor 2 at the crippled Fukushima No. 1 power plant has reached a maximum of 530 sieverts per hour, the highest since the triple core meltdown in March 2011, Tokyo Electric Power Co. Holdings Inc. said.
Tepco said on Thursday that the blazing radiation reading was taken near the entrance to the space just below the pressure vessel, which contains the reactor core.
The high figure indicates that some of the melted fuel that escaped the pressure vessel is nearby.
At 530 sieverts, a person could die from even brief exposure, highlighting the difficulties ahead as the government and Tepco grope their way toward dismantling all three reactors crippled by the March 2011 disaster.
Tepco also announced that, based on its analysis of images taken by a remote-controlled camera, that there is a 2-meter hole in the metal grating under the pressure vessel in the reactor’s primary containment vessel. It also thinks part of the grating is warped.
The hole could have been caused when the fuel escaped the pressure vessel after the mega-quake and massive tsunami triggered a station blackout that crippled the plant’s ability to cool the reactors.
The searing radiation level, described by some experts as “unimaginable,” far exceeds the previous high of 73 sieverts per hour at the reactor.
Tepco said it calculated the figure by analyzing the electronic noise in the camera images caused by the radiation. This estimation method has a margin of error of plus or minus 30 percent, it said.
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 the institute, 4 sieverts of radiation exposure would kill 1 in 2 people.
Experts say 1,000 millisieverts, or 1 sievert, could lead to infertility, loss of hair and cataracts, while exposure to doses above that increases the risk of cancer.
According to Tepco, readings of surface radiation on parts used inside a normally operating pressure vessel can reach several thousands sieverts per hour.
The discovery spells difficulty of removing the fuel debris to decommission at the plant. The government and Tepco hope to locate the fuel and start removing it in 2021.
In the coming weeks, the utility 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 takes into the interior because of the hole in the grating.
Also, given the extraordinary level of radiation, the robot would only be able to operate for less than two hours before it is destroyed.
That is because it 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.
Tepco has been probing reactor 2’s containment vessel since last week.
On Monday, it found a black mass deposited on the grating directly under the pressure vessel. The images, captured using a camera attached to a telescopic arm the same day, showed part of the grating was missing. Further analysis found the 2-meter hole in an area beyond the missing section on the structure.
If the deposits are confirmed to be melted fuel, it would be the first time the utility has found any of it at the three reactors that suffered core meltdowns.
The world’s worst nuclear disaster since Chernobyl in 1986 triggered core meltdowns in reactors 1 through 3. Portions of the core in each reactor are believed to have melted through their pressure vessels and pooled at the bottom of their containment vessels.
The actual condition of the melted fuel remains unknown because the radiation is too high to check it.
Meanwhile, a nuclear research organization unveiled on Friday a robot that will be tasked with surveying reactor 1 at the complex.
Tepco plans to send the robot into reactor 1 in March, while its survey plan for reactor 2 remains unclear because of the high radiation levels.
The stick-like robot is 70 cm long and equipped with a camera, according to the International Research Institute for Nuclear Decommissioning.
During a robotic survey in April 2015, the operator found no major obstacles in the path planned in reactor 1 but found water accumulating in the basement.
In the upcoming survey, it hopes to examine the water by deploying a camera and a radiation sensor.
“Confirming the conditions inside the reactor is a first step toward decommissioning,” Minister of Economy, Trade and Industry Hiroshige Seko said in a news conference Friday.
“While difficult tasks and unexpected matters may arise, we will mobilize all of Japan’s technological capabilities to steadily implement decommissioning work and rebuild Fukushima,” he added." End quote.
Mon Dieu!
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Responses:
[9716] [9717] |
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9716 |
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Date: February 03, 2017 at 22:31:45
From: Shirley/PA, [DNS_Address]
Subject: Fukushima nuclear reactor radiation at highest level since 2011 meltdo(NT) |
URL: https://www.theguardian.com/environment/2017/feb/03/fukushima-daiichi-radiation-levels-highest-since-2011-meltdown |
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Responses:
[9717] |
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9717 |
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Date: February 03, 2017 at 22:54:07
From: Shirley/PA, [DNS_Address]
Subject: Record radiation level detected inside damaged Fukushima reactor |
URL: https://www.japantoday.com/category/national/view/record-radiation-level-detected-inside-damaged-fukushima-reactor |
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From the "Comments" at the end of link article:
"Disillusioned Feb. 03, 2017 - 09:38AM JST
So, they finally admit the containment vessel was ruptured and rods melted through it. This scenario is exactly what was described in the movie, the China Syndrome. They are extremely lucky they were able to cool these melted rods. However, this does not mean they are clear of a China Syndrome disaster. At present, the technology does not exist for dealing with these melted fuel rods and if there is another major failure in the cooling system it will eventuate. This truly is a nuclear nightmare and far from 'under control' as Abe boldly stated to the IOC. And, the craziest thing about this whole scenario is, it could have easily been averted if TEPCO had not been lying about their safety upgrades and had implemented the advice from 2002 of getting the back up generators off the ground and waterproofing all electrical systems. Yeah, the first series of meltdowns were a catastrophe, but the next round could be Armageddon!"
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