Fukushima frozen wall status 2017; Unit 3 cover building installation — SimplyInfo.org

SimlyInfo.org shows a map of the current status of the frozen ice wall at Fukushima No. 1.

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Read SimplyInfo.org’s article on the current construction of a cover building for Fukushima Daiichi’s Unit 3, which will hopefully allow for robotic removal of spent fuel.

 

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Why the water cooling system at Fukushima nuclear plant stopped — Business Insider Australia

” The cooling system at the Fukushima nuclear plant is back online.

Earlier this morning, officials were “trying to establish what’s gone wrong” at the Fukushima nuclear plant.

A 7.3 magnitude earthquake struck 67km off the coast of Japan this morning, and tsunamis have been recorded hitting the east coast.

Officials at the plant originally said they had noted no irregularities with the plant, but at 9.15am AEDT, news came through that the plant’s water cooling system “appears to have stopped”, although the operator of the plant said there was no immediate danger.

At 10.05am AEDT, NHK confirmed the cooling equipment for the spent nuclear fuel pool in the reactor number three of Tepco’s Fukushima number two power plant wasn’t working.

An official spokesperson from operator Tepco says the earthquake “shook” water in the cooling tanks temporarily, leading to a decline in levels.

That triggered a warning and the plant’s cooling systems stopped, possibly as a precaution to stop them in turn overheating.

The cooling pumps have now resumed and the water in the towers is cooling again.

In the two hours the pumps were off, the spent rods heated the water from 27.7C at 6.10am to 29.5C. However, officials say that was “within safe range” and the water would have to heat for a week to reach a dangerous level.

The plant currently stores around 1000 tanks of contaminated water, and no leakage has been noted yet.

Chief cabinet secretary Yoshihide Suga says, “We have been informed that there is no immediate risk of radiation leaks or rise in the temperatures (of the cooling pool).” ”

by Peter Farquhar

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Bulk of melted fuel in No. 2 reactor at damaged Fukushima plant at bottom of pressure vessel: Tepco — The Japan Times

” Most of the melted nuclear fuel inside the No. 2 reactor at the disaster-hit Fukushima No. 1 power plant is likely located at the bottom of its pressure vessel, Tokyo Electric Power Company Holdings Inc. has revealed.

According to a study that used a cosmic ray imaging system, an estimated 130 tons of the so-called fuel debris remains at the bottom of the vessel, the first time the location and amount of the melted fuel have been estimated.

The finding, announced on Thursday, is important as the data could help the operator to narrow down methods to remove the fuel debris, the most challenging task in decommissioning the plant’s Nos. 1 to 3 reactors that experienced meltdowns in the nuclear crisis that began in March 2011.

Tepco plans to decide how to start removing the debris in two years, with work to start in 2021.

The cosmic-ray study was carried out by a team involving Tokyo Electric and the High Energy Accelerator Research Organization in Ibaraki Prefecture.

As high radiation levels are continuing to hamper direct access to the reactors, researchers have tracked muon elementary particles, which are produced as cosmic rays collide with atmospheric particles and change course when coming into contact with nuclear fuel.

The No. 2 reactor was in operation when the nuclear crisis was triggered by a powerful earthquake and subsequent tsunami that devastated Japan’s northeast.

About 160 tons of fuel assemblies are estimated to have been present inside the reactor vessel prior to the crisis. Most of the fuel is believed to have fallen to the bottom of the pressure vessel and mixed with nearby structures to form the debris.

In the nuclear crisis, massive amounts of radioactive substances were released into the environment, with the Nos. 1, 3 and 4 reactor buildings damaged by hydrogen explosions.

The No. 4 reactor was offline for routine maintenance work and all of its fuel was stored in the spent fuel pool, avoiding a meltdown. The utility removed all fuel rod assemblies from the pool and transported them to a more stable building in 2014.

Also on Thursday, Tepco said it plans to seek additional financial support from the government to cover soaring costs for dealing with the disaster.

Tepco specifically asked the government to clarify its views on how the costs for providing compensation to affected residents and the decommissioning of the plant should be shouldered.

Each request for additional aid will be carefully scrutinized by the government out of concern it could come under fire from taxpayers, sources said.

The government has already agreed to provide up to ¥9 trillion in loans to Tepco to cover ¥5.4 trillion in compensation to be paid to affected residents and ¥2.5 trillion in decontamination costs that were projected in January 2014.

But Tepco said compensation payments have already topped ¥6 trillion and that decontamination costs are increasingly likely to exceed estimates.

The utility also said it is concerned about massive costs to be incurred when it starts full-fledged decommissioning work at the damaged nuclear plant.

If the situation is left unaddressed, Tepco’s market value will suffer, Executive Officer Keita Nishiyama said.

Tepco President Naomi Hirose said that although overall compensation costs have not been fixed, his company will consult with the government on how those costs will be funded. ”

by Kyodo, Jiji

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Near miss at Fukushima is a warning for U.S., panel says — Richard Stone, Science

” Japan’s chief cabinet secretary called it “the devil’s scenario.” Two weeks after the 11 March 2011 earthquake and tsunami devastated the Fukushima Daiichi Nuclear Power Plant, causing three nuclear reactors to melt down and release radioactive plumes, officials were bracing for even worse. They feared that spent fuel stored in the reactor halls would catch fire and send radioactive smoke across a much wider swath of eastern Japan, including Tokyo.

Thanks to a lucky break detailed in a report released today by the U.S. National Academies, Japan dodged that bullet. The near calamity “should serve as a wake-up call for the industry,” says Joseph Shepherd, a mechanical engineer at the California Institute of Technology in Pasadena who chaired the academy committee that produced the report. Spent fuel accumulating at U.S. nuclear reactor plants is also vulnerable, the report warns. A major spent fuel fire at a U.S. nuclear plant “could dwarf the horrific consequences of the Fukushima accident,” says Edwin Lyman, a physicist at the Union of Concerned Scientists, a nonprofit in Washington, D.C., who was not on the panel.

After spent fuel is removed from a reactor core, the fission products continue to decay radioactively, generating heat. Many nuclear plants, like Fukushima, store the fuel onsite at the bottom of deep pools for at least 5 years while it slowly cools. It is seriously vulnerable there, as the Fukushima accident demonstrated, and so the academy panel recommends that the U.S. Nuclear Regulatory Commission (NRC) and nuclear plant operators beef up systems for monitoring the pools and topping up water levels in case a facility is damaged. It also calls for more robust security measures after a disaster. “Disruptions create opportunities for malevolent acts,” Shepherd says.

At Fukushima, the earthquake and tsunami cut power to pumps that circulated coolant through the reactor cores and cooled water in the spent fuel pools. The pump failure led to the core meltdowns. In the pools, found in all six of Fukushima’s reactor halls, radioactive decay gradually heated the water. Of preeminent concern were the pools in reactor Units 1 through 4: Those buildings had sustained heavy damage on 11 March and in subsequent days, when explosions occurred in Units 1, 3, and 4.

The “devil’s scenario” nearly played out in Unit 4, where the reactor was shut down for maintenance. The entire reactor core—all 548 assemblies—was in the spent fuel pool, and was hotter than fuel in the other pools. When an explosion blew off Unit 4’s roof on 15 March, plant operators assumed the cause was hydrogen—and they feared it had come from fuel in the pool that had been exposed to air. They could not confirm that, because the blast had destroyed instrumentation for monitoring the pool. (Tokyo Electric Power Company, the plant operator, later suggested that the hydrogen that had exploded had come not from exposed spent fuel but from the melted reactor core in the adjacent Unit 3.) But the possibility that the fuel had been exposed was plausible and alarming enough for then-NRC Chairman Gregory Jaczko on 16 March to urge more extensive evacuations than the Japanese government had advised—beyond a 20-kilometer radius from the plant.

Later that day, however, concerns abated after a helicopter overflight captured video of sunlight glinting off water in the spent fuel pool. In fact, the crisis was worsening: The pool’s water was boiling away because of the hot fuel. As the level fell perilously close to the top of the fuel assemblies, something “fortuitous” happened, Shepherd says. As part of routine maintenance, workers had flooded Unit 4’s reactor well, where the core normally sits. Separating the well and the spent fuel pool is a gate through which fuel assemblies are transferred. The gate allowed water from the reactor well to leak into the spent fuel pool, partially refilling it. Without that leakage, the academy panel’s own modeling predicted that the tops of the fuel assemblies would have been exposed by early April; as the water continued to evaporate, the odds of the assemblies’ zirconium cladding catching fire would have skyrocketed. Only good fortune and makeshift measures to pump or spray water into all the spent fuel pools averted that disaster, the academy panel notes.

At U.S. nuclear plants, spent fuel is equally vulnerable. It is for the most part densely packed in pools, heightening the fire risk if cooling systems were to fail. NRC has estimated that a major fire in a U.S. spent fuel pool would displace, on average, 3.4 million people from an area larger than New Jersey. “We’re talking about trillion-dollar consequences,” says panelist Frank von Hippel, a nuclear security expert at Princeton University.

Besides developing better systems for monitoring the pools, the panel recommends that NRC take another look at the benefits of moving spent fuel to other storage as quickly as possible. Spent fuel can be shifted to concrete containers called dry casks as soon as it cools sufficiently, and the academy panel recommends that NRC “assess the risks and potential benefits of expedited transfer.” A wholesale transfer to dry casks at U.S. plants would cost roughly $4 billion. ”

by Richard Stone, Science

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**Writing the nuclear meltdown playbook — Arnie Gundersen via Fairewinds Energy Education

Arnie Gundersen: ” People today who are familiar with social media think that TMI means “Too Much Information”. But to me, and anyone listening to the news in 1979, TMI will always represent the disaster at Three Mile Island, when the public received too little information, not too much.

At the time of the nuclear disaster at TMI, there were plans to build more than 200 nuclear plants in the US, with some projections topping 1,000. Today, less than 100 nuclear plants are operating in the US. During the 1970’s, the total amount invested in those early plants easily exceeded one trillion dollars. If the public became fearful of nuclear power, then the nuclear industry, investors, and banks that had loaned money would face huge losses, so the nuclear industry and nuclear regulators tried desperately to minimize the significance of what was happening at the crippled reactor.

The pattern of denial created by the nuclear industry during the TMI meltdown had at least five steps in its playbook:

  1. Make it appear that “authorities” have the situation under control.
  2. Delay any evacuation orders for as long as possible.
  3. Claim radiation releases are much lower than they actually are.
  4. Claim radiation exposures are acceptable and that no one will die.
  5. And lastly, minimize conflicting information given to the press through paid off experts.

The formula for damage control at TMI was designed by the nuclear industry composed a one size fits all “playbook” the industry has followed for all nuclear catastrophes since TMI. Comments made during the triple meltdown at Fukushima Daiichi by utility owner Tokyo Electric could easily mimic those made at Chernobyl and TMI! When Maggie and I saw these old tricks being played again at Fukushima Daiichi, we dedicated ourselves to ensuring that the public has an accessible resource on which to rely that provides accurate information, and thus the Fairewinds videos were born.

In this video posted to commemorate the TMI disaster, I discuss the pattern of denial regarding nuclear power plant failures and meltdowns, not just for TMI but also for Chernobyl and Fukushima Daiichi as well. We at Fairewinds Energy Education hope you will watch it and think about sharing the true facts with others. ”

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