April 17, 2012, 8:44 PM JST
WSJ
Fukushima Daiichi’s Achilles Heel: Unit 4’s Spent Fuel?

By Phred Dvorak

Just how dangerous is the situation at Japan’s crippled Fukushima Daiichi nuclear plant? Very, according to U.S. Senator Ron Wyden, a senior member of the Senate’s energy committee who toured the plant earlier this month.

Another big earthquake or tsunami could send Fukushima Daiichi’s fragile reactor buildings tumbling down, resulting in “an even greater release of radiation than the initial accident,” Mr. Wyden warned in a Monday letter to Japanese Ambassador to the U.S. Ichiro Fujisaki.

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Fukushima Daiichi suffered meltdowns at three of its reactors last year after the March 11 earthquake and tsunami knocked out power in the area. Much of the nuclear fuel in those three reactors is thought to be in a melted lump at the bottom of the vessels that surround the core. That’s bad, but at least the vessels shield the outside world from the radioactive fuel.

But Fukushima Daiichi’s Unit 4 reactor was shut down for maintenance when last year’s accident took place, meaning the nuclear fuel rods were outside those protective vessels and sitting in a pool of water, high up in the reactor building, where they were being stored. The water in that “spent fuel pool” keeps the rods cool and insulates them from the outside. But if the pool should spring a leak, or another earthquake bring the pool crashing down, all that fuel would be exposed to the outside air, letting them heat up and release massive amounts of radiation. Other reactors have spent-fuel pools too, but they contain less fuel.

Tepco says an analysis it conducted on the Unit 4 pool showed the building didn’t need reinforcing, but it went ahead and reinforced the structure anyway, increasing its safety margin by 20%. Tepco says it’s working to remove the fuel rods as fast as it can. If all goes according to its timetable, the utility could start taking the rods out in 2014.

Mr. Wyden points out, though, that the schedule allows up to ten years to get all the spent fuel in all the Fukushima reactor pools out — something he says is too risky.

“This schedule carries extraordinary and continuing risk if further severe seismic events were to occur,” he wrote in his letter to Ambassador Fujisaki. “The true earthquake risk for the site was seriously underestimated and remains unresolved.”

NY Times
Life in the Sea Found Its Fate in a Paroxysm of Extinction
By ALANNA MITCHELL
Published: April 30, 2012

It may never be as well known as the Cretaceous extinction, the one that killed off the dinosaurs. Yet the much earlier Permian extinction — 252 million years ago — was by far the most catastrophic of the planet’s five known paroxysms of species loss.

No wonder it is called the Great Dying: Scientists calculate that about 95 percent of marine species, and an uncountable but probably comparable percentage of land species, went extinct in a geological heartbeat.

The cause or causes of the Permian extinction remain a mystery. Among the hypotheses are a devastating asteroid strike, as in the Cretaceous extinction; a catastrophic volcanic eruption; and a welling-up of oxygen-depleted water from the depths of the oceans.

Now, painstaking analyses of fossils from the period point to a different way to think about the problem. And at the same time, they are providing startling new clues to the behavior of modern marine life and its future.

In two recent papers, scientists from Stanford and the University of California, Santa Cruz, adopted a cellular approach to what they called the “killing mechanism”: not what might have happened to the entire planet, but what happened within the cells of the animals to finish them off.

Their study of nearly 50,000 marine invertebrate fossils in 8,900 collections from the Permian period has allowed them to peer into the inner workings of the ancient creatures, giving them the ability to describe precisely how some died while others lived.

“Before, scientists were all over the map,” said one of the authors, Matthew E. Clapham, an earth scientist at Santa Cruz. “We thought maybe lots of things were going on.”

Dr. Clapham and his co-author, Jonathan L. Payne, a Stanford geochemist, concluded that animals with skeletons or shells made of calcium carbonate, or limestone, were more likely to die than those with skeletons of other substances. And animals that had few ways of protecting their internal chemistry were more apt to disappear.

Being widely dispersed across the planet was little protection against extinction, and neither was being numerous. The deaths happened throughout the ocean. Nor was there any correlation between extinction and how a creature moved or what it ate.

Instead, the authors concluded, the animals died from a lack of dissolved oxygen in the water, an excess of carbon dioxide, a reduced ability to make shells from calcium carbonate, altered ocean acidity and higher water temperatures. They also concluded that all these stresses happened rapidly and that each one amplified the effects of the others.

That led to a wholesale change in the ocean’s dominant animals within just 200,000 years, or perhaps much less, Dr. Clapham said.

Among the hardest hit were corals; many types, including the horn-shaped bottom-dwellers known as rugose corals, disappeared altogether. Sea sponges were also devastated, along with the shelled creatures that commanded the Permian reefs and sea. Every single species of the once common trilobites, with their helmetlike front shells, vanished for good.

No major group of marine invertebrates or protists, a group of mainly one-celled microorganisms, went unscathed. Instead, gastropods like snails and bivalves like clams and scallops became the dominant creatures after the Permian. And that shift led directly to the assemblage of life in today’s oceans. “Modern marine ecology is shaped by the extinction spasms of the past,” Dr. Clapham said.

So what happened 252 million years ago to cause those physiological stresses in marine animals? Additional clues from carbon, calcium and nitrogen isotopes of the period, as well as from organic geochemistry, suggest a “perturbation of the global carbon cycle,” the scientists’ second paper concluded — a huge infusion of carbon into the atmosphere and the ocean.

But neither an asteroid strike nor an upwelling of oxygen-deprived deep-ocean water would explain the selective pattern of death.

Instead, the scientists suspect that the answer lies in the biggest volcanic event of the past 500 million years — the eruptions that formed the Siberian Traps, the stairlike hilly region in northern Russia. The eruptions sent catastrophic amounts of carbon gas into the atmosphere and, ultimately, the oceans; that led to long-term ocean acidification, ocean warming and vast areas of oxygen-poor ocean water.

The surprise to Dr. Clapham was how closely the findings from the Great Dying matched today’s trends in ocean chemistry. High concentrations of carbon-based gases in the atmosphere are leading to warming, rapid acidification and low-oxygen dead zones in the oceans.

The idea that changes in ocean chemistry, particularly acidification, could be a factor in a mass extinction is a relatively new idea, said Andrew H. Knoll, a Harvard geologist who wrote a seminal paper in 1996 exploring the consequences of a rapid increase in carbon dioxide in the atmosphere on the physiology of organisms.

“In terms of the overall pattern of change, what we’re seeing now and what is predicted in the next two centuries is riding a parallel track to what we think happened in the past,” he said.

Dr. Clapham noted that Permian and modern similarities are not exact. The Permian ocean was easier to acidify than today’s ocean because it had less deep-water calcium carbonate, which offsets the acid. But he said that corals are the most vulnerable creatures in the modern ocean for the same reason they were during the Permian extinction. They have little ability to govern their internal chemistry and they rely on calcium carbonate to build their reefs.

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Like Dr. Clapham, he cautioned that the trends between the two periods were not exactly comparable. Back in the Permian, the planet had a single supercontinent, Pangea, and ocean currents were different.

And he and Dr. Langdon noted that carbon was being injected into the atmosphere today far faster than during the Permian extinction. As Dr. Knoll put it, “Today, humans turn out to be every bit as good as volcanoes at putting carbon dioxide into the atmosphere.”

In the nuclear age we’ve grown up often thinking of “mutually assured destruction” as one big sudden explosive event. It turns out doing nothing meaningful towards fixing our long-term ecological problems for decades and decades is also an act of MADness. The pathetic-slow-grind-down-over-decades-because-humanity-can’t-help-itself version of mutually assured destruction may not have the fireworks of nuclear annihilation but it gets the job done.

And this is not to say that there won’t be plenty of radiation in our slow grind down...

(Mainichi Japan) March 17, 2012
Japan using overseas food aid to help dispel contamination fears

TOKYO (Kyodo) — Japan and the U.N. World Food Program exchanged notes Friday on using certified-safe food products from disaster-hit eastern Japan as overseas aid as a way to dispel fears over radioactive contamination.

Using 1 billion yen in a supplementary budget for fiscal 2011 ending this month, the WFP will procure canned fish products made in Aomori, Iwate, Ibaraki and Chiba prefectures and provide Cambodia and four other developing countries with these products for school lunches and other purposes, Japanese officials said.

The official development aid plan has come under fire from some citizens’ groups, which are concerned about radioactive contamination of food products as a result of the Fukushima Daiichi nuclear plant accident triggered by the March 2011 earthquake and tsunami.

“We would like to break down deep-rooted fears overseas by exporting food products that are certified as safe after being tested for radiation,” a senior Foreign Ministry official said.

Parliamentary Vice Foreign Minister Toshiyuki Kato told a ceremony for the exchange of notes that the aid is planned at a time when “fish-processing companies in the regions damaged gravely by the disaster are struggling to fully restart their business operations.”

Fukushima fish for school lunches? I can’t see any problems with this plan:

(Mainichi Japan) April 3, 2012
Cesium up to 100 times levels before disaster found in plankton far off nuke plant

Radioactive cesium up to 100 times pre-nuclear disaster levels has been detected in plankton inhabiting the sea far from the crippled nuclear plant following the March 2011 disaster, according to a survey conducted by Japanese and U.S. researchers.

The high concentration of cesium, which is believed to derive from the Fukushima No. 1 Nuclear Power Plant, suggests that radioactive substances that have leaked from the complex are spreading extensively in the sea.

Jun Nishikawa, research associate with the University of Tokyo’s Atmosphere and Ocean Research Institute, underscored the need for a long-term survey on the contamination of marine creatures with radioactive substances.

“Even though radiation levels detected from the plankton samples were still low, there is a possibility that large amounts of cesium will accumulate in fish through the food chain in a phenomenon called biological concentration. We need to continue our survey,” he said. “Each species of marine creatures that feed on animal plankton need to be monitored over the long term.”

The results of the survey were published in the Proceedings of the National Academy of Sciences of the United States on April 3.

In the survey, Nishikawa and other researchers including those with U.S. Woods Hole Oceanographic Institution collected samples of sea water and animal plankton at about 60 locations in the sea some 30 to 600 kilometers off the crippled plant in June last year, and measured the levels of radioactive cesium in them.

Radioactive cesium was detected in at least one sample taken at each of the locations.

The largest amount of radioactive cesium in animal plankton was found in a sample collected at a location 300 kilometers from the power plant — at 102 becquerels of cesium-134 and cesium-137 per kilogram in dry weight. This compares with the average amount before the accident, which stood at 0.1 to 1 becquerel of only cesium-137.

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WSJ
March 30, 2012, 3:18 p.m. ET
U.S. Approves New Nuclear Reactors in South Carolina

By RYAN TRACY

Federal regulators Friday approved Scana Corp.‘s proposal to build two new nuclear reactors in South Carolina, paving the way for the second license issued to a new nuclear power plant in two months after a drought that lasted more than 30 years.

The Nuclear Regulatory Commission voted 4–1 to green-light construction of the plant, with the agency’s chairman, Gregory Jaczko, dissenting.

Mr. Jaczko said the vote was a “significant milestone,” but that he still disagreed with other commissioners about some parts of the license. He didn’t specify his objections on Friday, but in February he objected to issuing a new reactor license to Southern Co. because the license didn’t include a provision requiring the company to comply with regulations adopted in light of Japan’s 2011 nuclear accident.

The two reactors to be built by Scana unit South Carolina Electric & Gas and state-owned utility Santee Cooper follow the two Southern Co. reactors in Georgia that received the NRC’s blessing last month. But those four reactors, if built, may be the last to go forward for some time due to the low cost of natural gas, which competes with nuclear as an available fuel for generating electricity.

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Japan Times
Thursday, March 29, 2012

Reactor 2 radiation too high for access
73 sieverts laid to low water; level will even cripple robots

By MINORU MATSUTANI
Staff writer

Radiation inside the reactor 2 containment vessel at the Fukushima No. 1 nuclear plant has reached a lethal 73 sieverts per hour and any attempt to send robots in to accurately gauge the situation will require them to have greater resistance than currently available, experts said Wednesday.

Exposure to 73 sieverts for a minute would cause nausea and seven minutes would cause death within a month, Tokyo Electric Power Co. said.

The experts said the high radiation level is due to the shallow level of coolant water — 60 cm — in the containment vessel, which Tepco said in January was believed to be 4 meters deep. Tepco has only peeked inside the reactor 2 containment vessel. It has few clues as to the status of reactors 1 and 3, which also suffered meltdowns, because there is no access to their insides.

The utility said the radiation level in the reactor 2 containment vessel is too high for robots, endoscopes and other devices to function properly.

Spokesman Junichi Matsumoto said it will be necessary to develop devices resistant to high radiation.

High radiation can damage the circuitry of computer chips and degrade camera-captured images.

For example, a series of Quince tracked robots designed to gather data inside reactors can properly function for only two or three hours during exposure to 73 sieverts, said Eiji Koyanagi, chief developer and vice director of the Future Robotics Technology Center of Chiba Institute of Technology.

That is unlikely to be enough for them to move around and collect video data and water samples, reactor experts said.

“Two or three hours would be too short. At least five or six hours would be necessary,” said Tsuyoshi Misawa, a reactor physics and engineering professor at Kyoto University’s Research Reactor Institute.

The high radiation level can be explained by the low water level. Water acts to block radiation.

“The shallowness of the water level is a surprise . . . the radiation level is awfully high,” Misawa said.

While the water temperature is considered in a safe zone at about 50 degrees, it is unknown if the melted fuel is fully submerged, but Tepco said in November that computer simulations suggested the height of the melted fuel in reactor 2’s containment vessel is probably 20 to 40 cm, Tepco spokeswoman Ai Tanaka said.

Tepco has inserted an endoscope and a radiation meter, but not a robot, in the containment vessel. It is way too early to know how long Tepco will need to operate robots in the vessel because it is unknown what the devices will have to do, Tanaka said.

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According to experts, even though high radiation in the containment vessel means additional trouble, it is not expected to further delay the decommissioning the three crippled reactors, a process Tepco said will take 40 years.

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Tepco has not been able to gauge the water depths and radiation levels of the containment vessels for reactors 1 and 3, as, unlike unit 2, there is no access.

The NYTimes also has an update with some additional info. The “cold shutdown” status of reactor 2 is now in question as the article points out that 9 tons of water getting pumped into the reactor 2 every hour, also suggesting that the radioactive water leakage could be much higher than previosly estimated. In addition, reactor 4 still has all the spent fuel rods sitting above it and officials acknowledge that any problems with keeping the vessel filled with water could result in another “colossal” radiation release from those spent rods. Adding to the risk of a radiation release is the fact that reactors 1 and 3 could be in even worse shape than reactor 2, but no one knows because they are still inaccessible and it’s thought that the hydrogen explosion that took place inside reactor 4 days after the tsunami was possibly due to a build up of hydrogen gas that leaked over from reactor 3. The one bit of good news in the report is that Tepco and the Japanese government appear to no longer have any credibility with the Japanese public, so that sort of progress:

NYTimes
Inquiry Suggests Worse Damage at Japan Nuclear Plant
By HIROKO TABUCHI
Published: March 29, 2012

The results of the inquiry, released this week by the operator of the Fukushima Daiichi Nuclear Power Plant, also cast doubt over the Japanese government’s declaration three months ago that the ravaged site is now under control.

Throughout the crisis that ensued after a powerful earthquake and tsunami last March, both the plant’s operator, Tokyo Electric Power, or Tepco, and the government were accused of playing down the dangers posed by the nuclear meltdown. Subsequent disclosures that the event was indeed far more severe than they let on have badly damaged their credibility, to the point that almost any statement from the authorities is now regarded as suspect by a dubious Japanese public.

Fukushima Daiichi’s vital cooling systems were knocked out in the early stages of the crisis last year. The uranium cores at three of the plant’s six reactors quickly melted down, breaching their containment vessels and setting off a large radiation leak.

Three reactors were later rocked by hydrogen explosions, which blew out their outer walls.

What followed was a frantic effort to keep the inner parts of the reactors flooded with cooling water to prevent their cores from again overheating. Officials at Tepco had previously said that operation was succeeding, and that the damaged fuel rods were safely submerged in water.

But earlier this week, an examination at one of the reactors showed the water level at its core to be lower than levels previously estimated, raising fears that the broken-down remnants of the uranium fuel rods there may not be completely submerged and in danger of heating up again.

Cooling water at the plant’s No. 2 reactor came up to just two feet from the bottom of the reactor’s containment vessel, a beaker-shaped structure that encases the fuel rods. That was below the 33-foot level estimated by officials when the government declared the plant stable in December.

The low water levels also raise concerns that radioactive water may be leaking out of the reactor at a higher rate than previously thought, possibly into a part of the reactor known as the suppression chamber, and into a network of pipes and chambers under the plant — or into the ocean.

At the No. 2 reactor, workers still pump about nine tons of water an hour into the core to keep it cool.

The investigation also found current radiation levels of 72.0 sieverts inside the containment vessel, enough to kill a person in a matter of minutes, as well as for electronic equipment to malfunction.

Kazuhiko Kudo, a professor of nuclear engineering at Kyushu University in southwestern Japan, said it was now suspect whether the nuclear fuel was being adequately cooled. And if some parts of the fuel remained above water, there was a risk that the fuel could again heat up and melt. That could set off a dangerous spike in the pressure inside the containment vessel, and lead to more radiation escaping the reactor, he said.

...

Two other badly damaged reactors — Nos. 1 and 3 — could be in even worse condition. Hydrogen explosions blew out the outer walls of those reactors, and officials believe that more nuclear fuel has breached the containment vessel at the No. 1 reactor than the others.

Experts also worry about a fourth reactor that was not operating at the time of the accident, but nevertheless poses a risk because of the large number of spent nuclear fuel rods stored in a water coolant tank there. The No. 4 reactor was also hit by a hydrogen explosion in the early days of the crisis, possibly due to hydrogen that leaked into the reactor from the adjacent No. 3 unit.

The spent fuel rods stored at the No. 4 reactor pose a particular threat, experts say, because they lie unprotected outside the unit’s containment vessel. Tokyo Electric has been racing to fortify the crumpled outer shell of the reactor, and to keep the tank fed with water. But should a problem also arise with cooling the spent fuel, the plant could run the risk of another colossal radiation leak, experts say.

The many aftershocks that continue to hit the Fukushima region are also a source of worry.

“The plant is still in a precarious state,” said Mr. Kudo of Kyushu University. “Unfortunately, all we can do is to keep pumping water inside the reactors,” he said, “and hope we don’t have another big earthquake.”

That last sentence is perhaps the most chilling statement found in either of the articles because if a successful multi-decade cleanup effort is contingent on no more large earthquakes in the region, it’s probably time for a preemptive evacuation...

Marketwatch
Fukushima flood defenses given good marks
March 22, 2012, 4:52 PM

The nuclear disaster following the destruction of Japan’s Fukushima power plant by a 9.0 magnitude earthquake last year had an upside. Really?

That’s what a couple of industry officials said at the Wall Street Journal’s ECO:nomics conference Thursday. While two of the plant’s four reactors suffered meltdowns, the facility held up remarkably well overall, preventing the kind of catastrophe seen at Chernobyl, said Jacques Besnainou, chief executive of Areva Inc.

Besnainou wasn’t alone in the assessment. Aris Candris, chief executive of Westinghouse Electric said the disaster showed that nuclear plants handled catastrophic flooding better than expected.

The two industry executives said they were bullish on nuclear energy, though not in the U.S. China remains the top market for nuclear energy growth with 25 plants in the works. Second on the list is India.
...

So a 50% meltdown rate during a flood was even better than expected performance? Great...

Reconstructed records show Japan leaders knew meltdown risk early, feared worse than Chernobyl

By Associated Press, Updated: Friday, March 9, 11:19 AM

TOKYO — Just four hours after the tsunami swept into the Fukushima nuclear power plant, Japan’s leaders knew the damage was so severe the reactors could melt down, but they kept their knowledge secret for months. Five days into the crisis, then-Prime Minister Naoto Kan voiced his fears it could turn worse than Chernobyl.

The revelations were in documents released Friday, almost a year after the disaster. The minutes of the government’s crisis management meetings from March 11 — the day the earthquake and tsunami struck — until late December were not recorded and had to be reconstructed retroactively.

They illustrate the confusion, lack of information, delayed response and miscommunication among government, affected towns and plant officials, as some ministers expressed sense that nobody was in charge when the plant conditions quickly deteriorated.

The minutes quoted an unidentified official explaining that cooling functions of the reactors were kept running only by batteries that would last only eight hours.

“If temperatures in the reactor cores keep rising beyond eight hours, there is a possibility of meltdown,” the official said during the first meeting that started about four hours after the magnitude 9.0 earthquake and tsunami hit the Fukushima Dai-ichi plant March 11, setting off the crisis.

Apparently the government tried to play down the severity of the damage. A spokesman for the Nuclear and Industrial Safety Agency was replaced after he slipped out a possibility of meltdown during a news conference March 12.

The plant operator, Tokyo Electric Power Co., acknowledged a partial meltdown much later, in May.

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It was nearly 10 days before one of his top nuclear advisers produced a worst-case scenario at his request. The March 25 paper, produced by the head of the Japan Atomic Energy Commission, warned that a disaster of that scale would require evacuating 30 million people from the greater Tokyo area. Fearing panic, the government kept the report a secret, but The Associated Press obtained it in January.

The failure to record the minutes of the government’s crisis management meetings properly has added to sharp public criticism about how the nuclear crisis was handled and deepened distrust of politicians and bureaucrats.

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Oil is more toxic than previously thought, study finds
By Dean Kuipers

December 27, 2011, 12:00 p.m.

Bad news for the Gulf of Mexico: a study released this week sheds new light on the toxicity of oil in aquatic environments, and shows that environmental impact studies currently in use may be inadequate. The report is to be published this week in the Proceedings of the National Academy of Sciences.

The study, spearheaded by the UC Davis Bodega Marine Laboratory in collaboration with NOAA, looked into the aftermath of the 2007 Cusco Busan spill, when that tanker hit the San Francisco-Oakland Bay Bridge and spilled 54,000 gallons of bunker fuel into the bay.

The key finding involved the embryos of Pacific herring that spawn in the bay. The fish embryos absorbed the oil and then, when exposed to UV rays in sunlight, physically disintegrated. This is called phototoxicity, and has not previously been taken into account when talking about oil spills.

“This phenomenon had been observed in the laboratory, but had never been observed in the field, and there were even some skeptics out there wondering if this was just a phenomenon that people would see under lab conditions,” said Gary Cherr, director of the marine lab and professor of environmental toxicology.

“One of the real take-home messages from our study was: yes, in fact, it definitely happens in the real world.”

This is another big jump in understanding the real damages from oil spills. Studies of the 1989 Exxon Valdez spill created an entirely new understanding of oil damage when it was found that oil was toxic in minute quantities measured in parts-per-billion and even parts-per-trillion – much lower than previously recognized. This finding of phototoxicity, however, presents a new challenge.

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“It’s kind of a new paradigm in thinking about the toxicity of oil,” adds Cherr. “Up until now, there has been this awareness of it in the laboratory studies, but it has not been taken into account in the real world, in environmental analyses, and certainly in regulating the amounts of oil that are spilled.”

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