Displaying items by tag: Nuclear
Read this story from Scientific American via Huffington Post on the worrisome state of America's largest and oldest nuclear waste site in southeast Washington State. (May 9, 2013)
The most toxic and voluminous nuclear waste in the U.S.—208 million liters —sits in decaying underground tanks at the Hanford Site (a nuclear reservation) in southeastern Washington State. It accumulated there from the middle of World War II, when the Manhattan Project invented the first nuclear weapon, to 1987, when the last reactor shut down. The federal government’s current attempt at a permanent solution for safely storing that waste for centuries—the Waste Treatment and Immobilization Plant here—has hit a major snag in the form of potential chain reactions, hydrogen explosions and leaks from metal corrosion. And the revelation last February that six more of the storage tanks are currently leaking has further ramped up the pressure for resolution.
After decades of research, experimentation and political inertia, the U.S. Department of Energy (DoE) started building the “Vit Plant” at Hanford in 2000. It’s intended to sequester the waste in stainless steel–encased glass logs, a process known as vitrification (hence “Vit”), so it cannot escape into the environment, barring natural disasters like earthquakes or catastrophic fires. But progress on the plant slowed to a crawl last August, when numerous interested parties acknowledged that the plant’s design might present serious safety risks. In response, then-Energy Secretary Steven Chu appointed an expert panel to find a way forward. Because 60 of the 177 underground tanks have already leaked and all are at increasing risk to do so, solving the problem is urgent.
Vitrification prep 101: Some tough homework
The plant’s construction, currently contracted by the DoE to Bechtel National, Inc., may be the most complicated engineering project underway in the U.S. But back in 2000 the DoE and Bechtel decided to save time and money by starting construction before crucial structures and processes had been designed and properly tested at a scale comparable to full operation. This wasn’t such a good idea, says Dirk Dunning, nuclear material specialist with the Oregon Department of Energy. “The worst possible time to save money is at the beginning. You’re better off to be very nearly complete on design before you begin construction.”
The vitrification project calls for the waste to be analyzed chemically and radiologically before it enters a pretreatment facility to be separated into various constituents such as cesium 137, strontium 90 and metals. After that, each separate waste stream is channeled as either high-level or low-activity waste into designated melters. The glass is created by mixing sand with a few additives like boron; the waste is stirred in, and the whole mess is melted, then decanted into the steel canisters. After the glass logs solidify the waste is trapped and should be isolated from the environment for long enough for most of the radioactivity to decay to safe levels.
The low-level waste canisters will be stored permanently at Hanford. Because the planned Yucca Mountain geologic repository project was halted by the Obama administration, the high-level waste canisters will be kept at Hanford in an as-yet unconstructed building. In January the DoE announced it is beginning work on a new “comprehensive management and disposal system” that will make a permanent geologic repository available by 2048. Yet even if all goes perfectly from now on, it will take until 2062 to vitrify all the waste.
The waste presents significant challenges for Vit Plant project engineers and nuclear chemists. For one thing, the waste varies wildly from tank to tank. The former nuclear weapons facility at Savannah River, Ga.—also part of the Manhattan Project—has been successfully vitrifying weapons waste for years, but only one fuel separation process was used there. At Hanford there were nine production reactors making plutonium and uranium fuel using at least six different radiochemical processes whose chemistry, and thus constituents, were very different. This remains true of the waste as well. There are large differences in composition from tank to tank that necessitate chemically profiling the waste in batches before it enters the Vit Plant, which may also require changes to the glass formula at the other end of the process.
Overall, the tanks hold every element in the periodic table, including half a ton of plutonium, various uranium isotopes and at least 44 other radionuclides—containing a total of about 176 million curies of radioactivity. This is almost twice the radioactivity released at Chernobyl, according to Plutopia: Nuclear Families, Atomic Cities, and the Great Soviet and American Plutonium Disasters, by Kate Brown, a history professor at the University of Maryland, Baltimore County. The waste is also physically hot as well as laced with numerous toxic and corrosive chemicals and heavy metals that threaten the integrity of the pipes and tanks carrying the waste, risking leakage.
The physical form of the waste causes problems, too. It’s very difficult to get a representative sample from any given tank because the waste has settled into layers, starting with a baked-on “hard heal” at the bottom, a layer of salt cake above that, a layer of gooey sludge, then fluid, and finally gases in the headspace between the fluid and the ceiling. Most of the radioactivity is in the solids and sludge whereas most of the volume is in the liquids and the salt cake.
Read more: http://www.huffingtonpost.com/2013/05/09/hanford-nuclear-cleanup-too-dangerous_n_3246263.html?utm_hp_ref=green
Read this story from The New York Times on the latest mishap at Japan's Fukushima Daiichi Nuclear Plant, which has remained in precarious condition, continuing to emit radioactive waste, ever since it was destroyed by an earthquake and tsunami over 2 years ago. (April 10, 2013)
TOKYO — More than two years after multiple meltdowns at the Fukushima Daiichi nuclear power plant, a series of recent mishaps — including a blackout set off by a dead rat and the discovery of leaks of thousands of gallons of radioactive water — have underscored just how vulnerable the plant remains.
Increasingly, experts are arguing that the plant’s operator, the Tokyo Electric Power Company, or Tepco, cannot be trusted to lead what is expected to be decades of cleanup and the decommissioning of the plant’s reactors without putting the public, and the environment, at risk.
At the same time, the country’s new nuclear regulator remains woefully understaffed. It announced Wednesday that it would send a ninth official to the site — to monitor the work of about 3,000 laborers.
“The Fukushima Daiichi plant remains in an unstable condition, and there is concern that we cannot prevent another accident,” Shunichi Tanaka, chairman of the Nuclear Regulation Authority, said at a news conference. “We have instructed Tepco to work on reducing some of the biggest risks, and we as regulators will step up monitoring.”
The biggest scare at the plant in recent days has been the discovery that at least three of seven underground storage pools are seeping thousands of gallons of radioactive water into the soil. On Wednesday, Tepco acknowledged that the lack of adequate storage space for contaminated water had become a “crisis,” and said it would begin emptying the pools. But the company said that the leaks will continue over the several weeks that it will likely take to transfer the water to other containers.
Plant workers dug these underground ponds about six months ago to store the ever-growing amount of contaminated water at the plant. There is about 400 tons daily from two sources: runoff from a makeshift cooling system rigged together after the site’s regular cooling equipment was knocked out by the earthquake and tsunami in March 2011, and a steady stream of groundwater seeping into damaged reactors.
Tepco stores more than a quarter-million tons of radioactive water at the site and says the amount could double within three years.
But as outside experts have discovered with horror, the company had lined the pits for the underground pools with only two layers of plastic each 1.5 millimeters thick, and a third, clay-based layer just 6.5 millimeters thick. And because the pools require many sheets hemmed together, leaks could be springing at the seams, Tepco has said.
“No wonder the water is leaking,” said Hideo Komine, a professor in civil engineering at Ibaraki University, just south of Fukushima. He said that the outer protective lining should have been hundreds of times thicker.
Tepco’s president, Naomi Hirose, traveled to Fukushima on Wednesday to apologize for the leaks, which he said had caused further distress to local residents. About 160,000 fled their homes in the wake of the disaster, and large areas around the plant remain off-limits.
Mr. Hirose said that Tepco would stop using the underground pits, and would pump the water out into more aboveground tanks. But Tepco says it is likely to take until at least the end of May to empty the pools. Mr. Hirose said that he did not think any water would reach the Pacific Ocean, because the pools lie at least half a mile inland.
“We’re going to get the water out of these underground pits and into tanks as soon as we can,” he said. “We’re aware that this is a crisis that we must attend to with urgency.”
But Muneo Morokuzu, a nuclear safety expert at the Tokyo University Graduate School of Public Policy, said that the plant required a more permanent solution that would reduce the flood of contaminated water into the plant in the first place, and that Tepco was simply unable to manage the situation. “It’s become obvious that Tepco is not at all capable of leading the cleanup,” he said. “It just doesn’t have the expertise, and because Fukushima Daiichi is never going to generate electricity again, every yen it spends on the decommissioning is thrown away.”
“That creates an incentive to cut corners, which is very dangerous,” he said. “The government needs to step in, take charge and assemble experts and technology from around the world to handle the decommissioning instead.”
Read more: http://www.nytimes.com/2013/04/11/world/asia/fukushima-nuclear-plant-is-still-unstable-japanese-official-says.html?pagewanted=all&_r=3&%20http://vancouver.mediacoop.ca/newsrelease/17034&
Ignoring Geology 101, governments (including Canada’s) have been pushing hard for many years to establish "Deep Ground Repositories" (GDRs) as a "final solution" to the growing problem of nuclear waste. So far, none have succeeded, although one is currently under construction in Finland...The International Atomic Energy Agency (IAEA) estimates that the volume of radioactive waste on the planet already exceeds 345,000 tonnes – 50,000 tonnes in Canada alone. We’ve created this disaster and, of course, we have to deal with it.
Read this story from Japan's Yomiuri Shimbun on manufacturing giant Toshiba's development of a small nuclear reactor to power bitumen extraction in the Alberta Tar Sands. (Jan 16, 2012)
Toshiba Corp. has been developing a small nuclear reactor for mining oil sands at the request of a firm engaged in such mining projects in Alberta Province, Canada, and aims to begin operating the reactor by 2020, it has been learned.
As the situation regarding the construction of new nuclear power plants and reactors in Japan remains unclear, Toshiba's move will likely attract attention as an effort toward utilizing the nation's nuclear technology in fields other than power generation.
Oil sands are sandstone deposits which contain a viscous form of petroleum, and can be used as petroleum-based fuel. Compared with oil fields, it has so far been difficult to develop oil sands. However, technological advances have led to the promotion of oil sands development in Venezuela and Canada. Canada is said to have about 100 oil sands deposits totaling about 170 billion barrels--the equivalent of about 100 years' worth of petroleum consumption in Japan.
The output of Toshiba's new small reactor will be 10,000 kilowatts to 50,000 kilowatts, about 1 percent-5 percent that of a regular nuclear reactor, according to the sources.
Steam generated in the reactor will be sent to strata located at a depth of about 300 meters, where oil sands are found, to turn the sand into slurry. The slurry will then be extracted from the strata using a separate pipe.
To ensure the reactor's safety, Toshiba reportedly plans to construct a nuclear reactor building underground, while the building itself will be equipped with an earthquake-absorbing structure.
The firm has completed a basic design for the reactor and has already started approval procedures for construction in the United States. After getting the official go-ahead from the U.S. government, Toshiba will then undergo safety checks in Canada.
Currently, oil sands are mined using boiler-generated steam. However, as this method requires natural gas to fuel the boilers, it is necessary to transport the gas as needed. Also, carbon dioxide emissions from burning natural gas is seen to be a problem.
By contrast, the planned small reactor would not require refueling for up to 30 years after construction or release any carbon dioxide. Furthermore, nuclear reactors would also be cheaper should the general price of natural gas increase.
Read more: http://www.yomiuri.co.jp/dy/business/T130115004424.htm
Read this story from Japan's Asahi News on ongoing troubles at the Fukushima nuclear disaster site. (Sept. 11, 2012)
The operator is having difficulty pumping water into destroyed reactors at the Fukushima No. 1 plant, tanks are rapidly filling with radioactive water, and hundreds of potentially volatile uranium fuel assemblies remain in a precarious storage pool that some warn could collapse in another strong earthquake.
But Tokyo Electric Power Co. is working on solving those problems, with plans to build new storage tanks, to erect an overhead crane to lift the fuel, and to decommission the destroyed reactors within 40 years.
Cooling the reactors produces about 450 tons of radioactive water daily. Some of that water is treated and reused as coolant, but as of Sept. 4 storage tanks at the site held about 200,000 tons of contaminated water.
TEPCO plans to build more tanks to increase the overall capacity to 700,000 tons.
Meanwhile, the volume of water pumped into the pressure vessels of the No. 1, No. 2 and No. 3 reactors fell below a mandated minimum level on Aug. 30, for the first time since immediately after the 2011 earthquake and tsunami.
The reactors remain in what is known as cold shutdown. Temperatures within the outer containment vessels and at the bottom of the pressure vessels remain largely stable, between 35 and 55 degrees.
However, lumps of melted nuclear fuel likely remain piled inside the reactors, mainly in the containment vessels.
TEPCO has been adjusting injected water to keep the reactors cool, but the fuel clusters continue to generate heat and the plant operator has yet to come up with a full solution.
The company suspects that the pipes carrying water to the reactors from tanks may have been choked by chips of polyethylene, a material used in the piping.
Another problem is groundwater, which flows into the reactor buildings and becomes contaminated. TEPCO plans to dig 12 wells west of the reactor buildings and pump out water, to lower the overall level of groundwater so that it will not enter the buildings.
It has also begun preparing to decommission the reactors, which will take an estimated 30 to 40 years.
The key task will be to remove molten nuclear fuel from the three crippled reactors. Before that, the company needs to understand fully what is going on inside.
Read more: http://ajw.asahi.com/article/0311disaster/fukushima/AJ201209110101
Miranda Holmes on the health impacts of Fukushima you haven't been hearing about from your government or the mainstream media: "Even though it wasn’t reported in the Proceedings of the National Academy of Sciences until May 2012, within five months of the Fukushima explosion scientists on the US Pacific coast found radioactive contamination levels ten times higher than normal in migrating bluefish tuna. Airborne radioactive pollution crossed the Pacific much faster. Health Canada tried to downplay the significance of massive spikes in radiation in BC and across Canada within weeks of the Fukushima nuclear plant explosion."
Read this story from The Guardian on a new report from a special Japanese parliamentary panel, which pins the blame for the nuclear catastrophe at the Fukushima-Daiichi plant on government-industry collusion and poor regulation. (July 5, 2012)
Last year's accident at the Fukushima Daiichi nuclear power plant was a manmade disaster caused by poor regulation and collusion between the government, the operator and the industry's watchdog, a report has said.
In a highly critical assessment published on Thursday, a Japanese parliamentary panel challenged claims by the plant's operator, Tokyo Electric Power (Tepco), that the triple meltdown at the plant in north-east Japan had been caused solely by a 14-metre tsunami on 11 March last year. The panel said the magnitude-9 earthquake that preceded the waves could not be ruled out as a cause of the accident.
It accused Tepco and regulators at the nuclear and industrial safety agency of failing to take adequate safety measures, despite evidence that the area was susceptible to powerful earthquakes and tsunamis.
"The Fukushima nuclear power plant accident was the result of collusion between the government, the regulators and Tepco, and the lack of governance by said parties," said the report, compiled by the Fukushima nuclear accident independent investigation commission.
"They effectively betrayed the nation's right to be safe from nuclear accidents. Therefore, we conclude that the accident was clearly 'man-made'.
"We believe that the root causes were the organisational and regulatory systems that supported faulty rationales for decisions and actions, rather than issues relating to the competency of any specific individual.
"Across the board, the commission found ignorance and arrogance unforgivable for anyone or any organisation that deals with nuclear power. We found a disregard for global trends and a disregard for public safety."
The commission's chairman, Kiyoshi Kurokawa, a professor emeritus at Tokyo University, said in a scathing introduction that cultural traits had caused the disaster.
He said: "What must be admitted – very painfully – is that this was a disaster 'Made in Japan.' Its fundamental causes are to be found in the ingrained conventions of Japanese culture: our reflexive obedience; our reluctance to question authority; our devotion to 'sticking with the programme'; our groupism; and our insularity.
"Had other Japanese been in the shoes of those who bear responsibility for this accident, the result may well have been the same."
The 641-page report was published on the same day a nuclear reactor in western Japan became the first to produce electricity since the accident. All of the country's 50 functioning reactors had been switched off after the crisis to undergo safety checks.
Read more: http://www.guardian.co.uk/environment/2012/jul/05/fukushima-meltdown-manmade-disaster?newsfeed=true
Read this update from The Japan Times, confirming that the collong system for the badly damaged reactor 4 at the Fukushima-Daiichi Nuclear Plant was successfully restarted Monday after malfunctioning over the weekend, once again bringing the plant to the brink of disaster. (July 2, 2012)
The cooling system for the No. 4 reactor's hazardous spent-fuel pool came back to life Sunday at the crippled Fukushima No. 1 power plant after emergency repairs succeeded, Tokyo Electric Power Co. said.
The cooling system automatically shut down on Saturday for unknown reasons, allowing the water in the pool to reach 42.9 degrees Sunday. The pool must stay filled to prevent the used rods from burning up.
The cooling system resumed shortly after 3 p.m. The temperature in the pool, which is sitting perilously atop the reactor in a heavily damaged building, was 33.3 degrees when the cooling system failed Saturday morning.
The company believes a part in the cooling system's emergency power unit caused the shutdown and plans to replace it "soon."
The pool contains 1,535 fuel assemblies — including 204 unused ones — that could all burn up if the remainder of the building collapses and dumps the water out. The same cooling system also was suspended on June 4.
Read original article: http://www.japantimes.co.jp/text/nn20120702a9.html#.T_DpZHCWCIY
Read this story from Reuter's, reporting that Japan's nuclear crisis minister told the media organization the country will be speeding up efforts to remove dangerous contaminated fuel rods from the badly-damaged reactor 4 building at the Fukushima-Daiichi nuclear plant. The move comes after mounting pressure from international media and a number of American and Japanese politicians, diplomats and nuclear experts - as reported by The Common Sense Canadian last month. (June 21, 2012)
TOKYO (Reuters) - Workers at the crippled Fukushima nuclear plant will begin removing fuel rods from a damaged reactors a year ahead of schedule, a government minister said Thursday, a move to address concerns about the risk of a new quake that could cause a further accident and scatter more radioactive debris.
"We would like to start taking out undamaged fuel this year. Preparation is now under way," Japan's nuclear crisis minister, Goshi Hosono, told Reuters in an interview.
"Doing it quickly is important. But we also have to make sure those workers out there, who are struggling under harsh conditions, will not be endangered by trying to move things fast."
Tokyo Electric Power Co (Tepco), operator of the plant hit by the world's worst nuclear accident since Chernobyl in 1986, had said in April it aimed to begin removing the fuel rods from the No. 4 reactor at the end of next year.
That would have left large quantities of radioactive fuel rods outside the protection of strong containment vessels for two and a half years after the accident.
Experts say the fuel rods, now covered only by water and a white plastic tarp, could present a risk of a knock-on accident if the reactor building collapsed or the water supply used to keep the rods cool were disrupted by another earthquake.
Some 1,535 fuel assemblies -- enough uranium fuel rods to power three reactors -- are being stored in a pool atop the mangled No. 4 reactor building. The reactor, which was shut down for maintenance at the time of the March 2011 earthquake and tsunami, was badly damaged by a series of powerful explosions that followed the disaster as power was cut off to the plant.
Hosono said last month during a visit to the Fukushima plant that he expected workers to begin removing fuel from the No.4 reactor's storage pool next year.
Work began in April to raise what amounts to a giant tent over the building to keep radioactive dust from scattering during the transport of the fuel rods.
Tepco says its analysis shows the No.4 reactor building would hold up in a strong earthquake. But Japanese safety regulators ordered Tepco to recheck its findings last month after measurements showed one of the walls of the reactor building was buckling out by about 3 centimetres (1.2 inches).
The removed uranium fuel rods will be placed in another storage pool at the Fukushima plant, 240 km (150 miles) northeast of Tokyo, officials have said.
Read more: http://af.reuters.com/article/worldNews/idAFBRE85K0JM20120621?pageNumber=1&virtualBrandChannel=0
It's the most important story nobody's talking about: the continued dire situation at Japan's Fukushima Daiichi nuclear plant. Judging by the assurances of the Japanese Government and drying up of mainstream media coverage, it's easy to see how most of the world has been lulled into a false sense of security. Yet recently - amid troubling warnings from American and Japanese politicians and nuclear experts about the instability of thousands of radioactive spent fuel rods - the mainstream media and global community are starting to take note...but will it be in time to stave of a potential disaster of incalculable proportions?