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Post Info TOPIC: Nuclear Waste Vault


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Radioactive material

A Pakistani public information campaign about what to do if you stumble across stray radioactive material is raising hairs on the necks of Western arms control experts.
The ads, which appeared last week in several Urdu-language newspapers, featured the large, yellow radiation symbol and a warning to report any lost or misplaced isotopes.

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New Symbol

New Symbol Launched to Warn Public About Radiation Dangers
With radiating waves, a skull and crossbones and a running person, a new ionising radiation warning symbol is being introduced to supplement the traditional international symbol for radiation, the three cornered trefoil.
The new symbol is being launched today by the IAEA and the International Organization for Standardization (ISO) to help reduce needless deaths and serious injuries from accidental exposure to large radioactive sources. It will serve as a supplementary warning to the trefoil, which has no intuitive meaning and little recognition beyond those educated in its significance.

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-- Edited by Blobrana at 03:00, 2007-03-24



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RE: Nuclear Waste Vault

Scientists have backed the government's plan to store the UK's nuclear waste deep underground.
The report, from experts working across science and technology, concluded there were "no insurmountable scientific or technological barriers" to the scheme.
It urged the government to maintain momentum in implementing the policy, but recommended key areas where more research was needed to move forward.
These included finding suitable sites and addressing skills shortages.

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Minerals intended to entrap nuclear waste for hundreds of thousands of years may be susceptible to structural breakdown within 1,400 years, a team from the University of Cambridge and the Pacific Northwest National Laboratory reported in the Jan. 11 issue of Nature.

The new study used nuclear magnetic resonance, or NMR, to show that the effects of radiation from plutonium incorporated into the mineral zircon rapidly degrades the mineral's crystal structure.
This could lead to swelling, loss of physical strength and possible cracking of the mineral as soon as 210 years, well before the radioactivity had decayed to safe levels, said lead author and Cambridge earth scientist Ian Farnan.
According to current thinking, highly radioactive substances could be rendered less mobile by combining them, before disposal, with glass or with a synthetic mineral at a very high temperature to form a crystal.
However, the crystal structure can only hold the radioactive elements for so long. Inside the crystal radioactive decay occurs, and tiny atomic fragments called alpha particles shoot away from the decaying nucleus, which recoils like a rifle, with both types repeatedly blasting the structure until it breaks down.
This may increase the likelihood for radioactive materials to leak, although co-author William J. Weber, a fellow at the Department of Energy national laboratory in Richland, Wash., who made the samples used in the study, cautioned that this work did not address leakage, and researchers detected no cracking. Weber noted that the "amorphous," or structurally degraded, natural radiation-containing zircon can remain intact for millions of years and is one of the most durable materials on earth.
Some earth and materials scientists believe it is possible to create a structure that rebuilds itself after these "alpha events" so that it can contain the radioactive elements for much longer. The tests developed by the Cambridge and PNNL team would enable scientists to screen different mineral and synthetic forms for durability.
As well as making the storage of the waste safer, new storage methods guided by the NMR technique could offer significant savings for nations facing disposal of large amounts of radioactive material. Countries including the United States, Britain, France, Germany and Japan are all considering burying their nuclear waste stockpiles hundreds of meters beneath the earth's surface. Doing so necessitates selection of a site with sufficiently stringent geological features to withstand any potential leakage at a cost of billions of dollars. For example, there is an ongoing debate over the safety of the Yucca Mountain site in Nevada. A figure published in Science in 2005 put that project's cost at $57 billion.

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Shewanella oneidensis

Since the discovery a little more than a decade ago of bacteria that chemically modify and neutralise toxic metals without apparent harm to themselves, scientists have wondered how on earth these microbes do it.

For Shewanella oneidensis, a microbe that modifies uranium chemistry, the pieces are coming together, and they resemble pearls that measure precisely 5 nanometers across enmeshed in a carpet of slime secreted by the bacteria.
The pearl is uranium dioxide, or uraninite, which moves much less freely in soil than its soluble counterpart, a groundwater-contamination threat at nuclear waste sites.
The U.S. Department of Energy estimates that uranium contaminates more than 2,500 billion litres of groundwater nationwide; over the past decade, the agency has support research into the ability of naturally-occurring microbes that can halt the uranium’s underground migration to prevent it from reaching streams used by plants, animals and people.
Assembling a battery of evidence, scientists have for the first time placed the bacterial enzymes responsible for converting uranium to uraninite at the scene of the slime, or "extracellular polymeric substance" (EPS), according to a study led by the DOE’s Pacific Northwest National Laboratory in today’s advance online edition of PLoS Biology.

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Nuclear Waste Vault

A nuclear waste vault in New Mexico will long outlive our society. Experts are working on elaborate ways to warn future civilizations.

Roger Nelson has a simple and unequivocal message for the people of the year 12006:

As chief scientist of the Waste Isolation Pilot Plant, Nelson oversees a cavernous salt mine that is the first geological lockbox for the "fiendishly toxic" detritus of nuclear weapons production: chemical sludge, lab gear and filters laced with tons of radioactive plutonium.

Nearly half a mile underground, workers push waste drums into crystalline labyrinths that seem as remote as the moon. A faint salty haze glows in powdery beams from miners' headlamps and settles on the lips like a desert kiss. Computer projections predict that within 1,000 years the ceilings and walls will collapse in a crushing embrace that seals the plutonium in place.
But plutonium remains deadly for 250 times that long — an unsettling reminder that some of today's hazards will outlast the civilizations that created them. The "forever problem," unique to the modern technological age, has made crafting the user manual for this toxic tomb the final daunting task in an already monumental project. The result is a gargantuan system that borrows elements equally from Stonehenge and "Star Trek."

Communicating danger may seem relatively straightforward, but countless human efforts to bridge the ages have failed as societies fall, languages die and words once poetic or portentous become the indecipherable marks of a long-forgotten scribbler.
To future generations, warnings about Nelson's dump may seem as impenetrable as the 600-year-old "Canterbury Tales" are for all but a few scholars today.

"No culture has ever tried, self-consciously and scientifically, to design a symbol that would last 10,000 years and still be intelligible. And even if we succeed, would the message be believed?" - David B. Givens, an anthropologist who helped plan the nuclear-site warnings.

The Energy Department predicted such a problem when it began planning for the $9-billion waste dump, dubbed WIPP, in 1974 and for a similar repository in Nevada at Yucca Mountain, near Las Vegas. That site has not yet been opened. Eventually it will store highly radioactive spent fuel from nuclear power plants as well as high-level waste from the weapons program.
Trying to communicate across 500 generations posed an unprecedented challenge of linguistics, semiotics and materials science, so the government first asked scientists, futurists and historians to envision what the far-distant future might be like.
Their report combines dry analysis and projections worthy of sci-fi disaster films, including massive climate change and feminist corporations that disbelieve WIPP warnings because they were written by men. Civilization is so interdependent and fragile, one panellist grimly noted, "that any massive global catastrophe might lead to reversion to at least a preindustrial era."
Greed or desperation could give rise to legends that WIPP holds buried treasure — apparently confirmed by surface warnings to keep out.

In a sense, they're right. Oil and gas deposits lie thousands of feet below the plant. In 100 or 5,000 years, an energy-poor government, company or gasoline-addicted tribe in a ruined society, like those depicted in the film "The Road Warrior," could adopt a "drill first, ask questions later" policy — piercing the repository and pulling death to the surface.

Others predicted the invention of self-guided robotic "mole miners" that would penetrate the site from the side or below. In a scenario set in the year 11991, robotic slaves are infected with a computer virus that compels them to override their safety programming as they compulsively drill and construct mine shafts.
Opportunities for WIPP to fail, the experts agreed, are limited only by the imagination.
The government formed a separate panel of scientists, linguists and artists to create a warning scheme to counter the pessimistic projections. That group immediately rejected digital or paper records — only a solution cast in stone could hope to solve a problem for the ages.

If Egyptian pyramids have lasted more than 5,000 years, today's monuments should fare better — if built from prosaic materials, such as ultra-hard concrete. Scavengers stripped the pyramids bare for their once-shimmering marble skins.
The trefoil symbol for radioactive material might seem a natural alternative to text, but experts doubt that it will be understood by future societies any better than today's English. Consider the swastika, first used on pottery by European tribes in 4000 BC. It was adopted by ancient Troy and later became a holy icon of Hinduism. When the Nazis claimed it, the symbol became widely reviled.

The panellists also considered the plaque on the 1972 Pioneer space probe, now headed for deep space. It pictures a nude man and woman, a schematic drawing of the craft escaping our solar system and a basic interstellar map. They soon rejected it as a model, said Jon Lomberg, an artist who designed the plaque with the late astronomer Carl Sagan.

"[I] You'd think it would be easier to communicate with humans" than extraterrestrials, he said. "But the (Pioneer) spacecraft will never land, so it's only going to be found by some highly developed technological culture. All we can guess about the future inhabitants of the area near WIPP is that they are human — unless they are cyborgs…. Once you have people with augmented brains or genetically engineered minds with enhanced perceptions, you can't be sure how human they will be."

There are at least two universally understood pictographic forms. The human stick figure has survived nearly unchanged from Stone Age cave drawings to the doors of modern public restrooms. And the sequential panel, or comic strip, was developed independently by ancient Egyptians, American Indians and medieval Japanese.
They also are far from foolproof. The South Africa Chamber of Mines learned this when it used a simple picture sequence to train illiterate miners to clear rocks from mine tracks. Instead of improving, the rock problem worsened.

"Miners were indeed reading the message, but from right to left. They obligingly dumped their rocks on the tracks" - Lomberg, a former WIPP advisor.

Nelson considers such concerns far-fetched, citing 30,000-year-old cave drawings.

"I understand those cave drawings and I don't speak Neanderthal…. He's killing a bison, 'bison — food!' I can do pictographs just as well. I can convey an absolute sense of danger."

Yet the same Stone Age caves contain markings and handprints whose meaning remains obscure.

"The scribbles, we have no idea what they are…. The handprints — is that the artist's signature? We don't know. Of course the big difference is that these were not intended as messages to the future — so far as we can tell."

With so many ways to fail, WIPP's planners opted for the classic American approach: Think big and leave no stone unturned. The plan will take more than a century to implement.
To grasp the scale of the warnings, start with the Great Pyramid in Egypt, built from more than 6.5 million tons of stone covering 13 acres. Multiply that mass by five, and you have the first warning layer: a 98-foot-wide, 33-foot-tall, 2-mile-long berm surrounding the site. That's just to get the attention of anyone who happens by.

"Size equates with importance. The bigger the animal the more that animal is to be reckoned with" - Givens.

Powerful magnets and radar reflectors would be buried inside the berm so that remote sensors could recognize the site as purposefully and elaborately designed.
It would be surrounded by 48 granite or concrete markers, 32 outside the berm and 16 inside, each 25 feet high and weighing 105 tons, engraved with warnings in English, Spanish, Russian, French, Chinese, Arabic and Navajo, with room for future discoverers to add warnings in contemporary languages. Pictures would denote buried hazards and human faces of horror and revulsion.

The same symbols would be printed on metal, plastic and ceramic disks with abrasion-resistant coatings, 9 inches in diameter, that would be buried just below the surface.
Three information rooms would archive detailed drawings of WIPP's chambers and the physics of its hazards on stone tablets. They would also provide a world map showing all other known waste repositories and a star chart to calculate the year the site was sealed.
One such room would stand in the centre of the site. Another would be buried inside the berm, its only entrance a 2-foot hole to inhibit theft of the tablets, sealed with a 1,600-pound stone plug. The third room would be off site — perhaps inside the nearby Carlsbad Caverns.
The final thing WIPP needs is a kind of Rosetta stone, a pictorial dictionary to aid in translation.
The markers will take decades to build and test, to help ensure they stand the test of time. But there's no hurry. WIPP won't be full until 2033. It would then be guarded by the Energy Department for 100 years until it is abandoned; no one who designed the markers would be alive to see them succeed for even a single day.
Inspired by so long a view, one of the site's expert panels, in an epigraph to its report, quoted Rabbi Tarfon, a Jewish sage who lived 1,900 years ago:

"You are not obliged to finish the task, nor are you released from undertaking it."

Once the vault is locked, some of WIPP's advisors want the site left unmarked because any warnings would draw only more attention, they say. Warnings, they argue, would be misunderstood or dismissed, the same way ancient grave robbers ignored curses inscribed on the tombs of Egyptian pharaohs to seize the riches inside.
Leave it bare, they contend, and the site will melt unseen into the harsh New Mexico desert.

"Any monument would become a tourist attraction. People come; they need hotels. Hotels need water. They drill for water and break into the vault. 'No marker' is a strategy, but people regard it as immoral" - Gregory Benford, a UC Irvine physicist and former WIPP advisor.

Such views reflect WIPP's one certainty: No one knows what will happen far in the future.

"I have to assume that the divine creator is going to take care of most of this stuff. No matter what confounded thing we come up with, all it takes is one catastrophic event and it's gone." - Steve Casey, the WIPP engineer charged with overseeing construction of the warning system.

That so much time and effort are spent even thinking about how to warn future generations reflects a significant shift in nuclear attitudes. The past still can be glimpsed a short drive from WIPP at a site where an atomic warhead was detonated 1,151 feet underground in 1961.
Two corroded plaques glued to a 4-foot concrete slab commemorate the test, dubbed Project Gnome. The monument has been nudged several yards over the decades by cattle that use it as a rubbing post. Spent rifle shells crunch underfoot; the pockmarked shrine is favoured by locals for target practice.
A third plaque was pried off, perhaps as a souvenir. According to earlier visitors, it read, in plain English, "This site will remain dangerous for 24,000 years."

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