Federal experts believe that a major earthquake could trigger fires at Los Alamos National Laboratory, releasing radioactive materials and endangering lives. The rupture of a seismic fault that runs underneath the lab would shake the ground more than scientists previously thought, according to a new report (PDF). A natural disaster here would be bad news, since the lab, just west of Santa Fe, is the main plutonium factory in the United States, believed to hold thousands of pounds of plutonium for use in nuclear weapons (the actual amount is classified).
Researchers study plutonium inside glove boxes—a Hollywood movie staple, consisting of a sealed enclosure with gloves so that someone outside the box can work on dangerous materials inside. A major earthquake would shake the ground enough to topple the glove boxes, says the new study. Some glove boxes are enormous and even contain furnaces to cast and mold plutonium. If one of these were to crash, the resulting fire would be uncontrollable and would create a vaporized plutonium cloud that could drift outside of the lab, says the safety report. In a worst-case scenario, a fire could release so much airborne plutonium that a person on the boundary of the lab would get a dose of radiation—potentially many thousands of times greater than a chest X-ray—that could be fatal in weeks, according to individuals knowledgeable about the study [Los Angeles Times].
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Here’s one direct and obvious effect of the economic stimulus package passed in February: The toxic sites where scientists ushered in the nuclear age are getting cleaned up. In Los Alamos, New Mexico, a dump that contains refuse of the Manhattan Project and that was sealed up decades ago is finally being explored, thanks to $212 million from the American Recovery and Reinvestment Act.
But experts aren’t sure what they’ll find inside the dump. At the very least, there is probably a truck down there that was contaminated in 1945 at the Trinity test site, where the world’s first nuclear explosion seared the sky and melted the desert sand 200 miles south of here during World War II [The New York Times]. It may also contain explosive chemicals that could have become more dangerous over the years of burial.
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When North Korea announced on May 25th that it had conducted its second underground test of a nuclear weapon, scientists weren’t surprised: They had already picked up seismic readings indicating a subterranean explosion. While seismologists say the readings carried subtle signatures that strongly suggest that the blast was caused by a nuclear device rather than conventional explosives, scientists were still waiting for one more piece of evidence–detecting radionuclide evidence in the form of radioactive gas is the “smoking gun”. And the big news here is that they have not found that signal [BBC Two].
Unlike other nuclear debris, xenon, an unreactive noble gas, can filter out through fissures in the rock after an underground test. Once in the atmosphere, plumes of xenon isotopes can be blown for thousands of miles. In 2006, for example, a [nuclear monitoring] station in Yellowknife, Canada, detected traces of xenon-133 two weeks after North Korea’s first test [Nature News]. But monitoring stations set up by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) have failed to detect any trace of xenon following the May blast, and now it may be too late. Researcher Lassina Zerbo of the CTBTO notes that these xenon isotopes rapidly decay in the atmosphere. This long after the blast, he says, “there is very little chance that we will pick up anything” [Nature News].
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Even before North Korea announced that it had conducted its second underground test of a nuclear weapon, scientists around the world were putting together a picture of what had happened. With a combination of seismic and radiation monitoring, scientists expect to soon have a working idea of how far the rogue nation’s nuclear program has advanced.
At 9:55 a.m. local time on Monday, two seismic monitoring stations on the Japanese coast detected seismic waves coming from the area where North Korea last tested a nuclear weapon, in 2006. The region has little natural seismic activity, and experts noted that the waves didn’t match patterns produced by earthquakes. Movements along natural fault lines transmit most of their energy through ’s-waves’, whereas explosions at a single point release a greater proportion through compressional p-waves. In the waves detected in Japan, the s-wave component was just one-fifth that of the p-wave. “You can’t say it’s impossible for a natural earthquake, but it would be very rare,” says Gen Aoki of the Japan Meteorological Agency in Tokyo [Nature News].
Experts note that the network of blast detectors intended for the Comprehensive Test Ban Treaty, which has not yet come into force, seems to have perfectly identified the explosion as a nuclear test, despite its small size. [In 1998, the U.S. Senate] rejected the CTBT partly over fears that countries could cheat, by claiming small covert weapons tests were earthquakes. The detection of the North Korean test raises hopes that the Senate will no longer be able to object [New Scientist]. But scientists had to do more than simply show that an underground explosion had sent ripples through the earth; they also have to determine how big the bomb was, and prove that the tremors weren’t caused by conventional explosives.
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To explore the dark reaches of the solar system, NASA is going to need a lot more plutonium-238, the space agency has told the Department of Energy. NASA’s deep space probes are powered by pellets of the plutonium isotope: The electricity that powers onboard instruments comes from devices called radioisotope power generators. The RPGs make electricity with the heat from the radioactive decay of small amounts of plutonium-238 carried on board [Los Angeles Times]. Such devices are the only option for probes that voyage far from the sun and can’t absorb enough solar energy to power their operations.
But a new report from the National Research Council notes that the world’s stockpile of Pu-238 is rapidly dwindling, and explains that NASA only has enough left for a couple more missions. The isotope isn’t found in nature, and its production is at a dead halt all around the world. The United States stopped making Pu-238 at the end of the Cold War; although the isotope cannot be used in nuclear weapons, it’s a byproduct of the production of weapons-grade Pu-239. For the past few years NASA has been buying its supply from Russia, but Russia’s plutonium-making reactors were also shut down years ago. NASA will soon receive its last shipment of the isotope from Russia, after which the space agency will be looking for a new supplier.
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By tracing radioactive pollution created by the nuclear tests of the 1950s, researchers have settled the question of whether the human heart creates new cells during a person’s lifespan. “The dogma has always been that cell division in the heart pretty much stops after birth…. In medical school, we teach that you’ll die with the heart cells you’re born with” [Science News], comments cardiovascular expert Charles Murry. However, a new study has overturned this dogma, and found that the heart does regenerate, albeit slowly.
Cell turnover rates can easily be measured in animals by making their cells radioactive and seeing how fast they are replaced. Such an experiment, called pulse-labeling, could not ethically be done in people. But Dr. Frisen realized several years ago that nuclear weapons tested in the atmosphere until 1963 had in fact labeled the cells of the entire world’s population [The New York Times]. The Cold War tests produced a radioactive form of carbon called carbon-14, which was absorbed by plants and worked its way up the food chain; in humans, carbon-14 gets into the DNA of new cells and remains unchanged for the cells’ lives.
Once nuclear tests ended in 1963, levels of carbon-14 began to gradually decline. Because the level of carbon-14 in the atmosphere falls each year, the amount of carbon-14 in the DNA can serve to indicate the cell’s birth date [The New York Times], says lead researcher Jonas Frisén. His team found that people’s hearts have cells that are younger than the people themselves, indicating that new cells have grown since birth. Heart experts say it’s a remarkable use of the nuclear tests’ impacts. “I am very excited about how they have used this novel technology to get something useful out of such a terrible environmental disaster” [Technology Review], says Murry.
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Israeli researchers say they’ve developed a way to modify nuclear fuel so that it can be used only in power plants, and can’t be recycled later to build nuclear weapons. Lead researcher Yigal Ronen says the work could help “de-claw” some countries if nuclear fuel producers – the US, Russia, Germany, France and Japan – agree to put the denaturing additive they have proven effective into all plutonium [Jerusalem Post].
Israeli scientists suggest in their study that the element americium be added to the fuel at a level of 0.1 percent [Israel National News]. According to their research, the addition would neutralize the fissile plutonium produced by nuclear reactors, making that “denatured” plutonium unusable in a weapon. The research will be published in the journal Science and Global Security next month.
Ronen explains that when a country purchases a nuclear reactor from one of the five nuclear fuel producers, the sale includes nuclear fuel for the reactor. “Thus, if the five agree to insert the additive into fuel for countries now developing nuclear power – such as Bahrain, Egypt, Kuwait, Libya, Malaysia, Namibia, Qatar, Oman, United Arab Emirates, Saudi Arabia and Yemen – they will have to use it for peaceful purposes rather than warfare” [The Register], says Ronen. However, the researchers say that countries with more advanced nuclear programs, like Iran, have other ways to produce weapons-grade fuel.
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The North Korean government announced yesterday that it’s preparing to launch a communications satellite on a North Korean-made rocket, a move that has been widely interpreted as a test firing of its long-range missile. South Korea and the United States say any test-firing, whether a purported satellite launch or a missile test, would be provocative since the technology is dual-use, and would breach UN resolutions [AFP]. Experts say that the long-range Taepodong-2 rocket has a range of about 4,200 miles, which gives it the theoretical capacity to hit Alaska. But in the only previous test of the long-range rocket, in 2006, it exploded 40 seconds after launch.
North Korea has insisted that the launch is a purely scientific endeavor. “The preparations for launching an experimental communications satellite … are now making brisk headway,” North Korea’s KCNA news agency said. “When this satellite launch proves successful, the nation’s space science and technology will make another giant stride forward in building an economic power” [Reuters]. South Korean news sources have reported that the rocket has not yet been moved to the launch pad, but that there is a great deal of activity around the site.
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It’s one of the biggest cleanup jobs the United States has ever undertaken, and it’s a long way from being done. Near the Columbia River in Hanford, Washington, contractors are decontaminating a nuclear fuel processing site that has 177 underground tanks holding 53 million gallons of nuclear waste, some of which has already leaked into the soil and groundwater. And the cleanup crew has learned that the known hazards are just the beginning. [S]loppy work by the contractors running the site saw all kinds of chemical and radioactive waste indiscriminately buried in pits underground over the 40 years Hanford was operational, earning it the accolade of the dirtiest place on Earth. In 2004, clean-up work uncovered a battered, rusted, and broken old safe containing a glass jug inside which was 400 millilitres of plutonium [New Scientist].
In a new study published in Analytical Chemistry [subscription required], researchers announced that the plutonium inside that jug had quite an impressive and terrible pedigree. Analyzing the sample’s isotopes and studying the historical records revealed that it was processed into plutonium-239 in December of 1944, as part of the first batch of weapons-grade plutonium ever made. Just eight months later, Hanford plutonium was used in the nuclear bomb that fell on the Japanese city of Nagasaki.
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An international group has given India special approval to buy nuclear technology to further its nuclear power program, although the country has steadfastly refused to sign the nuclear non-proliferation treaty. The decision, made by the 45-nation Nuclear Suppliers Group (NSG), was strongly supported by the United States, which hopes to sell the technology to India. The NSG adopted a one-off waiver of a 34-year-old global ban on nuclear trade with India, allowing New Delhi and Washington to do business [Reuters].
The proposed deal between the United States and India still has to be approved by the U.S. Congress, and there are several roadblocks to its immediate passage. Congress will be in session for only two weeks this September before breaking again for the final flurry of campaigning before the November election, and supporters of the India deal will have to pass special legislation to expedite the approval process. ‘‘I’d say the chances of it getting past the senate are 50-50,” a Senate aide said. ”Senators are good at tying things up in knots” [Times of India].
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