If a country fires an airborne nuclear missile, the source of the attack is obvious. But what about the more fluid threat that hangs over the 21st century—terrorists sneaking a nuclear device into a city and setting it off? In a study in the Proceedings of the National Academy of Sciences this week, researchers suggest that even in the charred aftermath of a nuclear explosion, there could be evidence left behind that helps to identify the source of the bomb.
Physicist Albert Fahey and company went back to the beginning of the atomic age, to the United States’ first atomic bomb test in New Mexico in July 1945. As that bomb test was called “Trinity,” the glass left behind by the blast is called “trinitite.” Fahey obtained some of that glass to show that all these years later, it still contained evidence of the bomb’s makeup.
“Prior to this study, people didn’t realise that other components of the bomb could be discerned from looking at ground debris and seeing what’s associated [with it],” said Dr Fahey. “But there are some distinctive signatures that were in the bomb other than fission products and plutonium, and that gives you hope that you can get some additional information out of it – like where it was made.” [BBC News]
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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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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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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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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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