By Steve Elwart
Scientists from the University of Edinburgh in Scotland, working in conjunction with associates from the United States and Canada, have developed a uranium compound that could help in nuclear waste disposal.
The study, funded by Scotland’s Office of Science and Technology and the University of Edinburgh, was published in Nature Chemistry.
The butterfly-shaped uranium molecule is similar to its radioactive cousins that are the key components in nuclear waste. These compounds, however, had not been seen before by scientists, who believed they had an extremely short half-life. The researchers who created the compound have found that the man-made compound has a longer half-life, which suggests that it could mimic the natural molecule in radioactive waste.
Researchers made the molecule by reacting common uranium compounds with nitrogen and carbon-based materials. The result was a compound with a distinctive butterfly shape.
According to Professor Polly Arnold of the University of Edinburgh’s School of Chemistry, “We have made a molecule that, in theory, should not exist, because its bridge-shaped structure suggests it would quickly react with other chemicals. This discovery that this particular form of uranium is so stable could help optimize processes to recycle valuable radioactive materials and so help manage the UK’s nuclear legacy.”
By utilizing this new type of molecule, it would be easier for all the radioactive materials from spent fuel to be recovered and made safe or used again. This could spell a breakthrough in preventing terrorist groups from acquiring the material needed to construct a “dirty bomb.”
A dirty bomb is a device that combines radioactive material with conventional explosives. The purpose of the weapon is to contaminate the area around the explosion with radioactive material, hence the name “dirty.” It is likely to be a simple device in which TNT or fuel oil and fertilizer explosives are combined with highly radioactive materials. The detonated bomb spreads toxic isotopes, propelling them into the air.
While a bomb using conventional explosives is more likely to have more immediate lethal effects, a dirty bomb would spread radioactive material across an area. It may produce a non-lethal effect, but the dispersal would cause major disruptions to people’s everyday life.
If detonated in a populated area, there would be elevated levels of radiation in the vicinity. Even if the radiation level was at a non-lethal level, the area would be uninhabitable until there was, at best, a thorough test of the area or, at worst, a major clean-up effort.
Because the main purpose of a dirty bomb is to create psychological not physical harm through mass panic and terror, these devices are sometimes called “weapons of mass disruption.”
Additionally, containment and decontamination of thousands of victims, as well as decontamination of the affected area might require considerable time and expense, rendering areas unusable and causing major economic damage.
There have only ever been two known cases of cesium-containing dirty bombs being deployed. Both occurred in Chechnya. The first attempt of radiological terror was carried out in November 1995 by a group of Chechen separatists who buried a cesium-137 source wrapped in explosives at the Izmaylovsky Park in Moscow. A Chechen rebel leader alerted the media, and the bomb was rendered harmless.
The second attempt occurred in December 1998. The Chechen Security Service discovered a container filled with radioactive materials attached to an explosive mine. The bomb was hidden near a railway line about 10 miles east of the Chechen capital of Grozny.
While neither of these terror attacks was successful, the odds of a group acquiring spent fuel to implement a successful attack are increasing every year. According to Harvard University’s Hui Zhang, each year, a typical 1 gigawatt (GWe) nuclear reactor discharges about 20 to 30 metric tons of heavy metal (tHM) in spent nuclear fuel. The spent fuel is extremely radioactive — many times more radioactive than the reactor core itself. Approximately 10,000 tHM spent fuel is generated annually. By 2000, more than 150,000 tHM spent fuels were in storage, almost all of them in spent fuel rod pools at reactor sites or in away-from-reactor facilities.
In June 2004, technicians at a Vermont nuclear power plant found two pieces of spent nuclear fuel at the plant’s spent fuel storage pool three months after they were reported missing, according to the Associated Press. Two earlier searches of the pool conducted by robots failed to find the container, and its existence became known only after a record was found at a California laboratory showing that the canister had been sent to the Vermont plant during the 1980s.
Prior to the discovery, Rep. Edward Markey, D-Mass., said, “The NRC says it has no idea where the spent nuclear fuel is, but insists that it is safe, wherever it is. This sounds like a faith-based approach to nuclear security to me.”
The potential of theft is not limited to nuclear power plants alone. In 1993, three fuel rods were stolen from the Sevmorput naval shipyard on the Northern edge of Murmansk, Russia. Sawing through a padlock gave the two thieves access to hundreds of fuel rods. The ease with which the thieves were able to carry out their plan prompted Russian Navel Security Officer Tikhomirov to remark, “Even potatoes are guarded better.”
There are literally millions of radioactive sources used globally in industry, medicine and agriculture. In medicine, the most powerful radioactive sources are used for radiotherapy for cancer. Many of these sources could be used for a dirty bomb, and many are not kept securely.
The abandonment or delay in the reprocessing of spent nuclear material and the absence of established geologic repositories through the world have resulted in an increase of spent fuel stored on site in power plants, hospitals and research centers.
Having a more efficient method to reclaim this spent fuel and place back into production would go a long way to secure these potential sources of terror.
Steve Elwart, P.E. is the Senior Research Analyst with the Koinonia Institute and a Subject Matter Expert for the Department of Homeland Security. He can be contacted at [email protected]