Joint U.S., Soviet Recycling Program of Weapons-grade Uranium

USEC Inc., a global energy company and provider of enriched uranium fuel and nuclear industry-related services for commercial nuclear power plants, announced it has completed by 90 per cent the conversion of weapons-grade uranium from dismantled former Soviet Union nuclear warheads into low enriched uranium fuel under the program called Megatons to Megawatts(TM).

Megatons to Megawatts(TM) is a 20-year, commercially financed government-industry partnership in which 500 metric tonnes of Russian weapons-grade uranium is transformed to low enriched uranium for use as commercial reactor fuel. USEC, as executive agent for the U.S. government, and JSC "Techsnabexport" (TENEX), for the Russian government, implement the programme.

Its main focus was to convert the equivalent of 20,000 nuclear warheads into nuclear fuel by end 2013. So far, the fuel generated from the conversion equals more than 193 billion gallons of gasoline, corresponding to more than 17 months of U.S. consumption

In past years, this type of fuel has helped generate 10 per cent of the United States' electricity needs.

"For nearly two decades, the Megatons to Megawatts(TM) program has provided a reliable source of fuel for commercial nuclear power plants while reducing the quantities of weapons-grade uranium remaining in the world," John K. Welch, USEC president and CEO, said in a statement.

"As we near the end of this historic nonproliferation program, USEC is preparing to transition to our new contract with TENEX, which will continue to provide a reliable supply of LEU for the company while we work to deploy the American Centrifuge technology."

Chemist finds new material (ZIF-8): Remove radioactive gas from spent nuclear fuel

Sandia chemist Tina Nenoff heads a team of researchers focused on removal of radioactive iodine from spent nuclear fuel.

They identified a metal-organic framework that captures and holds the volatile gas, a discovery that could be used for nuclear fuel reprocessing and other applications. (Photo by Randy Montoya)

The Sandia researchers have used metal-organic frameworks (MOFs) to capture and remove volatile radioactive gas from spent nuclear fuel.

“This is one of the first attempts to use a MOF for iodine capture,” said chemist Tina Nenoff of Sandia’s Surface and Interface Sciences Department.

The discovery could be applied to nuclear fuel reprocessing or to clean up nuclear reactor accidents.

A characteristic of nuclear energy is that used fuel can be reprocessed to recover fissile materials and provide fresh fuel for nuclear power plants. Countries such as France, Russia and India are reprocessing spent fuel.

The process also reduces the volume of high-level wastes, a key concern of the Sandia researchers. “The goal is to find a methodology for highly selective separations that result in less waste being interred,” Nenoff said.

Part of the challenge of reprocessing is to separate and isolate radioactive components that can’t be burned as fuel. The Sandia team focused on removing iodine, whose isotopes have a half-life of 16 million years, from spent fuel.

They studied known materials, including silver-loaded zeolite, a crystalline, porous mineral with regular pore openings, high surface area and high mechanical, thermal and chemical stability.

Various zeolite frameworks can trap and remove iodine from a stream of spent nuclear fuel, but need added silver to work well.

“Silver attracts iodine to form silver iodide,” Nenoff said. “The zeolite holds the silver in its pores and then reacts with iodine to trap silver iodide.”

But silver is expensive and poses environmental problems, so the team set out to engineer materials without silver that would work like zeolites but have higher capacity for the gas molecules.

They explored why and how zeolite absorbs iodine, and used the critical components discovered to find the best MOF, named ZIF-8.

Radioactive waste: Technology makes waste storage safer

Queensland University of Technology (QUT) researchers have developed new technology capable of removing radioactive material from contaminated water and aiding clean-up efforts following nuclear disasters.

The innovation could also solve the problem of how to clean up millions of tonnes of water contaminated by dangerous radioactive material and safely store the concentrated waste.

Professor Huai-Yong Zhu from QUT Chemistry said the world-first intelligent absorbent, which uses titanate nanofibre and nanotube technology, differed from current clean-up methods, such as layered clays and zeolites, because it could efficiently lock in deadly radioactive material from contaminated water.

The used absorbents can then be safely disposed without the risk of leakage, even if the material became wet.

“One gram of the nanofibres can effectively purify at least one tonne of polluted water,” Professor Zhu said.

“This saves large amounts of dangerous water needing to be stored somewhere and also prevents the risk of contaminated products leaking into the soil.”

The technology, which was developed in collaboration with the Australian Nuclear Science and Technology Organisation (ANSTO) and Pennsylvania State University in America, works by running the contaminated water through the fine nanotubes and fibres, which trap the radioactive Cesium (Cs+) ions through a structural change.

“Every year we hear of at least one nuclear accident. Not only is there a risk of contamination where human error is concerned, but there is also a risk from natural disasters such as what we saw in Japan this year,” he said.

Professor Zhu and his research team believed the technology would also benefit industries as diverse as mining and medicine.

By adding silver oxide nanocrystals to the outer surface, the nanostructures are able to capture and immobilise radioactive iodine (I-) ions used in treatments for thyroid cancer, in probes and markers for medical diagnosis, as well as found in leaks of nuclear accidents.

“It is our view that just taking the radioactive material in the adsorbents isn’t good enough. We should make it safe before disposing it,” he said.

“The same goes for Australian sites where we mine nuclear products. We need a solution before we have a problem, rather than looking for fixes when it could be too late.”

With a growing need to find alternatives to meet global energy needs, Professor Zhu said now was the time to put safeguards in place.

Chernobyl: The aftermath goes on!

Souz Chernobyl

The monument to Chernobyl in Sochi, a resort city on the Black Sea. On its base is part of a poem about the fate of the people who were drafted or volunteered to clean up the reactor: "We thought that our Motherland was with us. We were proud of the glitter of our golden epaulets. The steps of our rubber boots took measure. Of Chernobyl's deadly testing ground."

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