Progress made in securing weapons-usable nuclear materials

The recent announcement that nearly 20 kilograms of highly enriched uranium (HEU) in spent fuel was secretly shipped from a disused research reactor outside San Diego to a secure government facility for storage served as a reminder that considerable quantities of potentially weapons-usable material remain outside government control, including within the US. That is the case despite years of US and Russian efforts to reclaim the HEU that they provided decades ago to their allies for reactors and isotope production facilities.

On 8 November, the Department of Energy’s National Nuclear Security Administration and the Nuclear Regulatory Commission announced they had completed the transfer of 19.7 kg of HEU spent fuel from an unspecified location in suburban San Diego to an undisclosed “secure federal facility.”

Until the 1990s, General Atomics, a privately owned company, operated two of the eponymous TRIGA (Training, Research, Isotope, General Atomics) class of research reactors at its complex just inland of La Jolla. Both reactors are being decommissioned, and their spent fuel was scheduled to be removed from the premises during 2010, according to NRC’s website.

The spent fuel was transported in three shipments during August and September, the agencies said, to a location about 1000 miles away. That distance corresponds to Idaho National Laboratory, where stainless steel–clad spent-fuel elements from other TRIGA reactors are in storage.

Since 2004 the NNSA’s global threat reduction initiative (GTRI) has converted 22 HEU-fueled research reactors located in the US and abroad to operate with low-enriched uranium (LEU) fuel. That includes two reactors located in China and five Soviet-supplied reactors located in former Soviet states, in Eastern Europe, and in Libya. Six of the 32 operating US research reactors, all but one located at universities, have been converted by the NNSA during the same period.

According to the NNSA, the GTRI has converted or verified the conversion of 72 of the 200 research reactors that are within its “program scope.” The World Nuclear Association says 230 such reactors in 56 countries are currently in operation. Another 361 reactors have been shut down or decommissioned, half of them in the US.

Rounding up HEU

Still, there clearly is much work to be done to round up the HEU that remains in civilian hands and make good on President Obama’s April 2009 goal to secure all nuclear materials around the world within four years. A number of US reactors still operate with HEU, including at least two that are government-owned: NIST’s Center for Neutron Research in suburban Washington, DC, and the High Flux Isotope Reactor at Oak Ridge National Laboratory. Some, like the ones at MIT and the University of Missouri, continue using HEU while awaiting the development of an LEU fuel that is tailored to their core configurations

The US shipped dozens of research reactors and HEU fuel to its allies beginning with the “atoms for peace” program in the 1950s. The commonly used fuel was enriched to 93% uranium—sufficient for a nuclear explosive. In 1978 with proliferation concerns growing, the US began research on retrofitting the reactors to run on low-enriched fuels. The US has also been accepting returns of US-origin HEU fuel.

The NNSA has also been striving to secure Soviet-origin weapons-usable materials—from all sources. On 18 November the agency announced that it had completed the shipment of 10 metric tons of HEU and 3 tons of plutonium—enough to make 775 nuclear weapons, it said—from the Soviet-built BN-350 fast reactor in Aktau, Kazakhstan, to a secure storage site in the northeastern part of that country, home to the former Soviet nuclear test site Semipalatinsk.

The material was placed into 60 specially fabricated casks and shipped more than 3000 km on specially built railcars. The US paid $219 million for the operation, while the UK contributed $4 million, according to published reports. The year-long operation also required the construction of new railroad track.

Located on the eastern shore of the Caspian Sea, the BN-350 was designed to both generate electric power and breed plutonium for the Soviet nuclear weapons program. It was shut down more than a decade ago, and a temporary storage site was built with US help. The BN-350 cache dwarfs the 1479-kg total Soviet-origin HEU fuel, both fresh and spent, that the NNSA had previously secured by returning it to Russia. In most cases, the US has paid the entire cost for packaging and transportation of the material, according to the NNSA.

David Kramer