The Sum of All Fears
ORNL plays a role in securing nuclear materials in Kazakhstan.
Sixty casks rise like towering white silos over a remote storage pad in the Kazakhstan steppe, 40 miles from the closest town and, more significantly, thousands of miles from terrorist hands. The casks, which hold more than 100 tons of nuclear material, are the result of an international nonproliferation project that has lasted more than a decade to secure nuclear fuel left in a former Soviet Republic.
Working alongside hundreds of Kazakh, Russian and American partners, ORNL scientists and engineers have been key players in a mission to safely move one of the world's largest stockpiles of spent nuclear fuel from a facility in western Kazakhstan to a more secure—and far more remote—area 2000 miles away. A November 18, 2010, completion ceremony marked the last shipment of nuclear material as officials, diplomats and representatives from the United States, Kazakhstan, the United Kingdom and the International Atomic Energy Agency (IAEA) gathered to celebrate the success of the unprecedented project.
The target was a Soviet-era nuclear reactor known as BN-350, located in Aktau, Kazakhstan. The reactor has been a top priority in international nonproliferation efforts because of the quantity and quality of its spent fuel—enough for approximately 775 nuclear weapons. Originally built in the early 1970s to produce electricity, desalinize water and synthesize weapons-grade plutonium, the reactor was shut down in 1999, 8 years after the collapse of the Soviet Union and the establishment of Kazakhstan as an independent state. As Kazakhstan adopted a non-nuclear foreign policy, the spent fuel remained at the site, stored in reactor pools. Although the BN-350 material was sealed, secured and carefully monitored in accordance with IAEA requirements, the reactor's location generated concern among officials worried about terrorist efforts to obtain similar materials needed to build a nuclear weapon.
Located in westernmost Kazakhstan on the shores of the Caspian Sea, the BN-350 reactor lies only a few hundred miles across the water from Iran and the Russian Republic of Chechnya, regions that are home to terrorist groups known to be looking to obtain nuclear material. Concerns were heightened by the fact that the BN-350 fuel was unique. The spent fuel was weapons grade, containing approximately 10 tons of highly enriched uranium and 3 tons of plutonium.
"This fuel is well known," says Randy Snipes, an engineer in ORNL's Global Nuclear Security and Technology Division. Snipes, who has been involved since 2001 in the international project to secure the BN-350 material, says the international effort was designed to deter nuclear materials from falling into terrorist hands.
A package deal
Initial efforts to secure the BN-350 fuel started in the 1990s, as fuel assemblies stored in the reactor pools were removed, conditioned and stored in canisters. The project gained momentum in 2002 when a feasibility study recommended moving the material from Aktau. "The project's primary focus was to package the fuel more securely and transport it to a safer area within Kazakhstan agreed upon by both the United States and the Kazakhstan governments," Snipes says.
Packaging the fuel was critical to the project's success. The fuel casks had to serve the dual roles of keeping intruders outside and the fuel inside. As project lead for the cask design, ORNL, along with contractor NAC International, assisted Russian designers in developing and certifying a specialized container for the BN-350 material. Snipes says the concept stemmed from a family of similar metal and concrete casks used by the Russians to store fuel from nuclear submarines and civilian reactors.
"Much of ORNL's activity in this project was on the front end, which involved working with the Russians on designing and certifying the package," Snipes says. "The casks may look like big hunks of metal, but in fact they are very sophisticated items." Two Russian manufacturers produced a total of 60 casks for the project. ORNL staff helped provide oversight to ensure the fabrication met Russian and Kazakh guidelines for certification.
Inside the casks' thick metal and concrete walls is a metal framework, called a spacing grid, which houses the fuel canisters. Once the canisters are loaded into the spacing grid, each cask weighs approximately 100 tons—an unwieldy container to transport and maneuver. The specially designed casks required specialized equipment to move and manipulate them. ORNL researchers monitored the development of cask-handling machinery, including an up-ending yoke that clasps onto the cask and upends or lays it down following fabrication. Other Department of Energy labs, including Sandia, Los Alamos, Idaho and Pacific Northwest, contributed supervision of associated project elements, such as the design of the cask-handling crane and storage pad, physical protection of the casks and other nuclear safeguards measures.
"The most vulnerable part"
In addition to oversight of the cask design, ORNL served as the project lead for the transport phase. "The need to protect the fuel made transportation the most vulnerable part of the entire activity," says Snipes, one of four primary U.S. team members responsible for overseeing the shipments. "The U.S. intent was that the right security levels were provided by Kazakhstan during the transport phase."
The 3-week journey of 2000 miles originated in Aktau, where five casks per shipment were loaded onto railcars for the trip's first leg. Specially designed for the project, the railcars carried the 100-ton cask plus an armor-like overpack weighing an additional 25 tons.
"Even though Russia uses a very similar cask and overpack for some of their civilian power plant fuel, they had no experience using rail transport, so these were the first railcars designed and manufactured for these specific casks," Snipes says. Researchers from ORNL's National Transportation Research Center supported the rail effort.
A convoy of five vehicles, flanked by guard and buffer vehicles to protect the fuel from potential attack, wheeled out a total of 12 shipments beginning in January 2010. The rail convoy brought the fuel to a transfer point 70 kilometers from its final destination. Because the railways did not extend the entire distance, tractor trailers carried the 125-ton packages the last leg of the trip to a remote complex. The storage pad, located in northeastern Kazakhstan, is part of the Semipalatinsk Test Site where the Soviets conducted hundreds of nuclear detonations before the site closed in 1991.
The task is not over
For now, the 60 casks will remain at the storage pad, primarily a concrete and rebar slab 1 meter thick. Officials from the IAEA and project participants will continue to monitor the casks to ensure their integrity and security. "We envision visiting every 3 to 6 months to work with the Kazakhs to ensure that the assets are properly maintained," Snipes says, indicating that the cask visits would be more like a checkup than a tuneup. "We prefer something that will last up to 50 years in storage, with minimal maintenance. We don't want a research project, where we simply open the casks after 5 years and see what they look like."
Although Snipes does not view the BN-350 casks as an experiment in progress, he does believe the cask design and fabrication serve as a template for future nuclear storage projects. "We can apply the lessons learned from this project to other similar applications, which at present would primarily be related to civilian fuel," Snipes says, noting that there have been proposals to use the same cask design for nonproliferation projects in other former Soviet states.
"The international community wants to protect all the fuel. We must keep in mind that conventional power plant fuel still has components that we don't want in the hands of terrorists."