If an interim storage facility for the nation’s spent nuclear fuel like the one proposed in southeastern New Mexico or a permanent repository elsewhere comes to fruition, the fuel may need to be transported thousands of miles before reaching its destination.
Researchers from Albuquerque’s Sandia National Laboratories spent eight months last year testing how safe transporting the highly radioactive fuel would be.
“We hope this will provide more assurances that the transportation of spent nuclear fuel is very safe,” said Sylvia Saltzstein, manager of Sandia’s transportation projects.
Testing was partially funded by the U.S. Department of Energy and also included researchers from Spain, South Korea and the Argonne and Pacific Northwest national laboratories. It involved shipping a cask laden with mock spent nuclear fuel assemblies by truck, ship and train nearly 15,000 miles.
A fuel assembly consists of around 300 thin, hollow metal tubes – called cladding – containing small, stacked uranium pellets. The cask used in the experiment was of Spanish design, but very similar to those used in the United States, Saltzstein said. The Spanish model used can hold 32 fuel assemblies.
Much of the nation’s spent nuclear fuel is stored in such casks, sitting above ground and constantly guarded.
Three mock assemblies, which contained no radioactive materials, were placed inside the cask, and the remaining spaces were filled in with concrete.
Assemblies were fitted with accelerometers and strain gauges to measure their movement.
Data collection units made the journey alongside the cask, powered by 20 marine batteries weighing 4,000 pounds total.
Every two weeks, researchers downloaded the data and recharged the batteries.
Initially, before the full cask weighing 330,000 pounds began its trek in Spain, it was placed onto a concrete pad with varying levels of force similar to those it might experience in the normal transport process.
Then, the cask was taken around 250 miles by truck to the coast, where it was loaded onto a barge. The barge hugged the Spanish and French coasts, landing in Belgium.
After that, it was transferred to a cargo ship and made a nearly 4,000-mile trip across the Atlantic to Baltimore.
It was then loaded onto a 12-axle train car and transported 2,000 miles west to the Transportation Technology Center Inc., near Pueblo, Colo., where it underwent more rigorous testing on its 50 miles of test track.
After that, it was sent back to Spain the same way it came.
“Nothing even approaching being broken or damaged at all,” Saltzstein said of the preliminary data.
She estimated it will take several more months to fully analyze the data.
Saltzstein said the enormous weight of the cask did not present a concern for U.S. railroads, something critics of a possible interim storage site have mentioned as a possible roadblock to transport to southeastern New Mexico.
Holtec International, which hopes to build the interim storage facility near Carlsbad, has said it would use its HI-STAR 100 MB cask to transport spent nuclear fuel to the site.
Holtec spokeswoman Caitlin Marmion said the weight of the HI-STAR 100 MB isn’t yet publicly available.
“The HI-STAR 100 MB complies with all applicable DOT and railroad requirements,” Marmion wrote in an email.
Still, a critic of the interim storage facility sees a flaw in the test.
“Among the problems that the Holtec cask has that Sandia isn’t testing is what happens when up to 10,000 of those heavy canisters are transported on railroad tracks that have a gross weight limit of 286,000 pounds, which is the case of some lines in New Mexico and many other states?” said Don Hancock, director of the Nuclear Waste Safety program at Albuquerque’s Southwest Research and Information Center, in an email.
A rail car intended to specifically carry high-level radioactive waste is in the preliminary design phase with the Department of Energy.
Saltzstein said the experiment was designed to test the effects normal travel would have on the fuel rods.
Sandia conducted tests in the 1980s on how the casks responded in catastrophic instances, like being involved in an accident.
“We know the container can withstand normal conditions of transport and accidents,” she said. “We’re curious what happens to the fuel.”
Saltzstein said each of the participating countries was most interested in a particular leg of the journey: Spain in the truck transport, South Korea in the sea portion and the U.S. in rail.
The United States has 99 nuclear reactors, Spain has seven and South Korea has 24, according to the World Nuclear Association.
A permanent disposal option for spent nuclear fuel has yet to be found.