Stress Test: Sending Nuclear Waste on a 14,500-Mile Triathlon to Gauge Safety

Researchers at Sandia National Laboratories conducted a hyper-realistic test of nuclear fuel transport to better quantify the associated risks.

Test cask beginning the first leg of its journey. (Image credit: Sandia National Labs.)

Test cask beginning the first leg of its journey. (Image credit: Sandia National Labs.)

The Problem with Nuclear Power

Nuclear energy is among the best answers that science currently has to one of humanity’s biggest questions: How do we power the world in a sustainable way? Nuclear energy production is carbon neutral and accounts for nearly 14 percent of the world’s electricity, but it comes with a significant drawback. Vast quantities of highly toxic, radioactive waste are a byproduct of the nuclear fission responsible for all that power.

Nuclear facilities are built with storage space for the dangerous spent fuel they produce, but the theoretical capacity of these areas is often far outstripped by reality. As a result, a steadily growing percentage of all used nuclear fuel must be transported off-site to dedicated waste zones. That process comes with risks. In order to better understand these risks, researchers from Sandia National Laboratories designed a kind of triathlon to mimic the conditions spent fuel would be subjected to in real-world scenarios. 

The Stress Test

An overview of the triathlon. (Image courtesy of Michael Vittitow.)

An overview of the triathlon. (Image courtesy of Michael Vittitow.)

The test contrived by the research team used three dummy fuel rod assemblies inside the same cask model that’s currently used to transport nuclear waste. The mock rods were made of zirconium alloy tubes filled with pellets made of lead or molybdenum to match as closely as possible the uranium pellets inside an actual spent nuclear fuel rod. Once loaded, the cask was sent on its way.

The route planned by the Sandia team would ultimately span more than 14,500 miles and incorporate three modes of transport: truck, train and ship. From its starting point in northern Spain, the test cask wound its way through Western Europe to Belgium, where it was loaded onto a transatlantic cargo ship that was bound for Baltimore, Md. The 4,000-mile ocean crossing took about 12 days. Upon its arrival in the United States, the cask traveled from the East Coast to Colorado by rail car. It then reversed course and headed back to Spain. All the while, the container’s onboard data acquisition system recorded each bounce, shock and vibration the cask experienced. Analyzing the high volume of data collected during the journey could take the Sandia team up to a year.

Quantifying the Safety of the Long-Distance Movement of Nuclear Waste

The researchers will need to sift through all the information gathered during the test trip to truly quantify the safety of transporting spent nuclear fuel rods over long distances. With that said, we do know a few things already.

First, the dummy rods survived their grueling triathlon without breaking or sustaining material damage of any kind. Next, previous (and less comprehensive) tests conducted by Sandia indicate that the stresses associated with normal transportation are up to 100 times less intense than the forces needed to damage nuclear fuel rods. Finally, initial results of the latest test are positive, showing relatively insignificant shock and vibration levels throughout the long journey. Still, the final results will be important. The stakes of transporting nuclear waste couldn’t be higher. In order to feel confident in arranging long-range transport and storage, nuclear producers must be absolutely certain that spent fuel rods won’t break.

A test like Sandia’s triathlon will go a long way toward confirming that the accumulation of small shocks and vibrations throughout such a journey won’t lead to a catastrophic nuclear accident.

If you’re interested in reading about other, less traditional ways that physicists are trying to deal with nuclear waste, check out this article.