Over the coming weeks, a team from Los Alamos National Laboratories (LANL) will head to a nuclear waste storage facility in Idaho, select one of dozens of concrete storage casks, and attempt the unprecedented task of making sure that all the waste is still inside.

Using an experimental imaging process called muon tomography, the technology should allow researchers to look through the cask’s heavy radiation shielding and make the first ever direct, detailed verification of a cask’s nuclear contents after it has been filled and sealed.

One the one hand, the test is a step towards improving nuclear security in North America. But the technique could have an ever greater impact on oversight of the world’s most volatile nuclear nations, where stolen or redirected nuclear waste could be used to create a dirty bomb—or even a nuclear weapon.