Testing Nuclear Battery Safety

Wired highlights how the Department of Energy tested nuclear batteries used for powering spacecraft to see how well they could prevent radioactive contamination of the environment in the event of an accident:

To explore the solar system’s darkest, deepest, and most frigid territories, nuclear batteries are the best power sources available. There is, however, a downside: The isotope of plutonium inside them (plutonium-238) is some 270 times more radioactive than the isotope of plutonium inside nuclear bombs (plutonium-239).
As a result, anti-nuclear activists consistently protest the launches of NASA’s plutonium-powered probes. They posit that space exploration isn’t worth the risk of catastrophe. But the Department of Energy, which builds the batteries inside NASA’s fleet of deep-space robots, spared no abuses in assessing their safety.
“They wanted proof of the worst that could happen, so we did our best to smash them, blown them up, shoot them and break them,” said Mary Ann Reimus, an impact test engineer at Los Alamos National Laboratory who tested the safety of nuclear batteries throughout the 1980s and 1990s.
Reimus and others carried out most of their tests in remote deserts near Albuquerque, New Mexico while looking on from concrete bunkers.

My favorite test, along with pictures:

A second rocket-sled test sliced a nuclear battery with a thin aluminum plate traveling at 684 mph, nearly the speed of sound.
“That was fun to watch from the TV in the bunker,” Reimus said. “We were several hundred feet away, but you could hear a fsssssh sound, a boom and a heavy thud.”
Remarkably, a GPHS and a fuel capsule sliced edge-on survived the hit with only a small amount of fuel escaping.

That looks like fun.  They also warn that deep-space exploration may be in danger because the country's scientific stockpile of plutonium-238 is running out.  More could be produced, but it doesn't look too likely right now.