More than 2 million visitors flock each year to California’s San Onofre state beach, a dreamy slice of coastline just north of San Diego. The beach is popular with surfers, lies across one of the largest Marine Corps bases in the Unites States and has a 10,000-year-old sacred Native American site nearby. It even landed a shout-out in the Beach Boys’ 1963 classic Surfin’ USA.

But for all the good vibes and stellar sunsets, beneath the surface hides a potential threat: 3.6m lb of nuclear waste from a group of nuclear reactors shut down nearly a decade ago. Decades of political gridlock have left it indefinitely stranded, susceptible to threats including corrosion, earthquakes and sea level rise.

The San Onofre reactors are among dozens across the United States phasing out, but experts say they best represent the uncertain future of nuclear energy.

“It’s a combination of failures, really,” said Gregory Jaczko, who chaired the US Nuclear Regulatory Commission (NRC), the top federal enforcer, between 2009 and 2012, of the situation at San […]