But for all the good vibes and stellar sunsets of  San Onofre state beach in California, 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 Onofre. That waste is the byproduct of the San Onofre Nuclear Generating Station (Songs), three nuclear reactors primarily owned by the utility Southern California Edison (SCE) that has shut down….

Since there is not central repository for the final disposition of nuclear wasted in the United States,  the California Coastal Commission approved in 2015 the construction of an installation at San Onofre to store it until 2035. In August 2020, workers concluded the multi-year burial process, loading the last of 73 canisters of waste into a concrete enclosure. San Onofre is not the only place where waste is left stranded. As more nuclear sites shut down, communities across the country are stuck with the waste left behind. Spent fuel is stored at 76 reactor sites in 34 states….

At San Onofre, the waste is buried about 100ft from the shoreline, along the I-5 highway, one of the nation’s busiest thoroughfares, and not far from a pair of faults that experts say could generate a 7.4 magnitude earthquake. Another potential problem is corrosion. In its 2015 approval, the Coastal Commission noted the site could have a serious impact on the environment in case of coastal flooding and erosion hazards beyond its design capacity, 

Concerns have also been raised about government oversight of the site. Just after San Onofre closed, SCE began seeking exemptions from the NRC’s operating rules for nuclear plants. The utility asked and received permission to loosen rules on-site, including those dealing with record-keeping, radiological emergency plans for reactors, emergency planning zones and on-site staffing.

San Onofre isn’t the only closed reactor to receive exemptions to its operating licence. The NRC’s regulations historically focused on operating reactors and assumed that, when a reactor shut down, the waste would be removed quickly.

It’s true that the risk of accidents decreases when a plant isn’t operating, said Dave Lochbaum of the Union of Concerned Scientists. But adapting regulations through exemptions greatly reduces public transparency, he argued. “Exemptions are wink-wink, nudge-nudge deals with the NRC,” he said. “In general, it’s not really a great practice,” former NRC chair Jaczko said about the exemptions. “If the NRC is regulating by exemption, it means that there’s something wrong with the rules … either the NRC believes the rules are not effective, and they’re not really useful, or the NRC is not holding the line where the NRC should be holding line,” he said…

It’s worth considering how things fail, though, argued Rod Ewing, nuclear security professor at Stanford University’s center for international security and cooperation, and author of a 2021 report about spent nuclear waste that focuses on San Onofre. “The problem with our safety analysis approach is we spend a lot of time proving things are safe. We don’t spend much time imagining how systems will fail,” he said. “And I think the latter is what’s most important.”

Excerpts from Kate Mishkin, ‘A combination of failures:’ why 3.6m pounds of nuclear waste is buried on a popular California beach, Guardian, Aug.