The San Onofre nuclear power plant hasn’t generated any electricity in more than ten years.  But even as the iconic plant is being dismantled, it is still generating controversy over what to do with some of the radioactive material on the site.  

San Onofre, wedged between the 5 Freeway and the Pacific Ocean along Interstate 5 near San Clemente, first went online in 1968. Like many nuclear power plants, it was not universally embraced.

For decades, activists fought to get it shut down and, in 2013, they got their wish.

Ten years later, however, some of those same activists are raising other concerns: this time about the 1,600 metric tons of spent nuclear fuel still being stored on the site.

San Onofre nuclear power plant
The famous domes of the San Onofre nuclear power plant near San Clemente, California. October 2023.

KTLA was recently granted an exclusive tour of the current state of operations.

40 of San Onofre’s 62 structures have already been dismantled. The famous domes will be the last to go, managers told us.

“The estimated amount of material that we’re going to remove is about one billion pounds … about 500,000 tons,” said Ron Pontes, who is part of the decommissioning team.

The radiation levels of some of the remaining materials are too high to be sent to a landfill, so much of it has to be transported by train or truck to specialized sites in other states. Some material is too radioactive to be transported anywhere – at least for now.

Spent nuclear fuel from the old reactors is still stored in containers next to the ocean. But for those who envision heaps of glowing, green radioactive goop like in a cartoon or movie, that’s not the case.

San Onofre nuclear power plant
There are 73 vaults and 50 additional canisters storing 16,000 metric tons of spent fuel at the San Onofre nuclear power plant. October 2023.

Pontes showed us tiny ceramic pellets that are stored inside large steel canisters and lowered into steel and concrete vaults. On top of those vaults are 15-ton lids. 

There are 73 vaults and 50 additional canisters in a different storage system protecting 16,000 metric tons of spent fuel at San Onofre.

“This is the safest configuration for onsite storage of spent nuclear fuel,” insists Manuel Camargo, SoCal Edison’s Principal Manager for Strategic Planning. “There are no accident scenarios at this point that would result in an offsite release of radiological materials. So even on our worst day, if you were sitting here at the beach or having coffee in San Clemente, there would be nothing from this plant that would affect your health.”

 San Onofre spent fuel pellet
Tiny ceramic pellets store spent nuclear fuel at San Onofre. October 2023.

Not everyone is so confident.

Activist Donna Gilmore, who runs, says -among other things- that she believes the canister walls are too thin.

“The location is bad … but our biggest threat is those containers,” she says.

SoCal Edison believes those concerns are misguided. But regardless of the perceived risks, the larger issue now is what to do with the spent fuel.  

Rep. Mike Levin (D-49th District) says the federal government’s long-term plan to store it at Yucca Mountain roughly 100 miles northwest of Las Vegas, fell through due to strong opposition from Nevadans.

Now, with funds from Congress, the Department of Energy is seeking a new approach called “Consent-Based Siting” – which is a fancy term for only shipping waste to places that are incentivized to accept it.

“The reality is, if you do not have consent, you’re not going to get very far,” Rep. Levin told us. “What that might require is … a direct payment. It could be some sort of financial payment to a community … but also making sure that at the end of the day, wherever we send the waste, the place actually wants it. That’s the key”

That process will take time.

The last containment dome is expected to be demolished sometime in 2028. The thousands of tons of spent nuclear fuel, managers say, could remain on the site for another ten years beyond that, or more.

Visit SoCal Edison’s San Onofre public information page here.