Coastal Erosion Renewed Concerns at San Onofre Site

The decommissioned California plant holds millions of pounds of spent nuclear fuel just 100 feet from the coastline.

Updated on Sept. 20, 2026 in Nuclear

Isometric editorial illustration showing a massive industrial storage canister on a concrete pad overlooking a stylized ocean cliff. — Southern California Edison continues to manage spent nuclear fuel at the San Onofre site as coastal erosion intensifies, leaving waste vulnerable while federal repository plans remain stalled. AI Illustration. Upload story photo >

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Escalating coastal erosion has intensified scrutiny of the San Onofre Nuclear Generating Station, where 3.6 million pounds of spent nuclear fuel remain stored in canisters on a concrete pad. The site, which ceased operations in 2013, sits just 100 feet from the shoreline.

Why it matters

The lack of a permanent federal repository following the collapse of the Yucca Mountain project leaves waste stranded in vulnerable coastal zones. This impasse currently forces taxpayers to cover $2 million in daily storage expense claims.

The San Onofre facility houses 3.6 million pounds of spent nuclear fuel stored in steel canisters, designed to withstand a 7.0 magnitude earthquake. These units are currently checked for structural cracking and temperature fluctuations.

The players

Southern California Edison

An electric utility provider responsible for the maintenance and monitoring of the retired San Onofre Nuclear Generating Station.

U.S. Department of Energy

The federal agency tasked with developing national energy policy and managing the disposal of high-level radioactive waste.

The details

Spent fuel is housed in steel canisters shielded by a concrete pad located behind a seawall to mitigate flood risk. Southern California Edison manages the site by monitoring radioactivity levels and performing visual inspections for material degradation. The facility operates under a containment strategy intended to bridge the gap until federal transport becomes available.

2013: San Onofre nuclear power plant ceased operations.
July 2026: The U.S. Department of Energy reached storage site exploration deals with five states.
Early 2027: The plant's twin domes are expected to be dismantled.
2103: A potential start date for transferring fuel into new storage canisters.

The Tech Race

The site's status follows the collapse of the Yucca Mountain project, which was originally intended to serve as the nation's primary permanent waste repository. The U.S. Department of Energy is now racing to establish new storage frameworks after securing exploration agreements with five states in July 2026.

California taxpayers currently bear the financial burden of this storage impasse through a daily $2 million expense claim. While the current storage design meets safety benchmarks for seismic activity, the long-term containment timeline extends until at least 2103.

The takeaway

The ongoing storage of nuclear material at San Onofre underscores the national failure to finalize a permanent disposal facility. Watch for the outcome of the Department of Energy’s state-level exploration deals as a potential signal for future waste transport routes.