Canister storage at San Onofre
Dry canister nuclear waste storage at the San Onofre Nuclear Generating Station. Courtesy Southern California Edison

The tsunami advisory that woke up the West Coast Jan. 15 should serve as a wake-up call on flooding dangers at the nuclear waste storage facility in San Onofre. 

The facility is 100 feet from the beach. During high tides, waves crash into an aging bulkhead that separates the sea from the storage vault — a kind of crypt that holds 73 thin-walled, metal canisters jam-packed with 3.6 million pounds of deadly, radioactive waste. According to Southern California Edison, the sprawling, concrete vault will flood from a storm at high tide.

If the ocean were to swamp the so-called Independent Spent Fuel Storage Installation, we could have an unsurpassed disaster on our hands, an uncontrolled criticality, one that has never occurred in the U.S. commercial power industry. 

The undersea volcanic eruption this month near Tonga sent waves across the Pacific. Officials in Hawaii reported tsunami wave heights of nearly 3 feet.  At San Diego Harbor, officials measured more than a half-foot of sea level rise. Meanwhile, officials from shuttered San Onofre Nuclear Generating Station remained conspicuously silent. 

Edison and the Nuclear Regulatory Commission both have succeeded in hiding the true consequences of severe flooding at SONGS. 

That was my takeaway after a June 2020 meeting of the Nuclear Regulatory Commission’s Petition Review Board. At the meeting, I testified in support of a filing from the Public Watchdogs nonprofit group. The petition demanded immediate action to analyze flooding at San Onofre.  

The NRC has withheld this information from the public. More than one year and one tsunami later, flooding questions remain unanswered. 

During a major flood of the storage vault and the 18-foot-tall canisters it holds, salt water, silt and all manner of debris would clog vents that are crucial for the air-cooled facility to operate.  

It is also possible that the cool ocean water could compromise the integrity of the spent-fuel containers.  Rapid thermal stresses could trigger uncontrolled nuclear reactions necessitating a large-scale evacuation. This kind of catastrophe could exceed that of Fukushima.  

Meanwhile, Edison and regulators have left us in the dark. The NRC redacted information on flooding in a report by Edison’s contractor, Holtec International, after identifying the information as proprietary. Emergency and recovery plans, if they do exist, have been withheld from the public.  

We need all of that information.  

Publicly-accessible licensing documents filed with the NRC show Edison has no equipment or procedures in place to recover from a major flooding event.  

For the most part, the Jan. 15 tsunami was a non-event in San Diego County. On a different day, however, a different volcanic or seismic event could produce a tsunami that would be catastrophic for San Onofre and all of Southern California. 

Paul Blanch is a 50-year nuclear energy consultant, a professional engineer in California, and former reactor operator and instructor for U.S. Navy nuclear plants. Southern California residents can learn more about the dangers posed by storage of spent fuel at San Onofre on www.samuellawrencefoundation.org.

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