The opinion piece by Sarah Mosko (Dust-ups Continue over Radioactive Waste Storage at San Onofre, posted Sept. 10) contains many errors of fact and omission that must be addressed so Voice of OC readers get the full story.

Canister Safety
The statement regarding Cesium-137 and Chernobyl ignores how it is released during an operating reactor accident. SONGS is no longer operating, of course. The cesium must be at an elevated temperature to form a plume that can travel off-site. SONGS’ fuel has cooled to the point at which the Cs-137 is not hot enough to form a plume—i.e., Cs-137 is not volatile at dry storage temperatures, so it remains encased in a ceramic fuel pellet.

If a spent nuclear fuel canister were to begin “degrading,” the risk of a release that would affect the health or safety of the public is vanishingly small. Even with a through-wall crack, the ceramic spent fuel pellets are still well-contained in sealed zirconium-alloy fuel rods. The robust shielding of the overall system remains as well. A microscopic crack would not release high levels of radiation any more than a small crack in your oven’s window would heat your home by hundreds of degrees.

The fact that the Nuclear Regulatory Commission has yet to evaluate nor approve a canister repair method does not mean the agency can’t or won’t in the future. In this area, Southern California Edison is leading the industry. Spent nuclear fuel has been stored safely for 35 years in the U.S. without the need for repair. The only canisters ever needing to be returned to a spent fuel pool were bolted-lid casks, the type Mosko is advocating for. Those thick-wall casks have mechanical seals, not welds, and those O-ring seals may need to be replaced. In the U.S., 93% of the canisters used today are the welded-lid, stainless steel canisters used at SONGS.

Mosko calls the dry fuel storage canisters “inferior,” but offers no factual evidence to support the claim. The Department of Energy encouraged the industry to develop welded-lid, multipurpose canisters (storage and transportation) and the industry responded with systems that have, thus far, a zero failure rate.

The 2019 report from the Nuclear Waste Transportation Review Board is also mischaracterized. The SONGS Community Engagement Panel hosted a NWTRB representative at its November 2019, meeting, who specifically said the NWTRB did not suggest spent fuel from nuclear plants, including SONGS, would need to be repackaged. Currently, more than 80% of the spent nuclear fuel at SONGS is eligible for transportation, if a federally licensed site was available for relocation.

Canister Integrity
Regarding canister life-span, the warranty is 10 years on the Holtec system and 25 years on the canisters. But the design life is 60 years and the service life, or how long the canister can perform its safety function, is 100 years or more. Those are the key numbers Mosko omits.

The “16-years” through-wall crack fallacy stems from an error in a presentation six years ago referring to a water tank at South Africa’s Koeberg Nuclear Plant. A recent report by the Electric Power Research Institute corrected the original error. The NRC has weighed in on this issue, explaining that in a marine climate like California, a through-wall crack in a canister would take 80 years to occur, if no action were taken to mitigate it. This was pointed out to Mosko last year via email, and in a Voice of OC op-ed posted Oct. 7, 2019.

Calling for a “hot cell” and reloading fuel into thick-wall casks is not a well-reasoned recommendation. No dry storage canister has ever released radioactive material to the environment, and there’s no indication canister failure is even remotely imminent. Reloading 3,885 fuel assemblies from dry storage canisters to thick-wall casks would only introduce additional risk with no obvious benefit.

Spent nuclear fuel is stored safely in the U.S. Where attention needs to focus is on finding long-term storage or disposal solutions. We are now more than 20 years past the date when the DOE was to begin picking up spent fuel from nuclear sites around the country. If we want the fuel moved once and for all out of Southern California, we need advocates for federal action, armed with facts.

John Dobken, Public Information Officer, San Onofre Nuclear Generating Station

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For a different view on this issue, consider: 

Mosko: Dust-ups Continue over Radioactive Waste Storage at San Onofre

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