After a ‘near-miss’ last year, Southern California Edison said it is confident transfer operations will go smoothly.
Almost one year after a 50-ton canister filled with nuclear waste got wedged inside a storage cavity and was left suspended on a metal flange about 18 feet from the ground, the operator of the San Onofre Nuclear Generating Station, also known as SONGS, announced Monday the resumption of transfer operations at the now-shuttered plant.
The restart comes two months after the U.S. Nuclear Regulatory Commission gave Southern California Edison, or SCE, the green light to continue moving the canisters from wet storage pools at SONGS to a newly constructed dry storage facility on the plant’s premises.
Prep work for the transfers began Monday afternoon and by Tuesday workers using heavy equipment will start moving a canister that had been sitting in a fuel-handling building at SONGS since last August. Within 36 to 48 hours, an SCE official said, the canister will be lowered into its assigned storage cavity. Another 43 canisters are scheduled to follow in the coming months.
“We’ve done a lot of work to ensure that going forward we will be successful in safely loading and storing each and every spent fuel canister,” Doug Bauder, SCE vice president and chief nuclear officer, said in a statement. “We’re confident the improvements we’ve made are effective and sustainable. Our job now is to demonstrate that to our stakeholders.”
Each heavy canister at SONGS, filled with fuel assemblies dating back to when the now-shuttered plant produced electricity, is taken about 1,500 feet by slow-moving transporters to individual storage enclosures, where the canisters are lowered vertically. The canisters are designed to remain there until the federal government comes up with a site to store the country’s growing stockpile of spent fuel accumulated by commercial nuclear power plants over the years.
Last August, workers thought they had successfully lowered a canister into a cavity about 20 feet deep. Instead, it came to rest on an inner-ring near the top of the enclosure. The canister was left unsupported for up to an hour by the rigging and lifting equipment intended to shoulder the canister’s weight.
Workers realized the mistake after a few minutes but it took about 45 minutes to an hour to successfully lower the canister.
News of the incident came to light after an industrial safety worker disclosed details at a public meeting six days later.
SCE officials said even if the canister had fallen, it posed no radiological threat to workers or the public but they described the incident as a “near-miss” and suspended future transfers.
The NRC launched a special inspection and earlier this year fined SCE $116,000, criticizing the company for failing “to establish a rigorous process to ensure adequate procedures, training and oversight guidance.”
The inspection disclosed that the Aug. 3 incident marked the first time the crane operator of the transporter had actually completed a downloading operation. It was also the first time the “rigger/spotter” — who watches the top of the canister to make sure it is properly lowered — had attempted a download.
The commission also cited SCE for not reporting the incident to NRC officials within 24 hours.
Since then, SCE said it has instituted “more than 70 corrective actions,” including boosting the number of workers for transfer operations, adding cameras and load-monitoring gauges and promising more aggressive oversight of Holtec International, its primary contractor.
Holtec designed the canisters and dry storage facility; it also conducted the transfer operations at the time of the August incident.
“It is essential (SCE carry out the restart) with the utmost attention to safety,” said Edwin Lyman, acting director of the Nuclear Safety Project for the Union of Concerned Scientists, “because in order to get to a desirable end goal, you have to make sure you’re not cutting corners along the way. You want to make sure the procedures are in place, the training is being done and the supervision is rigorous so you don’t risk damaging the casks in a way which would potentially compromise their long-term integrity.”
Ray Lutz, national coordinator for the advocacy group Citizens Oversight and a long-time critic of SCE, opposes resuming transfers.
“What we learned from this near catastrophe was that the design of the canister system was insufficient, and the care in operations by SCE was horrible,” Lutz said. “I hope they will start to live-stream the canister movement so the public can help them keep an eye on their work. Trusting them is impossible after this.”
In an email to the Union-Tribune, congressman Mike Levin, D-San Juan Capistrano, reiterated his request for the NRC to place a full-time inspector at SONGS, saying, “There is a clear need for continuous oversight at the facility” and “regulators should be doing all they can to ensure history does not repeat itself.”
NRC chairwoman Kristine Svinicki turned down Levin’s request last month, saying in a letter a full-time inspector “is not necessary” and not “necessarily the best method for effective regulatory oversight at the site.”
After the commission approved the resumption of spent fuel transfers, an NRC director announced it would conduct surprise inspections at SONGS.
Holtec has come under fire from some critics for its canister and storage facility designs at SONGS.
The canisters fit very snugly into the cavity enclosures, with less than a half-inch of clearance, and that has resulted in scratches on the exterior of some of the canisters.
In March of last year, workers at SONGS discovered a pin had come loose from a canister. It turned out the loose pin resulted from a new design Holtec had made but the company did not notify the NRC ahead of time because it considered the redesign to be minor.
Torgen Johnson of the Del Mar-based Samuel Lawrence Foundation in an email called the system “seriously defective and deficient” and said it should be recalled.
Saying the Holtec system meets “stringent safety requirements,” SCE spokesman John Dobken pointed out that the stainless steel canisters are designed to reduce the risk of cracking and are better suited for a marine environment like the one at SONGS.
“SCE will safely store the spent nuclear fuel at San Onofre until there is an off-site storage solution,” Dobken said in an email. “Downloading the used fuel into canisters is an important step to getting the fuel eventually shipped off site.”
Before transfers were suspended last August, 29 canisters had been downloaded. Dobken said SONGS officials anticipate the remaining canisters will be moved by the end of the first quarter of next year.
The plant has not produced electricity since shutting down after a leak in a steam generator tube in 2012. SONGS is now in the process of being decommissioned.