The Nuclear Regulatory Commission has issued its preliminary report on a special inspection into a “near miss” accident at the San Onofre nuclear power plant. The report leaves some important questions unanswered.
In August, a whistleblower revealed that a canister loaded with radioactive spent fuel was nearly dropped 18 feet into a concrete cask, while being transferred from spent fuel pools to dry storage. The canister got stuck on a flange inside the concrete container.
The special inspection concluded the “near miss” accident was the result of "Southern California Edison's deficiencies involving training, equipment, procedures, oversight, and corrective actions.”
“The NRC observed instances where personnel involved in important-to-safety tasks were not trained and certified or under direct supervision,” the report said.
NRC inspectors concluded that they do not suspect the canister has been damaged. They said Holtec, the manufacturer, produced an analysis to suggest the canister would not have been damaged if it had fallen. However, the NRC concluded that, had the canister dropped, the 37 spent fuel rods inside probably would have been damaged.
“We currently believe that the fuel assemblies inside the MPC-37 canister would probably incur some damage after such a drop. However, the containment boundary represented by the MPC-37 is believed to remain intact even after a drop. So a release of radioactive material to the outside environment is not considered likely.”
Charles Langley of Public Watchdogs said the NRC is trying to minimize the seriousness of the incident. He said a full investigation is needed, including an inspection of the canister. He called the preliminary report a 'slap on the wrist' for Edison.
Edison's response
Tom Palmisano, Edison’s chief nuclear officer, said he agreed with many the inspection’s findings.
“Many of these findings match our own conclusions,” he said, in a letter to Edison’s Community Engagement Panel, a group that meets to review San Onofre’s decommissioning.
“We are re-writing procedures, developing new processes, installing new monitoring technology, and continuing to develop appropriate training programs,” he said.
Palmisano stressed that third-party experts conclude the canister would “maintain its integrity, with margin, if dropped.”
Unanswered question
But the NRC is still reviewing whether it is necessary to check if the canisters or their contents are damaged. The Commission said licensees are supposed to be able to pull the canisters back out of the casks.
“Under NRC regulations... dry cask storage licensees must be able to safely remove, with no operational safety problems, the spent fuel from storage for further processing or disposal.”
Palmisano has resisted pulling the stainless steel canisters back out of the dry casks. After a previous incident where a pin broke inside one of the casks, he said no one has ever retrieved a canister and returned it to the fuel pools.
When asked whether Edison could do this, spokesman John Dobken said the company would wait for the final inspection report before responding.
Meanwhile, the process of transferring the spent fuel from the cooling pools to the concrete casks is on voluntary hold.
Dobken said when the final report is issued, probably before the end of the year, there will be a special meeting of the Community Engagement Panel to discuss it.
The next scheduled meeting of the panel is November 29th
Alternatives
In the meantime, little progress has been made to find an alternative place to keep high-level nuclear waste, like the spent fuel rods now being buried near the beach at San Onofre.
The military is unwilling to allow Edison to store it on the Camp Pendleton mesa east of Interstate Five, which would be a few hundred feet higher than the current sea level site
The U.S. Senate has yet to vote on whether interim storage sites in places like Texas and New Mexico are legal. That vote depends on whether a long-term storage site can be found.
President Donald Trump said this week he is against the idea of using Yucca Mountain in Nevada as a long-term storage repository.
