Evacuation plan for San Onofre is scaled back
Safety concerns rise as officials drop emergency plans regarding San Onofre
Officials say the risk has declined since the nuclear plant was retired.
Nuclear-emergency precautions and escape plans are being scaled back for communities near the retired San Onofre power plant in northern San Diego County because federal safety officials regard a major disaster as increasingly unlikely.
The U.S. Nuclear Regulatory Commission has approved a request by nuclear plant operator Southern California Edison to do away with elaborate plans for the evacuation, sheltering and medical treatment of people living within a 10-mile radius of San Onofre’s twin domes to guard against an airborne radiation plume.
The decision to discontinue emergency planning, except within the plant’s boundaries, officially puts to rest a decades-long era of anxiety reinforced by periodic testing of air-raid-style sirens and the distribution of household potassium iodide or “KI” tablets that can block radioactive iodine from damaging the thyroid gland.
At the same time, new safety concerns about the storage of spent nuclear fuel are emerging and are likely to endure for generations as engineers test the capabilities of waste casks and bunkers.
Donna Gilmore of San Clemente, who lives within five miles of the plant, says it is too soon to relax evacuation planning and notification systems when the effects of corrosion on nuclear storage casks are not fully understood.
“Their justification is that nothing is going to go wrong,” said Gilmore, an activist and retired systems analyst. “It’s critical that people know we have this ticking time bomb standing there at San Onofre.”
San Onofre’s twin beachfront reactors — halfway between downtown San Diego and Los Angeles — have not produced power since January 2012, when a small radiation leak was traced to rapid wear on newly installed steam generators. Edison retired the facility in June 2013.
Discontinued emergency plans were focused most intently on communities within 10 miles of the plant, including San Clemente, San Juan Capistrano and Dana Point, along with people who come and go from San Onofre State Beach and Marine Corps Base Camp Pendleton.
Similar exemptions to emergency plans have been granted at other U.S. nuclear plants as they are closed down and dismantled. Edison spokeswoman Maureen Brown said the company will continue to alert local emergency response agencies if dangers arise at the plant.
In a news release, the Nuclear Regulatory Commission said that “Edison provided analyses to show the [emergency plan] exemptions are warranted because, when compared to an operating power reactor, the risk of an off-site radiological release is significantly lower and the types of possible ac- cidents significantly fewer at a nuclear power reactor that has permanently ceased operations and removed fuel from the reactor vessel.”
Encinitas resident Torgen Johnson, an activist on nuclear safety issues since the 2011 tsunami and nuclear disaster in Japan, worries that authorities are downplaying potential problems related to spent nuclear fuel at San Onofre.
Safeguarding spent nuclear fuel at the Fukushima Daiichi site in Japan became a critical safety issue after the earthquake. An explosion blew the roof off the reactor No. 4 building, exposing a cooling pool packed with fuel-rod assemblies and inciting fears that they might overheat and combust.
Those events eventually led to the installation of new instrumentation at U.S. fuel pools. Some shortcomings in U.S. regulatory oversight of spent fuel pools were highlighted in a March report from the commission’s in- spector general’s office.
Johnson wants direct public access to radiological monitoring at the plant without delays, so that neighbors of the plant don’t have to wait on cues from the plant operator and local agencies.
“Until all the fuel is removed from the site, then stepping down the emergency preparation is an unethical thing to do,” Johnson said.
The nuclear commission continues to analyze radiological problems that might accompany a massive earthquake or other unpredictable events at San Onofre.
Most of the spent nuclear fuel at San Onofre is being stored in pools of water for cooling. Were the pools to rupture or drain somehow, exposed nuclear fuel assemblies could eventually overheat and ignite.
The Nuclear Regulatory Commission estimates that San Onofre’s exposed spent fuel would take more than 13 hours before getting hot enough (at about 600 degrees Celsius) to begin destroying its metal casing. Edison has several backup strategies for dousing the fuel before that happens. It would take more than 17 hours unattended for the nuclear fuel to reach the auto-ignition temperature of 900 degrees.
That leaves enough time, federal officials say, to “initiate appropriate mitigating actions, and if needed, for off-site authorities to implement protective actions.”
Edison also will be doing away with emergency provisions protecting consumers from exposure to escaped radiation through agricultural products, water and livestock. That emergency zone extended 50 miles outward from the plant, south past Pacific Beach and to the east beyond Ramona, Valley Center and Temecula.
San Onofre operators say they no longer need a specialized network of emergency sirens in outlying communities, though the sirens will be available to local authorities through 2019. Edison says neighbors of the plant can dispose of their potassium iodide pills without worry.
The nuclear plant will continue to employ its own emergency staff and conduct continued radiological monitoring at the plant, while off-site responsibilities shift toward the Federal Emergency Management Agency and local governments.
Edison plans to move all its spent nuclear fuel from San Onofre’s cooling pools to steel-and-concrete casks that will then be entombed in an underground concrete bunker.
That project could be completed as early as 2019. Dismantling the reactors is expected to take about 20 years and cost Southern California utility customers about $4 billion. Most of those funds already have been collected and set aside in a special investment fund.