California nuclear plant to shut: a case of unforgiving nuclear economics
Southern California Edison is shutting the remaining two reactors at San Onofre, citing high repair costs and an NRC ruling that the utility says would delay reactor restarts.
The San Onofre Nuclear Generating Station (SONGS), a nuclear power plant set into the seaside bluffs in northern San Diego County, is closing after the high cost of repairs and a Nuclear Regulatory Commission board ruling prompted its owner, Southern California Edison, to pull the plug on the 45-year-old facility.Skip to next paragraph
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The announcement Friday that San Onofre’s two functioning reactors were being shut down brings to four the number of reactors that nuclear utilities have slated for closure since last November. Meanwhile, nuclear utilities have three new reactors on the drawing boards.
At least for now, "we're losing them faster than we're building them," quips David Lochbaum, a nuclear engineer by training who focuses on nuclear-energy issues at the Union of Concerned Scientists in Washington.
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In February, Duke Energy announced it was shutting down the reactor at its Crystal River power station in Florida after workers discovered a crack in the containment dome. The crack was created during efforts to replace a critical component of the reactor system that transfers heat to water in order to generate steam for the plant's turbines.
In early May, the utility Dominion shuttered its single-reactor Kewaunee nuclear plant in Carleton, Wis., a casualty of cheaper sources of electricity and an inability to build additional reactors to take advantage of what the company called economies of scale.
"Nuclear economics is tenuous at best," Mr. Lochbaum says. "If you do everything right, you can make money at this. But if you stumble, there's a big price to pay, and not just from a Fukushima-type tragedy."
Financial setbacks can take their toll as well, he says, whether a setback comes from lost business or from hardware failures or human error that sets the stage for costly repairs.
In announcing San Onofre's closure Friday, Ted Craver, Southern California Edison's chairman and chief executive officer, noted that the station has been generating electricity for more than 40 years, "but we have concluded that the continuing uncertainty about when or if SONGS might return to service was not good for our customers, our investors, or the need to plan for our region's long-term electricity needs."
The utility first broke ground on SONGS in 1964. The plant initially hosted one nuclear reactor. Two more were added and came on line in 1983 and '84. Since then, the plant's first reactor was decomissioned, leaving units 2 and 3 to help power southern California's voracious demand for energy.
Both units sported relatively new sets of steam generators – components that along with the reactor sit inside a concrete containment building. The steam generator houses bundles of tubes through which high-pressure, superheated steam from the nuclear reactor flows. Pumps force water past the searingly hot tubes to produce the steam that drives the plant's generators.
In early January 2012, the utility took Unit 2 down for a routine refueling outage. At the end of the month, operators running Unit 3 detected a small leak in a steam generator tube that allowed radioactive steam to mix with the steam sent outside the containment building to the generators.
The utility shut down Unit 3 and began an exhaustive inspection of the steam generators for both reactors. The inspections revealed unexpected wear and tear on a significant proportion of the tubes.