San Onofre, R.I.P.

Southern California Edison on Friday made its smartest decision yet about the troubled San Onofre nuclear power plant: It announced it was closing the facility once and for all. A year after the plant was taken off-line as a result of several problem-ridden steam generators, one of which had leaked a small amount of radioactive steam, the company finally decided to cut its losses and move on.

It didn’t have to be this way. If Edison had gone through full regulatory oversight in 2010 and 2011, when its then-new $670-million steam generators were being designed and built, rather than choosing the cheaper and more expedient route of claiming that the new machinery was virtually the same as the old, there’s a good chance the design errors would have been caught in time. Edison might have a thriving nuclear plant today, well-positioned for license renewal in several years, which would have kept the two reactors operating for decades to come.

Instead, it will now have to spend untold millions of dollars to cool its radioactive fuel and then store it in a system of leak-proof casks that will then be embedded in concrete. The U.S. Nuclear Regulatory Commission also should require Edison to demolish the buildings as soon as it is safe to do so, shipping the pieces off to licensed, low-level radioactive waste dumps.

GRAPHIC: Wear and tear at San Onofre

To its credit, Edison was trying to replace its old steam generators with ones that were better and safer when it contracted with Mitsubishi Heavy Industries. But the design should have been subjected to the tightest scrutiny of NRC experts; instead, Edison insisted that the replacements were not significantly different from the original generators. That obviously proved untrue, as the tubes in the generators began to wear out with a speed never experienced in the industry.

Edison closed both Units 2 and 3 early in 2012 but then compounded its original error by resisting calls by environmental activists for full licensing hearings before the plant could reopen. Those hearings are time-consuming, taking up to a year or more, and the company hoped to have at least one of its reactors up and running much sooner. The environmentalists ultimately prevailed when the NRC’s Atomic Safety and Licensing Board determined in May that full hearings were the right way to go. Had Edison agreed to the full procedure from the start, those hearings might have been over by now. On Friday, the utility cited the time that the full proceedings would take as a factor in its decision to shutter the plant.

Still to be determined is where the power will come from to serve Edison’s customers, what the ultimate cost will be for ratepayers and what will happen to the estimated 1,100 employees who stand to lose their jobs.

San Onofre’s life expectancy should have been limited to its existing licenses anyway; those run to the end of this decade. An earthquake-prone area next to rising seas is not an appropriate place for a nuclear power plant. But its demise came even earlier, a lesson in doing things right the first time. Edison ran out of time for doing it over.