Giant Hole Being Cut in Reactor Dome

Crews at San Onofre are almost done cutting a massive hole -- what could possibly go wrong?

The 28-foot octagonal hole is being cut in the side of San Onofre's northern concrete containment dome, reported the North County Times. It's a key step in a two-year project to replace the aging steam generators at the nuclear power plant, officials told the paper. Containment domes are airtight, steel-reinforced safeguards that are designed to prevent the release of radioactive steam into the environment.

Most of the concrete is now gone, leaving a half-inch steel liner. Workers should be able to cut through it within a week, leaving the path clear for crews to hoist out the reactor's generators.

Some local anti-nuclear activists have expressed concerns about cutting through the domes. Though the operation has been successfully completed at many other nuclear plants in the United States, San Onofre's domes include extra internal bracing, making the surgery unique.

Plant engineers have insisted that they can safely remove and reinstall the bracing and patch the holes with new concrete that will allow the domes to be just as strong or stronger than they were previously.