San Onofre Restart Date Still in Limbo

Southern California Edison is aiming for a June restart of its idled San Onofre nuclear reactors, but officials from the company and the Nuclear Regulatory Commission stressed the date is not firm because “safety has no timeline.”

Meanwhile, the technical and administrative processes continue grinding forward to resume operations after a

Technicians have plugged about 1,300 of the thousands of tubes in steam generators in units 1 and 2——that can power the equivalent of more than 1.2 million single-family homes at any given time.

In each unit, reactors boil water in a closed system. The heat from the radioactive steam is used to boil pure water through a series of thousands of heat exchange tubes. The resulting pure-water steam turns a turbine that generates electricity.

The tubes were the site of the January leak, which released a small amount of radioactive steam.

As of May 7, according to an Edison press release, officials and technicians at the plant have:

• Filed a letter with the NRC promising the company will determine the cause of tube vibration and friction that created tube wear and make repairs.
• Worked to develop a protocol for future steam generator inspections, including mid-cycle shutdowns for inspections.
• Conducted in-situ pressure testing on 129 tubes in Unit 3 after initial inspections identified tube-to-tube wear. A total of eight tubes failed certain tests.
• Identified additional tube wear in two of the 19,454 tubes in the Unit 2 generators that was similar to the type of wear previously seen in Unit 3.
• Plugged a total of 510 tubes in Unit 2 steam generators and a total of 807 tubes in Unit 3.

Officials couldn’t give an exact restart date even if they had one. Because the reactors create such a huge infusion of energy into the power grid, announcing an exact date for restarting the plant—even after routine refueling outages—can affect wholesale electricity prices in California.

Typically, the company will announce the restart only within a week or so of the planned date.

Meanwhile, California’s Independent System Operator, the corporation resposible for routing and allocating power to utilities in the state, to keep the lights on if San Onofre remains on ice during the hot summer months.