Diablo unit powers up after refueling

Operators at Diablo Canyon nuclear power plant restarted the Unit 1 reactor at 2:10 p.m. Saturday after a 43-day refueling shutdown.

It was the unit’s 16th refueling and the 31st for the plant as a whole, said Jim Becker, site manager. “I’ve been here for every one of them,” said Becker, who started as a reactor operator before moving up the ranks.

In addition to replacing about 40 percent of the fuel in the reactor, workers installed a new reactor vessel head and performed thousands of maintenance, testing and repair tasks. The new vessel head is of a better design and has integrated components that require less maintenance, Becker said.

“That will pay off during future outages,” he said.

The vessel heads are the latest in a series of major components at Diablo Canyon that have been replaced in recent years. The biggest replacements are the steam generators. The low pressure turbines have also been replaced.

Each unit is refueled every three years, so there is an outage about every 18 months. Some 1,000 temporary workers are hired for each outage.

The temporary workers are a combination of local and itinerate technicians. The outages are specifically scheduled in the spring and fall to give the local hospitality industry a boost during the offseason, Becker said.

Outages are important events at the plant because work done when they occur dictates how reliably and safely the plant will operate for the next 18 months. One office is set aside for about 15 people who keep track of and schedule all the work that has to be completed during the outage.

“It’s an intense time,” Becker said.