New Issue at Diablo Canyon Nuclear Plant Raises Specter of Energy Crisis

22 Apr 2021

A new problem has surfaced at the troubled Diablo Canyon Nuclear Power Plant Unit 2, forcing it offline again this week. The 1,150 MW unit has suffered four crashes the last several months because of ongoing problems in the unit’s electric generator. Those have occurred since a $100 million rebuild in 2019.

“The current work involves adjustments to the cooling system within the main electrical generator and is not related to the earlier vibration issue,” Suzanne Hosn, Pacific Gas & Electric spokesperson, wrote in an April 21 email to Current. Earlier, a leak in the cooling fluid was discovered in the electric generator, which is separate from the nuclear side of the plant. That was subsequently attributed to irregular vibrations.  

Unit 2 recently completed its scheduled refueling April 17. After going back online, the new problem cropped up, causing a forced outage starting on Tuesday. The previous two days, Sunday and Monday, the unit ramped up to 48% capacity.

Hosn said Wednesday that additional repairs may be needed “during this monitoring window and our team of experts, as well as Siemens, are currently executing those plans.” How long that will take is not yet known.

The utility is focused on “ensuring Unit 2 is available to our customers prior to peak energy needs in the summer,” according to Hosn.

As we head into summer, the combination of a possible non-operational 1,150 MW Unit 2, a dry west and “super poor hydro conditions, starts to feel like the 2000-01 energy crisis to me,” Jesus Arredondo, Advantage Consulting principal, said.

Before the refueling at Unit 2, a series of tests were conducted with the unit both online and offline over several weeks to gather operational data.

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