How can Diablo Canyon nuclear power plant stay open? ‘It’s not a done deal’

Diablo Canyon nuclear power plant owned by PG&E discharges about 2.5 billion gallons of cooling water a day into the 40-acre cove along the Pacific Ocean. The ecology of the cove has shifted toward warmer-water species since it began operating in 1985 but is expected to return to previous conditions within a few years of shutdown of its two units, scheduled for 2024 and 2025. (David Middlecamp/

PG&E is preparing for two futures: one in which it closes Diablo Canyon Power Plant in 2025 and another in which it continues operating the nuclear power plant through 2030.

“It’s not a done deal,” PG&E director Tom Jones told the San Luis Obispo County Board of Supervisors on Tuesday. “We’re maintaining both tracks.”

Diablo Canyon was on track to shut down in 2025, but the California State Legislature passed Senate Bill 846 in October.

The bill, which Gov. Gavin Newsom signed into law on Sept. 2, creates resources to keep the power plant near Avila Beach open until 2030.

One of those resources is a $1.4 billion grant to the state Department of Water Resources. That department will then loan the money to PG&E.

The utility company will receive a $600 million loan this year, and another $800 million next year if approved by the California legislature, Jones told the Board of Supervisors.

PG&E applied for a grant with the U.S. Department of Energy to “back-fill those funds,” Jones said.

Diablo Canyon supplies California with 9% of its in-state generated energy and 20% of its greenhouse gas emission-free energy, Jones said, making the plant a key component of the state’s electricity grid.

Even though the state provided PG&E with new support, the utility company has to complete a few more steps to keep the power plant open, Jones said.

What’s next for Diablo Canyon?

In order to continue operating Diablo Canyon, PG&E must renew the power plant’s license to operate with the U.S. Nuclear Regulatory Commission, Jones said.

Normally, the federal commission requires a power plant to apply to renew its license five years before it expires.

Diablo Canyon, however, is two years away from an expired license, Jones said.

PG&E will apply for the renewed license anyway, and Jones said there’s a chance the commission will understand that PG&E’s renewal application was triggered by a state law and grant the license.

“This is a major change in energy policy,” Jones said. “It’s not a licensee that on a whim decided to go for license renewal. So they understand the gravity of the situation and they understand California’s energy needs.”

The Nuclear Regulatory Commission will inspect the power plant’s ability to safely operate for a long period of time. The inspections focus on “aging” parts of the power plant, such as pipes that service the pumps, Jones said.

For example, the inspection will check the pipes’ “wall thickness and (whether) is it adequate for an additional 20 years,” Jones said.

PG&E applied for a license renewal for Diablo Canyon in 2009.

Almost 90% of the review process was complete by 2018.

The power plant withdrew its application that year, Jones said, after the California Public Utilities Commission approved PG&E’s request to close the power plant in 2025.

PG&E hopes the commission will refer to information from that application along with its new inspections of the power plant, according to Jones.

“We have a good body of work,” Jones said.

Jones said PG&E has moved 40 staff members around in its in-house regulatory departments.

The utility company is prepared to hire more contractors should it transition to maintaining operations at Diablo Canyon, according to Jones.

PG&E wants to ensure it can retain its employees at Diablo Canyon if the power plant remains open, Jones said.

We have many people out there with 25, 30 years of experience and you can’t simply replace them,” Jones said.

The law requires the power plant to stay within the $1.4 billion budget in order to continue operating.

According to Jones, keeping Diablo Canyon open would change plans for storing the power plant’s spent fuel.

Originally, the power plant planned to transfer its spent fuel to dry storage within 3.25 years of the power plan shutting down in 2025. Now, it will transfer and store the spent fuel more slowly so it can be used for continued operations.

The power plant will also need to purchase more fuel, which must be completed two years in advance of when the fuel is needed, Jones said.

Unit 1 of the power plant has the most urgent fuel needs, as it currently doesn’t have enough fuel to operate beyond 2024, according to Jones.

If the Nuclear Regulatory Commission denies the power plant a renewed license, it will still need to close in 2025 as planned.

With that in mind, the power plant is also working on decommissioning activities such as managing funding and spent fuel, Jones said.

“When we get into decommissioning, we’re changing active systems to passive systems or retiring the systems, so we need to go through and update the procedures that our operators follow,” Jones said.