NRC Accepts PG&E’s Application for Diablo Canyon Power Plant

Nuclear Power Plant Reactors Allowed to Keep Running Past Expiration Dates During Review

Paula Gerfen, chief nuclear officer for PG&E, signs the license renewal application for Diablo Canyon nuclear power plant, which was deemed "sufficient" by the Nuclear Regulatory Commission. This is one of many steps to continue the production of electricity from Diablo beyond the facility's current closure date of 2025; NRC review customarily takes several years. | Credit: PG&E

Following Diablo Canyon Power Plant’s approval last week to run through 2029 and 2030 by the California Public Utilities Commission (CPUC), California’s last nuclear power plant received word that the federal Nuclear Regulatory Commission (NRC) found its renewal application sufficient. Pacific Gas & Electric, which operates Diablo, announced on Tuesday that the NRC’s sufficiency determination allows the company to continue running Diablo past its expiration dates, because the review generally takes several years.

At the CPUC hearing on December 14, the issue was largely the costs and benefits of extending Diablo’s operations for five years, as initiated in Senate Bill 846. That bill provided a $1.4 billion loan to PG&E to continue operations, as the Northern California energy provider had previously decided to close Diablo when the licenses for Reactor Units 1 and 2 ran out in 2024 and 2025. However, in the face of potential blackouts during California’s burning hot summer of 2020, the drought drying up hydroelectric power sources, and a 2030 completion timeframe for federal offshore wind energy projects, Governor Newsom backed the bill to keep Diablo in operation to bridge the gap.

The five CPUC commissioners voted 3-0 — one abstained, and one was absent — stating clean energy still lagged in production compared to Diablo, which produces 2,200 megawatts of electricity. The Proposed Decision notes energy storage and paired solar-storage projects had increased as of March 2023, but hundreds or thousands of megawatts would be missing if heat waves or wildfire challenged the grid and Diablo were offline. The decision also states no supply can be brought online that would generate Diablo’s 18,000 gigawatt-hours per year before the second reactor was to close in 2025.

The commissioners were also to evaluate whether the cost of keeping Diablo running was “too high to justify” or “not cost-effective or imprudent.” PG&E forecast that it would cost about $747 million annually to run the plant between 2023 and 2030. The commissioners essentially punted on whether this was too much, claiming a lack of information as Diablo’s Independent Safety Committee hadn’t yet weighed in on seismic safety upgrades or deferred maintenance. Nonetheless, PG&E will be allowed to spread the cost of Diablo’s extended operations among all ratepayers of PG&E, SoCal Edison, and San Diego Gas & Electric based on peak demand, the commission concluded, as keeping the nuclear facility is for system reliability as a public policy.

In addition to the safety concerns, the remaining question is whether PG&E intends to operate for five years or for 20 years, which is the timespan in the NRC license, given the embrittlement and seismic concerns at and around the plant. A PG&E spokesperson stated they would operate Diablo for five years past 2025 “as directed by California Senate Bill 846.” The NRC’s standard license renewal of 20 years would “allow the state maximum flexibility to ensure electric resource adequacy. The actual operating duration of DCPP will be controlled by the State legislative and regulatory processes.”

Sierra van der Brug contributed reporting to this story.