Notable Experts Question Wisdom of Extending Diablo Canyon’s Life
Testimony by nuclear, seismic, and energy experts was submitted to California Public Utilities Commission questioning the prudence of Diablo Canyon’s viability past 2025
The California Public Utilities Commission (CPUC) is evaluating the pros and cons of extending the Diablo Canyon Nuclear Power Plant’s (DCNPP) operation beyond the expiration dates of its twin reactors in 2024 and 2025.
On June 30, 2023, San Luis Obispo Mothers for Peace (MFP) and highly regarded nuclear, energy, and seismic experts submitted testimony to the CPUC, expressing serious concerns about the plant’s life extension. The testimony addressed issues relating to the cost of the plant’s operation, safety risks, seismic hazards, and the impact extending Diablo Canyon past 2025 would have on developing renewable energy sources.
Sabrina Venskus, legal counsel for MFP, addressed comments by the Administrative Law Judge for the CPUC ruling and the rigorous regulatory compliance processes that Diablo must undertake and costs associated with compliance if the CPUC decides to authorize the extension of the Diablo Canyon.
In September 2022, the California Legislature passed Senate Bill 846, approving the five-year extension for Diablo Canyon until 2030. The bill wisely included qualifications, such as analyzing the cost and impacts on ratepayers and taxpayers. The CPUC is obligated to consider these additional costs in their decision-making process, including, for example, the potential cost of replacing the once-through cooling system with cooling towers, estimated at $1.5 billion.
Venskus, in her testimony, stated, “The process of seeking approval from multiple federal and state statutes and regulations in extending operations of Diablo will incur significant costs,” including potential judicial challenges to approvals by other agencies with jurisdiction over Diablo.
While the legal costs could be substantial, the costs for hardware upgrades including seismic upgrades, pressure vessel restoration or replacement, replacement of steam generators, and constructing cooling towers would be even more significant. Venskus emphasized that these additional costs must be considered in the CPUC’s cost-benefit analysis when determining the cost-effectiveness and prudence of authorizing the plant’s extension.
PG&E, the power plant’s owner, is legally obligated to comply with the National Environmental Policy Act (NEPA). Compliance with NEPA requires a General Environmental Impact Statement (GEIS). However, according to MFP, Beyond Nuclear, and the Sierra Club, the current draft GEIS pending before the Nuclear Regulatory Commission (NRC) has significant deficiencies that must be addressed before the operating license can be extended.
Peter Bradford, a former NRC commissioner and former chair of the New York and Maine Public Utilities Commissions, based on his decades of experience, recommended that the CPUC take certain steps to determine if keeping Diablo Canyon running past 2024 and 2025 is prudent and necessary:
- Cost analysis needs to be undertaken as soon as possible before large sums are spent, and the development of alternative generating resources is foreclosed;
- The CPUC must consult with the Independent System Operator as to implementing competitive processes among all resources to determine whether continued operation of the Diablo power plants is in fact the best way to assure reliable power and meet California’s climate goals. No such testing has been done;
- The CPUC must advise the Energy Commission about the fiscal prudence of the $1.4 Billion forgivable loan agreement stated in SB 846;
- The process of determining Diablo’s fate should be made in a public process.
Bradford stated in his testimony, “The processes necessary to test such analyses are currently not in place.” He added, “Crucial information, such as market testing and updated resource plans and studies, will not be available for months in some cases and years in others. Meanwhile, the policy to extend Diablo Canyon operation is damaging the prospects for developing the resource base essential to meeting California’s goal of a carbon-free electric system by 2045.”
He concluded, “It is unimaginable that a prudently managed utility would have made a decision of this multibillion-dollar magnitude on the evidence and in the manner that California has pursued it to date.”
Samuel Miranda, an independent contractor with more than four decades of experience in reactor safety analysis and licensing, emphasized in his testimony the need for updates and improvements to the plant before any extension could be approved: “The costs of maintenance…should include improvements and updates to hardware, software, training, and procedures that could be required by regulations, market forces, and environmental requirements.” Yet, he said that deferred maintenance costs can be higher than normal (scheduled) maintenance costs. For example, he noted that the very costly steam generators at the Diablo units are 14 years old and would likely have to be replaced after 20 years – which would be before 2030.
Miranda added, “If the NRC does not impose a license condition of this sort [of design improvement or a plant operational modification], the consequences could be seen in an increased frequency of preventable accidents which could cause very costly damage.”
Dr. Peter Bird, Professor of Geophysics and Geology, Emeritus, UCLA, in his testimony, underscored the deficiencies in the seismic safety assessment. He said that Diablo’s 2015 Seismic Source Characterization (SSC) was deficient and biased in its assessment and recommended redoing the study, which could lead to shutdown or expensive reinforcements.
“I…show that seismicity near [Diablo] has been significantly underestimated, and that active earthquake faults may underlie the plant at shallow depths, implying materially higher seismic hazard. I believe that these considerations argue for a new SSC study of seismic hazard, using updated scientific methods,” Bird stated in his testimony.
Besides the cost, safety, and determining the prudence in keeping Diablo running, the experts also questioned if keeping Diablo operating past 2025 would contribute to or detract from meeting California’s energy requirements.
Rao Konidena, an independent energy consultant, addressed the energy issue and explained in his testimony: “Diablo cannot address operational grid issues and will not resolve California and CAISO’s operational problems.” Further, he said that imports could provide flexibility to meet California’s balancing needs, whereas Diablo’s power is inflexible.
Dr. Mark Cooper, Director of Research at the Consumer Federation of America, said in his testimony, “New renewable energy and zero-carbon resources are adequate to substitute for Diablo Canyon’s energy.” He added, “…nuclear power in general, but even as an insurance policy for the near term, is a very wasteful use of public resources.”