Lyman, a notorious anti-nuclear pundit, reported in mid-August on his extensive assessment of the seismic risks at the Diablo Canyon plant site. It is presented here as a record of that assessment. Lyman opined that in 2016, Pacific Gas & Electric (PG&E) announced a historic agreement with labor and environmental groups to shut down the two-unit Diablo Canyon nuclear plant in California by 2025 and replace its roughly 2,200 megawatts of electricity with low- and zero-carbon renewable energy, energy efficiency, and storage. Today, that agreement is in serious jeopardy after an academic study (underwritten in part by the nuclear industry [just as this "assessment is likely underwritten as a results of the underwriting by the anti-nuclear industries of wind and solar and the oil & gas companies and supporters]), combined with a sustained and vocal public relations campaign waged by Diablo Canyon supporters (including a Tik-Tok influencer [Nice try, Lyman]), have succeeded in raising doubts about the viability of the power replacement plan. Growing concerns [Lyman sounds like a Republican having concerns about the election] about climate change-related impacts on the reliability of the electrical grid have also prompted California governor Gavin Newsom to reconsider his position and seek to keep the plant open, at least in the short term. The U.S. Energy Department’s Office of Nuclear Energy is also doing its part to keep Diablo Canyon open by relaxing the original financial qualification criteria and extending the application deadline by more than three months for its recently established Civil Nuclear Credit Program. This will make it possible for PG&E to apply for a first round of federal subsidies aimed at helping utilities keep nuclear power plants open.[which is the purpose of those funds to prevent premature closings]
Although there is some basis for the criticism that PG&E and the State of California are not acting quickly enough to ensure that enough carbon-free power will be available to replace all of Diablo Canyon’s output, the California Public Utilities Commission’s historic decision last year to procure 11,500 megawatts of clean energy resources by 2026, along with 4,000 megawatts of new capacity (mostly battery storage) added to the grid in the last year, should help address that concern [but this extra cost in "storage" will not meet the energy requirements in California]. A recent analysis by Gridlab and Telos Energy [companies that are wind and solar supporters and supporting Energy Innovation, a pro-renewables thinktank] also found that renewable energy could replace Diablo Canyon and supply 85 percent of California’s electricity by 2030, while keeping the power on for its 40 million residents—even under stressful conditions such as low hydropower generation, retirements of fossil fuel-fired plants, and heatwaves similar to what caused rolling power outages in August 2020.
Nevertheless, the disagreement over the plant’s future has become a proxy for the larger debate over what role nuclear power should play in addressing climate change, given its safety and security risks. If PG&E’s original plan were to succeed, after all, it could undermine the nuclear advocates’ argument that nuclear power is an irreplaceable asset in all circumstances. But if Diablo Canyon is to remain open beyond 2025, PG&E will have to address a number of difficult issues. First, the company will have to prepare a new 20-year license renewal application and submit it to the US Nuclear Regulatory Commission (NRC) before the expiration of Unit 1’s operating license in 2024. PG&E will also have to undertake extensive inspections and equipment upgrades that were indefinitely postponed after it made the decision to shut the plant, as discussed in a June 2022 meeting of the Diablo Canyon Independent Safety Committee. And finally, it must take a hard look at the vulnerability of the plant to earthquakes and consider the need to make seismic upgrades to minimize the risk to the public over the period of extended operation.
Conflicting information on the seismic question has been reported. A spokesperson [Who?] for the California Public Utility Commission was quoted as saying that if PG&E were to resume the license renewal proceeding for the plant, it would need to make seismic upgrades. However, this statement is not consistent with the NRC’s current position. Following a review conducted in the aftermath of the 2011 Fukushima accident in Japan, the agency concluded that no seismic upgrades at Diablo Canyon or any other US nuclear plants were necessary, because the health and safety risks to the public were acceptable. Since the NRC has sole authority over the radiological safety aspects of Diablo Canyon, this means that the plant owner will not have to spend a penny to strengthen its seismic protection, no matter what the state of California wants.
Arguably, however, the NRC is not doing enough to reduce the risk that a severe earthquake could cause a Fukushima-like core meltdown and radiation release at Diablo Canyon (or, for that matter, other seismically vulnerable nuclear plants in the country). The agency, as part of its drive to transform into a more “risk-informed” regulator, cites the low calculated radiological risk to the public from nuclear plant accidents to justify not taking action to increase safety across a wide range of areas, including seismic protection. But there’s a major problem with this approach: Assessing the seismic risk involves understanding both the uncertainties associated with nuclear accidents and the even larger unknowns encountered in trying to predict earthquake behavior. These uncertainties raise doubts whether the seismic risks can be calculated with sufficient precision to support the NRC’s complacency.
Although other nuclear plants are also seismically vulnerable, according to current information, the potential peak ground motion that the Diablo Canyon site may experience from an earthquake occurring every 10,000 years on average is far higher than any other U.S. plant. But it is also important to consider this value in relation to the seismic standard that the plant was designed and built to meet and that is used as the basis for inspection and regulatory enforcement.[1] Diablo Canyon’s seismic risk actually may be lower than some other US reactors because, given its location, it was originally designed with additional earthquake resistance. But that doesn’t mean it is safe enough. Serious questions persist about whether Diablo Canyon’s design basis and “current licensing basis” meet a high enough seismic standard to adequately protect the public.
This is an issue with a very long history, as detailed in a 2013 report [of doubtful veracity] by the Union of Concerned Scientists’ former nuclear safety director Dave Lochbaum. Since that report, considerable additional information has been released about Diablo Canyon’s seismic risks. A review of this new information clearly shows there are gaps in the seismic safety of Diablo Canyon that should be closed if the plant is going to continue to operate beyond 2025. If California decides to support license renewal, a portion of the “transition costs” that the Energy Department and the state may provide to PG&E to keep the plant operating should be allocated to reducing its vulnerability to earthquakes. The risk is not negligible, and the potential costs of an earthquake-induced accident could, by our estimate, cause more than 10,000 cancer deaths and over $100 billion in damages.
[For the complete review by the editors of the I2M Web Portal, see (here)].
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