The devilish dangers of Diablo Canyon

Nuclear plant sits on fault lines and needs to close as planned

The Diablo Canyon Nuclear Power Plant, sitting on the California coast near San Luis Obispo, first came on line in 1985. It was protested then, given its location on several active fault lines. 

As a “once-through cooling system” design, the two reactors at Diablo Canyon draw in millions of gallons of sea water a day from Diablo Cove for cooling, then discharge it at heat back into the cove. This has resulted in a massive destruction of marine species and habitat, wiping out the bull kelp, causing withering syndrome among black abalone, and driving away indigenous marine species.

Diablo Canyon’s owners, Pacific Gas & Electric (PG&E), have long been planning to close the plant by 2025, given the high cost of making the necessary repairs and safety upgrades needed to shore up the plant against earthquake risk. The danger of this latter runs beyond meltdown to the large inventory of highly radioactive waste stored at the precarious site.

In 1971, more than 14,000 abalones were removed from Diablo Cove during construction of the Diablo Canyon nuclear power plant. Later, the abalone were further harmed by the hot water discharges from the plant. (Photo: US Department of Energy)

But recently, California governor, Gavin Newsom, publicly pondered the idea of seeking part of the Biden administration’s $6 billion bailout to keep old nuclear plants running, using the funds to delay Diablo Canyon’s closure.

It’s not actually Newsom’s decision, as PG&E would have to apply for the funds and, so far, the utility has signaled little enthusiasm. Given the billions of dollars needed to refurbish and upgrade the plant to reduce its marine impacts and protect against earthquakes, it makes more economic sense for PG&E to invest in renewable energy alternatives. And, as NRDC’s Ralph Cavanaugh pointed out to the LA Times, “solar, storage and other clean energy sources could replace Diablo cheaply and reliably.” 

The Times article itself pointed out “Rescuing Diablo Canyon is far from California’s only option for averting blackouts.” Some of those options, the Times, said, were “adding batteries to the grid, paying homes to use less energy and coordinating electricity supplies more closely with Western states. Longer-term options include investing in geothermal energy and offshore wind.”

In the meantime, Diablo Canyon keeps operating and the seismic risks persist. Just how great are they? California activist, Harvey Sherback, has studied them for years. Here is his assessment:

By Harvey Sherback

California’s Central Growing Valley is America’s most productive agricultural region providing more than half of the fruits, nuts and vegetables grown in the United States. Sadly, Diablo Canyon’s two nuclear reactors sit on our state’s central coastline and because coastal winds have a tendency to blow inland, there’s the frightening prospect that a megathrust earthquake, “The Big One”, could trigger a nuclear meltdown sending radioactive clouds into the Central Valley which would irradiate and poison much of the Central Valley’s produce.

Furthermore, Diablo’s radioactive plumes could contaminate the drinking water that flows from the Sierra Mountains through the Central Valley and into cities like San Francisco and Los Angeles, which would lead to a mass migration out of California.

Pacific Gas & Electric Company’s nuclear plant, located near Avila Beach in San Luis Obispo County, is surrounded by a confluence of 13 known fault lines on the seismically active “Pacific Ring of Fire” earthquake and tsunami zone.

Originally designed to withstand a magnitude 6.75 earthquake and later reconstructed to endure a magnitude 7.5 quake, Diablo’s tolerances underestimate the true seismic potential of today’s mega-thrust shakers.

Additionally, there are two fault lines, the “Diablo Cove Fault” and the “San Luis Range/“IOF” Thrust”, that run directly under the Diablo Canyon nuclear plant.  The Diablo Cove Fault extends through the foundation, under the power plants’ Unit One turbine generator and reactor containment vessel.

The east-west trending Diablo Cove Fault runs offshore and intersects with the nearby Shoreline Fault, which in turn is connected to the Hosgari Fault Line, a component of the San Andreas Fault System. The power stored within this network of seismically linked faults could create an earthquake sufficient to exceed Diablo Canyon’s safeguards.

On June 28th, 2016, the moment of truth as to Diablo’s vulnerability came to light. PG&E announced that it would not seek to renew the plant’s two operating licenses with the Nuclear Regulatory Commission, which would have permitted the nuclear facility to operate until 2045.

Instead, the company agreed to close the plant on August 26, 2025 if Diablo was allowed to “avoid” a proposed environmental impact assessment known as CEQA. The deal was accepted.

CEQA, or the California Environmental Quality Act, is a statute that requires both state and local agencies to identify “significant environmental impacts” and to avoid or mitigate those impacts if feasible. PG&E knew that Diablo would fail to get a clean bill of health if the CEQA review was allowed to proceed, especially after the catastrophic meltdowns at Japan’s Fukushima Daiichi nuclear power plant on March 11th, 2011.

The casks containing stored radioactive waste, along with the reactors themselves, are at risk of damage due to an earthquake at the Diablo Canyon nuclear power plant. (Photo:US NRC)

Unfortunately, PG&E’s Unit One Reactor has a documented history of being dangerously embrittled since 2003.  Knowing how “seismically vulnerable” the nuclear plant is, there were many calls to inspect and test Diablo’s radioactive containment vessel for embrittlement and cracks as well as investigate the rest of the facility for the mishandling of nuclear waste, “deferred maintenance”, earthquake vulnerability and managerial competence.

Once again, on February 28th, 2019, PG&E asked the Nuclear Regulatory Commission for relief from a “Reactor Vessel Internal Visual Examination” of its Units One and Two reactor containment vessels, which they received. The deeply troubling question is, why was PG&E so afraid of having its nuclear facility inspected for safety and reliance?

PG&E’s Diablo Canyon nuclear plant presents too many risks for the people and the economy of California. It isn’t an asset, it’s a horrendous liability!

The good news is that once manufactured and installed, solar panels emit no greenhouse gasses, use no water except for an occasional cleaning, have no moving parts, make no noise, are virtually maintenance free and are easily recycled. Furthermore, photovoltaic panels won’t suffer the potential of a catastrophic Fukushima-like nuclear meltdown over their estimated 20-25 year warranted lifetime.  

It’s time to embrace our move towards a “truly” renewable energy future both for us, our children, and future generations.

Harvey Sherback is a renewable energy advocate who lives in Berkeley, California.

Headline photo of Diablo Canyon nuclear power plant by US Nuclear Regulatory Commission.

The views expressed in articles by outside contributors and published on the Beyond Nuclear International website, are their own, and do not necessarily reflect the views or positions of Beyond Nuclear. However, we try to offer a broad variety of viewpoints and perspectives as part of our mission “to educate and activate the public about the connections between nuclear power and nuclear weapons and the need to abandon both to safeguard our future”.

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