To the California Central Coast Water Board: Shut Diablo Canyon!

To: NPDES Unit, Central Coast Water Board
895 Aerovista Place, Suite 101
San Luis Obispo, CA 93401

December 8, 2025

I am writing to oppose any further extension or relicensing of Diablo Canyon Nuclear Waste Generating Station (inappropriately known as DCNPP).

Every day, every operating nuclear reactor creates about 250 pounds of new high-level nuclear waste. This newly-created, extremely toxic waste is most radioactive when it is first removed from the reactor. Because it is so radioactive, it must be left in a cooling pool for five years or more before being moved to dry storage. And then what?

Even 100,000 years from now the waste will still be highly toxic, as well as containing components for nuclear bombs, which can be extracted and used by some future (unfortunate) civilization. We are providing humanity with the methods of our own destruction.

Meanwhile, we are providing California with a ready-made potential disaster. Push a wrong button, have a major part fail, suffer unthinkable sabotage... or just wait for an earthquake and/or tsunami.

There is no place on earth, and CERTAINLY not in California, to store the waste. And after 80+ years of making nuclear waste nationally and nearly as long in California, there is still no safe storage, no safe transport method, and no long-term storage plan to handle the growing piles of nuclear waste.

When first removed from a nuclear reactor, spent nuclear fuel is millions of times more toxic than it was before it was placed in the reactor just a few years earlier. Nuclear reactors manufacture toxic waste. As a way to produce electricity, there is nothing more expensive or more dangerous than nuclear power.

Conversely, there is none cheaper or safer than solar and wind power, and the rest of the world knows it, and is going gung-ho on truly clean energy. Jobs, energy security, and safety all come together.

Offshore wind and rooftop solar, aqueduct solar, parking lot solar and a variety of energy storage methods can easily replace DCNPP's unreliable and expensive electricity.

For off-peak times, there is a wide variety of options: Pumped water storage, lifted weight storage, underground vapor pressure storage, battery storage, spinning weight energy storage... an endless variety of options and more becoming available every year.

But back to the problem: DCNPP and the waste it produces.

Fortunately, most of the radioactive waste that is produced does not get out -- if everything goes as planned. However, accidents, sabotage, carelessness, abandonment, war... could all cause a massive unplanned radioactive release.

As long as it operates, about 2000 Curies of tritium is released every year at Diablo Canyon (1000 Curies per reactor per year). Tritium is extremely toxic -- its Relative Biological Effectiveness (RBE) is generally considered to be about 2, but there is a lot of evidence suggesting its RBE should be 3 or 4 (or even 5).

It would be very costly for DCNPP if they had to cut their tritium releases to half or a third, to meet a tighter standard. But it would be appropriate.

Tritium is often called a "low energy beta emitter" as if that makes it safe. However, the statement is both true and misleading at the same time. This fact was explained to me by nuclear physicist Marion Fulk, who was Lawrence Livermore National Labs tritium expert for many decades. What is misleading is that the emitted beta particle is a fast-moving charged particle with the same charge as an electron. (It becomes an electron as it slows to "terrestrial" speeds.) When ANY beta particle is near the speed of light, because it is a charged particle (or "ray" as some experts refer to it), it is moving too fast to have any effect on the other charged particles it passes.

Hence, ALL beta emissions, whether "low energy" or "high energy" do about the same amount of damage, except a higher-energy beta particle does its damage a microscopic distance further away from the source than a low-energy beta particle.

All beta particles are thousands of times more powerful than ANY chemical bond in our bodies, hence, tritium -- and all beta emitters -- are extremely hazardous when inside the body, especially if absorbed into (as part of) the body. Since tritium is usually part of a water molecule (as either HTO or T2O) it might be found just about anywhere in the body. Tritium has a half-life of about 12.3 years.

There is virtually NO natural tritium in the environment, especially below the top few feet of water. The tritium U.S. nuclear reactors release adversely affects fish, plant life, whales, seals, dolphins and people swimming nearby.

However, a greater concern even than the daily releases of tritium and other radionuclides (such as radioactive noble gasses, as well as smaller quantities of radioactive cesium, strontium, etc.) is the possibility of an accident.

I know the Water Board is going to claim they are "forbidden to rule on safety issues" but that's NOT the actual situation. You don't have to "rule on safety" to decide that ANY risk of an accident at DCNPP is too great. And besides: Many of the NRC's "safety assessments" are BASED ENTIRELY on very rough estimates of everything from the work ethics of steam generator assemblers in Japan to the usefulness of "coupons" to indicate the embrittlement of the reactor.

In fact, some data for the NRC's safety estimates, such are their earthquake estimates for DCNPP, are provided by California's own experts, who admit the estimates could be far off.

So you don't have to accept that those guesses "prove" that the reactor WON'T melt down if you extend the license of this decrepit, decaying rust-bucket for half-again its planned lifespan just because the utility wants you to and the craziest Federal government in history wants you to!

You can do the right thing for California instead.

Nuclear power has always had a triad of unsolvable problems: It is ridiculously expensive, frequently unreliable, and always incredibly risky.

All three problems have been a constant of the nuclear industry since its inception.

Regarding cost, the start of nuclear power included the bizarre claim that its electricity would soon be "too cheap to meter." It never was and never will be. How is it going? California has by far the most expensive electric rates in the country, in large part because of Diablo Canyon, especially considering that its owner (PG&E) made sure that solar rooftops cannot provide electricity for their local area when they have excess power, a vital framework for a statewide successful clean energy solution.

Nuclear energy is far from "too cheap to meter" but nevertheless a lot of its costs are hidden by government subsidies, a government-mandated insurance cap (California citizens will pay all uninsured costs of a catastrophe, plus suffer the health effects) and perhaps most of all, by the federal government's promise to take the waste (a broken promise thus far, after more than 60 years).

That broken promise makes the risk stay in California -- possibly forever. Certainly for many decades to come, and probably more than a century. Can we really afford to make more? Can we afford the risk?

The good news is that if we do stop making more nuclear waste in California, the potential size of any possible accident reduces significantly over time, especially in the first few decades after we stop.

The bad news is that even though the potential release size goes down by several orders of magnitude during the first century or so, there will still be enormous risk even after thousands and thousands of years.

The more waste we make, and the more recently we've made it, the greater the risk. That's why the sooner we close DCNPP, the better.

Any accident at Diablo Canyon Nuclear Power Plant is bound to poison the ocean: The ocean we love. The ocean we swim in. The ocean that makes California so nice and so valuable.

Ace Hoffman, [...] Carlsbad, California USA (images in online version only)

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Contact information for the author of this newsletter:

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Ace Hoffman
Carlsbad, California USA
Author, The Code Killers:
An Expose of the Nuclear Industry
Free download: acehoffman.org
Blog: acehoffman.blogspot.com
YouTube: youtube.com/user/AceHoffman
Email: ace [at] acehoffman.org
Founder & Owner, The Animated Software Company

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