Japan quake ignites Diablo nuclear concerns

March 18, 2011


In the aftermath of Japan’s nuclear calamity, concerns about Diablo Canyon nuclear power plant’s ability to withstand an earthquake and media reports that safety plans do not include earthquake procedures have the public demanding answers.

Even before last weeks earthquake and tsunami in Japan, PG&E’s application to extend its operating permit was controversial. The California Public Utilities Commission(PUC) directed the utility to do further seismic testing as part of its license renewal.

PG&E officials said the advanced seismic studies would be completed in 2013. Even so, they had asked for an April review hearing.

Early on Friday, the PUC announced they had postponed the April hearing so that it would have time to review safety lessons learned from the earthquake and tsunami in Japan.

Diablo’s seismic history

When the plant was first permitted in 1967, it was not required to have an earthquake emergency response plan. However, since then two faults have been discovered near the plant prompting earthquake procedures to be put in place.

Before the plant was put into operation, after the discovery of the Hosgri Fault in 1971 by Shell Oil, a long and contentious battle between the state and PG&E ensued raising the cost of construction, first estimated at $320 million, by over $5 billion. PG&E was also directed to hire geologists and seismologists to work in the plant’s geosciences department. As a result of finding the Hosgri Fault, Diablo’s design was changed and the plant was retrofitted to withstand a magnitude 7.5 earthquake.

In 1985, the $5.7 billion plant began producing energy.

In 2008, a second fault dubbed the Shoreline Fault was discovered less than a mile from the plant by U.S. Geological Survey (USGS) geologist Jeanne Hardebeck using data from USGS and PG&E monitors.

Even though the Nuclear Regulatory Commission concluded that Diablo Canyon’s design would withstand a potential earthquake on the Shoreline Fault, “The fault’s major characteristics are largely unknown, e.g., its length, proximity to the plant and relationship to the Hosgri Fault (whether an earthquake beginning on the Hosgri Fault could continue on the Shoreline Fault, or vice versa, causing a larger earthquake than if either fault broke on its own), and whether this fault or fault displays could extend beneath the plant,” a California Energy Commission research report says.

Both the USGS and PG&E geologist studied Diablo’s neighboring faults and arrived at different estimates of the highest credible magnitude earthquake that could occur on both the Hosgri Fault and the Shoreline Fault.

For the Shoreline Fault, the USGS study placed it at a maximum magnitude 6.5 and for the Hosgrie fault, a maximum magnitude 7.3. The USGS study was a collaborative study that has been peer reviewed.

Even though, according to the USGS study, the plant can withstand the highest magnitude earthquake likely to occur on the two neighboring faults, Hardebeck points at Japan’s failure to properly predict the highest magnitude earthquake that could hit the Fukushima nuclear plant, now in partial meltdown.

“Sometimes the estimates are wrong,” Hardebeck said. ‘They thought an 8.0 and they ended up getting a 9.0.”

PG&E studies of neighboring fault line were peer reviewed by geologists from five entities including Stanford University, the University of California Berkeley and the University of Southern California. Their studies placed the highest credible earthquake at a magnitude 6.5, and that is if the Shoreline Fault and the Hosgrie Fault have concurrent earthquakes.

Both PG&E officials and Hardebeck noted the differences in the type and size of faults neighboring Diablo and those off the coast of Japan.

“We do not have that type of earthquake,” Hardebeck said. “The types of faults on the Central Coast do not generate the tsunami seen in Japan. They are less disruptive.”

Several additional differences exist between the Fukushima plant and the Diablo plant. Diablo is a pressurized water reactor (PWR) and Fukushima is a boiling water reactor (BWR). PWRs have more places to cool and the steam is not radioactive, as it is at a BWR plant.

Diablo’s containment walls are 3 ½ feet deep while Fukushima are only 2 feet. Also, elevated above the Diablo plant is 5.5 million gallons of fresh water, held in two fresh water ponds that sit behind the plant at an elevation of 300 feet.

Disaster drill uncovers mistake

Every quarter, Diablo has an emergency drill to simulate several different disasters including earthquakes, terrorist attacks and forest fires. Plant employees have duties such as walking the plant to check equipment and taking radiation readings.

Once every one to two years, the plant undergoes a more fully evaluated drill by the Nuclear Regulatory Agency along with other state, local and federal agencies.

During a testing in Oct. 2009, personnel discovered a system to pump water into the reactor during an emergency had been accidentally disable for 18 months. Plant engineers had shortened the distance between a pair of valves to lessen the time it took to open them.

What they didn’t know, was two other valves where interlocked with the first pair.

While opponents of nuclear energy contend these types of incidents are frequent and unforgivable, PG&E points out that in the case of an emergency, plant operators could have opened the valves manually.

In addition to drills, the plant does radiation testing on an ongoing basis utilizing more than five different types of monitoring equipment.

For example, more than 10 environmental off-site radiation monitors located throughout San Luis Obispo County constantly monitor gamma radiation levels. Every minute, the monitors send information back to the plant.

As of Friday morning, no detectable radiation from Japan was noted on any of the monitors in San Luis Obispo County. All sensors at PG&E have been recording normal, natural background readings.

Proponents of nuclear energy note that the cost of electricity production at nuclear plants is less than half the cost of energy produced by natural gas, while opponents point at the cost of retrofitting the plant.

Dave Weisman,  with the Alliance for Nuclear Responsibility, said the $4.4 billion it cost to retrofit the plant after the discovery of the Hosgri Fault fell on the backs of the rate payers.

Diablo, which along with the San Onofre nuclear plant generates more than 12 percent of California’s electricity, is requesting to renew its operating licenses that expire in 2024 and 2025.

“Now they want another 10 to 20 years,” Weisman said. “Last time it cost $4.5 billion to retrofit the plant. What will it cost now?”


Nuke proponents, if your an enemy of the U.S. (one thing we have plenty of now and more in the future) what would be your dream targets? A missile just released in China can now destroy our carriers. I’m watching a brand new war start onTripoli as I type this by the way.

Look at your map, what’s closer to China than Diablow?


Except, to breach containment you need to go through 3 1/2 feet of reinforced concrete. Nope, not easy in the slightest. The only weapon that could be delivered at long range that’s capable of that is a tactical nuke. And, that’s going to have serious radiological consequences no matter what it hits.


From The Tribune readers forum, posted today under “Jazzman” (Maybe Karen can try to verify and/or clarify these important findings with Dr. Hall):

“In the coming weeks we will find that some respected scientists have significantly differing opinions about the magnitude of earthquakes that Diablo may be subject to.

They believe that several identified faults are linked together and thus do pose a significantly higher magnitude threat than what the PG&E study concluded. PG&E apparently has ignored studies that linke the San Gregorio, San Simeon, and Hosgri faults, which combined add up to a 265 mile fault, capable of much more damage than what PG&E concluded in its report.

PG&E workers, especially, should not take this lightly.

If you want verification on that, talk with Dr. Clarence Hall, former head of the geology department at UCLA, who has extensively studied the geology around Diablo. He will tell you he believes Diablo should have NEVER been built where it is, because of the significant earthquake threat that continues to exist and may, in fact, be growing greater at this very moment.

I make these comments with concern for the safety of the general public AND Diablo employees.

Am I saying the plant should be shut down forever? No. I’m making no conclusion on that. But if the plant is to remain active, I join many others in wanting it to do so ONLY if it is upgraded to standards in line with the latest scientific and technological standards and findings, which, in my opinion and that of others much more expert than I, it currently is NOT.”


The only upgrading that demonic symol of man’s quest to kill himself needs is to convert it to solar. Cover the surrounding hills with photovoltaic, motorized mirrors, panels, windmills, etc. It’s all ready hooked to the grid, has offices, generators,everything. Oh Yeah, an accident HAS to happen first.


The footprint left by a meltdown is much worse than that of solar and it’s much more permanent..

Diablo is only designed to withstand a 7.5 mag. We certainly could have a larger earthquake than that. How do you know that we can’t have a stronger earthquake? I have heard expert after expert in the last few days say that there is no way to know how strong of an earthquake we might have. We do live in a very active earthquake area and they still don’t have the tech. to know how hard we could get hit. The odds are strong though that we will get hit by ‘the big one’.

I believe that you’re wrong about faults not setting off other faults. A strong earthquake hit Tokyo 300 years ago that caused Mt. Fuji to erupt. I will do some research on that if I get few minutes but I believe that you’re wrong. If it can cause a chain reaction with a volcano I’m sure it could do the same with faults.

Calif. did have a small tsunami because of this recent quake in Japan. I have heard PG&E reps say that we can’t have large tsunamis but that makes no sense at all. If we can have a small one caused from thousands of miles away we certainly can have a large one if generated from a closer area.

Later if I have time then I will read up some more on this so I learn more but so far due to issues that have already occurred at Diablo and the expired life of the plant it needs to be shut down. The thing wasn’t built to be used for all of these years and it simply isn’t guaranteed to not have the ability to cause massive damage.


s/meltdown/criticality accident or containment failure/g

A meltdown, in and of itself destroys a reactor and results in massive cleanup bills for the utility company. Bad, but it’s not going to kill anyone. Consider Three Mile Island for example. Not a single radiological death or injury. I’m pretty sure that’s going to be the result at Fukashima.

If you are thinking of Chernobyl, that’s an entirely different accident. The reactor vessel itself exploded, sending heaps of reactor everywhere. Those bits of reactor are far more radioactive than lost coolant or steam. Thus the evacuation of Pripyat and the surrounding area. It’s extremely difficult to make any modern Western reactor do that. Even if you could, you also have to defeat the concrete dome (the “secondary containment” ) that’s made of 3.5′ thick reinforced concrete in order to have a release the most radioactive products of the reactor. The “magnitude 7.5” design specification comes from cooling and pipe fittings primarily. The secondary containment can withstand much more than that.


oh, I really wanted to wait to read some of the responses to this article… and to say I was not disappointed is an understatement! Unfortunately, we can’t harness all the hot air from the cat ladies for peace…. we could light the planet for a week!

San Luis Obispo produces some of the most extraordinary things in our state… but not without its challenges, it has been undergoing a brain-drain for years… the best and the brightest of our youth leave to find their lives and fortunes elsewhere… what remains … is what can remain or wishes foolishly to remain.

Personally, I feel comfortable with Nuclear Power… I’d like one for my home. ;) I know that others would like to go back to grinding their corn on stone or cooking with wood … but those days are more troubling than glorious, especially if you are a bit pudgy. If you have every walked a Civil War Battlefield that is now a forest, you will gently be reminded that the trees were gone from that era because they were fuel!

The world is full of decisions and remaining slaves to foreign oil shouldn’t be one of them… only 20 % of our nation’s power comes from nuclear energy… and that is a shame.



Roger, you need to throw your belief system in reverse. Go for a solo camping trip, start a nice campfire with your degrees, sit back with a doobie, look up at the stars and GET REAL. And I say that with kindness. Jeez. Too few Nukes? Early corn grinders and fire starters were troubled? Nuke weariness is wrong while Japan is evauates? Staying here is foolish?

I’d like to respond but where do I start?


Rogers seems oblivious and/or totally uncaring for the untold thousands, or millions of Japanese who are being irradiated at this very moment. Has the fear of having to grind corn so strong in him that he would perhaps allow millions of people to die or suffer illness simply so he can microwave his burritos?

Personally, if it means saving millions of lives, I would be happy to grind my own corn cook with wood for the rest of my life.

And if Roger wants to go melodramatic and claim he is suffering so harshly as a “slave”, I think he is once again insulting those suffering in Japan who at this moment, as they are being irradiated, might be happy to trade places with him in his “slave” quarters in San Luis Obispo.


Dearest Roger are you crazy, have you been in the intake tunnel? They won’t let you in there!

Why because concrete is not water proof and steel rusts, what used to be 1/1/4 rebar is now everywhere in the tunnels rusted down to a needle in diameter, you know how they check they tap on the walls until it sounds hollow with a hammer, then they, “me” cut into the walls and discover the immense damage rust can cause and Roger rust never sleeps, the place is in shambles, toast, done, spent, kaput, it has band-aids on bullet holes all over the whole plant,

the workers are trained to do one thing but, the money politics there is keep your mouth shut and never shut down productivity as I did once when, the rolling scaffolding bolts inside the induction incline started breaking out of the concrete with three men below it,

(from every movie and cartoon) when one strand of a rope breaks the others are to break soon after, so we have one cable blown out and these guys want to finish the job, I blew the whistle and shut it down until the cable was re-attached, saved the plant but it was not a good career move, also the respirator test to chip and cut concrete, fifty concrete masons took the mandatory test to get the high tech respirator, three men out of fifty passed, I WAS ONE OF THEM THE OTHERS HAD TO GRIND AND CUT, with a K-mart special or a paper mask, I asked why even when I knew why, the material on the test was not reviewed by the brilliant instructor, result, I after saving the scafolding from crashing down on top of the intake turbine and saving millions of dollars in fixxing it, not to mention my life and all the others in there was NOT RECOMMENDED FOR REHIRE BY PG&E EVEN THOUGH I NEVER WORKED FOR THEM

In closing for doing what they told me to do in all the pre-work classes I was black balled by PG&E officials, the higher ups, when my union tried to send me back out there access was denied. Somebody get the experts from another country in those tunnels it’s the only way you will get an unbiased opinion.

In closing this was 98 imagine what 14 more years of rust can do! Band-aids, splints, japan’s plant was safer than Diablo, and I agree totally with this,”Rogers seems oblivious and/or totally uncaring for the untold thousands, or millions of Japanese who are being irradiated at this very moment.” Wake up Roger and smell the death around us.


Interesting and scary post Chese. Did they hurt your career or were you able to move on? Did you blow the whisle on them?


I moved on and no I didn’t know who to blow the whistle to back then, I moved on until 09.

The place is really a wreak and nobody can say it isn’t, just look at a car left out in the rain for fifty years in Los Osos, multiply that by ten and you have the effects of saltwater on steel, sorry for my dim and scary outlook but remember I was looking out from the inside!


Mr. Freeberg, you might get your wish.

The little town of Galena, Alaska is so isolated that it is inaccessible by road. It’s 675 residents get their heat and motor fuel delivered by air and riverboat. All electricity is generated on site from these fuels.

Thankfully, Toshiba has developed a new type of reactor that’s based on molten salt. It will be the first civilian reactor in Alaska. It’s promoted as a “nuclear battery”. A sealed unit that produces hot steam to drive an external turbine for 20 years before refueling. It’s molten salt design should prevent “loss of cooling accidents” (like Three Mile Island or Fukushima I). The reactors aren’t quite small enough to fit in your back yard, but they are pretty close. Remember, this is intended to power a village of 675 people. That’s about half the size of Poly Canyon Village on the Cal Poly Campus.


It’s obvious we’ve got a bunch of DiaBLOW workers stuffing the ballot box here, it must be re-fueling time. What, you like paying high utility bills and living dangerously? Gimme a break.


Close Diablo now, Its a disaster waiting to happen.

Can you imagine the Coastline north and south of Avila being closed and uninhabitable FOREVER?

Seems like a no brainer to close Diablo. The only people that are gung ho for it are people that are making alot of money from this plant being here. Id rather see a WalMart sitting on the shoreline where Diablo is.

Diablo needs to go.


No not a wall mart, a planetarium, well two of them, and the buildings can be converted into low rent housing for the people displaced by the economy, or we just sit and wait for Alkeda to crash another Pan Am 740 into it. 100 years from now, (if we are still here) humans will look at these plants like doctors look at medical treatment of people in the 1400s.


I agree, when Diablo’s current license expires, let it die. Being that close to 2 faults is bad news.

Then go about 50 miles north of San Simeon, where there are no faults, and build about 2 more plants. Then, go to Vandenberg AFB and build 2 more there.

The construction and tech jobs associated with building and running 4 more nuke plants would bring our area back to full employment and prosperity. Not to mention, think about how many all-electric commuter cars could be powered daily by 4 nuke plants. We could probably remove every single gas powered commuter vehicle from the greater Los Angeles area.

Let me see….nuke plants here providing high paying jobs…..or……$105/barrel oil money being sent overseas to terror sponsoring countries….which side of that fence do you sit on?


There’s much more to this then just jobs. We don’t have the technology to make them safe, safety trumps $$$. We aren’t ready to do this. This isn’t like anything else, this is something that can really get out of control. Look at Chernobyl. All of these years later and it’s still inhabitable, there is still extremely high levels of radiation. Yes the safety procedures were bad and the place was built bad but it doesn’t make any difference. It only takes one man made mistake or earthquake to destroy not just a country but perhaps other countries, thousands of miles. Northern Japan might also be off limits for the next 25,000 years. This plant in Japan hasn’t even had a full melt down and yet radiation has been detected here on the central coast, not enough to hurt us but what if it does melt down?

What happens with the spent fuel, where does it go? What if Diablo closes or by some stretch PG&E goes under, what are they going to do with the spent fuel?


Gimme a break. There are nearly 500 reactors worldwide and there have now been 5 get out of control in 60 years. 1% in 60 years? Show me another industry with those kind of numbers. 3 Mile Island and these 3 are, or going to be, contained. That leave Chernobyl as the only one going off the reservation and that was due to the Russians trying to run a terrible design.

Spent fuel: I agree with Typoqueen (twice now, we are on a roll!), spent fuel must be addressed. I am in full favor of building a reprocessing plant in Nevada by that storage facility that they built. Rather than storing all that spent fuel, let’s reprocess it to the point that its volume is significantly reduced and its radioactivity is greatly reduced. Only then should it be stored away underground.

Don’t wimp out on this issue people. If the French can do it, so can we.


When I was for nuke energy I also was disappointed that we didn’t recycle the spent fuel. But now I realize that it doesn’t matter, we just don’t have the tech for this type of power. I’ve always been on the fence back and forth but now my feet are firmly planted against it.

500 reactors worldwide isn’t really that many to have the problems that we’ve had. It only takes 1 mistake to cause catastrophic destruction that we can’t control. I hate coal but I’d feel safer using that than nukes at this point,,,not that I like coal.

“Contained”,,, they are already finding radiation in the water in Tokyo and in their food and this could very easily get worse. Although it was very small and not enough (supposedly) to hurt us, the radiation plum has come all this way to be detected here. What if it had been (and still could be) more? This accident is too much, this is a signal that we aren’t ready, we have over stepped what we are capable of understanding. Humans make mistakes, they’ve had some stupid mistakes at Diablo that could have caused a catastrophic disaster. We can’t handle this energy. This isn’t like a cave-in at a coal mine or solar panels blocking some kangaroo rats sun, or birds flying into windmills. This damage that can and as effected thousands and thousands of people and the damage is permanent. 1 mistake is too much.


So, you are saying that Americans “can’t” while the French can?

Sorry, I don’t buy it. This is the United States of American. We can do anything we put our minds to doing. The reactors that have had problems started with poor designs and then were poorly run.

How much radioactive Iodine was found in Japanese water pre-disaster? Remember, we did drop 2 atomic weapons on them, so I would expect to find radioactivity in that country for the next 1,000 years or so.

Personally, I don’t mind having Diablo in my backyard. I also wouldn’t mind drilling platforms off the coast. What I do mind is sending my energy dollars overseas to entities who are determined to kill each and every one of us. Which has killed more people worldwide since 1970, nuclear power plants or terrorism?


The radio activity in Japan will be there for the next 25,000 years not 1,000 years. I never said that French can and we can’t. I really don’t have a say, if I did I would say NO ONE can use nuke energy. It’s equivelent to a 5 year old doing brain surgery, they just don’t have the know-how or skills to perform such a thing. We don’t have a control over nukes. We can’t clean it up, we can’t contain it. We are in over our head.


You are so correct, we are not ready for this, I look around at these giant American cars still with only one person power tripping away in them, pedal to the metal, we are children that have children that will all die from exposure to radiation.

One accident could and probably will destroy our planet with no where else to go, when the skin slides down your face and falls at your feet, then some of you will think hey what about Hydroelectric power, one wave, or the tide coming in and out of Morro bay every 6 hours, gee we might of been able to get by with, wind water and solar power, wake up Americans and go visit the disaster in Japan, then tell me how safe NUKEs are.


Look at the bright side, at least the dude that ran Oceano poop plant isn’t in charge..we’d all be hairless and glowing in the dark by now.


What’s nuclear power’s defense at this point? Let’s see, going down the check of things to do in case of a meltdown………ah, here it is,” Throw buckets of water on it.” See? High tech will save us every time. Close that mistake of the century NOW!!


Sorry I have to post this I am rolling on the ground holding my stomach because of the split points on this post, ” Throw buckets of water on it.” feels good to laugh, and even up the points 17-17 now. Just me is on the same plane as well just me?


Close it now, it’s time is up.