The headline is a hat tip to The Daily Bayonet, who we miss, still in hiatus. Excerpts from the Los Angeles Times:
June 19, 2012, 12:33 a.m.
Faulty computer modeling caused the equipment problems that are expected to keep the San Onofre nuclear plant dark through the summer, federal regulators said Monday.
Officials from the U.S. Nuclear Regulatory Commission gave their first public account of the initial findings of their investigation into the plant’s problems at a meeting in San Juan Capistrano.
What they did not give was any indication of how long the plant is likely to remain out of service, saying there are still questions plant operator Southern California Edison needs to answer and more inspections the NRC must do.
…
NRC officials said it appears that simulations by Mitsubishi underpredicted the velocity of steam and water flowing among the tubes by a factor of three or four. The high rate of flow caused the tubes to vibrate and knock against each other, leading to the wear.
It was not clear why the computer modeling was so far off. Mitsubishi had no representatives at the meeting and could not be immediately reached for comment. Collins, however, said that ultimate responsibility lies with Edison.
Full story here
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If a linear system like steam in pipes can’t be properly modeled, it makes you wonder how well the chaotic non-linear system of global climate does in computer models like GISS Model E.
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Bernd Felsche says:
June 20, 2012 at 8:37 am
I find the “acceptance” that tubes normally wear by rubbing against support structures to be quite disturbing. Can’t engineer the things so that that cannot happen? Seriously?
Any tube capable of vibrating at all should be attached to a support using an isolation mount, and if the tube is vibrating so much that it *does* wear thin is an indication that a pump is seriously out-of-balance.
Bottom line — more people than the modelers eff’ed this one up. Badly.
Why all the trust in computer models? I call it the “Star Trek” effect.
We can model many things quite well. Engineering models work well because of the centuries worth of base knowledge that goes into the field and because the models are constantly improved by real-world feedback.
Two-phase flow is tricky. The basic problem, however, is that some engineers and scientists put far too much faith in mathematical models. It is, as the French might say, a déformation professionnelle.
The very models of all those modern major-generals.
D.J. Hawkins: “I’d rather use my trusty Pickett N4-T”
PICKET? Only pinko industrial engineers used Pickets. Real engineers used Dietzgen Microglides, with rosewood base and teflon grooves!
Ah, for the days of the religious wars over slide rules! 🙂
How good do you think those models are for projecting climate effects for the end of the century? By the way the Met Office abandoned long range seasonal forecasts for the public because the ‘weather’ model was complete and utter crap. So there. 😉
It’s not the first time Mitsubishi equipment caused big problems for Americans.
Kasuha says:
June 20, 2012 at 8:18 am
That’s some pretty faulty logic used in the conclusion.
Models used for weather forecasts are quite reliable a few days in advance even though they are pretty useless for simulating steam flows.
REPLY: With weather models, the designers get feed back in a few days that helps them make the model better. With climate models, you have to wait 50-100 years, so its modeling without immediate feedback for improvement. Bedsides, global scale is far more complex with orders of magnitude more surface area and variables than synoptic scale modeling. Climate modeling is mostly an open ended shot in the dark on a large scale with no immediate feedback to test it.- Anthony
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Another thing to consider is that the “input” is only days away. A front moving east from Illinios will soon impact Ohio. Before there were such things as computer models there was a growing understanding of weather patterns thanks, in large part to the invention of the telegraph, telephone and radio. Real time data could be collected about where the front had been, where it was now and then relayed to where it was expected to go next. As more data was collected and technology advanced (radar, satelites) improving the quality and reliablity of the data, more accurate forecast could be made as these things made better hypothesis possible. Calculators replaced sliderules. Computers replaced calculators. Models replaced spreadsheets. But all of the theories and models could be shown to be good or bad very quickly, as Anthony pointed out. “Tweaks” could be made and tested.
Climate model “forecast”? The “real time data of where the ‘front’ has been” is based on broken hockey sticks in the models used by the CAGW crowd. The “long range forecast” that were made by those such as Hansen? They’re already wrong in just the short term.
Yet the CAGW crowd and the UN still are trying to spoil our picnic.
“It was not clear why the computer modeling was so far off”
Ummm, it’s called GIGO!
Re Andrew Russell says:
June 20, 2012 at 12:20 pm
D.J. Hawkins: “I’d rather use my trusty Pickett N4-T”
Pickett N4-ES (eyesaver yellow) is better for those of us with fading eyesight. Wood is better on the fingers when it is cold and damp, but wood swells and sticks in the rain. For field work, a 6-inch Pickett N200-ES is great.
Seriously, I just received a “Dear Customer” letter from Southern California Edison warning us to be prepared for power outages this summer, thanks to the situation with their steam generators:
http://www.sce.com/info/poweroutages/rotatingoutages/outagemaps/default.htm
polistra says: —- It’s not the first time Mitsubishi equipment caused big problems for Americans.
JK——————And they got nuked for it!
Thanks
JK
Well, some days a “sanity check” look at the data utput is needed. Hard to do in a complex system.
The example that pops into my conscious mind at this instant is Morton Thiokol’s stress analysis of the shuttle booster rockets was backward, as could have been discovered if anyone had envisioned a ballon with rubber bands around it.
According to World Nuclear News
“22 February 2011
Southern California Edison (SCE) announced that the reconnection to the grid of unit 3 of the San Onofre Nuclear Generating Station (SONGS) “signals the safe, successful completion of a massive ten-year construction project – replacing the plant’s largest components, its steam generators.” The company decided to replace the steam generators of the 1070 MWe unit 2 and 1100 MWe unit 3 pressurised (sic) water reactors at the SONGS plant after a cost-benefit study showed that the modernization would save customers some $1 billion during the plant’s current licence (sic) period, which runs until 2022. The steam generators of unit 2 were replaced in 2009. “
“15 March 2012
A small number of steam generator tubes have failed pressure tests at unit 3 of Southern California Edison’s San Onofre Nuclear Generating Station (SONGS) in California as the company investigates the cause of a leak in the recently installed components.”
Reference:
http://www.world-nuclear-news.org/results.aspx?sparam=San%20onofre
Tube wear after a year of operation? What an engineering disaster! If a design model failure caused the design flaw, there was a way too great a dependence on the computer models. Didn’t the head of the design department check to see that the steam generator design “looked right.” If it was the first of its kind, some testing of mock-ups should have been done. This was more than a failure of a model, it was a failure of good engineering practice.
Its ok, they probably had a team of system engineers working on it. I’m sure the documentation was beautiful 😀
How far must one have fallen, when one turns to children to spread their propaganda.
It defies reason.
u.k.(us) says:
June 20, 2012 at 6:03 pm
“How far must one have fallen, when one turns to children to spread their propaganda.
It defies reason.”
SOP in every major religion.
Steam and water in pipes is FAR from linear.
The reliability of weather models even a day out is pretty poor.
3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679 8214808651328230664709384460955058223172535940812848111745028410270193852110555964462294895493038196
4428810975665933446128475648233786783165271201909145648566923460348610454326648213393607260249141273
724587006606315588174881520920962829254091715364367892590360011330530548820466521384146951941511609
is that Humble Pi
[Moderator’s Note: I was going to snip this for being off-topic, I really was, but then I thought, “I’ve never seen pi calculated to so many digits…. but rather than being humble, it sure looks pretty ostentatious from where I’m sitting…. -REP]
As a fully fledged member of “Concerned Scientists”, shouldn’t Kenji weigh in on this? He could maybe wear a sandwich sign.
@Galane
“Feynman innocently questioned a NASA manager about the o-ring temperature issue. As the manager insisted that the o-rings would function properly even in extreme cold, Feynman took an o-ring sample he had obtained out of a cup of ice water in front of him. He then took the clamp off the o-ring which was being used to squish it flat. The o-ring remained flat, proving that in fact, resilliancy was lost with a temperature drop.”
http://creepyoldguys.wordpress.com/2007/10/02/feynman-solves-challenger-mystery/
u.k.(us) says:
June 20, 2012 at 6:03 pm
How far must one have fallen, when one turns to children to spread their propaganda.
Betcha nobody’s told her the sun’s just a big, self-sustaining, nuclear fireball, either.
Contrast the steam generator replacement at San Onofre with the history of replacements world wide. There have been a very large number of replacement projects implemented successfully, giving new life to aging nuclear plants and allowing them to extend their operating lives from 40 to 60 years. And, now, we have efforts beginning to extend from 60 to 80 years.
Looking back on 40 years of operating with problematic steam generators, before the highly successful replacements most plants have undergone, there are many options that have been implemented over the years that may be appropriate for SONGS. These have included such things as anti-vibration bar installation, plugging smaller radius bend tubes, in situ tube repair, etc., etc.
I suspect this issue will end with implementation of coping strategies similar to those implemented for aging steam generators in the late 80’s and 90’s in parallel with development of new replacement steam generators funded at MHI’s expense, at least partially, if not fully.
Oh, the ironing! ha ha classic!!
“Foul unbeliever!! Feel, thou miscreant, the sting of my K&E Log Log Duplex Decitrig (Pats. Pend.)!!!” :-))