Comment by keithflower | Hacker News Reader

Comment by keithflower | Hacker News Reader

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Wow, NASA-think redux!

I really don't think you want to use Three-Mile Island as some sort of exemplar of safe technology:

The lessons of Three Mile Island have been, for the most part, forgotten. The nuclear industry changed and improved somewhat, but the deep understanding of what went wrong was lost on the public in general and the real lessons that we could have learned as a society were, too. The financial mess we are experiencing right now isn’t all that different from Three Mile Island. If we’d taken better to heart the true lessons of TMI we might not be in our present jam.

Looking back at the accident with the benefit of knowing what it took to clean it up and what the workers found when they were finally able to send robots inside the containment, the TMI accident was very bad indeed. There were pressure spikes during the accident that would have cracked an average containment vessel, releasing radioactive gases into the atmosphere. Fortunately the Unit 2 containment wasn’t average. TMI-2 was built on the final approach path to Harrisburg International Airport, a former U.S. Air Force base, and was therefore beefed-up specifically to withstand the impact of a B-52 hitting the structure at 200 knots. A normal containment would have been breached.

TMI wasn’t caused by a computer failure but the accident was made vastly worse by an error of computer design. Specifically, TMI-2 had a terrible user interface.

What happened at Unit 2 was a little more complex. A cascading series of events caused the computer to notice SEVEN HUNDRED things wrong in the first few minutes of the accident. The ONE audible alarm started ringing and stayed ringing continuously until someone turned it off as useless. The ONE visual alarm was activated and blinked for days, indicating nothing useful at all. The line printer queue quickly contained 700 error reports followed by several thousand error report updates and corrections. The printer queue was almost instantly hours behind, so the operators knew they had a problem (700 problems actually, though they couldn’t know that) but had no idea what the problem was.

So they guessed.

Not good.

http://www.cringely.com/2009/03/31/three-mile-island-memorie...

I don't think you understood my point at all. I'm not saying that any nuclear incident is minor, or that there will never be one again.

A Chernobyl-style incident will never happen with a LWR reactor. That much is known, and the experts - nuclear engineers - are unanimous on this point. Feynman's point was, "when judging risk, ask the engineers that actually design and build the technology, not the management." The article I linked to (http://users.owt.com/smsrpm/Chernobyl/RBMKvsLWR.html) was written by nuclear engineers (who were students at the time, but have been in their field for many years now). The article you linked to was written by ... a journalist that writes about the computer industry? Now I'm left with the idea that you have missed Feynman's point.

Chernobyl won't, but Fukushima may. You also have the key weaknesses associated with waste containment.

I think we're unfortunate that nuclear power was built out in the 60s/70s. I'm sure we could build safer facilities today.

You're right. I don't think I understand your point because I don't think you know what your point is.

Are you trying to advance the theory that management had no hand in the terrible decision-making around TMI, including the numerous shortcuts that Cringely noted (nb: you are hardly using an engineering approach when you resort to ad hominem criticism of Cringely as a "journalist" without responding to any of the legitimate problems he noted). Or are you trying to advance the theory that no engineering mistakes were made at TMI?

And are you trying to advance the theory here that somehow, magically, management will not continue to make NASA-like management mistakes in current and future nuclear facilities?

Because if so, that's precisely Feynman's point, which you seem to be ignoring.

And c'mon, you're merely moving goal-posts around when you focus on the severity of Chernobyl vs TMI. That isn't speaking at all to how technology was misused in both instances by people making exactly the kinds of errors Feynman emphasizes.

> A Chernobyl-style incident will never happen with a LWR reactor [emphasis added]. That much is known, and the experts - nuclear engineers - are unanimous on this point [emphasis added].

Really? Never? Unanimous? That sounds like a really interesting engineering judgment. Could you kindly link to the unanimous consensus statement from nuclear engineers that support that strong but odd statement?

Because that sounds an awful lot like NASA management who claimed that the chances of loss of a space shuttle were so remote as to be negligible.

And your statement is even more curious when we read review papers like the one[1] from nuclear engineer Bah Sehgal[2] of the National Academy of Engineering, who concludes:

"The presently-installed LWR plants in Western countries have been addressing their safety performance from the day they were installed and operating...Clearly, not all the severe accident issues have been resolved for the presently-installed plants [emphasis added].

"The presently-installed LWR plants made improvements in components, systems, operator training, man-machine interface, safety culture, etc., thereby significantly reducing the probability of a severe accident occurring. They also instituted severe accident management backfits, systems and procedures, which are providing assurance of the elimination of an uncontrolled and large release of radioactivity even in case a severe accident occurs. Still, the presently-installed plants can not provide assurance of coolability of a melt pool/debris bed, which could be formed during a bounding severe accident. In that situation, the LWR owner can not assure the public that the accident has been terminated and that there is no further danger of the release of radioactivity. [emphasis added]"

Sorry. It is you with your pronouncements of never who is absolutely not getting Feynman's point whatsoever. In particular, he decried management and others with their own wishful pronouncements of never, which stood in stark contrast with the concerns of engineers who were well aware that there were quantifiable and real risks associated with their technology.

[1] http://www.kns.org/jknsfile/v38/JK0380697.pdf

[2] https://www.nae.edu/69277.aspx

dmfdmf wrote the following right here on hn five years ago. I'm reposting for the benefit of those that won't click on his comment:

"As a former design engineer in the nuclear business I have to make the following comments;

1) The lessons of TMI are far from forgotten. TMI is one of the most studied accidents and the lessons learned are incorporated throughout engineering and technical training.

2) Anyone who claims TMI was worse than Chernobyl is an idiot. One of the major lessons learned from TMI was that the design basis and safety strategies of western reactors work. This despite the serious operator training and control room design flaws that were exposed by the accident.

3) Anyone who mentions Chernobyl and TMI in the same breath does not know what they are talking about. A few facts about Chernobyl; these RMBK reactors were originally designed to generate plutonium for bombs and then scaled up for electric power generation which created all sorts of operational problems. When I was an undergrad my nuke prof said the design was inherently unstable and an accident was inevitable. The western countries had tried for years to get them to shut them down. On the night of the accident the engineers disabled 4 or 5 safety systems in order to run a turbine spin down test. This test was ordered by Moscow and the previous lead engineer was fired for not completing it prior to the last planned shutdown.

4) TMI experienced a partial core melt. I read an engineering report after the accident that it was technically and economically feasible to fix the damaged reactor. The PR nightmare this would create dictated that it would not be fixed. Chernobyl's core was blown sky high by a steam explosion and fuel rods littered the plant site, thus killing the responding firemen with lethal doses of radiation. There is no dispute regarding which core had more damage.

5) The claim that the containment would have cracked due to "pressure spikes" except that TMI was specially reinforced to protect against aircraft impact is engineering nonsense. First, these are different design requirements and operate on different physical principles. Second, if the accident exposed such a serious deficiency in the design of "normal" containment buildings it would have resulted in the shutdown or at least a reduced operating power at all other plants of similar design. No such regulatory action ever occurred.

6) While it is scary to write about "releasing radioactive gases into the atmosphere" the reality is that such releases are pretty harmless. These gases are typically biologically and physically inert and quickly dissipate in the wind to harmless background radiation levels. One of the major lessons learned from TMI was that the more dangerous biologically active materials like radioactive iodine or potassium do not escape and tend to stick to other material even in a core melt. That is if you have a containment building, unlike Chernobyl.

7) It is insulting to say that the operators did not know what was going on with the reactor "so they guessed" as if they started pushing buttons and pulling levers willy-nilly. The operators knew that the information they were receiving was not complete or wrong. The biggest problem was that their training was flawed and incorporated an assumption that was incorrect -- thus leading them to take actions that made the situation worse.

About the only thing that I agree with Cringely on is that we should be building nuclear reactors now."

I reckon your kind, single posting to HN from a "design engineer in the nuclear business"... who thinks the events leading to a partial nuclear meltdown at a LWR like TMI reflect a kind of engineering triumph and the kind of statistical confidence (that Feynman calls out) that would lead engineers to conclude that LWRs could never suffer a nuclear meltdown....instead of the requested posting of a link to a consensus statement about the impossibility of a major nuclear reactor accident by all nuclear engineers....is better than nothing.

Just kidding with you some. But I think we're done here. Have a nice day.

You lost all credibility by citing Cringely.

Here is my rebuttal to the oft repeated lie that the operators were just guessing or acting irrationally. https://news.ycombinator.com/item?id=993984

Here is my HN rebuttal nearly 5 years ago the last time I saw someone post a link to Cringley's non-sense. https://news.ycombinator.com/item?id=541550

Uh, why exactly are you arguing ad hominem about "Cringely" rather than about what "Cringely" (and most everyone else) concluded about TMI?

So Cringely points out widely acknowledged problems at TMI, including human factors and operators acting "inappropriately.

I'm also not sure why you're fixated on "the operators", but Cringely's observations there are not in dispute:

http://en.wikipedia.org/wiki/Three_Mile_Island_accident#Huma... http://en.wikipedia.org/wiki/Three_Mile_Island_accident#Inve... http://en.wikipedia.org/wiki/Three_Mile_Island:_A_Nuclear_Cr...

You and the parent for some reason also want to vehemently argue a really strange, irrelevant point, that Chernobyl was worse than TMI. Is that in dispute?

So what? The Apollo I fire was not as bad as the Space Shuttle disasters. Your point is....what?

Apollo I, Challenger, Columbia, Chernobyl, and TMI came about in large measure precisely as a result of the kind of silliness that Feynman decries, and that you and the parent for some reason don't want to address.

I don't think you really know what ad hominem means.

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