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Grex > Agora41 > #159: Two words you don't want to see used together: "nuclear" and "surprise" | |
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gull
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response 25 of 66:
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May 8 19:37 UTC 2002 |
Operator error can be encouraged by a poor design. I saw a good
example recently, in the form of an NTSB report. A pilot, attempting
to land a sailplane, overshot the end of the runway. The particular
aircraft he was flying has both flaps and spoilers. Both are
controlled by identical handles mounted a few inches apart. The pilot
noted that during the landing attempt, he deployed full spoilers; but
during the accident investigation the spoiler handle was found in the
closed position, and the flap handle in the fully extended position.
Should he have noticed that the airplane wasn't slowing down like it
would with the spoilers fully out? Sure. Training could have fixed
that problem. But if the two handles were different shapes it sure
would have helped.
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jp2
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response 26 of 66:
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May 8 19:51 UTC 2002 |
This response has been erased.
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slynne
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response 27 of 66:
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May 8 20:04 UTC 2002 |
Anyhow, everything I have seen shows that the operators turned off the
emergency cooling system because they had trouble understanding the
readings on some of the displays. Sure, this was an operator error. But
then the bad design really kicked in.
In a PBS special, Jim Higgons of the Nuclear Regulatory Commission was
quoted as saying: "There was such an avalanche of alarms that the
operators couldn't really address any of those on a real time basis.
They were just catching up and trying to -- trying to prioritize and
handle the most important ones and do what they could." It sounds like
he is describing a bad design to me.
In the same special Bob Long (supervising engineer) said, "There was so
much data being dumped to the computer and the process was so slow in
getting it analyzed and printed out, that when they'd go to look for
data from their computer print-out, it wasn't there until an hour-and-a-
half later. " Another description of the incident that describes bad
design.
A very quick search on google shows over 42,000 sites with information
on this. Obviously I got the above quotes from my quick search. I dont
have time to read all of those but every one that I did read says that
the incident started with a mechanical error which the workers didnt
fully understand because they had trouble reading displays (were those
displays poorly designed?). The workers then made a mistake by turning
off the cooling system. Then, they didnt realize what they had done
because the control room was too chaotic mostly because of bad design.
At any rate, my point is that it is normal for humans to make errors.
It should be expected.
re#26 I think the rare thing is the admission. *snort*
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senna
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response 28 of 66:
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May 9 03:53 UTC 2002 |
A couple meaningless notes on gull's points, not because they're relevant (my
suggestion isn't exactly unfeasible, but it's decades {centuries?} from being
a potential reality) but because I just can: Few launch vehicles explode in
midflight, preferring the launchpad as the incinerant location. Also, this
"suggestion" wouldn't be used until space was used for a lot more than just
the occasional exploration mission--travel would be a lot more commonplace,
at least for commercial purposes. Besides, we're talking about a REALLY BIG
vehicle here, given: 1. the mass of the waste it would have to carry to make
an impact on the waste problem, and 2. the mass of the vehicle required to
spring this waste from Earth orbit and on a path toward Sol.
Space is my default suggestion for everything, but now that I think about it
it's probably more likely that we'd establish nuclear power sources in space
and find a way to transmit the power to earth than lifting waste skyward.
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mdw
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response 29 of 66:
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May 9 06:46 UTC 2002 |
Um, it's not that uncommon for rockets to explode in midflight. Very
often, it's a deliberate choice, to explode a rocket that has had a
guidance failure but is still under limited ground control. It also
happens accidently, as the challenger accident. The launch pad is
certainly the place where there is the most opportunity, but it's by no
means the only possibility, either in theory or in practice. In any
event, unless nuclear waste can be packaged in such a fashion as to
safely survive a rocket disaster, I don't think we've got any business
using this method. There are almost certainly far cheaper methods to
more safely dispose of nuclear waste.
Rane offers automobiles as an example of the "failure" of design
engineering. In fact, automobiles are a good example of the success:
automobiles today are probably about twice as safe as automobiles made
in the 40's. Seat belts, crumple resistance, visibility,
instrumentation, tires, road design, etc., have all improved quite a bit
since then, and the results are clearly visible in accident statistics
then and now. Automobiles also offer one other sobering lesson: we
still have accidents today despite improved design. What is an
acceptable accident risk level for nuclear power plant engineering?
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mary
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response 30 of 66:
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May 9 14:01 UTC 2002 |
It's been a while since I read _The Warning_ but my impression afterward
was that the most terrifying part wasn't the mechanical failures or the
technician errors but that those in charge told the public it was safe and
under control when they *still didn't know* what the problem was.
Good read, by the way.
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slynne
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response 31 of 66:
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May 9 17:06 UTC 2002 |
re#30 That is a pretty scary thing.
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keesan
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response 32 of 66:
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May 11 12:46 UTC 2002 |
Rane states 40,000 people a year are killed by cars. The figure is much too
low and includes only Americans, if that. Cars are even more unsafe in most
of the world.
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rcurl
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response 33 of 66:
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May 11 16:52 UTC 2002 |
I meant only in the USA. The (preliminary) number for 2000 is 41,804.
I'd say by off-the-cuff guess was close enough.
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keesan
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response 34 of 66:
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May 11 16:59 UTC 2002 |
When I looked it up the number had stayed roughly constant for several years,
after going down slightly at one point, possibly because of better safety
measures. It was 47,000 or more. This despite more cars per year going more
miles, but possibly less people per car. Anyone know how many people are
killed by cars per year, not just American people? How many injured?
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russ
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response 35 of 66:
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May 28 01:39 UTC 2002 |
Re #1: Depends on the leak. The corrosion was found in the cap for
the *REACTOR PRESSURE VESSEL*, IIRC. If that blew out there wouldn't
be much left to hold coolant. OTOH, if it failed with a small crack
it wouldn't be that big a deal just to SCRAM the reactor and keep
pumping water into it until it cooled off.
The "most catastrophic" failure scenario used to be the "guillotine
break", where one of the coolant lines is sheared off right at the
pressure vessel. A hole in the pressure vessel itself would be
comparable.
Now that this problem has been found, I am making a prediction: there
will be regular inspections of reactor pressure vessels with ultrasound
and/or eddy currents to detect thinning of the metal, and no such
corrosion problem will ever get to the severity of this one and there
will never be a serious accident due to such corrosion.
Re #8: Design of the controls and control room has to go through the
Nuclear Regulatory Commission. Ironically, fixing the human-factors
errors is a violation of government regulations, because it alters
the licensed configuration of the controls! How's that for idiocy?
Re #10, #11: Yeah, "we" haven't... but they have. The French have
solved the problem of waste disposal. So have the Canadians. The
problem in the USA is political, not technical, and it is a problem
created by the left wing. So, get rid of the left wing and we'll be
mature enough (by definition). ;-)
Re #14: Dumb idea. Even aside from launch failures, it takes much
more energy (and much better navigation) to send a payload into the
Sun than it does to send it out of the Solar system. Makes a good
thought-free sound bite notion, though...
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bdh3
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response 36 of 66:
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May 28 07:11 UTC 2002 |
As I recall the incident cited in #0 where boric acid had eaten
completely through a 6-inch steel top the only thing between a
containment breach and the boric acid was a thin stainless steel
membrane that was never intended to but some how stood up under the
stress.
Again, I think safe nuclear power is not economical enough to
exist in the private sector.
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gull
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response 37 of 66:
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May 28 15:00 UTC 2002 |
Re #35: The French "solve" the problem by reprocessing fuel. That still
creates a certain amount of waste, though, and it's more corrosive, more
concentrated, and more highly radioactive than what you started with.
The reprocessing itself also carries some risks, as the Japanese have
demonstrated.
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rcurl
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response 38 of 66:
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May 28 19:02 UTC 2002 |
That containment breach would have started with a small leak that would
have grown in size. There has been no suggestion that it could have
led to a catastrophic failure.
But it is certainly true that nuclear power is non-economic to be fully
in the private sector. Both fuel processing and waste disposal are nearly
entirely government subsidized. Does anyone know what the REAL cost
of electricity from nuclear reactors, including everything? (The difference
betweeen that and for fossil-fuel powered generation is what we pay for
not producing greenhouse gases, although lots are produced by the
processing done in the nuclear industry, such as mining, fuel processing,
etc).
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gull
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response 39 of 66:
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May 28 19:46 UTC 2002 |
Don't forget the insurance provided by the government. I'm sure there are
lots of other industries that would *love* to have their liability insurance
paid for by U.S. taxpayers.
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russ
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response 40 of 66:
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May 29 04:07 UTC 2002 |
Re #37: Reprocessing doesn't increase the total amount of radioactives.
What it *does* do is segregate them by chemical properties. This is
exactly what you'd want to do to make certain that they are isolated
properly! You wouldn't want to use processes like Solvex or Purex
(which use organic solvents which are then contaminated themselves),
but molten-salt bath electrolytic refining apparently creates a stable
product.
If you recycle the uranium and plutonium portions of the spent fuel,
you can destroy a large fraction of each on the next pass through the
reactor. This decreases the total amount of radioactives produced,
and radically reduces the half-life.
(What is nuclear power except a system for rapidly and controllably
extracting the energy from natural radioactive materials, anyway?)
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i
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response 41 of 66:
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Jun 3 02:12 UTC 2002 |
(So fusion generally doesn't qualify as "nuclear power", eh?)
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rcurl
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response 42 of 66:
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Jun 3 05:15 UTC 2002 |
The only fusion being considered right now involve deuterium or tritium,
which are naturally radioactive. So, by this sneaky twist of sense,
fusion counts as "nuclear power" under #40.
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i
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response 43 of 66:
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Jun 3 10:51 UTC 2002 |
Deuterium being naturally radioactive seems to be newer news than my
old CRC. Do you have a half-life & decay mode that i could pencil in?
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rcurl
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response 44 of 66:
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Jun 3 15:14 UTC 2002 |
You are correct that deuterium itself is stable, but only the D + T
fusion reaction is being considered now, and *that* involves the
radioactive tritium. Hence, fusion involves radioactivity. I said
this was only in a "sneaky twist of sense".
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russ
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response 45 of 66:
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Jun 4 04:02 UTC 2002 |
Re #41: When fusion produces power, I'll have to refine the definition. ;-)
Some reactions, like p + B-11 -> 3 He4 produce no neutrons (and thus,
in theory at least, no radioactives). However, we're a long way from
being able to produce power from such reactions.
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orinoco
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response 46 of 66:
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Jun 4 07:34 UTC 2002 |
(I thought you needed extra neutrons to get a chain reaction going.)
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russ
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response 47 of 66:
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Jun 5 03:58 UTC 2002 |
Re #46: That's only true for fission reactions. Fusion or fusion-fission
reactions are propagated by heat, not unlike chemical reactions.
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rcurl
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response 48 of 66:
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Jun 5 05:36 UTC 2002 |
And pressure...
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bdh3
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response 49 of 66:
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Jun 5 08:14 UTC 2002 |
pressure is heat which is the fundamental understanding that most
folk missed years ago (fortunatley otherwise we might all be
typing with umlaughts).
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