| |
GM7HUD > ENERGY 27.05.05 23:24l 71 Lines 3539 Bytes #999 (0) @ WW
BID : 702419GM7HUD
Read: GUEST OE7FMI
Subj: Re: Hydrogen, ZL4AJS.
Path: DB0FHN<DB0FOR<DB0SIF<DB0EA<DB0RES<ON0AR<GB7ESX
Sent: 050527/2050z 36995@GB7ESX.#31.GBR.EU $:702419GM7HUD [Witham, Esx]NNA V3.1
PA7KK wrote:-
> Hello Andrew.
>
>>> If it can be done, then some fool will one day do it. (GM7HUD)
>
>>But it CAN'T be done. Computers controlling the reactors won't allow it,
>>and safety devices will cut in before anything can happen. Unless he is
>>a real fool and defeats the safety devices, well then he is a terrorist
>>and a criminal and probably won't be allowed near the plant!
>
>
> I hope everything will work 100%, always, and at every reactor
> everywhere. But things not always go the way you want it.
> Sometimes a l l safety devices refuse to work about which afterwards
> thick reports are written about. "This only happens once
> in a million years"
I'm delighted to see someone young and keen take part in some of these
meandering, ultimately futile yet entertaining debates we have.
The only slight problem is that with an Andrew and 2x Andy taking part
people will attribute things to the wrong Andy at some point! I can stop
that now by pointing out that in all arguments, discussions, debates etc. I
am always right and correct :-)
Anyway I think Andrew needs to go away and learn the terms "single point
failure", "multiple point failure". Most of the nuclear incidents have been
the result of a series of single point failures compounded with human
error, human stupidity. These lead to further failures that were not dreamt
possible by the original designers leading to scenarios that cannot be
coped with.
A related story. Jan 8th 1989 a 737 crashed onto on of the UK's main
motorways. (Kegworth Air Crash). The plane was new and had suffered a
double engine failure leading to a crash and fatalities. Only it hadn't
suffered a double engine failure. The left engine developed a fault leading
to vibration and the production of fumes. The crew (used to older 737s)
knew that the right engine was the source of cabin pressurisation and so
the shut that down and the fumes reduced and the vibration stopped. Just as
they were coming in to land the faulty left engine failed and the crew were
unable to restart the right engine and the plane crashed 1km short of the
runway.
The left engine was faulty and it just happened to stop vibrating after
they had shutdown the right engine. The crew experienced positive feedback
for their decision (shutdown "faulty engine" and less vibration) and so
believed they had made the right decision. Instead they should have
confirmed the engine was faulty and CONFIRMED the other engine was good.
But we like to simply what happens around us and the mental model the
pilots made fitted enough of the evidence that they believed they were
correct.
These experienced pilots were easily conned into thinking they had done the
right thing. A result of the crash was revision of training for pilots, and
a lot of extra instrumentation on engines to help pilots figure out what is
happening.
Of course double engine failure for no obvious reason is really rare.
Hundreds of millions to one against it happening. Which is why you can fly
the Atlantic on a twin engined aircraft. The pilots suspected they had made
a mistake when the left engine failed, because two engines dont fail and
that is why they tried to restart the other engine as it was probably good.
We dont have enough experience of reactors going wrong to truly know what
will happen and so it is easy to see that in the event of a failure, it is
possible to do the wrong thing with the best of intentions (computer
controlled or manually) and end up in an unrecoverable situation.
73 de Andy GM7HUD
Read previous mail | Read next mail
| |
