[ExI] Two Japanese reactors on red alert
painlord2k at libero.it
Tue Mar 15 15:24:55 UTC 2011
Il 15/03/2011 14.56, Richard Loosemore ha scritto:
> What distresses me about the nuclear plants is the Morgsatlarge post,
> (the one now lodged in modified form at http://mitnse.com/) describes a
> very reassuring "defense in depth" strategy, where things are allowed to
> fail but the designers have done such a good job that there is always
> another line of defense to fall back to.
> Only problem with this: those fallback positions have been going down
> like dominoes.
> It seems to me that the safety systems were all "Looks Good In
> Powerpoint Presentations To Senior Management" safety systems.
> On paper, great.
> On the ground, as thin as paper.
This is emotional thinking.
They have problems, but thy are manageable.
The earthquake hitting the power plant was 16 times stronger than the
security levels it was designed to withstand.
The plant resisted without problems and started the shut down.
The tsunami hit an hour after, damaging the diesel engines of the
cooling system and muddling the pond with the reserve water, making it
unsafe to use for cooling. By the way, the wave was 9 meters high where
the plant was designed to withstand 6 meter waves.
The chain reaction was halted immediately, when the control bars were
inserted back. The current problem is that without enough cooling the
decaying isotopes will overheat the core and damage the containment
vessel. The heat production is slowing down continuously, but will need
days to be reduced enough to avoid damages without cooling.
The radioactive isotopes leaked out, until now, are tiny quantities of
mainly short lived isotopes.
In Italy we had a major disaster when 270 millions m3 fell inside the
basin of the hydroelectric dam of Vajont. Near 2000 dead, the wave over
the dam was 100 m high. Anyway the dam lasted against a power 7 times
greater what is was designed to withstand. No consolation for the towns
down. We didn't stopped all hydroelectric power plants.
Japan will not stop its nuclear power plants, because it need them. No
low cost abundant energy, not high tech society.
I think some people would argue against nuclear power plant even if an
asteroid 50 m large fell over the reactors. Too risky.
Well, living is risky. Sane people assess risks rationally and not
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