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RE: NRC News release on Terrorists.
Title: RE: NRC News release on Terrorists.
Jaro,
I don't think you
would say that the WTC buildings were fragile. They stood for over an
hour after inpact. Will a four foot thick, reinforced concrete wall do as
well? If you don't know, say so.
-- John
<><><><><><><><><><>
John, the
reference books I have say that sprayed asbestos or mineral fiber covering on
steel columns has a fire resistance rating of roughly 2hrs per inch of thickness
(more precise numbers depend on construction details, materials, quality,
etc.).
Concrete offers roughly
the same fire protection per unit of thickness, for the steel rebar inside.
But with wall thickness
measured in FEET for NPP containment domes, we're looking at a fire rating
measured in DAYS, not hours (there is, in addition, usually a steel plate liner
on the inside surface of the dome).
PS. thanks for your
expression of confidence, saying "I don't think
you would say that the WTC buildings were fragile." ...indeed, if
you check what I actually wrote (see below), you will note that I was talking
about the sprayed-on fireproofing material, not the steel structure. I don't
have any figures handy at the moment on the relative strength of sprayed-on
fibrous material versus concrete in dome walls, but I presume its quite
substantial (flame away if you must....).
Jaro
OOOOPS -- I guess John meant burning jet fuel from the
airliner ! (thanks Phil !)
...but if nothing gets through the wall, what difference does
it make ? (ignoring destruction of the "balance of plant" for the
moment).
As we saw in the WTC disaster, much of the fuel was gone in
the initial fireball. I suspect this would be even more so in the case of a
disintegration of an airliner on the outside of a containment dome.... in
contrast to the WTC, where a significant fraction spilled throughout the
interior of the structure and ignited any combustible materials
there....
Also, in chemical/petrochemical industry, large concrete
basins are used for emergency/accidental spills to safely burn-off the
flammable liquid.
I think there is a big difference between the relatively
skimpy & fragile fireproofing of steel structures in highrises, and rebar
embedded in four-foot thick concrete walls !
Jaro