[meteorite-list] Not to worry. Nukes are good?

[almitt2 at localnet.com]

Greetings Sterling and all,

Last OT post for me here, right or wrong.

My information comes from a Cook Nuclear Scientist who gave our 
astronomy group a program topic a few years back. No doubt I can't 
remember exactly what he said and my information may need updating.

How ever one thing he did mention was with the use of water as a 
moderator, was a safety feature that would prevent a melt down. No 
water no reaction.

Cited is a Wikipedia article. It mentions graphite moderator componets.

http://en.wikipedia.org/wiki/Chernobyl_disaster

This event exposed the graphite moderator components of the reactor to 
air and they ignited;

Perhaps it was the compents that warped and the rods couldn't be moved, 
locking them in and allowing the core meltdown.

In any case it was a dangerous mess and your right the Japanese system 
works different.Hope they get things under control.

--AL Mitterling



Quoting "Sterling K. Webb" <sterling_k_webb at sbcglobal.net>:

> List,
>
> Al Mitterling pulled Chernobyl into this. Chernobyl
> was a graphite "pile" with pressurized water cooling
> and with NO containment vessel. In a graphite pile,
> graphite is NOT a control material and the control
> rods were not graphite rods. Fukushima is not a graphite
> pile; Chernobyl is irrelevant to the Fukushima discussion.
> And the suggestion that correct procedure for a water-
> moderated reactor is let it boil off and expose the core
> to a meltdown is ludicrous.
>
> Graphite is a "moderator." The moderator makes the
> chain reaction happen. Moderators are substances that slow
> the velocity of neutrons down until they are "thermalized,"
> or moving with the kinetic energy of room temperature.
> In the case of a neutron, that is the speed of an old man
> crossing his living room (or me on a bad day).
>
> Sterling K. Webb