[ RadSafe ] Fuel condition at TMI
terryj at iit.edu
Thu Aug 4 16:26:33 CDT 2011
Here is the link to the ANS description of TMI.
Sent from my iPhone
On Aug 4, 2011, at 3:09 PM, James Barnes <james.g.barnes at att.net> wrote:
> Dear all;
> Have a very specific question about the fuel failure at TMI.
> The sequence I recall is:
> 1) Reactor water levels dropped and tops of fuel bundles were exposed.
> 2) The Zircaloy fuel tubes overheated and cracked (with extensive melting of
> the Zircaloy), releasing fission products to the reactor and auxiliary systems.
> 3) Fuel pellets were then mechanically dislodged from the fuel bundles and
> fell down into the fuel assembly and reactor structures, and some quantity to
> the bottom of the reactor vessel.
> My question is this:
> The fuel pellets themselves are generally uranium in a ceramic matrix
> (correct?). My sense is that ceramic matrices don't melt, they crack into
> pieces ("sinter"; a point that the Wikipedia entry on ceramic fuels seems to
> imply). Thus, when the pellets were overheated and ejected, they tended to
> crack into pieces and one got tiny pieces of fuel circulating in the system and
> pieces of fuel pellets dropping into the reactor internals.
> Was there ever any evidence that that actual fuel pellets themselves had
> undergone melting. If so, can any of you send me credible references to this
> Jim Barnes, CHP
> james.g.barnes at att.net
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