TMI pressure vessel integrity.

vanesch

I would like to check something. If I understand well, in the TMI accident, the reactor vessel was never damaged (in the sense of: having lost major containment function) ? Can someone confirm this, or correct my understanding ?

Astronuc

AFAIK, the reactor pressure vessel was not perforated, but the liner and part of the carbon steel shell was damaged (partially melted or chemically reacted) from the core material that melted/interacted with the baffle and core support plate. I've seen pictures from the inside and it's a mess.

vanesch

Ah, was at some point the vessel completely emptied from water ? I thought it was just the upper part of the fuel elements that was out of the water and melted ?

Astronuc

Certainly the upper half of some of the fuel had disintegrated along with the control rod clusters (SS and Ag-In-Cd), but I also seem to remember the damage at one corner of the core.

Here is picture of the damaged TMI-2 core - http://americanhistory.si.edu/tmi/im...1_enlarged.jpg

and - http://americanhistory.si.edu/tmi/tmi08.htm

from - http://americanhistory.si.edu/tmi/tmi10.htm

There was some fuel particles/chunks which fell to the bottom of the RPV, and I believe they interacted with the stainless-steel liner on the bottom.

There are other pictures, but I can't seem to find them at the moment, but similar to

http://www.mpra.com/graphics/d-d_tmi2coredamage.gif

This last one shows that the one or two of the baffle plates were perforated, but the core barrel is apparently intact.