Display MoreThe overflow issue is entirely in IC2.
From another discussion I remember that IC2 specifies a 'chest' size of X for the reactor core. This is tied to the block ID, irrespective of damage value/etc. It just happens to /show/ us only the number of columns for the chambers we have installed. Every so often (every reactor tick?) it ejects the things stuffed in to the spaces that are unseen by automated insertions (which just take the next numerically open slot).
The easiest way of fixing this would actually be to just have the reactor stuff it's self with some (near) useless item. Wooden shovels for example. However I guess even those /burn/ which is exploitable... so something even /less/ valuable. Maybe a stone shovel with 1 HP of damage left.
Second easiest is a variant on the above, but simply not process the items in the hidden slots (leaving them to fill up until the unit is removed or something else empties them).
Third easiest is to, on each tick, have a 'pre tick' that goes through the 'hidden' spaces and stuffs whatever was in them in to the open slots within the reactor... before evicting the rest.
I -suspect- option #3 is what was chosen.
It's not actually a 'pre tick' it's on the tick where the power is produced. It goes through every slot checking for invalid items or items that are out of the "useable size" of the container and chucks them before it goes into the actual calculations for the reactor.
Also it was brought up earlier in this thread how other mods treat the reactor's inventory "kind of funny", this "add-on" takes out some of the funniness (or at least allows you to fill up the entire inventory, not just a row or so). Currently it doesn't have much of an impact, but fully automated reactors may be possible with the next release of red power 2.