I wonder if the latest version of Logistics Pipes can assist. Set up a Supplier Pipe to keep x 60k cooling cells and y nuclear material. As long as you don't have nuclear material and cooling cells pulled at the same time, it shouldn't get its wires crossed, although it is something of a risk I suppose. I believe LP can sent requests through an ME Network.
Ehhh... Although I agree that that might work, I wouldn't want to run that risk. Although getting a coolant cell and a uranium cell swapped would probably not be catastrophic, such a Logipipe-managed reactor would not be reliable enough in my opinion for commercial use.
Some problems that my thought-experiments indicate could come up, in no particular order:
1. Coolant cell gets pulled (by ME Fuzzy Bus, I assume), and enough time passes before Logipipes can replace it that the reactor explodes.
2. U-cell expires and leaves some depleted cells, LP tries to restock before AE pulls the depleted cell, either a U-cell or a coolant cell drops on the ground because it won't fit in the reactor. I'm not sure if this can actually happen in the current version of Logipipes, now that pipes don't usually drop things.
3. Several U-cells burn out at the same time several coolant cells get pulled, LP replaces the cells in the wrong places, leaving one U-cell adjacent to only other U-cells and maybe an OC vent (but no coolant cells), the OC vent melts, and the reactor explodes.
4. LP fails to restock uranium cells because it can't access the ME Molecular Assembler Chamber with U-cell recipes. Yes, I'm fully aware of the existence of workarounds to this problem (i.e. using Logistics Crafting Tables to craft quad cells on demand, using an Export Bus to craft quad cells and pump them into a chest with a provider pipe on it, using AE components to keep quad cells stocked in the AE network itself, etc.).
5. Supplier pipes turn out to work like precise busses, and refuses to mess with 75% cooled cells at all.
I think it's actually number 3 that I'm most worried about.
Side note: I'm currently writing a LUA script for an Inventory Turtle (introducing two MORE mods, ComputerCraft and MiscPeripherals) that replaces whatever happens to exist in the particular slots in the production reactors with uranium cells. Most of the code is written, but it keeps crashing when it tries to actually swap the items. I'm relying on AE flooding the whole reactor with coolant when the uranium cells expire and Buildcraft turning the reactor off when there's a space in it to prevent explosions.
EDIT: I've completed the LUA script. Setup is a bit complicated, as this is actually the first LUA program I've written aside from "Hello World!" and some short-lived programs intended to help me learn how some things work.
1. Position your Inventory Turtle (make sure that the inventory module is installed on the RIGHT-HAND side of the turtle) atop a Charging Station (facing upward), below the production reactors.
2. On your turtle command line, type "pastebin get FHWBDsAj NukeFuel", without quotes. This is for Shneeky's single-chamber double-stacker design.
3. Type "edit startup".
4. Type some simple startup script, such as:
5. Hit "Ctrl" on your keyboard to bring up the menu. Press "S" to save, then "Ctrl" followed by "E" (not at the same time) to exit the text editor.
6. Give the turtle some fuel to get it started, type "refuel all", then press and hold "Ctrl" and "R" for a few seconds to reboot the turtle.
7. You should see the "TurtleOS" thing, but not a command prompt.
8. When your nukes run out of fuel, give the back of the turtle a redstone signal, and it'll kick into action within a minute.
And because a picture tells a thousand words...
This shows the entire setup. Note the Fuzzy Export Busses on the LEFT side of the reactors, and the turtle on the RIGHT. The cobblestone at the top is also crucial- it tells the turtle when to stop.
Not shown around back (because I forgot to put them in) should be some Buildcraft gates, set to "Inventory Full" > "Redstone Signal". These turn the reactors off when there's a space in them, preventing explosions while swapping coolant cells. Make sure that these do not turn off the Fuzzy Export Busses, which are configured the same way as Shneeky's.
This is the GUI of the Fuzzy Export Busses. The only thing different from those in Shneeky's design is that they are "Active Without Signal"- so the turtle can turn them off. This isn't a problem, because if one coolant cell gets pulled while the (surprisingly fast) refueling is taking place, the BC gate will detect the empty space and turn the reactor off.
This is a closeup of the bottom of the tower. When it needs fuel, the turtle sends a redstone signal through the MiscPeripherals Turtle Charging Station (which is facing upward), turning off the redstone torch, allowing the splitter cable to transfer EU.
The ME Interface is set to keep four quad uranium cells stocked at all times. There may be problems if the ME network can't restock those cells faster than the turtle pulls them out.