Factorio Forums

TLDR: Title says it all. I want to be able to say only insert one item at a time into the nuclear plant.

The situation: I have a "smart" nuclear power plant which more or less decides how many plants I want on at the same time. The problem is it will insert 6 fuel into the plant when it turns on and will take like 20 mins before it uses that all up. 5 mins or however long it lasts is still a long time but its a lot more acceptable. While it is possible to make a machine that will only insert fuel every 5 mins or something. It is a very risky mechanic and I would prefer not to have the entire base relying on a timer that might go out of sync or something. I mean like.... I would love to see this on ALL buildings. Mostly for raising the stack size. But the nuclear one I find would be the most important to me.

It is no longer necessary to set up a timer for this. Since 0.15.7, the used up fuel cell is only produced by the reactor after the uranium fuel cell has been completely used up. So, you can set the stack limit of the inserter that feeds the reactor to 1 and make it wait for another inserter to remove the used up fuel cell before it inserts a new fuel cell. That way, you will never have more than one fuel cell in the reactor at once.

Here are two related threads about setting the stack size up to which an inserter will fill an entity:

viewtopic.php?f=6&t=50086 [0.15.23] inserter waits too long
viewtopic.php?f=6&t=50881 Fill target with inserters

These threads are more about increasing the stack size up to which an inserter will continue to operate, whereas you are more interested in decreasing this stack size. However, since a customizable stack size would also solve your problem, the suggestions I posted are related to your suggestion.

I suppose that would be a much simpler solution to my problem. Thanks for that.

The solution I use for this is to put an item on a belt loop that times the fuel insertion. A belt scanner set to pulse mode will cause an inserter to cycle exactly 1 time, which can have the stack size set to 1 to precisely and predictably insert 1 rod into each reactor.

My loop is actuated by steam pressure, whenever the steam pressure falls a certain amount it puts rods in. It won't insert again unless the steam pressure rises to prove that the reactors are properly operating.

I originally figured this out on a 480MW reactor setup, and currently have it operating on a 2.4GW reactor setup- with zero waste despite only ~30MW of load.