title
pack atm 9 0.55

yes, fuel rods empty

Could you give a bit more details?

What does "reset" mean? Do you find the fuel rods empty after a restart? Do you find an amount of reactants that is what is was at some times before the restart?

This is happening to me as well. All fuel, waste and energy that was in the reactor is voided when loading back into the world.

Minecraft 1.21.1
Modpack: ATM 10, version 2.34
Modloader: NeoForge 21.1.116
Extreme Reactors 2.4.21

Issue is also reported on the ATM 10 GitHub: AllTheMods/ATM-10#1931