Yesterday I built an RBMK reactor filled with MEP fuels. I started the reactor by igniting it with neutron source. It worked flawlessly i took some screenshots and after all that progress i quit and saved the game. This day i woke up started up minecraft and loaded my world I saved. And to my shock the RBMK reactor stopped working. I checked every fuel rod and it turns out none of it is producing any heat whatsoever it was static and the values didnt change, the water wasnt even flowing and the steam turbines stopped working. After this has happened i tried to re-ignite the fuel with the neutron source again. It worked, so I quit and saved the game again and then immediately afterwards opened it to see if the bug is still present. And unfortunately it did, this time however it decreased the heat values as you can see in the video below

I'm running this on NTM's latest version X5202, the world i was playing on originally started out with the old version X5193 and later once the new version dropped. changed it to X5202.

EDIT: I replicated this same exact bug on a new world on the new version of NTM. And the bug still persists as shown in the video in detail

This may be an issue with my code, I'll check into it later.

After this has happened i tried to re-ignite the fuel with the neutron source again

...which implies you actually took the neutron source out, which is something that works until it doesn't, evidently. When you load a world, chunk loading is slightly delayed and often unpredictable, chances are that half your reactor loaded in, bled a good amount of neutrons that it needs to remain operational into the still unloaded regions while receiving nothing in return, and only then did the neighboring chunks load in, where a similar thing happened.

After this has happened i tried to re-ignite the fuel with the neutron source again

...which implies you actually took the neutron source out, which is something that works until it doesn't, evidently. When you load a world, chunk loading is slightly delayed and often unpredictable, chances are that half your reactor loaded in, bled a good amount of neutrons that it needs to remain operational into the still unloaded regions while receiving nothing in return, and only then did the neighboring chunks load in, where a similar thing happened.

when I replaced the radium226 rod with MEP fuel this chain reaction persists and carries on as it normally should without any interruptions as i've done many times before in my other playthroughs. However you mentioned that chunk loading is slightly delayed which is true, but i created this RBMK design throughout my many survival playthroughs with the old NTM versions which didnt have this bug.

This may be an issue with my code, I'll check into it later.

Thank you, also I experimented with bug the second time and it turns out it is indeed a chunk loading error and when i tested it the entire reactor exploded once i stepped out of loaded the chunk areas. Remind you this has never happened to me before when i played with the old versions of NTM, this bug was fixed until the recent update. strangely enough this bug doesnt appear to be the case with the zirnox reactor, only the RBMK one.

Below is a video demonstrating the bug