1. Provide mod and mc versions
   Nuclearcraft version: 1.1.5 (Monifactory Beta 0.11.5)
   Minecraft version: 1.20.1

2. Attach screenshot/video/log (as much information as possible)
   While 2 fission reactors had fuel in them (Both use power production, have dimensions of 13x13x13, & zero active heatsinks. Left is a nonhollow checkerboard with Cryotheum heatsinks & Solid fuel cells. Right has various heatsinks, coolers, moderators, & fuel cells); the TPS began to spike heavily, jumping from 13ms to 50ms, sometimes higher. It did not matter if the reactors were on or not:
   

I ran a spark profiler for 40 seconds which you can find with more detail here (in case it conflicts with other mods): https://spark.lucko.me/ejCy0nC1iO

Both fission reactors are in their own chunks:

(Internals of said reactors:)

Yes. This is because i didn't removed scheduled re-validation. I already implemented event based re-validation, but not sure if it will work everytime. This is why reactors checking structure each 40 ticks. I need to get rid of this

I increased re-check structure delay. Plus it will be random, so there will be no more situation when all reactors re-checking at the same time.