Hm, quite an unusual error.. somehow the ingredient amount is read as near-infinite? I've tried running those 4 mods (248k, K2, Warptorio2 +expansion, and Reverse Factory) and I'm not getting the same error. However, I can see that there is a recipe called "fu_tokamak_1_recipe" that somehow requires 110,000 "fu_lead_fluid_coal", which is an insane amount, though I'm surprised to see that amount is even allowed as ingredients, but not as results.
Though it seems that with my minimal mod list, the reverse recipe for that item is not created. I've made a temporary patch that disables the category for that recipe, in case there were any other "fu_tokamak_reactor_crafting_category" recipes that used similar amounts of ingredients. It's annoyingly difficult to get the ingredient counts without a lot of code (due to needing to account for differing formats, including basic ingredients table, normal/expensive ingredients table, simple recipe without labels, etc)
It also seems that the mod portal is currently having issues with uploading mods, but I have the temporary patch ready for uploading. If you would like to implement this fix for your own version of the mod, you can extract the current version of the mod, open the "data.lua" file in a text editor, scroll to the bottom, and add the line:
table.insert(rf.norecycle_categories, "fu_tokamak_reactor_crafting_category")
