This article is a work-in-progress. It may be finished in the near future, check its history to see previous edits.
Moderators are used in a NuclearCraftFission Reactor. For now, the only available moderators are graphite and beryllium, and they both have the same effect in the reactor core, but there are plans to add more moderators and give them unique stats and possibly even placement rules.
Values are taken from the default NuclearCraft config (as of March 20 2018, v2.9e).