The quad nefastium cell seems impossible to have in your reactor since it produces more than 1.5T of heat and the max heat an heat exchanger is capable of tranfering is :72B, and even by using 4 of then it would not be enough, and even 4 ultimate cooling cells only holds 16T each, i mean that even if u use everything u can it's no possible to keep thosse in the reactor for a good amount of time. But i found a way, u must use 30+ heat outlets and using as max as you can ultimate heat vents so maybe it would hold 1 Quad nefastuim cell, wich is so frustrating...