I'd have to disagree...using a massfab, you can make lapis at a cost of roughly 80k EU each. So imagine a simple design with one LZH-Condenser next to a Quad uranium cell:
You get 12,000,000 EU
The cost to remake the lapis: 1,905,778 EU
The cost to remake the copper plates / tin cells used in the quad uranium cell: 544,700 EU
Profit!: 9,549,522 EU
And that's with just using two cells on the grid
Still a ton more expensive than just making a reactor that keeps going forever without needing anything.