@Athang the auto-sell cycle goes *after* the power is generated. So you have 145T capacity, but you are auto-selling 25T each tick... hence why you never see it going above 120T.
Is there any chance you could limit the reactor outlets so they don't put out more power than a component can handle? As it stands, 1 ultimate outlet requires 16 ultimate vents to keep cool, which means it also requires 8 heat exchangers. Which makes it useless, because now you're using 25 spaces to get just 16 vents worth of cooling.
Oh - the one I linked isn't *quite* totally stable because it is losing heat very slowly. Every couple hours need to top it off on heat again using the top-left corner.
http://imgur.com/ottvSRL - earn 6.3T/tick stable and idle. I'm only at half that in the screenshot because I'm so poor and can't afford the other 7 nefastium cells yet. Upgrades: Nefastium 7, Fission 7, alloys 13, power lines 14, wiring 13, all other relevant upgrades 8.
As it stands now, the game gets stale - you figure out the best layout, you build it, and then... there's nothing to think about until the next balance patch. Maybe a pattern of daily challenges would help? Things like unusual reactor grids (unbuildable tiles, tiles with modifiers like increased power or heat production, etc.), or only having specific components available, or a limited budget, or puzzles like that.
Something wonky is going on with heat outlets and vents. It *says* that my vents lower their heat by 885M per tick, and that my outlets take 506.25M out of the reactor to each component. But hooking one outlet up to 4 surrounding vents causes all four vents to quickly overheat and then explode.
http://imgur.com/9rWdEhN - just under 20B per tick idle abusing heat outlet glitch. I think it's actually losing heat *ever so slowly*, but waiting several minutes I didn't see the heat drop by .001B so I figure it's basically stable. I couldn't find a way to *legitimately* use the new heat outlets for more power than I could manage ignoring them though.
http://imgur.com/sq3kse9 I think this is an optimal fully-idle layout with the current version. This gets 40 dual nefastium, and 39 neutron reflectors supporting 2 dual nefastium each, for 59.5 dual nefastium equivalent. I can't find any layouts that get more than 59.5 dual nefastium equivalent.
I managed to push my single-nefastium no-overlap reactor up to 3.7B per tick before some reckless tinkering made it blow up. Guess it's time to try double nefastium.
It looks like ~600M/tick, or ~3.6B/second, is the highest idle income rate you can manage without upgrades costing over a quadrillion. Even if you got several times that high by making use of coolant cells and not idling - let's be generous and assume you somehow managed 20B per second - that's still about 3 full days to get the 5 quadrillion nefastium generator upgrade. And closer to a month to get the 50 quadrillion nefastium upgrade, probably about a year to get all the upgrades. I feel like maybe the upgrade costs at the upper end were boosted a little too much in the latest patch.
@Cazaan you've got one more plate than you actually need (80 plates is sufficient, instead of 81). You will earn *ever so slightly, fractionally* more if you replace one plate with a neutron reflector. Not that it's really going to make a significant difference.
http://imgur.com/LELQhPz - 576M income per tick, with 553M of it idle (have to click "collect" button every once in a while). Replacing one neutron reflector with a plate and replacing a plate with bank cuts it to 557M, all idle. Plus it has a turtle.
3-vent nefastium is generally a touch more efficient in the new build than 2-vent nefastium. You need to have over 26 nefastium generators before 2-vent generators become more efficient.
Neutron reflectors would be more useful if there were upgrades for them that made them more heat-efficient. As it is, I don't really see the point of them.
http://i.imgur.com/b5OYbRZ.jpg - if you aren't ready to spend on nefastium and don't want to keep track of coolant cells, I think this is a fairly effective layout (a bit over $100M per tick). The bottom right corner is me trying some new stuff out now that I bought a few more upgrades, and doesn't really fit the pattern.
 "Reactor Incremental"){kind=icon}