I’m not really that thrilled with the inclusion of a steam buffer in my reactor setup. I just don’t see a better solution.
The way I see it, the problems are:
1. Reactor heat output is somewhat irregular. My thorium reactor produces about 950 HU/sec, but it’s not a steady figure. Eyeballing it, it appears to be +/- 30 HU/sec.
2. You can’t safely throttle the hot coolant output of a fluid reactor. If you regulate output to anything less than the actual average, eventually the hot coolant tank fills up and the reactor starts heating up. This is fixable with Nuclear Control - I have a temperature safety on my reactor even though this should never happen - but you’re throwing away heat if you do this.
One possible solution is an external hot coolant buffer. You can test if that’s nearly full, and shut down the reactor before the internal tank starts backing up.
3. Steam production is unpredictable because of (1) and (2).
4. Because turbines lose efficiency if starved, it’s best to have a slight overproduction of steam relative to turbine consumption, rather than a deficit. Matching it exactly isn’t really possible.
5. You can tune fluid regulators on the turbines to slightly overconsume steam, but that’s almost certainly going to irregularly starve some turbines. The more turbines in your setup, the more likely that one turbine is going to see a significant deficit.
For example, my reactor appears to produce 76,000 L/sec of steam, +/- 2,400 L. Turbines 1 and 2 consume 24,000 L each, turbine 3 consumes 27,000, for a total of 75,000. If I tune for the maximum (78,400) by adding 1000 L consumption to each, turbine 3 might only get 23,600 L, a shortfall of 3,400 L.
6. A buffer solves this problem, and lets you run all turbines at exactly 100%. You can easily see if you’re over or under producing steam over time, smoothing over small production irregularities (to a limit, obviously it didn’t solve the huge swings I was seeing).
7. If the system is tuned to slightly overproduce, eventually you want to shut off for a short period to avoid steam overflow (and destruction). You can’t really test this without a fair sized tank, flow in pipes is too irregular.
8. Most tank mods are pretty low capacity. Railcraft’s steel tanks hold more than almost anything else, but have a different drawback - a limit of 20,000 L/sec per valve. My setup requires a minimum of 4 input and 4 output valves, which means a 5x5x4 tank, minimum. That’s what I built, and it adds substantially to the bulk of the reactor system.