I Have that setup:
https://imgur.com/NaT6q4O
Reactor produce 480MW of Heat. Water pumps are not throughput (tested!) 8 heat exchangers at 900C so needs 480MW of heat power but...
Two heat exchangers produce only lower than 50% of 900C steam... They produce only 2351 stream per second instead of 2712. Whatis a problem? Thermal troughput of heatpipes?

I have calculated that:
- Laplace 4way should take:
- 226 steam (900 degrees),
- 272 steam (750 degrees),
- 412 steam (500 degrees).
- Carnot 4way should take:
- 452 steam (900 degrees),
- 544 steam (750 degrees),
- 825 steam (500 degrees).
- Turbine should has 44.1MW instead of 20MW (because tortuqe has 1KJ/degree).
- Extreme turbine should has 53.1MW instead of 30MW (because exteme tortuqe has 1KJ/degree).
- Torque formulas (per second):
- Torque:
- on input: 400 steam (750 degrees): 58.8 MJ,
- on output: 290 steam (500 degrees): 28.1MJ, 250 torque (750 degrees): 183.75MJ,
(output - input should be 0, is: +153MJ).
- my proposition: 60 steam (500 degrees): 5.8MJ and 72 torque (750 degrees): 52.9 MJ (52.9MJ + 5.8MJ = 58.7MJ - looks better).
- Extreme torque:
- on input: 800 steam (900 degrees): 141.6MJ,
- on output: 410 steam (750 degrees): 60.27MJ, 190 extreme torque (900 degrees): 168.15MJ (60.27MJ +168.15MJ = 228.42MJ),
- my proposition: 96 steam (750 degrees): 14.11MJ and 144 extreme torque (900 degrees): 127.44MJ (14.11MJ + 127.44MJ = 141.55MJ).

I've back to Factorio and your mod and.. Created whole system for 8 reactors (1,12 GW of Heat) that at end Produce 1,66 GW of Electricity.
Is about 1,48 conversion ratio. Very, very nice.

Here is image of that: https://i.ibb.co/8zsrqcr/image.png

Of course, is some overbuilt (heat is 1,12 GW, but demand is 1,2GW) but there is some space for some changes on power demand.