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Reactors and heat on Titan
Two small modular reactors give Kraken Shore its electricity and its heat, because the Sun at Saturn is about a hundred times fainter than at Earth.
See it in the tour: chapter kraken shore, shot 4.3.
No sun to speak of
Saturn is about 9.7 AU from the Sun on the reference date. Sunlight there is about 100 times fainter than at Earth, roughly 1% physics. Titan's haze blocks much of what arrives physics.
On the reference date the Sun at Kraken Shore climbs to 28° at noon and drops to 1° below the horizon at midnight, and a solar day lasts about 15.9 Earth days physics. Solar panels are not practical here design.
A reactor ignores the Sun and the haze. Its output depends on its fuel and its radiators.
Two reactors
The first autonomous industrial landing at Kraken Shore, in 2061, delivered two small modular reactors and an ice-mining plant fiction. The reactors supply almost all of the town's electricity and heat design. They stand in the reactor yard, apart from the halls and behind a berm design.
The electricity runs the ice plant, the electrolysis that splits water into oxygen and hydrogen, the hydrocarbon processing, the lights and the charging of the rotorcraft packs design. A rotorcraft hovers on 39.4 kW and cruises on 212 kW design. The 95 kWh pack covers two hours of hover design. See Water, oxygen and electrolysis.
Most of the heat is not electricity
A heat engine turns only part of a reactor's heat into power. The nuclear-electric tug shows the ratio: 5.8 MW of reactor heat, 1.74 MW of electricity, a conversion efficiency of 0.3 physics. About 70% of the heat is left over.
In space that leftover is a burden. It can only leave as light, so the tug carries 790 m² of radiators at 500 K design. See Electric propulsion.
Heat as a resource at 94 K
On Titan the leftover heat has a use, because everything around the plant is at 93.65 K physics. It does two jobs design.
- It keeps the rooms warm in the residential wings and the Garden Hall.
- It melts mined ice for electrolysis.
A cold sink helps the reactor too. The colder the place heat is dumped, the more of it a plant can turn into work physics. Titan is a very good place to reject heat, and a very poor place to be a warm room. Reactor heat pays for the second with the first. See Building for 94 K and 1.5 bar.
Other reactors in the fleet
The reactor in a nuclear-thermal shuttle is a different machine. It gives 929 MW of heat for a burn and puts it straight into propellant design. See Nuclear-thermal rockets. Fusion powers the long crossing, at 10.6 GW challenge. See Fusion propulsion and helium-3.
Key numbers
| Quantity | Value | Basis |
|---|---|---|
| Distance from the Sun | about 9.7 AU | physics |
| Sunlight at Saturn | about 1% of Earth's, before haze | physics |
| Titan solar day | about 15.9 Earth days | physics |
| Sun at Kraken Shore, noon / midnight | 28° / −1° | physics |
| Surface temperature | 93.65 K | physics |
| Town reactors | 2 small modular reactors, landed 2061 | fiction |
| Tug reactor heat / electricity | 5.8 MW / 1.74 MW | physics |
| Tug conversion efficiency | 0.3 | physics |
| Rotorcraft hover / cruise power | 39.4 kW / 212 kW | design |
| Shuttle reactor heat | 929 MW | design |