How can a space station prevent docked ships from irradiating each other or the station?

I've been puzzling over the logistics of orbital spaceports, and this has been the one sticking point I keep coming to: radiation control between docked, or even neighboring, ships. Mass limitations on ships without "torch" engines, which are engines without a high enough thrust and specific impulse to overcome the limits of the rocket equation, would prevent a designer from efficiently using anything more than a shadow shield that only shields the direction of the ship itself from radiation. Anything covering more of the reactor would require more propellant to gain the same total delta-v, which adds mass and reduces the thrust-weight ratio, requiring a larger engine to offset in a very delicate balance. That's all well and good until you need to dock; said shield would only protect a small fraction of the surrounding space, while pouring out radiation on any nearby ships.

I'd like to figure out a way to build an orbital spaceport that doesn't require everyone besides an incoming ship to live in a radiation-proof bunker, but I'm not seeing any good solutions short of "don't use nuclear power". The radiation concern in this case is the reactor of the ship, which would be providing the majority of the electrical power necessary to operate ship systems. Main engines wouldn't be used for docking proper, but short of battery power, the reactor would have to run to sustain ship systems such as life support while not directly docked, and my understanding of radiation tells me that even a shut-down reactor is radioactive to a degree.

While extending the shadow shield to cover the entire reactor is mostly possible (a direct cone behind the reactor doesn't work as well since the reactor has to feed into the engine somehow, and pointing the thinnest point for piping/etc straight back is safest), it also negatively impacts a ship's performance to a degree I don't find workable"”lead and water are heavy, not to mention any other materials that could be involved.

My setting's tech level is fairly near-future; the main breakthrough relevant to this question is the development of working nuclear salt-water rockets, which allow for much faster interplanetary travel but are, as implied, very radioactive thanks to the reactor used to power them (and to power the rest of a ship). No energy shields or anything of the sort; if a solution is possible with current real-world technology or something achievable from ongoing research and development, that would be preferable. I'm trying to stick as close to that general idea as possible.

Please let me know if I have some fundamental misunderstanding!

(First time posting, so I apologize if this isn't structured well. I've tried to use as much real world terminology as possible; I'm still in the early stages of building my setting, so I don't have the clearest grasp on any of my own potential quirks yet.)

For a visual idea of the "shadow shield" I'm referring to, courtesy of Winchell Chung's "Atomic Rockets" site:

posted over 7 years ago

SkyeAuroline‭

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