Pebble Bed Nuclear Reactors

First conceived by Prof. Dr. Farrington Daniels at Oak Ridge in 1947, this safe, clean, and passive fission reactor design was first develped by Professor Dr. Rudolf Schulten of Germany in the 1950s. There was little further development until China licensed the technology in the late 90s as one of the early steps of the Bountiful Sky Project. These reactors have proven durable and versatile, were a mission-critical component during the Climb, and were an essential source of power during the early days of settlement.

In Bountiful Sky Outreach
The small size and modularity of the reactors developed for the Bountiful Sky project made them easily transportable. Consequently, they were often used to provide on-site power for rectenna construction crews in locales lacking in power infrastructure. Once the rectenna was providing power, the reactor was either removed or sold to the client. Many of these reactors remained in use well into the Collapse.

In Fueling Launch Vehicles
To eliminate the need to store large quantities of fuel, the Black Tortoise launch vehicles were fueled at sea by a barge with an array of reactors. These barges filtered and distilled seawater, which was then separated into hydrogen and oxygen fuel at the launch site, which was refrigerated and pumped directly into the launch vehicle.

In the Tugs
Pebble bed reactors were chosen for the ore and crop tugs for their safety, simple design, and low maintenance needs. In addition, the use of helium for heat transfer meant they could draw on the same helium supply used to cool the mass-driver electromagnets. This design choice simplified the system by using a single heat-transfer medium for both the reactor and the electromagnets, despite the difficulty in storing large amounts of helium.