Has the time arrived for the Atomic Outboard, a novel marine propulsion concept, to make its mark?
Everyone's all hyped up about Small Modular Reactors (SMRs) these days when it comes to nuclear power. It's like the industry's holding out hope for a 'nuclear renaissance' on this fresh concept. Even though it might seem exciting, it's not exactly new: small reactors date back to the atomic era's glory days. There were a few prototypes, and a ton more on paper that we can smirk at today. One in particular caught our eye, an atomic outboard motor described in an article by Steve Wientz.
This baby started as an offshoot from General Electric's 1950s work on airborne nuclear reactors. GE's proposal definitely screams "1950s" - a refractory, air-cooled reactor serving as the heat source for a large turboprop engine. Yup, complete with open-loop cooling. Naturally, those didn't fly (pun intended, as always). To salvage some investment, GE proposed various applications for this small, reactor-driven gas turbine. Instead of pushing the idea of connecting it to a turboprop and potentially spewing radioactive exhaust directly into the atmosphere, GE came up with a brilliant idea: podding up the reactor with a closed-cycle gas turbine into one small, hermetically sealed module.
Bolt-On Nuclear Power
There were two variants of this sealed reactor/turbine module proposed by GE: the 601A, which would connect the turbine to an electric generator, and 601B, which would link it to a gearbox and bronze propeller for use as a marine propulsion pod. While almost no info seems to have survived about 601A, which was likely aimed at the US Army, the marine propulsion pod is fairly well documented, especially in GE-ANP 910: Application Studies. This document lists various applications; 601 is the only one a modern reader might not deem utterly bonkers.
The pod would be slung under a ship or submarine, similar to the popular steerable electric azimuth thrusters on modern cruise ships and cargo vessels. Unlike them, this pod wouldn't require any electrical plant onboard ship, freeing up a whole lot of internal space. It would likely have been fixed in orientation, at least if it had been built in 1961. But now that such thrusters are proven technology, there's no reason an atomic version couldn't be put on a swivel.
Two sizes were discussed, a larger pod 1.5 meters in diameter and 9.1 meters long (45,000 lbs, outputting 11 MW), and a smaller one producing 2796 kW over the same runtime. The working gas of the turbines would have been neon to minimize turbine redesign. Steve seems to think that this podded arrangement would create drag that would prove fatally noisy for a warship. However, the Spanish Navy appears to differ, given they're fitting azimuth thrusters under their flagship. A submarine might be another issue, but let's leave that to the experts. The bigger problem with using these on a warship is the low power for military applications. Modern destroyers make 63 MW with their steam turbines, so the two-pod ship in the illustration would be both quite small and rather slow.
However, in civilian applications, this sort of small, modular reactor sounds perfect for the new fleet of nuclear cargo ships the UN is pushing for to combat climate change. The International Maritime Organization's goal of net-zero emissions by 2050 is a tall order without nuclear power or a complete overhaul of our shipping infrastructure. Most of the planning seems to center on next-generation SMRs, everything from pebble-bed to thorium. While this Cold War relic of an idea has a few disadvantages, like limited runtime, it does have some merits.
For instance, the ship and its nuclear power plant are wholly separate, which should please regulators and insurers. Converting a ship to use azimuth thrusters is a known factor, and not a huge job in dry dock. There are a great many ships afloat today that will need new engines anyway if they aren't to be scrapped early and the shipping sector is to meet its ambitious emissions targets. Pulling out their original power plants and popping 'atomic outboards' underneath might just be the easiest possible solution.
So, was GE's "atomic outboard" way ahead of its time? What do you think?
In the realm of retrofitted nuclear technologies, the idea of an "atomic outboard" motor, a small, reactor-driven gas turbine proposed by General Electric, showcases an interesting blend of science and finance from the 1950s. Despite initial failures in aviation, this concept was envisioned for civilians, particularly for the upcoming fleet of nuclear cargo ships, a crucial part of the United Nations' efforts to combat climate change.
