Friday, December 21, 2012

APEX-910 (Part 2)

Sorry for how long it took to get to this - grad school is like that.   But, here we go with the rest of the material from GE-ANP APEX-910: Application Studies.

First up, we have nuclear power-package applications.

This is a really interesting idea.   There's not much information in the document about it and I haven't had time to go looking elsewhere, but the basic idea was to take the concepts developed for the GE direct-cycle nuclear turbojet - an air-cooled, ceramic-fueled reactor - and turn it into a miniaturized helium-cooled reactor for "mobile" applications.   These would be simple, compact power reactors designed to run until their fuel was exhausted, then either refurbished and refueled or disposed of.   Two versions were proposed, 601A - for electrical power - and 601B - for maritime propulsion.

There's not much information on the 601A other than this picture:

I'm guessing GE was hoping to get in on the Army Nuclear Power Program with this model.   ANPP was intended to power remote military installations like DEW RADAR sites, where even the high cost of miniaturized nuclear reactors would be cheap compared to the staggeringly high cost of shipping all that diesel fuel.   The 601A was apparently primarily intended for use in places where it could be put underwater, so that the water could act as radiation shielding and as a heat sink.   A tantalizing note says this "makes possible the production of an array of undersea weapons", but what weapons are not specified.   The system would have to be modified to add additional shielding and waste heat exchanger to be used on land.   In some respects, this idea of a mass-produced, simplified, small power reactor reminds me a little bit of modern Small Modular Reactor proposals.

601B power packages would be designed for use on submarines or surface ships, and would be mounted on pylons outside the hull, so that the ocean water could be used as part of the shielding, so that they could be used on vehicles not originally designed for nuclear propulsion, and so that they could be swapped out for new reactors when it was time for maintenance or replacement.

601B's were considered for destroyer escorts and other small surface vessels:

For submarines:

And for hydrofoils and commercial vessels (no pictures of those, sadly).   Incidentally, I don't know anything to speak of about submarines, but I can't help but think the drag from those pods would be pretty noisy.   Any commenters with more knowledge are welcome to chime in.

Finally, we have some more goodies about the nuclear rocket mentioned in my post on APEX-901:

The study was conducted in 1960-1 - i.e., right around the time ANP was winding down, and I suspect GE was looking for new applications for the technology it had spent the last decade developing.   APEX-910 says they hoped to develop of advanced ceramic fuel elements that would allow the same reactor to be used with either air or hydrogen as coolant - quite a feat if they could manage it, given that air is oxidizing and hydrogen reducing.   The reactors would be fast-spectrum - apparently the materials they had in mind have a high absorption cross-section for thermal neutrons, making them impractical for thermal reactors.

What GE had in mind was the development of launch vehicles that would start off as direct-cycle nuclear turbojets, basically analogous to what they'd been developing for ANP.   They consisted of a central, main vehicle:

With three recoverable, unmanned booster vehicles:

Attached at the tips of the wings:

The boosters are nuclear-powered turbo-ramjets, while the main vehicle is a turbo-ram-rocket.   Turbojets, with hydrogen fuel for chemical augmentation, are used to reach Mach 3; the engine then transitions to nuclear ramjet mode to reach Mach 6, where the boosters fall away and the main vehicle transitions from ramjet mode to a nuclear thermal rocket using hydrogen propellant.   The vehicle drops off its whole forward nose section in orbit and returns to Earth:

The report as a whole is kind of confusing - it has these booster vehicles, but then also says "staging is unnecessary"; and it mentions the use of hydrogen in the turbo-ram boosters during the turbojet phase, but then repeatedly refers to the vehicle as an "all-nuclear combination".   Also, there are a bunch of reactors mounted in the aft of the main vehicle that are apparently for "both ramjet and rocket modes of operation", but which are separate from the main power plant for the turbo-ram-rocket?

In any event, these vehicles are used to build up a stockpile of hydrogen in orbit:

Finally, two complete vehicles, each retaining one turbo-ram booster, are mated to the stack to form a very ungainly looking interplanetary vehicle:

This stack then makes the trip to Mars.   As described, the system contains no actual crew landing vehicle, but the turbo-ram boosters would be detached to operate as unmanned reconnaissance drones:

Later flights, we are assured, would actually land on the Red Planet.

Anyway, that's it for APEX-910.   I'm currently working on another article of Those Magnificent Men and their Atomic Machines, tentatively titled "Burning Metal: Early AEC Reactor Development and the Los Alamos Molten Plutonium Reactor Experiment", which should hopefully be done by the end of the Christmas break.   We'll see if I actually manage it.

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