Treasure trove of documents about the ML-1, the US Army’s trailer-mounted, nitrogen-cooled, atomic fission-heated generator
I recently published an article featuring a video from the Army Nuclear Power Program that focused on the Army’s mobile, low power closed cycle nitrogen cooled nuclear reactor designated the ML-1.
The article generated a good discussion that indicated a strong desire for more information about the program. My initial searches didn’t turn up a great deal of information, but this morning I happened across a treasure trove of documents that answer almost any question one might think of asking about the program. The key was finding a reference to a unique program acronym.
The seven documents are a sampling of Army Gas Cooled Reactor Systems Program (AGCRSP) quarterly progress reports with dates ranging from January 1960 – January 1966. They are available as excellent quality scanned PDFs from the University of North Texas digital library. Each document includes a good bibliography that might provide useful search terms to locate even more detailed information.
One of the more useful parts of the treasure trove was an appendix in the final report in the series titled ML-1 Plant Characteristics. It provides ten pages worth of tabulated information about pressures, temperatures, burn-up, dose rates, weights, dimensions, consumables, auxiliary power requirements, neutron flux and many other details for the technically minded.
The UNT digital library also includes a copy of the ML-1 Design Report, a must read document for all who are intensely interested in this subject.
One of the more intriguing aspects about the document library was seeing the General Tire logo on each of the cover pages. Who knew?
Now I’m on the hunt for a preliminary feasibility study for the ML-2 that was mentioned in the progress reports.
I’m also starting the search for the record of decision that resulted in AGCRSP defunding and cancellation at the end of October 1965. The case is very cold, since the final act happened almost exactly 50 years ago, but it will be interesting to see if it’s possible to determine who killed the promising program.
The wiki entry on Aerojet is interesting. Started by Theo von Karman. The connection to General Tire is from the rubber compounds used in the solid rocket fuel.
I used to cross the “Aerojet canal” on my drive from Key Largo to Turkey Point.
https://en.wikipedia.org/wiki/Aerojet
Rod – thanks for these! As you say, it’s a treasure trove.
The ML-1 Plant Characteristics report confirmed my initial judgement that the reactor is fueled with highly enriched uranium 235 – it’s 93% HEU. I judge that right now, regulators, non-military users, the general public, and especially anti-nuclears, won’t be willing to accept the stigma of HEU. They also won’t be particularly comfortable with the dose rates from the shut down reactor during transport. Even though the dose rates IMO wouldn’t present a hazard to the vehicle drivers, never mind anyone a kilometer distant.
Still, It’s a great peek at the technical aspects of reactor engineering. Thanks again!
@Andrew Jaremko
Don’t forget that we’ve had more than 50 years worth of technical developments since the ML-1. It is a marker and a hint of a path not (yet) taken.
My fascination with closed cycle gas turbines stems from a long lived desire to marry the characteristics of atomic fission (energy dense fuel, emission free heat production, essentially inexhaustible fuel sources) with the same low cost heat conversion systems that make natural gas power plants so cheap, light, simple to operate, and easy to maintain when compared to steam turbine power plants with the same power capacity.
As Bob Hargraves repeats, nuclear energy will succeed when it is cheaper than coal.
If someone can skillfully combine a better fuel source and a cheaper power conversion system, it would take a lot of creative hurdle erection to prevent a closed cycle gas turbine from being more expensive than a competitive coal (or natural gas) power plant.
Rod – how much do you know about supercritical C02 and what is your opinion of a supercritical C02 power conversion system?
@Todd Neuman
Supercritical CO2 is technically interesting. It isn’t a proven path to dramatic cost reductions by simple adaptation of machines that are already in series production.
Nitrogen interests me because it’s enough like air to use the same turbo machinery.
Have they released the info on the Nuclear powered airplane yet?
@Rich
Who is “they” in this context? Do you mean the digital library at University of North Texas?
In the 60’s at Navy Nuclear Power School I heard about the Air Force working on one. Even with our security clearance the instructors could not tell us much about it. As I recall it was a Turbojet like propulsion system. Wouldn’t what they worked on then be applicable to the gas cooled pebble-bed reactors and wouldn’t there be info on metallurgy problems at these temperatures/pressures? From my limited knowledge of the systems, it seems like it could provide the link between your Atomic Engine and the Pebble Bed reactor needed to make a viable product.
@Rich
Yes. There is a good deal of information available about the Aircraft Nuclear Propulsion Program and the HTRE’s (high temperature reactor experiments) that were conducted as part of the program.
Here is a link to an overview – http://www.atomicengines.com/ANP_intro.html
Here is a link to a 1952 vintage document describing the reactor systems http://web.ornl.gov/info/reports/1952/3445603605846.pdf
From the data I’ve seen until now, I’m not convinced natural gas power plants are really easy to maintain.
Whilst gas is a small part of the French generation it’s definitively a disproportionate portion of the unscheduled non-usability incident registered by the French grid operator RTE https://clients.rte-france.com/lang/fr/visiteurs/vie/prod/indisponibilites.jsp
Coal has quite a lot too, but the remaining units are near their end of life.
@jmdesp
You are probably right about the maintenance issues associated with natural gas heated Brayton cycle power plants operated as peaker units. My unprovable estimation, however, is that a closed Brayton cycle machine operating as a baseload or intermediate load follower with a clean, inert gas working fluid would have fewer maintenance problems. Many equipment failures are caused by either cyclic load stresses, repeated temperature cycles, or chemical corrosion. All of those causes are mitigated in my currently non-existent machines.