Just digitized: a 1962 film featuring the PM-1 radar-powering nuclear microreactor in Wyoming

We’re extremely excited to announce the first of four historical nuclear films in our latest batch of 4K digitizations from 16mm film at the National Archives. It features the 1 MWe PM-1 military microreactor, a small modular reactor that the US Army manufactured and tested in a factory, disassembled into 16 modules, and air-lifted to the closest airfield by C-130, trucked to site, re-assembled, and then powered a remote Cold War radar station back in 1962. It had direct air cooling, meaning it did not need to be near any water supply. It was designed to be disassembled, moved, and re-assembled as necessary. No field welding was needed for re-assembly. It was a PWR that could be operated by a crew of 2.

1962 US Atomic Energy Commission video about the PM-1 military microreactor, digitized by us from the National Archives (NAID 88220)

Catalog description: A filmed story of the PM-1 nuclear power plant (a pressurized water system), a joint project of the USAEC and the U. S. Air Force, which supplies the power for the radar and space heating of a remote Air Defense Command radar station in Wyoming. The film breaks down the types and contents of 16 air transportable packages, a total weight of about 30,000 pounds: reactor, steam generator, waste tank, heat-transfer apparatus, control room, turbogenerator, etc. Details are given on major components and the design and operation of the system by information on: 741 nuclear fuel tubes in 7 fuel bundles, the "flow" of primary water, the secondary water, details on the makeup of the fuel element tubes, criticality testing, nature of the control rods, tests to determine heat transfer and flow characteristics. The film recounts the airlift of the packages, erection and assembly of the power plant, the work to achieve criticality, and the varied safety controls.

Thanks to Ross Koningstein for his help in making this happen.

Read more about PM-1

As for what happened in the end, the PM-1 Final Summary Report explains the situation clearly. This report contains the lessons learned after operating the military microreactor for 4 years. It highlights all the unplanned outages, maintenance costs, and lists the performance of each individual system. It’s highly readable, but to summarize briefly:

The reactor was difficult to perform maintenance on because of its compactness. The operators recommend designing the next microreactor with maintenance requirements satisfied first, and then compactness requirements
The conventional steam plant cause roughly half of the unplanned outages and required a lot of maintenance, leading the authors to suggest that perhaps a non-steam approach is needed at this small scale (e.g. other energy conversion systems).
The nuclear instrumentation system was oversensitive and overcomplicated for a field plant.
The HVAC system and building design were wholly inadequate
It was difficult to maintain qualified staff to operate and maintain the reactor
The reactor was used as a training reactor for crews headed to Antarctica to operate the sister plant PM-3A, which reduced PM-1’s overall performance.

The best zingers inside include:

In an attempt to correct some of these original design oversights, several modifications and additions have been made to the plant which have made it virtually a stationary plant. Consequently, the Air Force now has a plant that is neither portable nor easily maintainable or operable.

Introduction

Factors that have resulted in this high cost of power production are numerous; however, many of these costs could be reduced or brought into a realistic value by equating a plant such as the PM-1 to a compatible mission. The problems such as overmanning, excessive modification requirement, training requirement due to the policy of giving maximum training to the majority of the crew members, loss of personnel by premature transfers, operating the plant below capacity, and excessive down time (especially during the first 2 years of operation for design improvement) have all added up to present a dim economical picture of nuclear power production.

Summary

Note: I obtained this report through a FOIA request 😎.

There were 5 reactors total built in the Army Nuclear Power Program in remote locations.

Contents of the film by timestamp include:

00:00 Intro
02:30 Package (module) descriptions
03:04 Primary system modules
03:23 Secondary system modules
03:41 Turbine/generator module
03:55 Switchgear module
04:43 Heat transfer equipment module
05:21 Maintenance module
05:50 Decontamination and water chemistry module
06:22 Animations of design
08:37 Fuel element fabrication
10:00 Core testing in the critical facility
12:20 Magnetic jack control rod drives
13:01 Flow testing in 1/4 scale model
13:27 Factory fab and initial assembly
13:51 Airlifting the reactor and flight testing
15:10 Field re-assembly
15:45 Startup testing and criticality
17:10 2-person operation team
17:40 Safety and reliability
19:05 Summary

These are loaded into the youtube video as chapters for your convenience.

Just digitized: a 1962 film featuring the PM-1 radar-powering nuclear microreactor in Wyoming

Some stills from the film

Read more about PM-1

See Also