1961 film, 'Remote Repair and Modification of the HRE-2 Core Vessel' digitized

By Dr. Nick Touran, Ph.D., P.E., 2023-07-05 , Reading time: 5 minutes

We’re super excited to announce the recent digitization of a 1961 film detailing a major repair of the Homogeneous Reactor Experiment-2 (HRE-2), a fluid-fueled aqueous homogeneous reactor at the Oak Ridge National Lab in Tennessee This reactor was an early predecessor to molten salt reactors. This is the third of four historical nuclear films in our latest batch of 4K digitizations from 16mm film at the National Archives.

HRE-2 developed a hole that leaked fluid fuel from the core region into the heavy water blanket region. They adjusted procedures and operated in this condition for a while. Later, it developed a second hole and they decided to repair it. This film shows highly specialized tools and equipment allowing them to diagnose and repair the holes remotely. Inside the core the radiation dose rate was a nearly-unbelievable 100,000 R/hr.

I read the story of the HRE-2 vessel leak many years ago in Alvin Weinberg’s autobiography (pg 124), so when I learned that there was an old video describing its repair, I knew it had to be digitized. This is an extremely rare film that probably hasn’t been viewed by hardly anyone since the 1960s… until today!

1961 US Atomic Energy Commission video entitled “Remote Repair and Modification of the HRE-2 Core Vessel” showing the repair of the HRE-2 core vessel after it got two holes in it, digitized by us from the National Archives (NAID 88244)

Catalog description: Illustrates the remote repair and modification of the HRE-2 core vessel, following the formation of two holes which permitted transfer of fuel to the blanket side of the reactor. Shows how special equipment had to be designed for repairing the HRE-2, and the problems involved in working with the reactor where the radiation level in the vessel was greater than 100,000 Roentgen per hour.

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

Some stills from the film

Read more about HRE-2

Contents of the film by timestamp include:

  • 00:00 Intro
  • 01:14 Description of HRE-2 systems
  • 03:09 Description of core vessel and first hole
  • 04:22 Remote viewing and diagnostics
  • 05:02 This is the hole
  • 05:18 Full-scale mockup flow tests
  • 07:14 Repair and modification plans
  • 08:17 Access options and hazards
  • 09:10 Development and testing of repair tools
  • 10:59 Blanket viewing device
  • 11:34 Articulated TV camera
  • 12:23 Underwater cutting of diffuser plates
  • 14:48 Cleaning tools
  • 15:21 Thermoplastic hole impression device
  • 16:30 Specimen removal saw
  • 17:55 Patch placement tool and patching
  • 19:23 Upper hole patch with dissolvable head
  • 20:06 Tool contamination precautions
  • 20:35 The actual repair
  • 21:28 Resuming operation at low power

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

See Also

All our video digitization announcements:


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