Project Y: the Los Alamos Story - Edith C. Truslow, Ralph Carlisle Smith
Edith C. Truslow, Ralph Carlisle Smith - Project Y: the Los Alamos Story, pp.334-335.
Metal fabrication
The Metal Fabrication Group, CM-7, was supervised by J. M. Taub, until December 1945 when it became CMR-6. There were no changes in the group functions or leadership. The group did extremely varied work for CMR Division and the other technical divisions. Its routine services included refractories, general foundry work with uranium and special alloys, plastic services, electroplating, and general powder metallurgy.
CMR-6 also conducted research on problems peculiar to their work and completed a new process for fabricating uranium spheres in July 1946. This process involved new vacuum casting furnaces and machining jigs and made it possible to make two, or possibly three, castings per day instead of one.
[...]
Another interesting job was recovery of normal uranium metal from the shop turnings. Vacuum casting charges of 100% down to 50% briquetted turnings with the rest good uranium metal yielded only 50% metal recovery. In August 1946, a different method consisting of melting in air under a barium chloride flux and then bottom-pouring into a graphite mold was first used. This yielded recoveries up to 65% when one-third of the charge was virgin metal. When Ames biscuit metal was used as the virgin metal, the metal recovery increased to 77% of the turnings, with 100% recovery of the virgin metal assumed. Remelting of the uranium turnings (approximately 7000 pounds were on hand) began October. With the equipment available, one man could process 60 lb of turnings per day. Larger briquetting dies were in process, which wouId at least triple this output.
Metal production
The methods for recovery and purification of U-235 at the end of 1945 were not well worked out and were inefficient and unsafe.
Group CMR-8, supervised by R. D. Baker, carried the production load as well as conducting research in the field. In fact, CMR-8 continued to produce all the U-235 metal for the Manhattan Engineering District. However, it was impossible for the group to conduct intensified research until it had absorbed the personnel from CMR-10 in February 1946. After that, it began to develop processes for recovery of U-235 from all residues originating at the project.
A more efficient, less hazardous hydrofluorination process for converting purified oxide to the tetrafluoride made it possible to start putting large quantities of U-235 back into circulation.
Late in 1946, all the installations the group used in D and M Buildings were overhauled to reduce the contamination danger. Dryboxes and equipment for enclosing the reduction operations on U-235 were installed.
Metal fabrication
The Metal Fabrication Group, CM-7, was supervised by J. M. Taub, until December 1945 when it became CMR-6. There were no changes in the group functions or leadership. The group did extremely varied work for CMR Division and the other technical divisions. Its routine services included refractories, general foundry work with uranium and special alloys, plastic services, electroplating, and general powder metallurgy.
CMR-6 also conducted research on problems peculiar to their work and completed a new process for fabricating uranium spheres in July 1946. This process involved new vacuum casting furnaces and machining jigs and made it possible to make two, or possibly three, castings per day instead of one.
[...]
Another interesting job was recovery of normal uranium metal from the shop turnings. Vacuum casting charges of 100% down to 50% briquetted turnings with the rest good uranium metal yielded only 50% metal recovery. In August 1946, a different method consisting of melting in air under a barium chloride flux and then bottom-pouring into a graphite mold was first used. This yielded recoveries up to 65% when one-third of the charge was virgin metal. When Ames biscuit metal was used as the virgin metal, the metal recovery increased to 77% of the turnings, with 100% recovery of the virgin metal assumed. Remelting of the uranium turnings (approximately 7000 pounds were on hand) began October. With the equipment available, one man could process 60 lb of turnings per day. Larger briquetting dies were in process, which wouId at least triple this output.
Metal production
The methods for recovery and purification of U-235 at the end of 1945 were not well worked out and were inefficient and unsafe.
Group CMR-8, supervised by R. D. Baker, carried the production load as well as conducting research in the field. In fact, CMR-8 continued to produce all the U-235 metal for the Manhattan Engineering District. However, it was impossible for the group to conduct intensified research until it had absorbed the personnel from CMR-10 in February 1946. After that, it began to develop processes for recovery of U-235 from all residues originating at the project.
A more efficient, less hazardous hydrofluorination process for converting purified oxide to the tetrafluoride made it possible to start putting large quantities of U-235 back into circulation.
Late in 1946, all the installations the group used in D and M Buildings were overhauled to reduce the contamination danger. Dryboxes and equipment for enclosing the reduction operations on U-235 were installed.