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The first
step in Fernald’s production process was the purification of
uranium. In the early years, the site processed uranium ore,
including pitchblende ore from the Belgian Congo, through a series
of chemical processes. Later, Fernald extracted uranium from scrap
metal or recycled material (i.e., floor sweepings, dust collector
and production residues) received from on-site operations and
other nuclear weapons complex sites.
Incoming
material was weighed, sampled, dried, ground and classified using
crushers, mills and samplers in Plant 1, and then drummed and transported to
Plants 2&3, where the material was converted to
uranium trioxide. Initially, the material was dissolved in
nitric acid to produce a crude uranyl nitrate (UNH) solution for
solvent extraction purification. Purified UNH was then
concentrated by evaporation and thermally denitrated to uranium
trioxide, called orange oxide. The orange oxide was either
shipped to the gaseous diffusion plant in Paducah, Ky., or was
transported to Plant 4,
where it was converted to uranium tetrafluoride, called green
salt, for reduction to metal.
As an
intermediate step, uranium trioxide was converted to uranium
dioxide, called brown oxide, by reducing it with hydrogen. The brown oxide was then reacted with anhydrous hydrogen fluoride
to produce green salt. Fernald also produced green salt from
uranium hexafluoride received from other sites in the nuclear
weapons complex.
The green
salt was packaged in 10-gallon cans and transported to the metal
production operations in Plant 5,
where it was blended with magnesium-metal granules, placed in a
closed reduction pot and heated until the contents reacted,
producing a uranium mass called a derby. The product, which
resembled the top of a man’s derby hat, weighed up to 370
pounds.
Fernald
shipped some derbies to other DOE sites but most were re-melted
inside a vacuum induction furnace and poured into pre-heated
graphite molds to form ingots.
Ingots varied in weight, size and shape, from 10 inches in
diameter, 23 to 40 inches in length, and weighing up to 1,400
pounds. Fernald sent ingots to the RMI Facility in Astabula,
Ohio, where most were extruded and then sent back to the Fernald
site for heat treatment and final machining to target element
cores for Savannah River in South Carolina. Enriched uranium ingots were
prepared by RMI to produce a billet for direct shipment to Hanford
in Washington. In Plant
6, ingots were cut to various lengths and
then machined to very tight specifications for the Savannah River
site.
The Fernald
site served as the thorium repository for DOE and maintained
long-term storage facilities for a variety of thorium materials. On several occasions from 1954 through 1975, the Fernald site
produced small amounts of thorium in Plant 8, Plant 9 and
the Pilot Plant.
Throughout
the production years, the Fernald site’s products were used at
many different sites within the nuclear weapons complex. From 1952 through 1976, depleted, normal
and enriched uranium cores and fuel core elements were fabricated for both Hanford and Savannah River.
From 1976
until 1989, the main products were depleted uranium fuel elements
for Savannah River, enriched extrusion ingots and billets for
Hanford, derbies for Oak Ridge in Tennessee and Rocky Flats in
Colorado, and slab billets for Rocky Flats.
Over the
years, Fernald site personnel also shared their expertise and site
resources with other government sites and private industry as part
of the Work-for-Others program. The purpose of the program
was to share beneficial uranium technologies with other sites. A variety of products were produced for the program, including
armor-piercing uranium missile components and uranium ballasts.
In July
1989, Fernald site management shut down uranium metal production
to focus on environmental compliance and waste management issues. Later that year, the U.S. Environmental Protection Agency added
Fernald to its National Priorities List of federal facilities
needing remediation. Since then, the Fernald workforce has been
dedicated to cleanup, waste management and final restoration of
the site.
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