NEWS MEDIA CONTACTS:
September 29, 1999
Steven Wyatt, 423/576-0885
Jeff Sherwood, 202/586-5806
Past Recycled Uranium Programs Under Review as
Energy Department Investigation Continues
Provides Updated Information on Cold War Era Operations
The Department of Energy (DOE) has completed an initial stage of a technical
review of past operations involving recycled uranium at gaseous diffusion
plants located in Paducah, Kentucky; Oak Ridge, Tennessee; and Piketon,
Ohio. The study of recycled uranium is being conducted in parallel with a
two-phase investigation ordered by Secretary of Energy Bill Richardson into
environment, safety and health concerns at the gaseous diffusion plants.
The review of the gaseous diffusion plants provides updated information on
the nature and extent of past activities involving the processing,
conversion and enrichment of recycled uranium containing trace quantities of
plutonium, as well as neptunium and technetium-99.
"We reviewed these sites first because of the nature of the work they
conducted and a higher potential for worker exposure to contamination than
other sites involved in uranium recycling operations," said David Michaels,
Assistant Secretary for Environment, Safety and Health. "Today's
information on material flow is intended to clarify and update what is known
about past operations at the gaseous diffusion plants from the early 1950s.
The numbers are preliminary, and as we validate and refine our results they
could change, but I don't expect them to change significantly."
The technical review is part of a DOE-wide study of the flow of recycled
uranium to determine where and how much processed recycled uranium was
shipped as well as an assessment of the potential for worker radiation
exposure. (The attached chart lists DOE sites currently identified as
having a role in activities involving recycled uranium.) This information
will enable the Energy Department to determine if more extensive reviews of
personnel exposures or environmental contamination are required.
Activities involving recycled uranium use at the Paducah Gaseous Diffusion
Plant are much better known than at other DOE sites because the issue of
contaminants in the Paducah feed was reviewed during the 1980s. To gather
information on uranium recycling activities at other sites, DOE has formed a
department-wide working group and will task teams at the sites to gather
data. The overall data collection is expected to be completed in March
2000, with a final consolidated department-wide report to be prepared by
June 2000. The complex-wide review will also include depleted uranium
hexafluoride storage cylinders as well as depleted uranium used in other
applications.
To date, the department has identified 10 DOE sites in addition to the
Paducah plant that processed recycled feed materials containing trace
quantities of plutonium and other transuranics from the 1950s. The amounts
of materials processed, the numbers of workers involved and the relative
concentrations of contaminants varied widely between these sites and will be
confirmed in the ongoing study. For example, current estimates show the
Paducah plant processed the majority of these materials, with the Oak Ridge
Gaseous Diffusion plant handling about a sixth as much and the Portsmouth
plant in Ohio processing approximately 1% of the amount processed at
Paducah. The Fernald facility in Ohio also processed amounts and
concentrations comparable to those of the gaseous diffusion plants.
Chemical separation facilities that made uranium feed materials -- such as,
Savannah River, Hanford, Idaho and West Valley -- and material processing
sites that processed uranium oxide into metals or other forms in various
amounts -- such as Weldon Spring -- are not believed to have the potential
for worker exposures from processes that concentrated transuranics which are
being examined at the gaseous diffusion plants.
Other DOE and military facilities have been identified on a preliminary
basis as receiving uranium material for component fabrication and
applications of a commercial or military nature. While the trace
concentrations associated with this latter category of facilities are
believed to be insignificant from a safety standpoint, as part of its
ongoing investigation, DOE is working with the Defense Department, the
Nuclear Regulatory Commission and other agencies to confirm amounts
processed and concentrations involved.
At the Paducah uranium enrichment plant, recycled uranium was introduced
into the enrichment "cascade" shortly after the startup of the plant in 1953
and continued through 1964. Activities were resumed in 1969 and continued
through 1976. Paducah received approximately 100,000 tons (90,000 metric
tons) of recycled uranium containing an estimated 328 grams of plutonium,
18.4 kilograms of neptunium and 661 kilograms of technetium-99. Operations
at Paducah included the conversion of uranium oxide to uranium hexafluoride
at a feed plant located onsite. The converted material was subsequently
introduced into the gaseous diffusion "cascade" for further enrichment.
The average concentration of plutonium in recycled uranium at all three
gaseous diffusion plants is estimated to be about four parts per billion.
At both Paducah and Oak Ridge sites, the majority of the plutonium and
neptunium was separated out as waste during the initial chemical conversion
to uranium hexafluoride. Because of this, only a fraction of the plutonium
contamination was actually introduced to the gaseous diffusion cascade at
either plant. This waste was subsequently reprocessed to recover additional
uranium and then reused.
Of the 328 grams of plutonium present in the 100,000 tons of recycled
uranium processed at the Paducah plant, only 0.1 gram of plutonium is
estimated to have been introduced into the Paducah cascade. Transuranics
including plutonium are believed to have been deposited on internal surfaces
of the feed process equipment, with concentrations also being deposited in
waste products.
Processing of recycled uranium at the Oak Ridge Gaseous Diffusion Plant
began in the early 1950s with the first shipments of recycled uranium oxide
from Hanford. A uranium hexafluoride feed plant was operated at Oak Ridge
from 1952 until 1961. Recycled uranium was fed to the Oak Ridge enrichment
cascade from 1958 to 1962, from 1970 to 1974 and from 1976 to 1977.
The Oak Ridge Plant received approximately 17,800 tons (16,238 metric tons)
of recycled uranium. DOE officials believe that the majority of this
recycled uranium went through the process of conversion from uranium oxide
to uranium hexafluoride. A small fraction of this material was of foreign
or commercial origin. Of the recycled uranium received, it is known that
approximately 5,800 tons of this amount were fed into the Oak Ridge
enrichment cascade. The majority of the remaining 12,200 tons of recycled
uranium is assumed to have been enriched at Paducah.
Of the 17,800 tons of recycled uranium received at Oak Ridge and converted
to uranium hexafluoride, DOE estimates that the material could have
originally contained up to 60 grams of plutonium, 3.5 kilograms of neptunium
and 103 kilograms of technetium-99. An additional 121 kilograms of
technetium-99 was received from enriched uranium initially processed at
Paducah and further enriched in the Oak Ridge plant.
It is currently estimated that the Portsmouth Plant processed a relatively
small quantity of recycled uranium as compared to Paducah and Oak Ridge
plants. Up to 1,320 tons (1,200 metric tons) of this material entered the
enrichment cascade at Portsmouth. Most of this material, 1,210 tons (1,100
metric tons), was received as uranium hexafluoride from Oak Ridge and
Paducah sites. The remaining material came from a variety of facilities in
the DOE complex.
At the Portsmouth site, the oxide conversion facility processed recycled
uranium from 1958 to 1977. Recycled uranium was fed to the Portsmouth
cascade from 1955 to 1958 and in 1961, 1969 and 1974. No estimates are
currently available for the amount of plutonium or neptunium present in the
uranium recycled materials at Portsmouth. However, based on the amount of
recycled uranium received, the amount would likely have been small. The
Portsmouth plant received approximately 85 kilograms of technetium-99
primarily from uranium previously enriched at Paducah and refed into the
Portsmouth cascade.
DOE officials briefed regulators from Kentucky, Tennessee and Ohio on the
review as part of a regular meeting to discuss a number of DOE-related
issues. The meeting was held today in Lexington, Kentucky.
-DOE-
R-99-262