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Pangea is currently engaged in remediation activities at the
Spectrulite Consortium Inc. (SCI) facility in Madison, IL. The facility was originally built during World War II to build
tank torrents. Starting in the 1950’s, the facility was used to produce
a magnesium-thorium alloy (MgTh). Although radioactive, this alloy was
commonly used in military aircraft from that period. The last
production run of MgTh was in 1982; shortly before the facility was
purchased by SCI.
May 2003
Pangea conducted a Multi-Agency Radiation Survey & Site Investigation (MARSSIM).
This initial step in the decommissioning process helped to define the
criteria necessary for a more comprehensive characterization effort
performed by Pangea in October 2004. The data produced by the
characterization effort was in turn used by Pangea to craft a
decommissioning plan that was accepted by the Illinois Emergency
Management Agency in December of 2005. The decommissioning effort
encompassed the final steps for terminating the SCI radioactive
materials license and returning the facility to unrestricted use.
Excavation of Contaminated
Soils:
The primary radiological contamination source on the site was the
production of a series of MgTh alloys. Magnesium was introduced via
ingots that were melted in large casting “pots” and a Thorium “hardener”
was added. The former license holders (prior to SCI ownership) used an
area outside of the casting building to clean the pots with an acid wash
solution and dumped the resultant waste on the ground. Contaminates in
soil were discovered as far as 6 feet below the surface. The excavation
was a complicated process due the maze of utilities running through the
area, all encased in vitrified clay pipe dating from the construction of
the facility. Pangea needed to excavate the contaminated soil, perform
radiological walkover surveys to ensure that all contaminates were
removed, and performed soil sampling to confirm that the contamination
levels in the soil were below release criteria.
Rafter Vacuuming:
The facility has an open floor plan with multiple acres under roof.
Most of this area is served by a system of mobile cranes that are
perched approximately 50 feet above the work area. The rafter system
begins at approximately 60 feet above the work area and is covered in
sediment. The sediments are a mixture of contaminated and
uncontaminated dust from casting and other operations as well as
biological matter from birds that have historically roosted inside the
buildings. Pangea used high velocity HEPA vacuums to remove the
sediment and radiological surveys were performed to confirm that the
rafters fall below the area-based contamination guidelines.
Remediation of the Dross Storage
Room:
As a part of the casting process, contaminates (including Thorium)
would be liberated from the molten material and separated. The
undesirable compounds, referred to as “dross”, were collected and placed
into 55-gallon barrels. Unfortunately, several barrels in the
Dross Storage room underwent expansion, structural failure, and
eventual loss of contents in the late 1990s. All material in the
area has been removed along with the legacy asbestos materials as part
of the remediation process. Floors and walls were then
scabbled, removing up to 3/4 inch of contaminated concrete.
Radiological surveys later confirmed that contamination levels were
below release criteria.
Transportation and Disposal:
The Spectrulite Decommissioning Project generated considerable amounts
of waste: contaminated soils, rafter sediments, scabbled building
materials, and used personal protective equipment. Pangea used a
combination of high-sided gondola cars and roll-off trailers to minimize
both transportation cost and demurrage. Aggressive waste segregation
and multiple disposal sites were used to minimize disposal costs and
turn around times for transportation containers.
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