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FOR IMMEDIATE RELEASE:
January 22, 1999
For additional information
contact:
James Jordan, President
of the Radioactive Isolation Consortium james.jordan@ricllc.com
Technology Development
Data Sheet on the AVS technology
Development of an
Advanced Vitrification System (AVS)
Problem. For permanent
disposal of high level radioactive nuclear waste material (HLW) now stored
at former nuclear materials production sites, such as Hanford and Savannah
River, the HLW must be incorporated into a stable, environmentally safe
glass that can be placed in a long-term geologic repository. The presently
proposed approach for producing the HLW glass involves melting a mixture
of HLW and glass-making material ("frit") in a large, open, electrically
heated, high temperature, refractory lined container (the "melter") and
pouring the resultant highly radioactive liquid glass into open stainless
steel canisters, which are then welded shut, externally decontaminated,
and sent to the repository.
The above approach is expensive,
requires complex multiple remote handling operations, and generates a large
amount of radioactive emissions and contamination. Moreover, the melter
and its associated equipment must operate reliably for many years at high
temperatures (~1200C), while subjected to corrosive molten glass. Furthermore,
because of the material and operational limitations of the melter, the
HLW loading in the product glass is low, only about 25% by weight, necessitating
a large number of disposal canisters, and the melter is restricted in the
composition of the HLW waste it can process.
Solution. The
Advanced Vitrification System (AVS) is a new approach in which HLW/frit
mixtures are directly melted inside final disposal modules, which, after
cooling, are sent to the geologic repository. An AVS module (figure below)
consists of a conventional stainless steel canister having an internal
alumina lined graphite crucible. The crucible holds the HLW/frit mixture
to be melted and is thermally insulated from the module's outer steel canister.
When inductively heated by a low frequency (~30 Hertz), externally applied,
AC magnetic field (~300 Gauss), the graphite/alumina crucible reaches a
high temperature (i.e., ~1300C or greater), while the insulated outer steel
canister remains at near ambient temperature. Radioactive emissions and
contamination are minimized during module processing, since the modules
are connected to an off-gas handling system prior to their final sealing.
The AVS technology is reliable
and robust for three principal reasons: 1) The high temperature materials
in the module are exposed to molten glass only once for only a few hours,
instead of the many planned operating cycles for conventional melters;
2) One-time use of the melter means that the AVS module can process a wider
range of HLW compositions than a conventional melter; and, 3) Failure of
a module will not stop system operation, which is not the case for conventional
melters.
The AVS technology is more
economical because the AVS modules will vitrify a higher percentage of
HLW, typically 70%, instead of the 25% for conventional melters. This
feature reduces the number of disposal canisters required and the consequent
cost of disposal. The AVS technology may be the only technology available
to produce fewer than 8,000 canisters from the Hanford high level wastes.
Application and Benefits.
The AVS system can be applied to a wide range of high level wastes, low-level
wastes, mixed wastes, and toxic wastes stored at numerous sites, including
former production sites like Hanford, Savannah River, Idaho National Engineering
Laboratory, Rocky Flats, etc. It would also have direct application to
vitrify weapons grade plutonium and uranium at sites in the U.S. and former
Soviet Union.
As compared to the conventional
melter approach for HLW vitrification, the AVS system offers the following
benefits:
-
Increased safety and reduced
environmental impact and worker exposure from lower radioactive emissions
and contamination, during operation and after decommissioning.
-
Greater system reliability and
robustness.
-
Higher HLW loading in product
glass and fewer disposal canisters.
-
Can handle a wider range of
HLW compositions.
-
Lower costs, both capital and
operating, than conventional melter facilities.
-
Can be implemented more quickly
and finish the vitrification campaign earlier.
-
Can operate in a cost-effective
manner at sites with relatively small amounts of HLW.
-
Able to technically evolve more
easily than large, fixed, costly conventional melters (i.e., new-HLW waste
types, higher loadings, etc.).
In addition, the closed AVS
graphite crucible is a geologically stable engineered safely barrier for
the product glass it holds, in contrast to the stainless container in conventional
canisters, which is assumed to corrode and disappear in a few hundred years.
The graphite container is expected to survive for millions of years, preventing
leaching of the radioactive HLW product glass.
Technology.
Technology for the various module components already is in place. Initial
tests of simulated HLW AVS product glass have demonstrated successful vitrification
at simulated HLW waste loadings of 70%. The graphite and alumina crucibles,
thermal insulation, and stainless canisters can be manufactured in existing
commercial factories at modest cost. The inductive AC heating and air cooling
equipment for the module are also available commercially.
Preliminary design of an
AVS module process facility has been carried out. The module remote handling
and inspection equipment, hot cells, etc., all appear well within the present
state of the art. The cost of the AVS process facility has been estimated
to be well below the cost of an equivalent facility based on the conventional
melter approach.
Schedule. Demonstration
of an operating sub-scale AVS module prototype facility using simulated
HLW feed would be completed 24 months after initiation of a funded project. The facility would
produce 2 scale modules (i.e., 1 foot in diameter compared to 2 feet full
scale and 6 feet in length compared to 15 feet full scale). The next step
would be a full scale hot (i.e., actual radioactive HLW feed) pilot facility
at Hanford, which could be in operation about 3 years after the completion
of the 2 scale prototype.
Contacts
Mr. James Jordan, Chief
Executive Officer
Mr. Louis Ventre, Executive
Vice President
Dr. Morris Reich, Co-Principal
Investigator
Dr. James Powell, Co-Principal
Investigator
Radioactive Isolation Consortium,
LLC
708 East Broad St.
Falls Church, VA 22046-3610-3610
Tel # (703) 241-8711
Fax # (703) 241-8714
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