HANFORD-THE COLD
WAR LEGACY
WAR LEGACY
HANFORD TANK WASTE
The United States of America has embarked on a multi-decade, many hundred billion dollar
program to remediate the radioactive waste problem resulting from the production of
nuclear weapons fissile material by reprocessing “low burn-up” fuel irradiated in production
reactors. A significant component of the waste problem exists at the Hanford a where
hundreds of large tanks store hundreds of thousands of cubic meters of radioactive solids
and liquids. The current plan is to separate this material into high-level and low-level
components and then subsequently vitrify both streams for ultimate disposal. The U.S.
Government estimate of the radioactive waste to be vitrified at the Hanford reservation is
shown below. The DOE requested a proposal for an LVPP Demonstration project.
program to remediate the radioactive waste problem resulting from the production of
nuclear weapons fissile material by reprocessing “low burn-up” fuel irradiated in production
reactors. A significant component of the waste problem exists at the Hanford a where
hundreds of large tanks store hundreds of thousands of cubic meters of radioactive solids
and liquids. The current plan is to separate this material into high-level and low-level
components and then subsequently vitrify both streams for ultimate disposal. The U.S.
Government estimate of the radioactive waste to be vitrified at the Hanford reservation is
shown below. The DOE requested a proposal for an LVPP Demonstration project.
The U.S. and all other
nations use “wet chemical”
techniques to separate the
waste stream into high and
low level components. This
approach substantially adds
to the mass of the material
eventually to be disposed
and is very complex, adding
the risk of system failure
sometime during the 30 to
50 year remediation
schedule. Of course, such
risk can be mitigated by
systems redundancy but will
come at a still higher cost
(and further increase the
material ultimately to be
disposed).
nations use “wet chemical”
techniques to separate the
waste stream into high and
low level components. This
approach substantially adds
to the mass of the material
eventually to be disposed
and is very complex, adding
the risk of system failure
sometime during the 30 to
50 year remediation
schedule. Of course, such
risk can be mitigated by
systems redundancy but will
come at a still higher cost
(and further increase the
material ultimately to be
disposed).
The LVPP offers a separation science based on plasma processing, a technology that has already
contributed significantly to progress in the microelectronics industry by replacing “wet chemistry”
manufacturing steps. Our estimates indicate that the LVPP process will result in much lower cost
weapons waste disposal, will eliminate the need to characterize tank materials, will reduce the radioactive
inventory in process flow streams and will eliminate most of the low level waste.
This robust technology incorporates systems initially developed for fusion research and development. In
particular, the “Tokamak” technology has been incorporated in this invention because of its ability,
without electrodes, to routinely produce plasma temperatures and densities high enough to ionize solids
and to confine these ions while they diffuse to the collection system in the plasma chamber and along
specially designed magnetic field paths to deposition stages (divertors and downstream collectors).
A second version of the LVPP incorporates electron beams to efficiently ionize solids in a linear magnetic
geometry.
A key element of the LVPP concept is to ionize and separate the solids in less than a millisecond. This is
to avoid radiation losses from high Z ions. (A single oxygen ion can radiate up to 1 million electron volts
in a microsecond. ) The Tokamak version used in the concept has "poor" confinement time in fusion
reactor terms, but adequate for sufficient mixing to allow separation via the thermal differentiation
technique employed in the concept.
contributed significantly to progress in the microelectronics industry by replacing “wet chemistry”
manufacturing steps. Our estimates indicate that the LVPP process will result in much lower cost
weapons waste disposal, will eliminate the need to characterize tank materials, will reduce the radioactive
inventory in process flow streams and will eliminate most of the low level waste.
This robust technology incorporates systems initially developed for fusion research and development. In
particular, the “Tokamak” technology has been incorporated in this invention because of its ability,
without electrodes, to routinely produce plasma temperatures and densities high enough to ionize solids
and to confine these ions while they diffuse to the collection system in the plasma chamber and along
specially designed magnetic field paths to deposition stages (divertors and downstream collectors).
A second version of the LVPP incorporates electron beams to efficiently ionize solids in a linear magnetic
geometry.
A key element of the LVPP concept is to ionize and separate the solids in less than a millisecond. This is
to avoid radiation losses from high Z ions. (A single oxygen ion can radiate up to 1 million electron volts
in a microsecond. ) The Tokamak version used in the concept has "poor" confinement time in fusion
reactor terms, but adequate for sufficient mixing to allow separation via the thermal differentiation
technique employed in the concept.
A block diagram of the key LVPP subsystems
involved in the waste separation process is shown
on the right (other subsystems such as magnets,
current drive, remote handling, etc. are omitted for
clarity). After de-watering (in the case of weapons
waste) or another head-end process (in the case of
Spent nuclear fuel), the process feed is injected as
pellets or streams into a toroidal “tokamak” plasma
with an initial plasma average “temperature” of about
10,000,000C. The pellets ablate and all of the
constituent atoms are ionized to states
corresponding to a resultant average temperature of
about 1,000,000 C. During the ionization step,
additional power is injected into the toroidal plasma
to maintain the tokamak electromagnetic
configuration and confine the elemental ions while
they diffuse towards the walls of the chamber, where
they 1) strike the collection system in the plasma
chamber and either stick, or 2) are returned to the
plasma or 3) are swept along the specially designed
magnetic guiding fields and are collected on the
“divertor.” Gases. such as hydrogen, oxygen and
nitrogen are primarily collected on cryogenic louvers
located downstream of the divertor deposition.
involved in the waste separation process is shown
on the right (other subsystems such as magnets,
current drive, remote handling, etc. are omitted for
clarity). After de-watering (in the case of weapons
waste) or another head-end process (in the case of
Spent nuclear fuel), the process feed is injected as
pellets or streams into a toroidal “tokamak” plasma
with an initial plasma average “temperature” of about
10,000,000C. The pellets ablate and all of the
constituent atoms are ionized to states
corresponding to a resultant average temperature of
about 1,000,000 C. During the ionization step,
additional power is injected into the toroidal plasma
to maintain the tokamak electromagnetic
configuration and confine the elemental ions while
they diffuse towards the walls of the chamber, where
they 1) strike the collection system in the plasma
chamber and either stick, or 2) are returned to the
plasma or 3) are swept along the specially designed
magnetic guiding fields and are collected on the
“divertor.” Gases. such as hydrogen, oxygen and
nitrogen are primarily collected on cryogenic louvers
located downstream of the divertor deposition.
A mathematical model of the separation process has been developed to predict the deposition of
selected materials in specific subsystems. The Table below presents the results of calculations for a
configuration in which the collection system in the plasma chamber and on the divertor plate are
maintained at a temperature of 900C. The model assumes a maximum ion confinement time of 10
milliseconds (the time it takes for the density of the ionized pellet ions to be reduced to a factor of
1/, or 0.368). It is also assumed that one pellet is injected every seven (7) confinement times. (The
degree of separation becomes increasingly better as the number of confinement times increases.)
The calculation results in the are presented in metric tons of each species and are representative of
the results of processing all the Hanford tank waste via this method. The different louvers (LV1...etc)
collect different elements.
selected materials in specific subsystems. The Table below presents the results of calculations for a
configuration in which the collection system in the plasma chamber and on the divertor plate are
maintained at a temperature of 900C. The model assumes a maximum ion confinement time of 10
milliseconds (the time it takes for the density of the ionized pellet ions to be reduced to a factor of
1/, or 0.368). It is also assumed that one pellet is injected every seven (7) confinement times. (The
degree of separation becomes increasingly better as the number of confinement times increases.)
The calculation results in the are presented in metric tons of each species and are representative of
the results of processing all the Hanford tank waste via this method. The different louvers (LV1...etc)
collect different elements.
