Plutonium and Neptunium
Conversion Using Modified
Direct Denitration
L. K. Felker
Nuclear Science and Technology Division
Oak Ridge National Laboratory
Actinide and Fission Product Partitioning and Transmutation
Eighth Information Exchange Meeting
Las Vegas, Nevada
November 9-11, 2004
Development of Direct Denitration
 Initial development work on uranyl nitrate
conversion to uranium oxide
 Direct denitration produced a low-surface-area
glassy product
 Product would require further processing to obtain
desired ceramic properties
 Ceramic properties should be comparable to oxide
obtain by ammonium diuranate (ADU) process
 Incorporation of an additive to the uranyl nitrate
solution produced oxide with desired ceramic
properties; thus named the Modified Direct
Denitration (MDD) process
OAK RIDGE NATIONAL LABORATORY
U. S. DEPARTMENT OF ENERGY
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Why Direct Denitration?
 Spent fuel processing
produces a number of
purified product streams
 Typical product is in nitric
acid solution
Reactors
 Conversion to solid form
needed for recycle, storage,
or disposal
Chemical Processing
 Direct conversion to oxide
with proper ceramic
properties for recycle ideal
Fuel Fabrication
OAK RIDGE NATIONAL LABORATORY
U. S. DEPARTMENT OF ENERGY
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Scope of MDD Study
 Establish capability to prepare oxides by MDD
method on a laboratory scale
 Convert Pu/Np product fractions from nitrate
solutions to oxides via the MDD method
 Co-convert U/Pu and other uranium mixtures to
oxides via the MDD method
 Determine ceramic properties of the oxide products
for comparison with fuel fabrication specifications
OAK RIDGE NATIONAL LABORATORY
U. S. DEPARTMENT OF ENERGY
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Schematic of MDD Test Equipment
O ff-g as
C o n d en se r
F eed
T an k
S c ru b b e r
A ir p u rg e
P um p
C o n d en sa te
C o lel c toi n
R o ta ry K inl F u rn ace
O x di e P ro d u c t
OAK RIDGE NATIONAL LABORATORY
U. S. DEPARTMENT OF ENERGY
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Photograph of MDD Test Equipment
OAK RIDGE NATIONAL LABORATORY
U. S. DEPARTMENT OF ENERGY
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Cerium Nitrate Testing
 Established basic
parameters:
 Established operational
parameters
- Furnace temperature
- Feed concentration
- Incline angle
- Feed addition rate
- Tube rotation rate
- Material balances
- Air purge
- Condensate carryover
- Vacuum
- Condensate recycle
OAK RIDGE NATIONAL LABORATORY
U. S. DEPARTMENT OF ENERGY
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Cerium Testing Results and
Observations
 A slight incline angle resulted
in stable temperature, steady
off-gas rate, and constant
product rate
 Concentrated feed reduced
evaporative loading of the
furnace
 Air purge adjusted to move
vapors but limit entrainment
 Material balances complicated
by accumulation of oxide
inside furnace tube
 Good acid balance between
feed and condensate
 Cerium oxide product was
agglomerated but easily
broken by sieving
 Average particle size in the
range of 200 μm
 Tap density of cerium oxide
measured to be ~0.7 g/cm3
 Cerium oxide in the
condensate removed by
filtration
 Acidic condensate recycle
was investigated and proved
successful
OAK RIDGE NATIONAL LABORATORY
U. S. DEPARTMENT OF ENERGY
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Plutonium Conversion Results and
Observations
 Feed contained lower than
desired Pu conc and higher H+
conc
 Dilute feed resulted in higher
off-gas rate and increased
entrainment
 Pu loss to the condensate was
~1%
 With neutralization and filtration,
Pu in condensate reduced by a
factor of ~300
 Pu oxide product was freeflowing powder with tap density
of ~3 g/cm3
OAK RIDGE NATIONAL LABORATORY
U. S. DEPARTMENT OF ENERGY
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Future Direction
 Test Pu nitrate conversion at higher Pu
concentration
 Investigate the co-conversion of U/Pu
solutions
 Investigate the co-conversion of U/Pu/minor
actinide solutions
OAK RIDGE NATIONAL LABORATORY
U. S. DEPARTMENT OF ENERGY
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Acknowledgements
Technical Direction: Emory Collins
Equipment Design: Ray Vedder
MDD Operation: Ray Vedder and Ron Brunson
Funding: DOE Office of Nuclear Energy
through AFCI Separations
Jim Laidler, National Technical Director
OAK RIDGE NATIONAL LABORATORY
U. S. DEPARTMENT OF ENERGY
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