Hydrothermal Testing of K Basin Sludge and N Reactor Fuel at Sludge Treatment Project Operating Conditions

Technical Report · Fri Mar 30 04:00:00 EDT 2007

DOI:https://doi.org/10.2172/936766· OSTI ID:936766

Delegard, Calvin H; Schmidt, Andrew J; Thornton, Brenda M

The Sludge Treatment Project (STP), managed for the U. S. DOE by Fluor Hanford (FH), was created to design and operate a process to eliminate uranium metal from K Basin sludge prior to packaging for Waste Isolation Pilot Plant (WIPP). The STP process uses high temperature liquid water to accelerate the reaction, produce uranium dioxide from the uranium metal, and safely discharge the hydrogen. Under nominal process conditions, the sludge will be heated in pressurized water at 185°C for as long as 72 hours to assure the complete reaction (corrosion) of up to 0.25-inch diameter uranium metal pieces. Under contract to FH, the Pacific Northwest National Laboratory (PNNL) conducted bench-scale testing of the STP hydrothermal process in November and December 2006. Five tests (~50 ml each) were conducted in sealed, un-agitated reaction vessels under the hydrothermal conditions (e.g., 7 to 72 h at 185°C) of the STP corrosion process using radioactive sludge samples collected from the K East Basin and particles/coupons of N Reactor fuel also taken from the K Basins. The tests were designed to evaluate and understand the chemical changes that may be occurring and the effects that any changes would have on sludge rheological properties. The tests were not designed to evaluate engineering aspects of the process. The hydrothermal treatment affected the chemical and physical properties of the sludge. In each test, significant uranium compound phase changes were identified, resulting from dehydration and chemical reduction reactions. Physical properties of the sludge were significantly altered from their initial, as-settled sludge values, including, shear strength, settled density, weight percent water, and gas retention.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 936766
• Report Number(s): PNNL-16496; 830403000
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
CORROSION
DEHYDRATION
DESIGN
HYDROGEN
Hanford
K Basin
K Basin Closure (KBC)
K West Basin
KE Basin
K East Basin
KW Basin
N Reactor Fuel
N-REACTOR
PACKAGING
PHOSPHORS
PHYSICAL PROPERTIES
RETENTION
SHEAR PROPERTIES
SLUDGES
Sludge Treatment Project (STP)
TESTING
URANIUM
URANIUM COMPOUNDS
URANIUM DIOXIDE
WATER
WIPP
X-ray diffraction (XRD)
characterization
corrosion process
dehydrated schoepite
energy dispersive spectroscopy (EDS)
hydrothermal treatment
ianthinite
metaschoepite
phase identification
scanning electron microscopy (SEM)
shear strength
sludge rheology
soddyite
spent nuclear fuel
unconfined compressive strength
uranium
uranium metal reaction