Microstructure of the simulated Idaho Chemical Processing Plant (ICPP) nuclear wastes and the effect of radiation damage

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5566779

Chan, H W.E.

The simulated Idaho Chemical Processing Plant (ICPP) nuclear wastes are composed of both crystalline and amorphous ceramic phases. The Hot Isostatically Pressed (HIP) waste forms contain cubic CaF{sub 2}, monoclinic and Cubic ZrO{sub 2}, tetragonal ZrSiO{sub 4} and amorphous silicate phases including phase separated glasses. Crystalline phases (radiophases) containing zirconium are tailored to accommodate specific actinides with a 4+ valence such as U{sup 4+}, and CaF{sub 2} is the inert phase (encapsulant phase) of the simulated waste forms. Radiations resulted from fission in actual waste can introduce both displacement and ionization damage which may alter the chemistry, structure and leaching resistance of the different phases. The crystalline phases of the simulated ICPP waste forms are very resistant to both displacement and ionization damage. At doses approaching zircon metamictization, the zirconia and zircon in the simulated wastes retain their crystallinity although displacement defects can be observed in them. There is subgrain formation and rotation suggested by CaF{sub 2} electron diffraction, but CaF{sub 2} remains crystalline after irradiated with an equivalent of 10{sup 20} {alpha}/cm{sup 3} lead ions. The amorphous phases do suffer oxygen bubble formation from ionization damage, and {gamma}-rays are the most while electrons are the least efficient means of introducing these volume defects into the glass phases. Some glassy regions also undergo phase separation from {gamma}-irradiation, and such phase separation can be either a spinodal decomposition type or the albite-mullite phase separation found in the soda-alumina-silica system.

• Research Organization: California Univ., Davis, CA (USA)
• OSTI ID: 5566779
• Country of Publication: United States
• Language: English

Related Subjects

052000* -- Nuclear Fuels-- Waste Management
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
ALKALINE EARTH METAL COMPOUNDS
AMORPHOUS STATE
CALCIUM COMPOUNDS
CALCIUM FLUORIDES
CALCIUM HALIDES
CERAMICS
CHALCOGENIDES
CHEMICAL PROPERTIES
COHERENT SCATTERING
CRYSTAL STRUCTURE
DIFFRACTION
DISSOLUTION
ELECTROMAGNETIC RADIATION
ELECTRON DIFFRACTION
FISSION PRODUCTS
FLUORIDES
FLUORINE COMPOUNDS
FUEL REPROCESSING PLANTS
GAMMA RADIATION
GLASS
HALIDES
HALOGEN COMPOUNDS
IDAHO CHEMICAL PROCESSING PLANT
IONIZATION
IONIZING RADIATIONS
IRRADIATION
ISOTOPES
LEACHING
MATERIALS
MICROSTRUCTURE
NATIONAL ORGANIZATIONS
NUCLEAR FACILITIES
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
RADIATION EFFECTS
RADIATIONS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
SCATTERING
SEPARATION PROCESSES
SILICATES
SILICON COMPOUNDS
SIMULATION
TRANSITION ELEMENT COMPOUNDS
US AEC
US DOE
US ERDA
US ORGANIZATIONS
WASTE FORMS
WASTES
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES
ZIRCONIUM SILICATES