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Annual Report

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This project will examine inert fuels containing ZrO2 and MgO as the inert matrix. Ceramics with this inert matrix, Ce, U and eventually Pu will be synthesized and examined. While the Advanced Fuel Cycle Initiative focus is on inert fuels with Pu as the fissile component, this task will perform initial laboratory experiments with Ce and U. The initial work with Ce will be performed early in the project with results used as a basis for U studies. Reactor physics calculations will be used to examine suitable quantities of burnable poisons from the candidate elements Gd, Er, or Hf. Most fuels use Gd or Er, but the chemical properties of Hf lend themselves to formation of solid solutions with Zr and the tetravalent actinides and will therefore be investigated. This project will provide the necessary data for evaluating the performance, reprocessing, and waste behavior of the MgO-ZrO2 fuels from a quantified, chemical perspective. Reactor physics calculations are used to examine suitable quantities of burnable poisons from the candidate elements Gd, Er, or Hf with reactor grade Pu providing the fissile component, with up to 10% of 239Pu. Ceramics are synthesized and characterized based on the reactor physics results. The solubility of the fuel ceramics, in reactor conditions, reprocessing conditions, and repository conditions, are investigated in a manner to provide thermodynamic data necessary for modeling.

The research objectives of this project are as follows:

• To examine the neutronic behavior of MgO-ZrO2 inert fuels. Variation of MgO and ZrO2 composition ranges from 30% to 70% MgO in ZrO2. Analysis of Gd, Er, and Hf for reactivity control ranging from 5-10% lanthanides. Analysis of reactor grade Pu as fissile component ranging from 5-10% Pu. Results will be used as parameters for fuel composition.

• To synthesize and characterize MgO-ZrO2 ceramics containing burnable poison and fissile composition. Synthesis is based on a precipitation method. Range of MgO in ZrO2, fissile component concentration, and burnable poison concentration based on results of neutronic calculations. Characterization of ceramics will include density, X-ray diffraction (XRD), surface area analysis, X-ray absorption fine structure, and chemical composition. Results will be applied to behavior in high temperature water, acid, and environmental conditions.

• To describe the chemical behavior of synthesized ceramics. Chemical thermodynamic and kinetic analysis will use equilibrium data, kinetic data, and surface area normalized dissolution. Different conditions will include reactor conditions (high temperature and high pressure water) and reprocessing conditions (nitric acid and elevated temperature). Environmental conditions will be near neutral solution conditions.

• To utilize project data in kinetic and thermodynamic modeling codes to evaluate the speciation of the elements in the ceramics under reactor, reprocessing, and repository conditions.


Ceramics; Cerium; Magnesium oxide; Mixed oxide fuels (Nuclear engineering); Nuclear chemistry; Nuclear fuels; Plutonium; Solid oxide fuel cells; Zirconium oxide


Ceramic Materials | Nuclear | Nuclear Engineering | Oil, Gas, and Energy | Radiochemistry