Nuclear Energy Materials
Nuclear Fuels, Fuel Reprocessing

Current Projects

Project Title: NERI-Optimization of oxide compounds for Inert Matrix Materials
Funding Agency: Department of Energy
Contract Number:DE-FC07-05ID14647

Management of the increasing amounts of plutonium and minor actinides that are generated as a result of dismantled nuclear weapons as well as the nuclear fuel cycle has received a great deal of attention in the past few years. As a potential transmutation solution, the concept of an inert matrix fuel (IMF) was introduced where the fertile nuclides such as 238U are substituted by a non-fertile matrix, thus eliminating the generation of additional Pu. Candidate matrix materials must meet several critical requirements, including high temperature stability, good radiation resistance, high thermal conductivity, good corrosion resistance under hot water and the suitability to undergo aqueous reprocessing. An MgO-Pyrochlore ceramic-ceramic (cercer) composite has been proposed as an IMF candidate; as part of the ongoing assessment of its potential, the hot water resistance and aqueous reprocessing of the cercer composite is being investigated. Furthermore, although significant improvement in current IMF composites is essential, further exploration for a single phase IMF is of great interest. From the out-of-pile properties of MgAl₂O₄ it can be inferred that other oxides with the spinel crystal structure may be potential candidates for inert matrix materials.

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Project Title: BiI₃ single crystal for Gamma-Ray detection
Funding Agency: DOD - Defense Threat Reduction Agency (DTRA)
Contract Number: HDTRA 1 – 07 – 1 – 0013

This project will investigate the performance of bismuth iodide (BiI₃) as a potential material for gamma-ray detection and spectroscopy. BiI₃ is a wide band-gap semiconductor material that may be able to operate at room temperature without any necessary cooling mechanism. This material has a much higher effective atomic number than germanium, and thus has higher gamma-ray detection efficiency, particularly for moderate and high energy gamma-rays. Unfortunately, not much is known about BiI₃, and general properties of the material (work function, electron and hole mobility, trapping times, etc.) will need to be investigated. The primary effort of this project will be devoted towards BiI₃ single crystal growth. We will investigate the electrical and semiconducting properties of BiI₃. We will also investigate the use and control of different dopants/impurities to grow better detector crystals (larger crystals, better resistivity, improved charge transport properties, etc.). The anticipated outcome of this project is a novel wide band-gap semiconductor material that can function as a high efficiency gamma-ray spectrometer without any necessary cryogenic or mechanical cooling. In addition, the project may also result in a gamma-ray spectrometer with better energy resolution than other current state-of-the-art compound semiconductor or scintillator materials. This work could have significant impact on Department of Defense capabilities by improving handheld, portable gamma-ray detectors for weapons of mass destruction detection. Moreover, this project could have a significant impact in other fields where improve radiation sensors are necessary, including astronomy/astrophysics, environmental monitoring, and nuclear waste assessment.