Description:
Reference #: 01312
The University of South Carolina is offering licensing opportunities for Composite uranium silicide-uranium dioxide nuclear fuel.
Background:
The advantages of nitride fuel are high thermal conductivity, very high melting point, and high density. These benefits have long been recognized. The sodium cooled BR-10 reactor in Russia operated for 18 years on uranium nitride fuel, used as the driver fuel for two core loads. The potential advantages of a light water reactor are a large power up-grade, increased cycle lengths, and possible high burn-up. However, the advantages of the fuel are offset by uranium nitride’s extremely low oxidation resistance (uranium nitride powders oxidize in air and uranium nitride pellets decompose in hot water). Innovative research is proposed to solve this problem and thereby provide an accident tolerant light water reactor fuel that would resist water leaks and high temperature steam oxidation/spalling during an accident.
Invention Description:
Uranium silicide materials being considered as advanced nuclear fuel replacements for uranium dioxide fuel in light water reactors (LWRs). The silicides have a substantially high thermal conductivity and thus can operate in a reactor at significantly lower temperatures for the same level of power production. In addition, the heat capacity of a silicide is lower than that of the oxide so that less heat is stored in the fuel that would need to be removed under accident conditions. The silicide fuel also offers commercial advantages as it contains a higher uranium density (uranium atoms/unit volume and thus the same energy can be obtained from a smaller volume of fuel in a reactor. A disadvantage of silicide fuel is its significant susceptibility to oxidation in the presence of water, steam, or air that exceeds that of UO2. Thus, a composite silicide fuel form is proposed to replace the solely UO2 cylindrical ceramic pellets currently found in light water reactors, where the second phase would protect the silicide from oxidation. The composite fuel pellet would have the same oxidation tolerance as UO2, yet largely contain the advantages of the proposed invention.
Potential Applications:
The subject invention would replace current UO2 pellet fuel in largely the same configuration in light water reactors, but have a higher uranium concentration, higher thermal conductivity, and lower heat capacity, and thus provide for a more efficient fuel with the safety advantages of the improved thermal properties.
Advantages and Benefits:
The silicides have advantages over uranium dioxide (UO2) in having a substantially higher thermal conductivity and thus can operate in a reactor at significantly lower temperatures for the same level of power production, and thus improved safety performance. In addition, the heat capacity of a silicide is lower than that of the oxide so that less heat is stored in the fuel that would need to be removed under accident conditions. The silicide fuel also offers commercial advantages as it contains a higher uranium density (uranium atoms/unit volume) than found in UO2 and thus the same energy can be obtained from a smaller volume of fuel in a reactor.