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Nuclear and Hydro Power
Published in Anco S. Blazev, Energy Security for The 21st Century, 2021
Ceramic nuclear materials, in addition to the oxides, also have high heat conductivities and melting points, but they are more prone to swelling than oxide fuels and are not understood as well. Uranium nitride (UN) is used in NASA reactor designs, because it has a better thermal conductivity than UO2, since it has a very high melting point. UN fuel has the disadvantage that a large amount of 14C would be generated from the nitrogen by the (n,p) reaction. As the nitrogen required for such a fuel would be so expensive it is likely that the fuel would have to be reprocessed by a pyro method to enable the 15N to be recovered. It is likely that if the fuel was processed and dissolved in nitric acid that the nitrogen enriched with 15N would be diluted with the common 14N.Uranium carbide was used in the form of pin-type fuel elements for liquid-metal fast breeder reactors during their intense study during the 60s and 70s. Recently there has been a revived interest in uranium carbide in the form of plate fuel and most notably, micro fuel particles (such as TRISO particles).
The Other Energy Markets
Published in Anco S. Blazev, Global Energy Market Trends, 2021
Some of the ceramic nuclear materials are: Uranium nitride (UN) is used in NASA reactor designs, because it has a better thermal conductivity than UO2, since it has a very high melting point. UN fuel has the disadvantage that a large amount of 14C would be generated from the nitrogen by the (n,p) reaction. As the nitrogen required for such a fuel would be so expensive it is likely that the fuel would have to be reprocessed by a pyro method to enable the 15N to be recovered. It is likely that if the fuel was processed and dissolved in nitric acid that the nitrogen enriched with 15N would be diluted with the common 14N.Uranium carbide was used in the form of pin-type fuel elements for liquid-metal fast breeder reactors during their intense study during the 60s and 70s. Recently there has been a revived interest in uranium carbide in the form of plate fuel and most notably, micro fuel particles (such as TRISO particles). The high thermal conductivity and high melting point makes uranium carbide an attractive fuel. In addition, because of the absence of oxygen in this fuel, as well as the ability to complement a ceramic coating, uranium carbide could be the ideal fuel candidate for certain Generation IV reactors such as the gas-cooled fast reactor.
The Other Energy Sources
Published in Anco S. Blazev, Power Generation and the Environment, 2021
Uranium nitride (UN) is used in NASA reactor designs, because it has a better thermal conductivity than UO2 which it has a very high melting point. UN fuel’s disadvantage is that a large amount of 14C would be generated from the nitrogen by the (n,p) reaction. As the nitrogen required for such a fuel would be so expensive, it is likely that the fuel would need to be reprocessed by a pyro method to enable the 15N to be recovered. It is likely that, if the fuel were processed and dissolved in nitric acid, the nitrogen enriched with 15N would be diluted with the common 14N.
Scoping Studies of Dopants for Stabilization of Uranium Nitride Fuel
Published in Nuclear Science and Engineering, 2019
Klara Insulander Björk, Aneta Herman, Marcus Hedberg, Christian Ekberg
Uranium nitride (UN) is considered a nuclear reactor fuel because of several inherent properties that make it superior to the currently predominant chemical form of uranium: uranium dioxide (UO2). In particular, the UN lattice has a higher uranium density, which is advantageous from a neutronics perspective, and the thermal conductivity is higher,1,2 slowing down fuel material degrading processes such as cracking and diffusion of fission products3 as well as providing a larger margin to fuel melting in accident scenarios. Because of these properties, UN is often mentioned as a candidate for the accident tolerant fuels discussed within the nuclear power industry in the aftermath of the Fukushima Daiichi nuclear reactor accident in 2011 (Ref. 4).
Searching for optimal accident tolerant fuel for the VVER-1200 reactor from the neutronic point of view
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
A. Abdelghafar Galahom, Ehab M. Aboelyazid, S.A. EL-Fiki, Moustafa Aziz
Uranium nitride (UN) ceramic fuels are receiving great interest due to their higher density and better thermal and mechanical properties than uranium dioxide. The UN has the property to withstand any potential reactor accident which could occur due to its better thermochemical response than conventional uranium dioxide fuel (Li and Shirvan, 2020; Mishchenko et al. 2021). Unlike UO2, UN has a higher thermal conductivity which increases by increasing the temperature (Mohsen, Abdel-Rahman, and Galahom 2021). The investigation of UN fuels has been connected mainly with fast reactors (Feng et al. 2011; IAEA 2009) and Accelerator Driven Systems (Wallenius et al. 2001; Zhang et al. 2011).
The Reaction of Uranium Deuteride with Nitrogen
Published in Fusion Science and Technology, 2023
J. Northall, E. H. Norris, J. P. Knowles, J. R. Petherbridge
Uranium powder readily absorbs hydrogen at room temperature and desorbs hydrogen at practicable rates when heated to 400°C under vacuum.[1–3] For these reasons, uranium is considered a useful media for the storage of tritium.[4,5] Tritium processing lines have been installed in inert nitrogen glove boxes where a potential exists for nitrogen in-leakage. Nitrogen is known to react with uranium and uranium hydride at elevated temperatures.[6,7] The reaction of uranium hydride with nitrogen is known to occur above 160°C, however the extent of the reaction at room temperature is unclear.[6] Uranium nitrides exist as three main compounds: uranium mononitride (UN), uranium dinitride (UN2), and uranium sesquinitride (U2N3).[6–9] A number of other minor compounds and complexes can also be formed.[6–9] UN2 can be formed from the ammonolysis of UF4 by heating UF4 at 800°C for 1 h under ammonia and from glow plasma nitriding uranium at 350°C.[10,11] U2N3 can be formed from the decomposition of UN2 at 675°C under argon, the reaction of U or UH3 with a mixture of H2 and N2 at 300°C, and the reaction of UH3 with NH3 at room temperature.[6,9,10,12] UN can be formed from the decomposition of U2N3 at 975°C under argon, the reaction of UH3 with N2 at 160°C increasing in rate to 240°C, and the reaction of UH3 to NH3 at 300°C.[6,9,10] Heating uranium nitrides to about 300°C in the presence of excess UH3 is reported to bring about the conversion to lower nitrides and the release of hydrogen.[9]