Fabrication and microstructural analysis of UN-U3Si2 composites for accident tolerant fuel applications

“…A UN/U 3 Si 2 composite fuel (10-40 vol.% U 3 Si 2 ) has recently been recommended to deal with some of the aforementioned issues [15,16,17]. The central concept for this composite fuel is to combine the better U 3 Si 2 pulverization resistance in an oxidation atmosphere, with the high fissile density of UN.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…Despite being of more recent interest, the initial concept for the UN/U 3 Si 2 composite fuel was developed in the early 1960's [16][17][18] , with the goal to improve the sintering of UN. The composite fuel was proposed as an alternative for required very high sintering temperatures of UN, where the UN/U 3 Si 2 combination takes advantage of liquid-phase sintering fostered by the U 3 Si 2 , achieving suitable densities at T < 1600 °C.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…Initial reports of the so far limited efforts on UN/U 3 Si 2 have shown that the addition of 25-35vol.% U 3 Si 2 has allowed production of compacts of 89-94% of theoretical density (TD) in conventional sintering at 1700 o C [15]This compares to the 1900-2000 o C required to achieve the same density for solely UN [9]. Despite these promising results, evidence of reaction between UN and U 3 Si 2 was detected, suggesting the formation of an as-yet unidentified ternary U-Si-N phase [15,16]. The composition of the ternary phase has been hard to assess due to the large error associated with energy-dispersive X-ray spectroscopy (EDS) when heavy and light elements are simultaneously present, in this case, uranium and nitrogen.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

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Experimental and computational assessment of U Si N ternary phases

Lopes

Wilson

Kocevski

et al. 2019

Journal of Nuclear Materials

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Uranium nitride-silicide composites are being considered as a high-density and high thermal conductivity fuel option for light water reactors. During development, chemical interactions were observed near the silicide melting point which resulted in formation of an unknown U-SiN ternary phase. In the present work, U-SiN composite samples were produced by arc-melting U 3 Si 2 under an argon-nitrogen atmosphere to form the ternary phase. The resulting samples were characterized by SEM/EDS-EPMA and XRD, and demonstrated an equilibrium between U 3 Si 2 , UN, USi and a U-SiN phase with a distinct crystallographic structure. Rietveld refinement of the ternary structure was performed, considering the ternary structures existent in the analogue U-Si-C system, and a good fit was obtained for the hexagonal U 20 Si 16 N 3 phase. DFT+U calculations were performed in parallel to evaluate the thermodynamic and dynamic stability of the ternaries U 20 Si 16 N 3 and U 3 Si 2 N 2. The calculated enthalpy of formation and phonon dispersion support the existence of stable U 20 Si 16 N 3 and U 3 Si 2 N 2 , although some soft modes in the

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“…ATF technology options being investigated are chromiumcoated clads, 15,16 silicon carbide (SiC) clads, 17 doped uranium dioxide 18,19 (UO 2 ), uranium silicide 20 (U 3 Si 2 ) fuel, steel clads, 21 and metallic fuel. 22 The ultimate goal of the U.S. R&D program is the introduction of ATFs into the LWR fleet for the second half of the 2020s.…”

mentioning

confidence: 99%

Risk-Informed Safety Analysis for Accident Tolerant Fuels

Parisi

Mandelli

et al. 2020

Nuclear Science and Engineering

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Accident tolerant fuels (ATFs) are being tested by different nuclear vendors and research organizations, and their introduction into the U.S light water reactor fleet is planned for the second half of the 2020s. Under the framework of the U.S. Department of Energy Light Water Reactor Sustainability (LWRS) Program, as part of the LWRS Risk-Informed Systems Analysis Pathway, research is being conducted at the Idaho National Laboratory (INL) to develop tools and methods that can help the industry to quantify the benefits from adopting ATF technology. In this paper we describe the developed risk-informed methodology including the safety analysis code improvements, and we present some results for selected accident scenarios. The developed methodology combines the INL state-of-the-art deterministic Best Estimate code RELAP5-3D and the probabilistic risk analysis tools RAVEN and SAPHIRE. The analyses are performed on a three-loop pressurized water reactor, simulating station blackout and large-break loss-of-coolant accidents and considering near-term ATFs or iron-chromium-aluminum and chromium-coated clads. Finally, we show how, applying our methodology, the new core damage frequency (CDF) can be assessed. The results indicate that the main benefit in introducing near-term ATFs is a significant reduction in hydrogen production during accident conditions. No significant CDF reduction was found.

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Fabrication and microstructural analysis of UN-U3Si2 composites for accident tolerant fuel applications

Cited by 81 publications

References 15 publications

Non-stoichiometry in U3Si2

Non-stoichiometry in U3Si2

Experimental and computational assessment of U Si N ternary phases

Risk-Informed Safety Analysis for Accident Tolerant Fuels

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