当前位置: X-MOL 学术J. Nucl. Mater. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Oxidation of UN/U2N3-UO2 composites: an evaluation of UO2 as an oxidation barrier for the nitride phases
Journal of Nuclear Materials ( IF 3.1 ) Pub Date : 2020-11-27 , DOI: 10.1016/j.jnucmat.2020.152700
Diogo Ribeiro Costa , Marcus Hedberg , Simon C. Middleburgh , Janne Wallenius , Pär Olsson , Denise Adorno Lopes

Composite fuels such as UN-UO2 are being considered to address the lower oxidation resistance of the UN fuel from a safety perspective for use in light water reactors, whilst improving the in-reactor behaviour of the more ubiquitous UO2 fuel. An innovative UN-UO2 accident tolerant fuel has recently been fabricated and studied: UN microspheres embedded in UO2 matrix. In the present study, detailed oxidative thermogravimetric investigations (TGA/DSC) of high-density UN/U2N3-UO2 composite fuels (91-97 %TD), as well as post oxidised microstructures obtained by SEM, are reported and analysed. Triplicate TGA measurements of each specimen were carried out at 5 K/min up to 973 K in a synthetic air atmosphere to assess their oxidation kinetics. The mass variation due to the oxidation reactions (%), the oxidation onset temperatures (OOTs), and the maximum reaction temperatures (MRTs) are also presented and discussed. The results show that all composites have similar post oxidised microstructures with mostly intergranular cracking and spalling. The oxidation resistance of the pellet with initially 10 wt% of UN microspheres is surprisingly better than the UO2 reference. Moreover, there is no significant difference in the OOT (~557 K) and MRT (~615 K) when 30 wt% or 50 wt% of embedded UN microspheres are used. Therefore, the findings in this article demonstrate that the UO2 matrix acts as a barrier to improve the oxidation resistance of the nitride phases at the beginning of life conditions.



中文翻译:

UN-U 2 N 3 / UO 2复合材料的氧化:UO 2作为氮化物相的氧化阻挡层的评估

从安全角度出发,考虑将UN-UO 2之类的复合燃料用于联合国燃料的低抗氧化性,以用于轻水反应堆,同时改善普遍存在的UO 2燃料的反应器内性能。最近已经制造和研究了一种创新的UN-UO 2耐事故性燃料:嵌入UO 2基质中的UN微球。在本研究中,对高密度UN-U 2 N 3 / UO 2的详细氧化热重研究(TGA / DSC)报告并分析了复合燃料(91-97%TD)以及通过SEM获得的后氧化微结构。在合成空气中,以5 K / min的速度对每个样品进行三重TGA测量,直至973 K,以评估其氧化动力学。还介绍并讨论了由于氧化反应(%),氧化起始温度(OOT)和最大反应温度(MRT)而引起的质量变化。结果表明,所有复合材料均具有相似的后氧化微结构,且大多数为晶间裂纹和剥落。最初含10%(重量)UN微球的颗粒的抗氧化性比UO 2出乎意料的好参考。此外,当使用嵌入的联合国微球的30 wt%或50 wt%时,OOT(〜557 K)和MRT(〜615 K)没有显着差异。因此,本文中的发现表明,在使用寿命开始时,UO 2基体可作为提高氮化物相抗氧化性的屏障。

更新日期:2020-12-04
down
wechat
bug