Effect of neighbouring rods in cladding deformation and rupture opening size during loss of coolant accidents

IF 2.8 2区工程技术 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Nuclear Materials Pub Date : 2025-04-22 DOI:10.1016/j.jnucmat.2025.155848

Cristina Dominguez, Tatiana Taurines, Georges Repetto

{"title":"Effect of neighbouring rods in cladding deformation and rupture opening size during loss of coolant accidents","authors":"Cristina Dominguez, Tatiana Taurines, Georges Repetto","doi":"10.1016/j.jnucmat.2025.155848","DOIUrl":null,"url":null,"abstract":"<div><div>The COCAGNE experiments aim to study the deformation and burst of fuel cladding under Loss-Of-Coolant-Accident (LOCA) conditions in a “multi-rod” configuration. This configuration enables the study of cladding ballooning in situations of contact/blockage between peripheral rods, burst conditions with various azimuthal temperature gradients, or after contact. The main objective is to measure online the three-dimensional mechanical behaviour of pressurised rods surrounded by structures simulating four neighbouring fuel rods, under a geometrically and thermally representative environment.</div><div>Twenty-three ramp tests were conducted on single-sided or double-sided pre-oxidised Zircaloy-4 claddings at heating rates between 1 and 10 °C/s and pressures from 2 to 10 MPa. The effect of temperature differences between the test rod and the guards simulating surrounding rods was also investigated.</div><div>The presence of the neighbouring rods affects the size and shape of balloons and burst openings. In “multi-rod” tests, deformation is constrained by the guards resulting in maximal strains up to 50 % lower compared to single-rod tests. Additionally, the formed balloon adapts to the available space between the guards leading to square shapes. Moreover, cladding thermal profiles are relatively flat in single-rod tests, but they become uneven in the presence of guards, leading to greater axial temperature gradients and shorter balloons in multi-rod tests. Nevertheless, under certain conditions, ballooning can extend axially producing ballons nearly 100 mm long.</div><div>Additionally, an internal pre-oxide layer significantly reduces burst strain by up to three times and opening dimensions by over 75 %.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"612 ","pages":"Article 155848"},"PeriodicalIF":2.8000,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Nuclear Materials","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0022311525002429","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}

引用次数: 0

Abstract

The COCAGNE experiments aim to study the deformation and burst of fuel cladding under Loss-Of-Coolant-Accident (LOCA) conditions in a “multi-rod” configuration. This configuration enables the study of cladding ballooning in situations of contact/blockage between peripheral rods, burst conditions with various azimuthal temperature gradients, or after contact. The main objective is to measure online the three-dimensional mechanical behaviour of pressurised rods surrounded by structures simulating four neighbouring fuel rods, under a geometrically and thermally representative environment.

Twenty-three ramp tests were conducted on single-sided or double-sided pre-oxidised Zircaloy-4 claddings at heating rates between 1 and 10 °C/s and pressures from 2 to 10 MPa. The effect of temperature differences between the test rod and the guards simulating surrounding rods was also investigated.

The presence of the neighbouring rods affects the size and shape of balloons and burst openings. In “multi-rod” tests, deformation is constrained by the guards resulting in maximal strains up to 50 % lower compared to single-rod tests. Additionally, the formed balloon adapts to the available space between the guards leading to square shapes. Moreover, cladding thermal profiles are relatively flat in single-rod tests, but they become uneven in the presence of guards, leading to greater axial temperature gradients and shorter balloons in multi-rod tests. Nevertheless, under certain conditions, ballooning can extend axially producing ballons nearly 100 mm long.

Additionally, an internal pre-oxide layer significantly reduces burst strain by up to three times and opening dimensions by over 75 %.

Abstract Image

查看原文本刊更多论文

失冷事故中相邻棒对包层变形和破裂口尺寸的影响

COCAGNE实验旨在研究在“多棒”结构下冷却剂损失事故（LOCA）条件下燃料包壳的变形和爆裂。这种结构可以研究包层在周围棒之间接触/堵塞的情况下的膨胀，具有不同方位温度梯度的破裂条件，或接触后的膨胀。主要目标是在线测量被模拟四个相邻燃料棒的结构包围的受压棒在几何和热代表性环境下的三维力学行为。在加热速率为1 ~ 10℃/s，压力为2 ~ 10 MPa的条件下，对单面或双面预氧化锆-4包层进行了23次斜坡试验。试验棒与模拟周围棒的防护罩之间温差的影响也进行了研究。相邻杆的存在会影响气球和爆裂口的大小和形状。在“多杆”测试中，变形受到保护装置的约束，与单杆测试相比，最大应变降低了50%。此外，形成的气球适应警卫之间的可用空间，导致方形形状。此外，在单棒试验中，包层热剖面相对平坦，但在有保护装置的情况下，包层热剖面变得不均匀，导致多棒试验中轴向温度梯度增大，气球变短。然而，在一定条件下，气球可以轴向延伸，产生近100毫米长的气球。此外，内部预氧化层可将爆裂应变降低三倍，并将开口尺寸减小75%以上。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Journal of Nuclear Materials 工程技术-材料科学：综合

CiteScore

5.70

自引率

25.80%

发文量

601

审稿时长

63 days

期刊介绍： The Journal of Nuclear Materials publishes high quality papers in materials research for nuclear applications, primarily fission reactors, fusion reactors, and similar environments including radiation areas of charged particle accelerators. Both original research and critical review papers covering experimental, theoretical, and computational aspects of either fundamental or applied nature are welcome. The breadth of the field is such that a wide range of processes and properties in the field of materials science and engineering is of interest to the readership, spanning atom-scale processes, microstructures, thermodynamics, mechanical properties, physical properties, and corrosion, for example. Topics covered by JNM Fission reactor materials, including fuels, cladding, core structures, pressure vessels, coolant interactions with materials, moderator and control components, fission product behavior. Materials aspects of the entire fuel cycle. Materials aspects of the actinides and their compounds. Performance of nuclear waste materials; materials aspects of the immobilization of wastes. Fusion reactor materials, including first walls, blankets, insulators and magnets. Neutron and charged particle radiation effects in materials, including defects, transmutations, microstructures, phase changes and macroscopic properties. Interaction of plasmas, ion beams, electron beams and electromagnetic radiation with materials relevant to nuclear systems.