Aluminium corrosion reactivation in MKPC and Portland-based wasteforms under simulated alkaline repository conditions

IF 3.2 2区工程技术 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Nuclear Materials Pub Date : 2025-07-27 DOI:10.1016/j.jnucmat.2025.156064

C. Fernández-García, M.C. Alonso

{"title":"Aluminium corrosion reactivation in MKPC and Portland-based wasteforms under simulated alkaline repository conditions","authors":"C. Fernández-García, M.C. Alonso","doi":"10.1016/j.jnucmat.2025.156064","DOIUrl":null,"url":null,"abstract":"<div><div>The long-term stability of aluminium (Al) in cementitious wasteforms is challenged by matrix alkalinisation resulting from interaction with alkaline waters from engineered barriers in low- to intermediate-level radioactive waste (LILRW) repositories. This study evaluates the corrosion of Al (A1050) and Al-Mg (AA5754) alloys and the physicochemical evolution of magnesium potassium phosphate cement (MKPC) and Portland-based matrices (CEM I and CEM <em>I</em> + 50% silica fume (SF)) under simulated alkaline exposure. Over 250 days, specimens were subjected to synthetic alkaline water (SPAW), while MKPC was also embedded in a CEM I mortar (AM) to simulate repository contact conditions. In MKPC, alkaline plume diffusion from the external source triggered ion exchange with the matrix, leading to alkalinisation (pH >11), reactivation of Al corrosion, and H₂ release to levels comparable to those observed in CEM I. K-struvite dissolution, Ca–P-rich phase formation, and fly ash hydration were also observed, evidencing long-term destabilisation of the MKPC matrix. In contrast, CEM <em>I</em> + 50%SF, despite being exposed to a highly alkaline plume, maintained the pore solution pH at 10.7 over time due to the advanced hydration of SF, effectively limiting Al reactivity and H₂ generation without matrix alteration.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"616 ","pages":"Article 156064"},"PeriodicalIF":3.2000,"publicationDate":"2025-07-27","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/S0022311525004581","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 long-term stability of aluminium (Al) in cementitious wasteforms is challenged by matrix alkalinisation resulting from interaction with alkaline waters from engineered barriers in low- to intermediate-level radioactive waste (LILRW) repositories. This study evaluates the corrosion of Al (A1050) and Al-Mg (AA5754) alloys and the physicochemical evolution of magnesium potassium phosphate cement (MKPC) and Portland-based matrices (CEM I and CEM I + 50% silica fume (SF)) under simulated alkaline exposure. Over 250 days, specimens were subjected to synthetic alkaline water (SPAW), while MKPC was also embedded in a CEM I mortar (AM) to simulate repository contact conditions. In MKPC, alkaline plume diffusion from the external source triggered ion exchange with the matrix, leading to alkalinisation (pH >11), reactivation of Al corrosion, and H₂ release to levels comparable to those observed in CEM I. K-struvite dissolution, Ca–P-rich phase formation, and fly ash hydration were also observed, evidencing long-term destabilisation of the MKPC matrix. In contrast, CEM I + 50%SF, despite being exposed to a highly alkaline plume, maintained the pore solution pH at 10.7 over time due to the advanced hydration of SF, effectively limiting Al reactivity and H₂ generation without matrix alteration.

Abstract Image

查看原文本刊更多论文

在模拟碱性储存库条件下，MKPC和波特兰基废物中的铝腐蚀再活化

在中低水平放射性废物（LILRW）储存库中，由于与工程屏障产生的碱性水相互作用，铝（Al）在胶凝废物形态中的长期稳定性受到了基质碱化的挑战。本研究评估了Al （A1050）和Al- mg （AA5754）合金在模拟碱性暴露下的腐蚀，以及磷酸镁钾水泥（MKPC）和波特兰基基质（CEM I和CEM I + 50%硅灰（SF））的物理化学演变。在超过250天的时间里，标本被置于合成碱性水（SPAW）中，同时MKPC也被嵌入CEM I砂浆（AM）中，以模拟储存库接触条件。在MKPC中，来自外部源的碱性烟柱扩散触发了与基体的离子交换，导致碱化（pH >11），铝腐蚀的再活化，以及H₂释放水平与CEM i中观察到的水平相当。k -鸟鸟石溶解，富ca - p相形成和粉煤灰水化也被观察到，证明了MKPC基质的长期不稳定。相比之下，尽管CEM I + 50%SF暴露在高碱性烟柱中，但由于SF的高度水化，随着时间的推移，孔隙溶液pH保持在10.7，有效地限制了Al反应性和H 2的生成，而不会改变基质。

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.