On the evaluation of spent nuclear fuel baskets system materials corrosion resistance and the new arrangement proposed to replace them

• Grant number: 24/01015-6
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: February 01, 2025
• End date: January 31, 2028
• Field of knowledge: Engineering - Materials and Metallurgical Engineering
• Principal Investigator: Isolda Costa
• Grantee: João Victor de Sousa Araujo
• Host Institution: Instituto de Pesquisas Energéticas e Nucleares (IPEN). Secretaria de Desenvolvimento Econômico (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

This research project aims to evaluate the corrosion resistance behaviour of the materials involved in the new structure proposed for the storage of CNQ (burnt nuclear fuel) from the IPEN research reactor (IEA-R1): stainless steel, aluminium alloy AA6061 -T6 and in post-lamination condition, and BORALCAN (aluminium composite and B4C). The proposal aims to evaluate the corrosion behaviour of the new configuration suggested to replace the current CNQ storage baskets in which the corrosion resistance of the proposed materials will be investigated. In this sense, for this investigation to be carried out systematically, a detailed study will be carried out through microstructural characterization using the techniques of Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Kelvin Force Microscopy (SKPFM). The corrosion resistance of the individual samples (not galvanically coupled) will be studied through electrochemical cyclic polarization tests (simulating the effect of storage in the reactor pool). The effect of galvanic coupling will be studied by localized electrochemical tests, specifically by SVET (Scanning Vibrating Electrode Technique). The corrosion resistance of the individual (uncoupled) and coupled samples will be studied through long-term immersion tests (> 1 year) in the IEA-R1 reactor pool. The susceptibility to corrosion by pitting, in crevices and by galvanic coupling between the materials proposed for the new configuration (new basket) and those that make up the reactor structure (which will be directly in contact), will be studied, indicating where the corrosion process is started. And, finally, an investigation will be carried out into the environmental conditions that originate the corrosive process to define the water control conditions for the proposed new storage structure.The development of this study should contribute to the feasibility of the new arrangement proposed for storing CNQ in the structure of the IEA reactor, located at IPEN, for which the preservation of its integrity is of fundamental importance in the field of health, biomedicine, and materials sciences.