Corrosion behavior of B4C/Al neutron absorber material in spent nuclear fuel pool environment

B 4 C/Al neutron absorber materials are critical for the criticality safety of spent nuclear fuel wet storage, yet their corrosion-induced degradation poses a significant challenge to long-term operational reliability. This study systematically investigated the corrosion behavior and failure mechanism of a commercial B 4 C/Al composite during long-term immersion in a simulated spent fuel pool environment (2700 ppm boric acid at 40°C) via microstructural characterization and electrochemical analyses. Results indicate that the corrosion product layer exhibits a decelerating growth trend, and is mainly composed of non-protective aluminum oxides and hydroxides. Scanning kelvin probe (SKP) and in-situ scanning vibrating electrode technique (SVET) mapping revealed that preferential corrosion occurs at the interface, driven by the micro-galvanic coupling between the noble B 4 C particles (micro-cathodes) and the active Al matrix (micro-anodes). The rapid interfacial dissolution undermines the matrix support, causing the neutron-absorbing B 4 C particles to undergo mechanical loosening and detach along with the shedding of the loose corrosion product layer, thereby posing a potential risk to the material’s functional performance.