Al–B₄C metal matrix composites have been utilized as a neutron absorber for the past two decades to manage the neutron flux and the criticality of spent nuclear fuel pools. Recently, premature surface corrosion has been found from an eight-year-old surveillance coupon although 40 years of service life was guaranteed based on separated corrosion tests and gamma irradiation tests. Suspecting the premature corrosion was assisted by radiation damage effects from energetic particles emitted from ¹⁰B(n, α)⁷Li reaction, nanoscale characterization and neutron attenuation tests were carried out on the surveillance coupons used in a spent nuclear fuel pool for 33, 52, and 99 months to investigate the degradation mechanisms and ¹⁰B depletion. Highly radiation-damaged structures, such as numerous gas bubbles filled with helium and hydrogen in the aluminum matrix and microcracks in boron carbide particles, were observed from all absorber coupons with slightly reduced densities (<1%) matching with the porous structures. The neutron attenuation tests on 52 and 99 month-installed coupons showed ∼3.1% reduction of ¹⁰B areal density, which also indicates the needs for further investigation on the long-term safety and performance of the absorber material.

在过去的二十年中，Al–B ₄ C金属基复合材料已被用作中子吸收剂，以管理中子通量和乏核燃料池的临界性。近期，尽管使用单独的腐蚀测试和伽马射线辐照测试可以保证40年的使用寿命，但已经发现有八年历史的监控样板会过早地腐蚀表面。怀疑过早腐蚀是由¹⁰ B（n，α）⁷ Li反应产生的高能粒子产生的辐射损伤效应所辅助的，对用于乏核燃料池中33、52的监控试样进行了纳米级表征和中子衰减测试。和99个月的时间来研究降解机理和¹⁰B耗竭。从所有吸收器试件中观察到高度辐射破坏的结构，例如铝基质中充有氦和氢的大量气泡以及碳化硼颗粒中的微裂纹，其密度与多孔结构相符，密度略有降低（<1％）。在安装了52和99个月的试样上的中子衰减测试表明，¹⁰ B面密度降低了约3.1％，这也表明需要进一步研究吸收体材料的长期安全性和性能。