Abstract

Solid waste samples consisting of shredded cellulose, coated with either mesoparticles of metallic salts or dried metal nitrate (lutetium, ytterbium, or depleted uranium) solutions, were generated to mimic solid nuclear waste. After burning these samples, the masses of the aerosolized metal cations were quantified by leaching them from air filters and analyzing the leachate with inductively coupled plasma mass spectrometry. The airborne release fractions (ARFs) for Lu and depleted uranium nitrates were 1 × 10⁻⁴, and 3 × 10⁻³ for Lu and depleted uranium mesoparticle salts, respectively. Uncertainties in ARFs were approximately 10% for the metal nitrates and 30% for the metallic mesoparticles. These data are most applicable to waste materials with 1% metal mass loading where the initial respirable fraction of contaminant particles is one. ARFs were consistent across the two metals, but there was an order of magnitude difference with respect to the physical and chemical form (mesoparticle salt versus nitrate). Cellulose combustion literature indicates that combustion pathways were likely affected by off-gassing and endothermic decomposition reactions. In comparison to ARF values from DOE-HDBK-3010-94, “Airborne Release Fractions/Rates and Respirable Fractions for Nonreactor Nuclear Facilities,” this dataset was consistent with previous results but provides a well-characterized and reproducible method for doping cellulosic materials with nuclear waste surrogates to serve as a baseline for future experimental and computational works.

摘要

生成由切碎的纤维素组成的固体废物样品，表面涂有金属盐的中颗粒或干燥的金属硝酸盐（镥、镱或贫铀）溶液，以模拟固体核废物。燃烧这些样品后，通过从空气过滤器中浸出并用电感耦合等离子体质谱法分析浸出液来量化雾化金属阳离子的质量。Lu 和贫化硝酸铀的空气中释放分数 (ARF) 分别为 1 × 10 ^-4和 3 × 10 ^-3分别为 Lu 和贫铀中颗粒盐。ARF 的不确定性对于金属硝酸盐约为 10%，对于金属中颗粒约为 30%。这些数据最适用于金属质量负载为 1% 的废料，其中污染物颗粒的初始可吸入分数为 1。两种金属的 ARF 是一致的，但在物理和化学形式（中颗粒盐与硝酸盐）方面存在数量级差异。纤维素燃烧文献表明燃烧途径可能受到排气和吸热分解反应的影响。与 DOE-HDBK-3010-94 中的 ARF 值相比，“非反应堆核设施的空中释放分数/速率和可呼吸分数，