【摘要】 研究了模拟处置条件下Pu(Ⅳ)的溶解行为,测定了Pu(Ⅳ)在北山地下水和去离子水中的溶解度。采用过饱和法,使用低氧手套箱模拟地下无氧环境,利用超过滤实现固液分离,应用低本底液闪谱仪测量液相中钚的放射性活度。结果表明:溶解-沉淀平衡后,无论是在去离子水还是北山地下水中,钚的主要存在价态为+4。Pu(Ⅳ)在北山地下水和去离子水中的溶解度分别为(2.8±0.9)×10-8 mol/L和(1.6±0.8)×10-9 mol/L。通过计算确定了Pu(Ⅳ)在去离子水和北山地下水中的溶解度控制固相为Pu(OH)4(am)。在去离子水体系中,Pu(Ⅳ)的主要存在形态为Pu(OH)4(aq);北山地下水体系中,Pu(Ⅳ)的主要存在形态为Pu(OH)4(aq)和Pu(OH)2(CO3)2-2。更多还原

【Abstract】 Solubility of Pu(Ⅳ)was determined by oversaturation method under simulated disposal conditions.The underground anaerobic condition was simulated in glove-box.The solid-liquid separation was achieved by ultrafiltration.The plutonium radioactivity was measured by low background liquid scintillation spectrometer.The results show that the dominant oxidation state of plutonium either in deionized water or Beishan groundwater is tetravalent.The solubility of Pu(Ⅳ)in Beishan groundwater and deionized water is(2.8±0.9)×10-8 mol/L and(1.6±0.8)×10-9 mol/L.The specific ion interaction theory was used to calculate the thermodynamics constants under the experimental conditions.Either in deionized water or Beishan groundwater,the solubility-controlling solids phase is hydroxide plutonium(amorphous).In deionized water,the dominant species is hydroxide plutonium.In Beishan groundwater,the dominant species is hydroxide plutonium and Pu(OH)2(CO3)2-2.更多还原