【摘要】 研究了从HNO₃介质中用TOPO预分离铀、钚及PMBP萃取,HNO₃体系反萃分离希土的条件。应用偶氮氯膦-mA显色测定希土总量。提出了用草酸铵抑制钇的吸光度的合适条件,使钇与铈组元素的吸光度趋于一致。用本法实测了辐照后元件中的希土总量并由此计算了元件的燃耗值。其结果与质谱法、放化法所得结果在±2%内符合。本文提供了一个化学法测定燃耗的方法。更多还原

【Abstract】 Investigation was made into the operating conditions for the preliminaryseparation of uranium and plutonium from the dissolution solution of irradiatedfuels by TOPO--cyclohexane, and the extraction of total rare earths by PMBP-benzene. The content of total rare earths is determinated spectrophotometricallywith chlorophosphonazo--mA as the color developer. The optinium conditionfor reducing the absorptivity of yttrium with （NH₄）₂C₂O₄ was proposed. Underthis condition the absorptivities of yttrium and the cerium group tend tobe similar. The recovery of each rare earth element is about 97%. By means ofthis procedure the content of total rare earths in the irradiated uranium fuels isdetermined and the burn--up of the fuels is calculated. The result is consistentwith that obtained by mass spectrometric and radiochemical methods with adeviation less than ±2%. The procedure may be applied to the determinationof the burn--up of irradiated uranium fuel.更多还原