【摘要】 核燃料燃耗测定对新型核燃料研制和反应堆运行具有重要意义。目前,燃耗测定工作是依据我国核行业标准EJ/T20150.27-2018开展。在保持现有燃耗测量总体工艺不变的前提下,选用SCX双功能色谱分离材料,通过实验优选适用于新材料的色谱条件,获得铀和镧系元素在该色谱材料上的保留规律及机理,实现单根色谱柱对铀与所有镧系元素的基线分离,分离度最小可达1.9。对辐照后核燃料样品进行应用验证,样品中铀与镧系元素的质量浓度比约10~3～10~4量级,在高铀基体下,实现了裂变成因镧系元素的基线分离,镨和钕的分离度最小可达1.8;采用热电离质谱测量分离所得钕样品的钕同位素比值,测量RSD≤0.08%,表明没有同量异位素干扰,该分离方法可以用于燃耗测量中的钕监测体分离。更多还原

【Abstract】 The measurement of nuclear fuel burnup is of great significance for the development of new nuclear fuel and the operation of reactors. At present,the measurement of nuclear fuel burnup is carried out in accordance with Chinese nuclear industry standard EJ/T 20150. 27-2018. On the premise of maintaining the overall process of nuclear fuel burnup measurement,a SCX bifunctional chromatographic separation material was selected,and the chromatographic conditions suitable for the new material were optimized through experiments. The retention patterns and mechanisms of uranium and lanthanide elements on this material were obtained,and the baseline separation of uranium and all lanthanide elements on a single chromatographic column was achieved with a minimum separation degree of 1. 9. This method was verified by an irradiated nuclear fuel sample,in which the mass concentration ratio of uranium to lanthanide elements is in the range of 10~3～10~4. The results show that the baseline separation of lanthanide elements in fission products can be achieved in this high uranium matrix,and the minimum separation degree of Pr/Nd can reach 1. 8. The Nd isotope ratio of the separated Nd sample was measured by thermal ionization mass spectrometry,and the measured RSD was less than or equal to 0. 08%,indicating that there was no interference of nuclear isobars. The separation method can be used for the separation of Nd monitor in the burnup measurement of nuclear fuel.更多还原