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本文介绍用高分辨Ge(Li)探测器-多道计算机系统,不经化学分离而破坏性测定反应堆辐照燃料燃耗的研究结果。以~(137)Cs、~(144)Ce为燃耗监测体,采用与标准源直接比较的方法测定燃料溶解液中燃耗监测体的浓度;对ADC的分析时间和脉冲堆积引起的计数损失进行了精确的校准;比较了曲线拟合法、TPA法、峰外扣本底法、WASSON法求面积的精度。~(106)Ru、~(137)Cs、~(144)Ce放射性浓度的误差分别为±1.3％、±1.6％、±1.3％(置信度为95％),与放化分离法的偏差分别为-1.1％、+0.74％、+1.1％。根据燃料辐照历史的记录,采用辐照史校正程序精确计算了燃耗监测体的堆内衰变量、中子俘获反应的修正量和~(235)U、~(238)U、~(239)Pu、~(241)Pu的平均裂变产额。辐照史校正对由~(137)Cs、~(144)Ce获得燃耗值引入的误差分别为±0.2％和±0.3％。这两个燃耗监测体获得燃耗值的综合误差均为±2.0％。与同位素稀释质谱法测定~(148)Nd所得燃耗值的比值分别为0.98和0.99。
This article describes the results of a destructive determination of reactor fuel burnup using a high resolution Ge (Li) detector-multichannel computer system without chemical separation. The concentration of the fuel consumption monitor in the fuel solution was determined by directly comparing with 137 Cs and 144 Ce as the fuel consumption monitor. The ADC analysis time and pulse counting loss Accurate calibration was carried out. The curve fitting method, TPA method, peak-deduction background method and WASSON method were compared. The errors of radioactive concentrations of ~ (106) Ru, ~ (137) Cs and ~ (144) Ce were ± 1.3%, ± 1.6% and ± 1.3%, respectively -1.1%, + 0.74%, + 1.1%. According to the records of the history of the fuel irradiation, the decay amount of the fuel consumption monitoring body, the correction amount of the neutron capture reaction and the correction of ~ (235) U, ~ (238) U, ~ ) Pu, ~ (241) Pu average fission yield. The errors introduced by the calibration of irradiation history for the burnup values obtained from ~ (137) Cs and ~ (144) Ce were ± 0.2% and ± 0.3%, respectively. The combined error of the burnup values of the two burnup monitors was ± 2.0%. The ratio of the burnup value of ~ (148) Nd measured by isotope dilution mass spectrometry was 0.98 and 0.99, respectively.