基于安全壳近程探测数据的事故源项反演方法

在发生核电厂严重事故时，为更加快速准确地估算释放至环境的气载放射性核素泄漏速率，提出了一种新的源项反演方法。该方法基于在安全壳附近主动布设的移动探测点所获取的γ能谱数据反演源项，研究了合适探测距离的选择、移动探测点的有效布设及准确反演单个核素泄漏速率的方法。根据研究结果，选择气载放射性核素中泄漏量及特征γ射线能量均相对高的⁸⁸Kr作为特征核素进行能谱分析；确定合适的探测距离范围为距离安全壳100 m以内；建立γ能谱数据与特征核素泄漏速率的关系，在数值上准确反演放射性核素的泄漏速率。

Source Term Inversion Method Based on Containment Short-range Detection Data

A new source term inversion method was presented to accurately estimate leak rate of airborne radionuclides released into the environment under the circumstance of nuclear power plant severe accidents.The method is based on containment short-range gamma-ray spectrum data obtained by mobile detection points arranged near the containment.The choice of appropriate detection range,effective arrangement of mobile detection points,and accurate estimate of leak rate for a single radionuclide were stud-ied.As a result,88 Kr is selected as the characteristic nuclide among all airborne radio-nuclides due to its relatively high first characteristic gamma-ray energy and high leak rate.The detection range is determined as within 100 m from the containment.The relation between gamma-ray spectrum data and leak rate of characteristic radionuclide is established to obtain inversion result numerically.