中文摘要：

利用蒙特卡罗方法评估秦山第三核电有限公司现场物体计数系统（ISOCS）测量标准200 L钢桶活度时由于放射性物质随机分布而导致的测量结果的不确定度,并采用蒙特卡罗方法模拟计算钢桶内为4种密度填充物及10种核素时ISOCS测量结果的偏差,对ISOCS的测量提出修正。

英文摘要：

Monte-Carlo method was used to evaluate the uncertainty of the activity measurement which was caused by the random distribution of radioactive substance in standard 200 L barrel in normal in situ object count system. The correction coefficient of the measurement results of ten different nuclide species in four different densities was calculated by Monte-Carlo method in simulation models.