核废物密度对SGS测量影响的蒙特卡罗模拟

摘要

Aiming at the influence of nuclear waste density on segmented gamma scanning (SGS) measurement, to study the influence on pulse count, put forward the Monte Carlo simulation method and establish the SGS system through Monte Carlo software MCNP based on the prototype, fill the waste barrel with two different density waste, and use the transmission source and mixed source to measure the energy spectrum respectively, contrast the simulation results. It shows that, the nuclide characteristic peak amplitude decreases with increasing the density, stray energy pulse amplitude increases with density increases, and the density change has a greater influence on the transmission measurement, it’s necessary to take density factor into account when correction calculation for specific correction.%针对分层γ扫描(segmented gamma scanning，SGS)系统受核废物密度影响的问题，为研究核废物密度对特征能量脉冲计数的影响，提出一种蒙特卡罗仿真分析方法。采用蒙特卡罗软件MCNP(monte carlo n-particle transport code)建立基于原型的SGS仿真模型，将废物桶内分别填充密度相差较大的2种常见核废物，使用透射源、混合源分别进行透射测量和发射测量，对比能谱测量结果。结果表明：核素特征峰幅度随密度增大而减小，杂散能量脉冲幅度随密度增大而增大，且密度变化对透射测量影响较大，需要在后期校正计算时进行针对性修正。