“华龙一号”安全壳内气溶胶重力沉降特性研究

Study on Aerosol Gravitational SedimentationCharacteristics in Containment of HPR

采用具有滑移修正因子和动力形状修正因子的Stokes重力沉降模型,研究“华龙一号”设计基准大破口失水事故工况下安全壳内气溶胶的重力沉降特性。根据安全壳内气溶胶粒子本身特性,并结合“华龙一号”设计基准大破口失水事故工况下堆芯裂变产物释放情况和安全壳内的热工水力条件,确定了重力沉降模型中的重要参数,得到该工况下安全壳内气溶胶的重力沉降速率。结合“华龙一号”安全壳设计参数,获得安全壳内气溶胶的重力沉降去除系数。并对典型核素形成的气溶胶在安全壳气空间的活度变化进行对比分析。结果表明,对于“华龙一号”核电厂,安全壳内气溶胶重力沉降可明显降低事故情况下安全壳气空间的放射性活度水平及向外界环境的放射性释放。

Aerosol gravitational sedimentation characteristics in HPR containment during design basis large break loss of coolant accident(LB-LOCA)were studied using Stokes gravitational sedimentation model with flip and dynamic shape correction factors.Important parameters for the model were determined according to characteristics of aerosol,along with core fission produces releases and thermal-hydraulic conditions in containment during HPR LB-LOCA.Gravitational sedimentation velocities of aerosols were obtained.Then the aerosol gravitational sedimentation removal coefficients were obtained combining with design parameters of HPR containment.Activity of aerosols formed by representative nuclides in containment atmosphere were compared and analyzed with and without gravitational sedimentation.The results indicated that radioactivity in-containment atmosphere and released into offsite environment during accident conditions could be significantly reduced by aerosol gravitational sedimentation for HPR.