The hydrogen deflagration is one of the major risk contributors to threaten the integrity of the containment in a nuclear power plant, and hydrogen control in the case of severe accidents is required by nuclear regula...The hydrogen deflagration is one of the major risk contributors to threaten the integrity of the containment in a nuclear power plant, and hydrogen control in the case of severe accidents is required by nuclear regulations. Based on the large dry containment model developed with the integral severe-accident analysis tool, a small-break loss-of-coolant-accident (LOCA) without HPI, LPI, AFW and containment sprays, leading to the core degradation and large hydrogen generation, is calculated. Hydrogen and steam distribution in containment compartments is investi- gated. The analysis results show that significant hydrogen deflagration risk exits in the reactor coolant pump (RCP) compartment and the cavity during the early period, if no actions are taken to mitigate the effects of hydrogen accu- mulation.展开更多
A small scale field experiment (SSFE) was performed on vertical breakwaters in the surf zone. The following are some of the findings. Wind seas may yield breaking wave pressure notwithstanding some large deepwater wav...A small scale field experiment (SSFE) was performed on vertical breakwaters in the surf zone. The following are some of the findings. Wind seas may yield breaking wave pressure notwithstanding some large deepwater wave steepness, and small elevation of the wall above the mean water level. Caisson breakwaters can withstand some exceptionally high impulsive force peaks (even twice the weight in still water);whereas, with the same sea state and weight, a breakwater composed of layers of solid concrete blocks is destroyed.展开更多
研究了承压热冲击(PTS)事故发生时,变化的堆芯衰变热对反应堆压力容器(RPV)安全分析的影响。基于ACP1000三回路反应堆压力容器,对25 cm 2小破口失水事故工况应用三维流固热耦合方法进行模拟。计算了事故下2000 s内堆芯衰变热随时间的变...研究了承压热冲击(PTS)事故发生时,变化的堆芯衰变热对反应堆压力容器(RPV)安全分析的影响。基于ACP1000三回路反应堆压力容器,对25 cm 2小破口失水事故工况应用三维流固热耦合方法进行模拟。计算了事故下2000 s内堆芯衰变热随时间的变化函数,得到变化堆芯衰变热影响下冷却剂经过堆芯后的温升、三回路模型安注流动轨迹、确定RPV环腔内温度最低点(冷点)的位置,并在此处施加裂纹影响,得到变化堆芯衰变热影响下应力强度因子分析结果,并与1 MW/m 3堆芯衰变热结果进行比较。结果表明,在本瞬态工况下变化的堆芯衰变热对流经的冷却剂有明显的升温作用,RPV内壁应力也有16.02%的增幅,应力强度因子有30.1%的增幅。展开更多
文摘The hydrogen deflagration is one of the major risk contributors to threaten the integrity of the containment in a nuclear power plant, and hydrogen control in the case of severe accidents is required by nuclear regulations. Based on the large dry containment model developed with the integral severe-accident analysis tool, a small-break loss-of-coolant-accident (LOCA) without HPI, LPI, AFW and containment sprays, leading to the core degradation and large hydrogen generation, is calculated. Hydrogen and steam distribution in containment compartments is investi- gated. The analysis results show that significant hydrogen deflagration risk exits in the reactor coolant pump (RCP) compartment and the cavity during the early period, if no actions are taken to mitigate the effects of hydrogen accu- mulation.
文摘A small scale field experiment (SSFE) was performed on vertical breakwaters in the surf zone. The following are some of the findings. Wind seas may yield breaking wave pressure notwithstanding some large deepwater wave steepness, and small elevation of the wall above the mean water level. Caisson breakwaters can withstand some exceptionally high impulsive force peaks (even twice the weight in still water);whereas, with the same sea state and weight, a breakwater composed of layers of solid concrete blocks is destroyed.
