A detailed Loss of Coolant Accident (LOCA) analysis in an AP1000 NPP was performed, followed by a definition of the vulnerability analysis principles, and analysis of blast loads and fragments impact created by a nearby explosion. The AP1000 NPP performs excellently to small-break LOCA due to in-structure shock, with the 10 CFR 50.46 Acceptance Criteria fully accomplished. Impulsive dynamic loads resulting from blast waves and fragments impact of GBU-28 (Guided Bomb Unit) were considered for a nearby explosion. We model the structure and the main reactor components using the MSC/Dytran code to obtain accurate internal acceleration levels at critical points. We account for the appropriate blast wave interaction with the soil and the soil interaction with the containment structure, rather than using empirical formulas. The model includes the shielding structure with its concrete base, the support structures for the reactor, the steam generators, and the pressurizer. The combined effect of bomb fragmentation and blast loading was also considered using a cylindrical fragmentation model and the blast model of Kingery-Bulmash, assuming a hemispherical charge. A comprehensive risk assessment methodology composed of four phases was developed. The methodology is comprised of: (I) System analysis, (II) Hazard analysis, (III) Damage assessment, and (IV) Risk analysis of the in-structure shock consequences. Using seismic fragility curves for analysis of the expected failure modes according to explosion events faced difficulties since no published data was found. Adjustments to these fragility curves were made using median acceleration limits on components designed to withstand airplane crash, together with standard deviations taken from the given earthquake fragility tables. The findings reveal that the probabilities of failure of the reactor coolant system components resulting from a GBU-28 nearby hit, namely the pressurizer, the cooling pumps, and valves are quite high (greater than 1∙10⁻⁴).

在AP1000 NPP中进行了详细的冷却剂事故损失（LOCA）分析，然后定义了脆弱性分析原理，并分析了附近爆炸产生的爆炸载荷和碎片冲击。AP1000 NPP因结构内震动而在小断裂LOCA方面表现出色，完全符合10 CFR 50.46验收标准。爆炸附近的爆炸被认为是由爆炸波和GBU-28（导向炸弹部队）的碎片冲击产生的脉冲动载荷。我们使用MSC / Dytran代码对结构和主要反应堆组件进行建模，以在关键点获得准确的内部加速度水平。我们考虑了爆炸波与土壤的相互作用以及土壤与围护结构的相互作用，而不是使用经验公式。该模型包括具有混凝土基座的屏蔽结构，反应堆的支撑结构，蒸汽发生器和增压器。假设使用半球形电荷，还使用圆柱破碎模型和Kingery-Bulmash爆炸模型来考虑炸弹破碎和爆炸载荷的综合作用。制定了由四个阶段组成的综合风险评估方法。该方法包括：（I）系统分析，（II）危害分析，（III）损害评估，以及（IV）结构内冲击后果的风险分析。由于没有发现公开的数据，因此使用地震脆性曲线来分析根据爆炸事件的预期破坏模式面临困难。对这些脆弱性曲线的调整是通过设计用于承受飞机坠毁的部件的中值加速度极限，以及从给定地震脆弱性表中得出的标准偏差来进行的。研究结果表明，由附近的GBU-28撞击（即增压器，冷却泵和阀门）引起的反应堆冷却剂系统部件失效的可能性非常高（大于1∙10^-4）。