Effectiveness of shock attenuation by simple geometrical means in mitigating severe accident explosive loads

Simple obstacles are suggested as a means to attenuate shock waves that may arise from severe accident explosions in a nuclear power plant and the effectiveness is investigated by computations employing the FLUENT code. Two- and three-dimensional computations are validated against existing experiment and analysis. Effects of rectangular rigid obstacles on shock attenuation in simple geometries are preliminarily analyzed and a demonstrating plant scale analysis is performed by positioning multiple rigid obstacles below a reactor vessel. Incident circular shock wave is dispersed by the obstacles and the peak pressures at the reactor vessel bottom head center and the 45-degree regions are reduced by about 35 and 50%, respectively. (author)