A simulation of the effects of a distant underground detonation on a secondary containment of a Boiling Water Reactor type 5 of a nuclear power plant

• A distant interaction of an underground detonation with the secondary containment of a nuclear plant is simulated. • This is an insight into this dynamic situation. Several parameters can affect the dynamic response of the secondary containment. • It was determined that the frequency of the explosion waves did not resonate with the building. • Due to the characteristics of the problem, an explicit analysis is carried out. The effect of an underground blast, used to produce commodities near the secondary containment of a Boiling Water Reactor (BWR), has been reported. A reinforced concrete building with a 4 m foundation slab on a basalt soil was considered. The length of each side is 45 m, and its height is 55 m. Besides, 10 m of this containment is below ground level. The thickness of each wall is 1 m. Its natural frequency is 3.23 Hz. It was loaded with an explosive charge of 15 tons of TNT at 2 km from the secondary containment and 10 meters below ground level. Response spectra generated by this blast were obtained using the PRISM code in the range of frequencies between 0.5 Hz and 4.7 Hz. The dampness considered in the Operating Basis Earthquake (OBE) and Safe Shutdown Earthquake (SSE) were 4% and 7%, respectively. In the next step, a numerical evaluation was done with the ANSYS Autodyn code, and the response spectra were developed. The results showed that the postulated blast is not in resonance with the seismic response spectrum of the secondary containment structure. The USBM-RI-8507 was followed. The maximum horizontal velocity is 9.55 mm/s. It is lower than the maximum allowable (12.5 mm/s). It is important to note that in evaluations of similar cases, the parameters will change according to the terrain conditions. Therefore, the simulation presented can be considered an analysis that provides insight into the dynamic event being studied.