Impact assessment of internal explosives on physical barriers within nuclear facilities through demonstration testing

The objective of this study was to assess the impact of internal explosives on the physical barriers (reinforced concrete and fireproof doors) of nuclear facilities by conducting explosives demonstration tests and comparing the results with computer code results. In this study, we conducted internal explosion tests on physical barriers (reinforced concrete and fireproof doors) within a nuclear facility, with the weights of the explosives set at 20 g, 100 g and 150 g (TNT criteria), to measure the pressure changes corresponding to each weight. These tests aimed to analyzed the pressure distribution and displacement effects on the structure. An array of sensors, including LVDTs, and incident and reflect pressure gauges were used to record the blast tests and capture dynamic pressure and displacement responses at critical structural points. The experimental results indicated significant variations in pressure distributions according to the placement and quantity of the explosives. A notable finding in test B-2 revealed that despite the explosives being detonated at the same location as in other tests, the resulting pressures were usually higher at the ceiling rather than at the walls, contrary to the outcomes observed in other experiments. This pattern demonstrates the complexity of internal blast dynamics and suggests interference from reflected waves. In addition, the experiments indicated that as the weight of the explosives increased, the time intervals between successive pressure peaks decreased, suggesting a faster propagation of pressure waves with heavier explosives. To complement the experimental data, computational simulations using AUTODYN were conducted. These closely reflected the experimental results, with a maximum displacement discrepancy of 14.5 %. This research will contribute to the field by providing empirical data and validated models that can be used to enhance the design standards for blast protection for concrete walls and doors in major national facilities, particularly nuclear facilities.