CONDUCTING A NATURAL FIRE TEST IN THE VERTICAL CABLE TUNNEL OF A NUCLEAR POWER PLANT

Abstract

The article discusses conducting a full-scale fire test in the vertical cable tunnel of a nuclear power plant (NPP). Vertical cable tunnels in NPPs are used for laying cable lines, wires, safety system lines, connecting the equipment room, and the containment of the nuclear power plant block. The paper analyses research methods and selects options that will be effectively used to determine the temperature regime in the vertical cable tunnel of NPPs with known aerodynamic, technical, and geometric parameters and fire loads. The algorithm for conducting full-scale tests in the vertical cable tunnel of an NPP is described. Based on the research, the maximum temperature in the combustion zone is reached on the fourth minute of the full-scale tests in the vertical cable tunnels of nuclear power plants. By obtaining temperature graphs in the vertical cable tunnel of the NPP, it can be observed that the highest temperature is in plane D (800–900 °C), and it depends on the location of the control point. Thermal energy propagates more intensively in the direction opposite to the filling of the space, which is opposite to the exit of combustion products and ventilation openings. The temperature in plane C is in the range of 500–800 °C. Thermal energy propagates most intensively towards the filling to the exit of combustion products. This temperature significantly deviates from the standard temperature regime, which differs greatly from the full-scale experimental study of fires in the vertical cable tunnels of nuclear power plants. It can be concluded that the standard temperature regime of a fire is not adequate for testing the fire resistance of the structural elements of vertical cable tunnels in nuclear power plants. An important conclusion of these studies is the possibility of determining the fire resistance of building structures of vertical cable tunnels of NPPs with the selection of the most severe temperature regime, according to the conducted field test. It means that research results can be used in practice in designing and evaluating the safety of such objects. Keywords: fire, natural fire tests, nuclear power plant, vertical cable tunnel.