Architecture and management of a geological repository - Andra

11 – Operational SafetyTemperatureThe diagram [downstream distance from the fire (m) / time since outbreak of fire (s) / temperature(°C)] highlights the influence of the smoke clearance system 171 the operation of which deflects the risein temperature of the air in the drifts downstream of the fire ventilation airflow.The simulation (see Figure 11.4.6) shows that the evacuation of personnel located downstream of thefire should be possible under acceptable conditions even for personnel close to the seat of the fire.Personnel escaping at normal speed reach the interconnecting drift in an atmosphere at a airtemperature of below 30°C, and between 40°C and 50°C if they are slowed down by the presence of acasualty. These conditions remain acceptable with respect to the 80°C threshold mentioned previously.Arrival atinterconnectingdriftSmokeclearancesystem startsEvacuationat 0.5 m/sEvacuationat 1 m/sFireFigure 11.4.6Spatio-temporal evolution of the air temperature (°C) in the case of a fire in atype C waste cell access drift during nuclear operation – Representation of themovement of personnel located downstream the fore ventilation airflowCarbon monoxide concentrationUsing the same approach as before, the simulation shows that persons located downstream of the fireventilation, escaping at normal speed, can reach the interconnecting drift under healthy conditions. Atan evacuation speed reduced to 0.5 m/s, personnel arrive at the interconnecting drift in an atmospherewhose a carbon monoxide content (pf around 200 ppm) is still below the 500 ppm threshold.OpacityThe simulation shows that personnel escaping at 1 m/s can reach the interconnecting drift withoutbeing hindered by the opacity, which remains under 0.10 m -1 , corresponding to a visibility of around10 metres.171 It was considered that that the smoke clearance installations would be started up 5 minutes (300 seconds) after the outbreak of the fireand that a stable state would be established after 8 minutes. These data come from experiments in underground structuresDOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM462/495