Multi-Objective Optimization of Ventilation and Air Conditioning System at Interim Storage for Spent Nuclear Fuel R. Ratiko 1 1DVUXGGLQ : :XODQGDUL $ 5RVLGL ( 0DU]XNL Department of Mechanical Engineering Universitas Indonesia Depok, Indonesia ratiko@batan.go.id QDVUXGGLQ#HQJXLDFLG ZLQGDZXODQGDUL#HQJXLDFLG DLQXUURVLGL#HQJXLDFLG HGLPDU]XNL#HQJXLDFLG Abstract— A multi-objective optimization of ventilation and air conditioning system at Interim Storage for Spent Nuclear Fuel (ISSF) at BATAN, Serpong, Indonesia has been considered. The analysis of this research had obtained the results of three scenarios, economic single-objective, safety single-objective, and multi-objective optimizations. The original Pareto frontier between cost and safety function is determined by implementing multi-objective optimization using genetic algorithm. The cost function of the ventilation and air conditioning system was developed based on the present value of the total cost. The safety function of this system was based on contaminant concentration levels which were obtained by using air change rates, negative pressure, and temperature parameters. The economic and safety results have been obtained for three scenarios of optimized systems. The result shows that the multi-objective method by implementing multi-objective optimization using genetic algorithm satisfies the economic and safety criteria. Keywords— Multi-objective optimization; ventilation and air conditioning system; Interim Storage for Spent Nuclear Fuel. NOMENCLATURE Civ Contaminant concentration from inlet air velocity (Bq/m 3 ) Co Total energy cost at the ｿrst year of operation ($/year) Cov Contaminant concentration from outlet air velocity (Bq/m 3 ) Ct Contaminant concentration from room temperature (Bq/m 3 ) ECC Equivalent cooling cost ($/kWh) F Annuity factor g Gravitational acceleration (m/s 2 ) gel Inﾀation rate for electricity cost (%) Hyear Annual operational hours (hour) i Interest rate (%) k Number of operation years (year) ۦMass flow rate (kg/s) Pevap Pressure of evaporator (Pa) Pcond Pressure of condenser (Pa) PVC Present value capital cost ($) PVCChiller Present value capital cost of chiller ($) PVCAHU dc Present value capital cost of Air Handling Unit (AHU) and ducting system ($) PVCBlower Present value capital cost of blower ($) PVE Present value of electricity cost ($) PVT Present value of the total cost ($) Vin Inlet air volume flow from AHU (m 3 /h) Vout Outlet air volume flow to stack (m 3 /h) ܥblower in Power consumption of inlet air blower (kW) ܥblower out Power consumption of exhaust air blower (kW) ܥcomp Compressor power consumption (kW) ܥcond Condenser power consumption (kW) ܥevap Evaporator power consumption (kW) ܥtot Total power consumption of the system (kW) I. INTRODUCTION Spent nuclear fuel is a bundle of nuclear fuel that has been irradiated and has reached its economic life. The nuclear fuel in the operated reactor needs to be removed and replaced periodically with new nuclear fuel. The spent fuel continues to produce radiation and heat due to its radioactive decay. The heat decreases exponentially for many years after being removed from the reactor. 73 ,(((