LBLOCA accident investigation using TRACE code in a VVER-1000 reactor

The loss of coolant accident is due to the reduction of the coolant fluid volume in the first circuit. The direct cause of this accident is the mechanical failure or fatigue in the material of the first circuit components during the power plant operation. This accident, which is a design-based accident, is an important factor in assessing a nuclear power plant safety. If the break occurs in the main circuit of the first circuit with a diameter greater than 25% of the cross-section area, it shall be referred to as a large break. In this paper, this accident with a break diameter of 850 mm is modeled and analyzed using the TRACE code in a VVER-1000 reactor. The TRACE code is specifically designed for coolant loss accidents. With the help of this analysis, it is possible to have an accurate estimate of the reactor's safety and to obtain significant economic considerations instead of conservative assumptions assessment. Finally, the results of the TRACE code have been compared with the final safety analysis report of the power plant as well as previous research by the RELAP5. The results indicate the accuracy of the TRACE code in modeling the large break accident.