• Journal of Energy Engineering
• /
• v.25 no.2
• /
• pp.86-93
• /
• 2016

The existence of high temperature equipment such as steam pipe, deaerator, steam storage tanks and main steam stop valves makes relatively higher workplace temperature in a power plant of the turbine building. In order to cool down the air temperature in the turbine building, the outside air flow with lower temperature passes through the window and the hotter air in the building is extracted to the outside by installing the ventilation fan on the roof. Nevertheless, higher temperature regions near the high temperature equipment still exist in the turbine building and additional fans for the temperature reduction in the higher temperature region should be examined for the optimal location and mass flow rate. The purpose of the present study is to suggest the optimized location and capacity of the additional ventilation fans for a comfortable working environment. From the present study, it has been elucidated that the additional ventilation fans might be located near the high temperature deaerator and it could reduce the mean temperature in the turbine building by $3.0^{\circ}C$ and the temperature near the deaerator could be reduced by $4.2^{\circ}C$.

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.9 no.1
• /
• pp.15-19
• /
• 2013

The auxiliary feedwater is an important to remove the heat from the reactor core when the main feedwater system is unavailable. In most initiating events in Probabilistic Safety Assessment(PSA), the operaton of this system is required to mitigate the accidents. For one of domestic nuclear power plants, a design change of a turbine-driven auxiliary feedwater pump(TD-AFWP), pipe, and valves in the auxiliary system is implemented due to the aging related deterioration by long time operation. This change includes the replacement of the TD-AFWP, the relocation of some valves for improving the system availability, a new cross-tie line, and the installation of manual valves for maintenance. The design modification affects the PSA because the system is critical to mitigate the accidents. In this paper, the safety effect of the change of the auxiliary feedwater system is assessed with regard to the PSA view point. The results demonstrate that this change can supply the auxiliary feedwater from the TD-AFWP in the accident with the motor-driven auxiliary feedwater pump(MD-AFWP) unavailable due to test or maintenance. In addition, the change of MOV's normal position from "close" to "open" can deliver the water to steam generator in the loss of offsite power(LOOP) event. Therefore, it is confirmed that the design change of the auxiliary feedwater system reduces the total core damage frequency(CDF).