A study on optimized system design for PCCS and FCVS

Abstract

For the future light water reactor, PCCS and FCVS are necessary to prevent integrity of containment from the accident, especially LOCA and MSLB. PCCS control the pressure by condensing the steam and FCVS depressurize the containment pressure by venting non-condensable gas. Some designs are proposed in previous studies; however many of them are not available for Korean nuclear power plant. The objective of this research is to suggest the optimized design parameters of PCCS suitable for APR1400 plant and to suggest the design for FCVS accompanied with PCCS. For the analysis of PCCS, at first the PCCS design has proposed by a qualitative method. The computer code using MATLAB has been used to estimate the required heat transfer area and to simulate the performance in case of SBO induced SBLOCA and LBLOCA. The structure data and operating condition data were used as input data for the calculation which estimate the pressure change in the containment. Mass, momentum and en-ergy equation were used in the code and several correlations were applied. The analysis result indicated that the required heat transfer area not to exceed containment design pres-sure was reported that the area of 1650 m2 for SBLOCA and 19600 m2 for LBLOCA. The required number of PCCSHX tubes is 1320 and 15600, respectively. For the FCVS analysis, the design pressure to activation was 2.16bar, required mass flow rate of venting was 26.7kg/s, and the maximum coverage of venting volume without refilling of water was 6.64x10 m3. PCCS for SBLOCA can be installed in APR1400 without significant design change but it is inevitable to change design in case of LBLOCA. The proposed FCVS can be operated passively and have enough capacity.