Parametric study of CSR1000 thermal hydraulic stability

A parametric study is performed on thermal hydraulic stability of CSR1000 (a Chinese supercritical water-cooled reactor) using SCTHSAC (Single Channel Thermal Hydraulic Stability Analysis Code). This code uses RMM (system response matrix method) for analyzing the system stability in the frequency domain, a useful method to reveal detailed information about the operational thermodynamic parameters before and after onset of instability in the nuclear reactor. System response matrices are written for each node of the single coolant channel (by linearizing and perturbing conservation differential equations), which are solved for decay ratios. The maximum decay ratio represents stability of the whole system. The decay ratios are calculated for different values of reactor power and inlet orifice diameters. A parametric study of pressure, inlet temperature and moderator flow fraction is presented, which gives vital information about the thermal hydraulic stability bounds of CSR1000 in a sliding pressure startup scheme. The results show a similar trend with the stability charts of a typical SCWR, proving the novelty of RMM. Using this method, a stability surface is generated against power and flow fraction, giving a quick reference for designing a detailed startup scheme of CSR1000 in the future.