Parametric Study of CSR1000 Thermal Hydraulic Stability Using Response Matrix Method

A parametric study is performed on the thermal hydraulic stability of CSR1000 (a Chinese supercritical water-cooled reactor) using SCTHSAC (Single Channel Thermal Hydraulic Stability Analysis Code). This code uses the response matrix method for analyzing the system stability within time domain, a useful method to reveal detailed information about the operational thermodynamic parameters before and after the onset of instability in a nuclear power reactor. A system response matrix is built on each node of the single coolant channel by linearizing and perturbing conservation differential equations, which is solved to form an array of decay ratios. The maximum decay ratio represents stability of the whole system. A decay ratio map is generated to see the effect of power and inlet orifice diameter ratio on system stability. The parametric study of pressure, inlet temperature and moderator flow fraction gives vital information regarding thermal hydraulic stability of CSR1000 in a sliding pressure startup scheme. Using system response matrix method, a stability surface is plotted against power and flow fraction, providing a useful reference for designing a detailed startup scheme of CSR1000 in the future.