Numerical Analysis of Safety Injection System’s Flow Rate

Abstract

In this paper, a hydraulic model for Safety Injection System (SIS) of M310 reactor is extended. The model is checked and calibrated by test results under test conditions. Based on commissioning test criteria, the system’s maximum and minimum pressure drop coefficients are calibrated according to anti-extrapolation method. Considering modifications of various projects, analysis of 41 flow rate curves under different conditions has been performed using this model. These flow rate curves indicate the relationship between injection flow rates and primary circuit pressures. Accident analysis has taken these curves as input data. Also, the strategy for dealing with accident is established based on these curves. Results of accident analysis show that the design of SIS system can satisfy the safety requirements of M310 reactor. The sensitivity analysis of typical conditions illustrates that injection flow rate will increase as the primary circuit pressure decreases. With the same configuration, the injection flow rate during recirculation phase will be smaller than that during direct injection phase, which is mainly caused by the decrement of suction elevation and the increment of fluid temperature. When low head safety injection pump (LHSI PO) is boosting high head safety injection pump (HHSI PO), if the pressure is relatively high, the injection flow rate will not be improved apparently. If the pressure is relatively low, the boosting is necessary. These conclusions can be the basis for the later optimization design.