不同初因事件下的两相排放过程热工水力特性研究

本文针对稳压器安全阀开启后的复杂两相热工水力过程进行研究，确定不同初因事件下的稳压器安全阀两相排放特性。采用自主化系统分析程序ARSAC对稳压器安全阀的上下游进行建模分析，选取三种典型的阀门排放过程，包括稳压器安全阀误开启事故、导致一个或多个稳压器安全阀开启的主蒸汽流量完全丧失事故、以及低温超压保护条件下导致的稳压器安全阀间歇性开启的安注泵误启动事故，研究稳压器安全阀开启后水封及蒸汽（或水）排放过程中涉及的复杂两相热工水力特性，结果表明：ARSAC程序能够捕捉两相排放过程中管道内部的流型变化；水封通过下游管道会形成明显的流量峰值，且不同的上游初始条件下排放过程对于下游管道造成的流量峰值及时间特性不同。通过本文的研究可以为载荷分析、安全评价及设计优化提供指导性建议。

Study on Thermal Hydraulic Characteristics of Two-phase Discharge Process under Different Initial Events

This paper studies the complex two-phase thermal hydraulic process after the opening of the pressurizer safety valve so as to determine the two-phase discharge characteristics of the pressurizer safety valve under different initial events. In this paper, the autonomous system analysis program ARSAC is used to model and analyze the upstream and downstream of the pressurizer safety valve, and three typical valve discharge processes are selected, including the accidental opening of the pressurizer safety valve, the complete loss of main steam flow that causes the opening of one or more safety valves, and the accidental starting of the safety injection pump that causes the intermittent opening of the pressurizer safety valve under the condition of low temperature overpressure protection. The complex two-phase thermal hydraulic characteristics involved in the process of water seal and steam (or water) discharge after the opening of the pressurizer safety valve are studied. The results show that the ARSAC program can capture the flow pattern changes in the pipeline during two-phase discharge; the water seal will form an obvious flow peak through the downstream pipeline, and the flow peak and time characteristics of the downstream pipeline caused by the discharge process are different under different upstream initial conditions. The study in this paper can provide guidance for load analysis, safety evaluation and design optimization.