摇摆条件下两环路自然循环回路特性分析

在海上小型堆设计中,需要考虑海洋运动条件对热工水力特性的影响。本文建立了海洋运动条件下的附加惯性力模型,并将该模型应用于RELAP/SCDAP程序中,得到了适用于海洋运动条件下的系统分析程序,利用修改后的RELAP5程序,分析了在摇摆条件下自然循环回路的热工水力特性。分析结果表明,摇摆条件下,自然循环回路的平均流量小于静止条件下的自然循环流量,环路流量波动滞后于横摇运动,冷却水温波动滞后于环路流量波动,摇摆幅值越大,频率越高,流量波动幅值越大。当摇摆较剧烈时,环路上出现倒流现象。增加加热功率或提高冷热源之间高度差可增加系统的自然循环驱动力,减小横摇运动对自然循环的影响。

Characteristics Analysis of the Natural Circulation Circuit with Two-Loop Under Rolling Motion Conditions

In the design of off-shore small nuclear reactor,it is necessary to consider the effect of ocean motion conditions on thermal and hydraulic characteristics.In this paper,additional inertia forces models are estab?lished,and the model is applied to the RELAP/SCDAP program,the system analysis program for ocean motion is obtained.The thermal and hydraulic characteristics of natural circulation loop under swing condition are ana?lyzed by using modified RELAP program.The results show that the average flow rate under rolling conditions is less than that of the stationary conditions.The loop flow fluctuation lags behind the rolling motion and the cool?ing water temperature fluctuation lags behind the loop flow fluctuation.The fluctuation amplitude of the natural flow rate will increase as the rolling amplitude or frequency increases.When the rolling motion is severe enough,back-flow may occur in the loops.Increasing the heating power or increasing the height difference be?tween cold and heat sources can increase the driving force of natural circulation of the system and reduce the influence of rolling motion on natural circulation.