小破口失水事故喷放阶段临界时间的计算方法

A METHOD FOR CALCULATING THE CRITICAL TIME UNDER BLOWDWWN CONDITIONS DURING A SBLOCA

压水堆发生失水事故时，从喷放开始到发生临界热流密度ＣＨＦ这一段时间称为临界时间ｔＣＨＦ·ｔＣＨＦ决定了安全保护系统必须投入的时间，因此正确计算ｔＣＨＦ非常重要，论文分析了Ｇｒｉｆｆｉｔｈ方法的缺点，作了较大的改进，经与实验值比较，改进方法所得的ｔＣＨＦ值与实验值吻合较好。

The critical time is the period from the instant at which the blowdown occurs to the in-stant when the critical heat flux(CHF)happens. It determines the time of operating thesafety protection system when a LOCA occurs in PWR. It is important to calculate the criti-cal time correctly. The weakness of Griffith′s method is analyzed and a great improvement isdeveloped in this paper. The critical time calculated by the improved method agrees with theexperimental values.