基于RELAP5的螺旋管蒸汽发生器热工水力程序研发与验证

由于较高的换热效率和紧凑的结构设计，螺旋管式直流蒸汽发生器（HCOTSG）在多种模块化小型堆的设计中得到了广泛应用。RELAP5作为广泛应用于反应堆热工水力特性分析的大型系统程序之一，采用的热工水力关系式仅针对直管模型开发，不适用于HCOTSG一次侧和二次侧。本文选用螺旋管及横掠管束的热工水力模型，基于RELAP5程序开发了HCOTSG模块。采用实验数据及程序对比等方式对螺旋管模块的流动和换热模型进行了单独验证，利用开发的RELAP5-HCOTSG程序针对国际革新安全反应堆（IRIS）的蒸汽发生器设计进行了整体的热工水力模拟，与原始RELAP5的计算相比，RELAP5-HCOTSG程序计算得到的热工水力参数与设计值符合良好，确认了本文开发的程序模块在HCOTSG热工水力分析中的适用性。

Code Development and Validation for Thermal-hydraulic Analysis of Helical Coil Steam Generator Based on RELAP5

It is a common practice to employ a helical coil steam generator in several small modular reactor designs because of its enhanced heat transfer efficiency and advantages on compact structure. RELAP5 is one of the widely accepted thermal-hydraulic system analysis codes for reactors. However, the build-in empirical corrections are only suitable for straight tubes, but not for the primary side and secondary side of helical coil steam generators. In this study, the thermal-hydraulic models for helical tubes and tube bundles were selected and implemented in RELAP5 to develop a code module for helical coil once-through steam generator (HCOTSG). The validation for thermal-hydraulic models was carried out by experimental data and code-to-code comparison. Based on the validated RELAP5-HCOTSG, the integral benchmark simulation against the steam generator of the international reactor innovative and secure (IRIS) was performed. Compared with the original RELAP5 calculation, the thermal-hydraulic parameters obtained by RELAP5-HCOTSG are in good agreement with the design values, which confirms the applicability of the developed code in this study for thermal-hydraulic analysis of HCOTSG.