双重非均匀系统环形RPT计算方法研究

Research on Ring Reactivity-Equivalent Physical Transformation Method for Homogenization of Double-Heterogeneous Systems

弥散燃料与弥散可燃毒物由于具有双重非均匀性,采用传统体积均匀化方法(VHM)会带来较大的计算偏差。反应性等效物理转换(RPT)方法被应用于含弥散燃料的双重非均匀系统,具有方法简单且计算精度较高的特点。本文首先对传统RPT方法和改进RPT(IRPT)方法进行了分析和验证,结果表明,这2种方法对于含有弥散可燃毒物的双重非均匀系统燃耗过程中依然存在相对较大的计算偏差;然后提出环形RPT(RRPT)方法和2步环形RPT(TRRPT)方法分别用于处理含单一颗粒类型和含2种颗粒类型的双重非均匀系统,通过含不同类型可燃毒物的算例验证并与蒙卡颗粒模型基准解对比可知,本文提出的RRPT方法和TRRPT方法可用于处理含弥散燃料和弥散可燃毒物的双重非均匀系统,相比传统方法具有更高计算精度和更广适用范围。

Because of the double heterogeneity of the dispersed particle-type fuel and the burnable poison, the traditional volumetric homogenization method(VHM) on double-heterogeneous(DH) systems will bring unacceptable calculation deviation. The reactivity-equivalent physical transformation(RPT) method applied to the DH systems with particle-type dispersed fuel has the features of simplicity and high calculation accuracy. In this paper, the traditional RPT and IRPT methods have been analyzed and verified, and it suggests that for some DH systems with dispersed particle-type burnable poison with large absorption cross section, these two methods are with relatively large calculation deviation. Ring RPT(RRPT) method and Two-step ring RPT(TRRPT) method are proposed to deal with the DH systems of one and two types of particles. Results of depletion calculations for different types of dispersed particle-type fuel and burnable poisons and the comparison with Mote Carlo results of grain models prove the validity of RRPT method and TRRPT method. The preliminary conclusion can be obtained that Ring RPT method has wider scope of usage and higher accuracy than the traditional RPT method.