基于广义等价理论的高保真共振计算方法

High-fidelity resonance calculation method based on generalized equivalence theory

采用伪核素方法,建立了能够精确快速处理干涉效应的计算方法,在分析广义等价理论特点的基础上,提出了高保真的共振计算方法。该方法首先根据实际问题的几何,建立238 U的非均匀共振积分表,基于此核素采用广义等价理论处理栅元间的互屏效应,获得不同位置燃料棒的背景截面,然后根据背景截面在非均匀截面表中插值建立不同燃料棒的等效栅元,在此栅元的基础上根据实际问题中燃料棒内的温度分布和核素分布进行超细群计算,从而获得燃料棒内不同位置共振核素高保真的有效共振截面。

Resonance calculation must treat global and local effects, namely, the interference among different pins, the interference among different nuclides, nuclide distribution effect and temperature distribution effect. The conventional resonance method can＇t exactly solve all the problems, simultaneously. This paper uses pseudo isotope method to treat the interference effect among different nuclides with high precise and efficiency. According to the assessment of the generalized equivalence theory, a high-fidelity resonance calculation method is proposed. In order to incorporate the global effect, the iteration calculation is performed for the U-238 based heterogeneous table. After the background cross sections for different fuel pin are obtained, the interpolation of the table is carried out to find an equivalent pin. Then the ultra-fine calculation is carried out on the equivalence pin based on the real nuclide composition and temperature distribution to get the high-fidelity effective cross sections for the nuclide at different position in the fuel pin.