CAP1400数值反应堆系统关键技术研究及示范应用

本文系统介绍了“大型先进压水堆及高温气冷堆核电站”国家科技重大专项课题“CAP1400数值反应堆关键技术研究”的主要研究成果。课题首先分别开发了基于确定论方法和蒙特卡罗方法的高保真堆芯物理计算程序，然后开发了pin by pin先进子通道分析程序和基于精细网格的燃料棒性能分析程序，以此为基础建立了物理 热工 燃料性能多物理耦合的CAP1400数值反应堆系统。利用国际基准题VERA、AP1000启动物理实验参数对数值反应堆系统进行了验证和确认，并进一步实现了CAP1400大型先进压水堆的启动物理参数、循环模拟分析和部分功率能力分析的示范应用。数值结果表明，所开发的数值反应堆关键分析软件具有很高的计算精度，可直接服务于CAP1400的设计验证、物理启动和运行支持。

Development and Application of CAP1400 Numerical Reactor System

Numerical reactor technology describes a variety of physical phenomena in the core of a nuclear reactor through high precision, high resolution, high confidence and high fidelity numerical simulation method, based on high performance calculation and multi physics coupling, reveals the internal laws of various physical phenomena in nuclear reactors from mechanism, and accurately predicts the key safety parameters of nuclear reactors in service. It plays an important role in the whole life cycle of nuclear reactor R&D, design, safety analysis, operation support and decommissioning. This paper systematically introduces the main outcome of the major national science and technology project “Research on Key Technologies of CAP1400 Numerical Reactor” of “Large scale Advanced PWR and HTGR Nuclear Power Plant”. Firstly, the high fidelity reactor physics calculation codes based on deterministic method and Monte Carlo method were developed respectively, and then the pin by pin advanced sub channel analysis code and the fuel rod analysis code based on fine mesh were developed. Based on those codes, the CAP1400 numerical reactor system with neutronics/thermal hydraulics/fuel performance multi physics coupling was established. The numerical reactor system was verified and validated against the international benchmark VERA provided by CASL and AP1000 startup experimental data. For VERA problems, the comparison with the results of MC21/CTF coupling codes shows that the relative deviation of the power distribution of numerical reactor system is less than 25% for both Monte Carlo method and deterministic method. The maximum critical boron concentration deviation is less than 30 ppm. For AP1000 reactor of Sanmen unit 2, the deviations of developed numerical reactor compared with the measurements are as follows: 1) The maximum deviations of gray rod worth are -103 pcm, 73 pcm and 57 pcm, respectively; 2) The maximum relative deviation of black rod worth are 32%, -17% and 08%, respectively; 3) The ITC deviations are -0.597 pcm/℃, 0.280 pcm/℃, and 1570 pcm/℃, respectively. Compared with the industry codes, numerical reactor codes have higher precision. After verification and validation, the numerical reactor codes were applied to simulate the start up experiments of CAP1400 reactor. Taking the Monte Carlo results as references, the absolute deviation of the deterministic numerical reactor code for the critical boron concentration under HZP ARO condition is -236 ppm. The maximum absolute deviation for the value of the gray rod group (MA to MD) is -52 pcm, and for the black rod group, the maximum relative deviation of the value of (M1, M2, AO, SD1 to SD6) is 268%. The relative deviation of the total worth of black rods is -008%. Assembly power distributions of 14 core conditions were compared between Monte Carlo code and deterministic code. The most positive value of relative deviation is 224%, the most negative value is -247%, the average value is -006% and the standard deviation is 102%. The above numerical results show that the developed numerical reactor analysis program has high calculation accuracy and can directly serve the design verification, start up and operation support of CAP1400.