考虑源扰动效应的高阶蒙特卡罗微扰研究

Research on High-order Perturbation Calculation Method with Perturbed Source Effects

微扰计算可用于估计由特定反应堆参数扰动引起的有效增殖因子的变化,同时是反应堆敏感性分析及不确定性分析的基础。传统蒙特卡罗(蒙卡)微扰计算方法扰动阶数低,不易于向高阶推广,且由于没有考虑系统扰动引起的源扰动效应,计算误差较大。为了克服传统方法的缺点,提高蒙卡微扰计算的精度,对考虑源扰动效应的高阶蒙卡微扰方法进行研究。数值计算结果说明:源扰动效应在蒙卡微扰计算中起着重要的作用,不考虑源扰动效应会带来较大的计算误差;随着计算阶数的增加,微扰计算的结果更加精确。

Perturbation calculation can be used to estimate the changes of effective multiplication factor caused by perturbed system parameters, and is the fundamental of reactor sensitivity and uncertainty analysis. With the development of computer techniques and the increasing needs of new concept and complex reactoranalysis, Monte Carlo perturbation calculation is being used more and more widely. Traditional Monte Carlo perturbation .calculation methods, which are limited to low-order perturbation and not considering of perturbed source effects, could cause large errors in perturbation calculations. To overcome the shortages of traditional methods, the high-order differential operator method with perturbed source effects is research in this paper, and this method is implemented in the code RMC. Numerical tests show that the perturbed source effects are very important in perturbation calculation, and large errors will be caused if the perturbed source effects are not considered in the calculation. Also, from the results, we can notice, with higher order, the perturbation results are more accurate.