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福岛(Fukushima)核事故后,源项反演成为一种重要的核事故放射性释放源项定量计算分析方法。该文引入四维变分(4DVAR)资料同化法,结合中尺度大气扩散模型,提出一种针对核电厂事故的放射性释放源项反演方法。该方法利用核电厂周围监测数据,使用伴随方法迭代计算四维变分代价函数梯度,得到对释放源项的最佳估计。该方法考虑了完整时间序列上的放射性传输过程,对释放源项的估计结果为全局最优。风洞实验验证结果表明:源项估计的相对误差为20%左右。
After the Fukushima nuclear accident, source inversion has become an important quantitative analysis method for radioactive release of nuclear accidents. In this paper, the 4DVAR data assimilation method is introduced, and a mesoscale atmospheric diffusion model is proposed to propose a source inversion method for radioactive release of a nuclear power plant accident. The method uses the monitoring data around the NPP and iteratively computes the gradient of the four-dimensional variational cost function using the adjoint method to obtain the best estimate of the release source term. The proposed method takes into account the radioactive transmission over a complete time series, and the result of the estimation of the release source terms is globally optimal. The wind tunnel experimental results show that the relative error of source estimation is about 20%.