Using hybrid weight grey correlation analysis method to evaluate the environment safety grade of uranium waste rock heap

As a complex nonlinear gray system, the safety of uranium waste rock heap is affected by variety of factors, such as rock mass integrity, nuclear radiation, vegetation cover and so on. In order to rationally evaluate and predict its environmental safety, based on the theory of gray correlation analysis (GCA) method, the hybrid weight gray correlation analysis (HWGCA) method has been proposed, which combines the analytic hierarchy process (AHP) and entropy weight method (EWM) to calculate the hybrid weight. By using the hybrid weight to calculate the gray correlation grade, we then can evaluate and predict the environmental safety grade of the gray system. The HWGCA method has inherited the advantages of AHP and EWM; the subjective arbitrariness shortcomings in the analysis of environment safety could be avoided, and it can improve the evaluation accuracy and reliability. In this article, we have selected three types uranium waste rock heaps (UWRH) from one uranium mine in Sichuan province to evaluate its environmental safety using the HWGCA method. We used the three-scale AHP and EWM to calculate the hybrid weight, and then calculate the correlation coefficients of each factor. The detailed calculation process is shown in this paper, and the evaluation results and site survey results are consistent.