核电厂设计基准龙卷风评价的敏感性研究

Sensitivity Analysis of Design-Basis Tornado for Nuclear Power Plants

龙卷风是在核电厂选址、设计和安全评价中需要考虑的重要外部自然事件,对于可能发生龙卷风的厂址区域,应对设计基准龙卷风进行评价。本文针对我国7个滨海厂址,按照核安全导则HAD101/10中的龙卷风风险度评价方法,计算了7个厂址的设计基准龙卷风风速,并定量分析了设计基准龙卷风风速对拟合样本区间和高强度样本评级的敏感性。结果表明,高强度级别的龙卷风累积频数分布是否满足对数线性规律决定了设计基准龙卷风风速计算结果的稳定性。对于计算结果不确定性较大的厂址,本文给出了评价中应关注的问题和采取的对策。

Tornado is a kind of important external natural event which should be taken into account in the siting,design and safety evaluation of nuclear power plants.If it is potential for the occurrence of tornadoes in the region nearby a site,the design-basis tornado should be evaluated.The design-basis tornado wind speeds of seven coastal sites located from the north to the south of China have been assessed using the tornado risk evaluation methodology listed in the Nuclear Safety Guide HAD101/10.Sensitivity analysis of design-basis tornado wind speeds on the fitting sample sections and the classification of high intensity tornado samples has been quantitatively performed.The results show that whether or not the cumulative frequency distributions at high intensity scales satisfy the logarithm linear relationships determines the stability of the calculated design-basis tornado wind speeds.The issues which should be concerned in the evaluation process and their counter measures are given for the sites with larger uncertainties of design-basis tornadoes.