Radiation impact quantification analysis for fuel handing accident

Based on Hongyanhe nuclear power plant, research on radionuclide source, transfer and release pathways were carried out, for CPR1000 fuel handing accident. The source term analytical models were constructed, including fuel reserve room and environment. On this basis, the radiation impact of an assembly drop accident was quantitatively estimated. The results show that public doses with 16 directions of exclusion area boundary and planning restricted area outer boundary satisfied the GB6249-2011 dose limits with some margin. The above doses were determined using top 0.5% meteorology. By sensitivity analysis of key parameters, direction of the largest dose, predominant nuclide and key time period were identified. Furthermore, the rationality of accident cutoff time taken as 12 h, and the necessity of fuel operation starting time taken as 100 h were proved. Meanwhile, the effects of scrubbing depth and normal ventilation isolation delay time on public doses were studied. The results show that public dose decreased exponentially with the increase of scrubbing depth, while it increased rapidly with the extension of normal ventilation isolation delay time, which can support the decision of nuclear power plant design.