Preliminary Research on Multi-Reactor Accident Radiation Dose Evaluation Methodology in Near-Site

Multi-reactor accident source terms have the characteristics of multi-point simultaneous dispersion,stronger direct radiation exposure,combination of building radiation shielding effect and reflection effect,and more complex radioactive material concentration computing.Current radiation dose evaluation methodology and systems can not fully satisfy the need of near-site dose evaluation and emergency under multi-reactor accident.It has been proved that small scale wind field and atmospheric dispersion are key elements affecting plume exposure dose to emergency workers,thus the complex terrain and building effect can not be neglected by the atmospheric dispersion model.Through the analysis of main Chinese multi-reactor distribution and site condition,CFD has been recommended as near-site fluent field computation method.For the multi-reactor dose field computing,conservative method proves the virtue of computing time saving and strong operability,while realistic method needs much time with more precision,and it should be selected based on the nuclear accident emergency demand.