Source term analysis and impact study during a hypothetical accident in Haiyang nuclear power plant

Since 2018, the use of AP1000 nuclear technology has been growing due to its advantages in terms of nuclear safety and security. Knowing that the occurrence rate of the serious nuclear reactor accidents has increased due to the natural disasters that the world has encountered in recent decades, such as earthquakes, floods, tsunamis, etc., we propose to carry out an impact study and analyze the consequences of these accidents, with the aim of avoiding exposure of the public and workers to ionizing radiation. This work is divided into two sections: firstly, calculate the source term by using the ORIGEN-JR depletion code, and compare the obtained results with those published in the document AP1000 Design Control. The obtained results are in agreement with the literature. Secondly, starting from the results of the source term calculation, we have evaluated the atmospheric dispersion using health HotSpot code. The Total Effective Doses (TED) is estimated over two meteorological periods: the first period, from April to August, and the second one, from September to March. The simulation results showed that the TED was higher, around 27 Sv at 0.6 km from the source during the April–August period. However, for the second period, the TED is about 8 Sv at 2 km from the source. Generally, the TED of all radionuclide groups exceeds the IAEA annual regulatory limits, which are one millisievert per year (1 mSv/year) for public exposure and twenty millisieverts per year (20 mSv/year) for occupational exposure of workers. Therefore, the probability of risks to workers, the public, and the environment rises. There are generic criteria for acute doses, according to which preventive actions must be taken in all circumstances in order to minimize the serious effects of radionuclides on the population. •Computing the source term of eight radionuclide groups using the ORIGEN JR code for an AP1000 reactor.•Predicting the early atmospheric dispersion of radionuclides using the HotSpot code in the event of a hypothetical accident.•Compare the obtained results of the source term with those published in the document AP1000 Design Control.•The TED, GD, Different pathways of exposure and CEDE for some human body organs are estimated.•The results provide important information for severe accident management and safety assessment.