Assessment of Source Terms and Potential Doses Due to Steam Generator Tube Rupture of VVER-1200 at the El Dabaa Nuclear Power Plant in Egypt

Abstract

Background: As Egypt ventures into nuclear energy, ensuring the safety and security of its nuclear facilities is paramount. The ongoing construction of the El Dabaa Nuclear Power Plant (NPP) directs the necessity for Egypt to meticulously evaluate the potential outcomes of any conceivable accidents. A focused analysis on design-based accidents such as steam generator tube ruptures (SGTR) is imperative for assessing their impact on the local populace and the environment. Through comprehensive assessments, Egypt aims to enhance the safety protocols of its NPP. This preemptive strategy facilitates the identification and minimization of risk, along with the formulation of efficient emergency response frameworks. Such diligent preparations are essential for cultivating public confidence while ensuring compliance with international safety norms and securing the long-term sustainability of Egypt' s nuclear energy program. Materials and Methods:The hypothetical scenario of a SGTR at the El Dabaa NPP was modeled using the Radiological Assessment System for Consequence Analysis (RASCAL) code. This model examined the potential consequences of such an accident by incorporating meteorological data from 2013 to 2023 across all seasons to compute the source term, total effective dose equivalent (TEDE), and thyroid dose. Then, these metrics were evaluated against established safety thresholds to determine compliance. The outcomes of this analysis provide critical insights and aid in formulating strategies for effective response to an accident, especially if the calculated doses exceed the permissible limits. Results and Discussion:The analysis of the worst-case scenario for the SGTR accident at the El Dabaa NPP involves a U-tube breakage above the water level, exacerbated by a concurrent station blackout. This condition potentially leads to a considerable dispersal of radioactive materials, especially within a 0.4 km radius, with a TEDE reaching 4.80×10 3 mSv during autumn. However, the severity of this worst-case scenario fluctuates with seasonal weather conditions; notably in spring, the highest TEDE was 15 mSv at a 40 km distance. The source term distribution indicates that noble gases account for 31.6%, iodine group for 32.0%, and other sources constitute 36.4% of the total radioactive release. These findings confirmed that TEDE and thyroid dose exceeded the permissible thresholds, thereby highlighting the importance for protective measures to mitigate the potential risks of such accidents. Conclusion:A comprehensive assessment of SGTR accidents at the El Dabaa NPP emphasizes the critical necessity for stringent safety protocols and protective interventions in worst-case scenarios. By preemptively addressing these risks, Egypt can fortify its nuclear safety framework, emergency response capabilities, and adherence to global safety standards. This proactive stance not only assures the long-term sustainability of Egypt' s nuclear energy program but also solidifies public confidence.