###### Abstract  
The steel liner plays a key role in ensuring the leak-tightness of nuclear containment structures (NCSs). Once the liner is subjected to corrosion, its corrosion effects can severely impact the leak-tight function of the NCS, especially in severe accident scenarios. Therefore, evaluating the corrosion effects of the liner is essential to guaranteeing the safe operation of nuclear power plants. This paper presents a probabilistic safety analysis of the NCS under liner corrosion conditions. Firstly, the corrosion mechanism of the liner is elucidated, and a refined simulation method is developed to investigate the localized corrosion effects of the liner. Utilizing a probabilistic finite element method, the fragility of the NCS under loss-of-coolant accident (LOCA) conditions is evaluated. Finally, the leakage risk of the NCS at different degrees of liner corrosion is discussed. The results indicate that liner corrosion has a significant impact on the median pressure capacity and high-confidence-low-probability pressure capacity of the NCS. With the aggravation of liner corrosion, the safety margin of the NCS decreases, and the total probability of failure increases. Within the scope of this paper, the NCS can fulfill the probabilistic safety requirements. nuclear containment structures; liner corrosion; LOCA; pressure capacity; fragility; leakage risk +
Footnote †: journal: Medical  
The containment steel liner (hereafter, liner) is a layer of gas-tight steel plate anchored to the inner wall of the NCS. The liner is designed to safeguard the leak-tightness of the NCS, while its contribution to the bearing capacity of the NCS is usually neglected. Numerous experimental studies have demonstrated that the cracking of concrete occurs before the tearing of the liner when the NCS is subjected to overpressure loads [9; 10; 11]. Therefore, the leak-tightness of the NCS in severe accident scenarios is mainly ensured by the liner [12; 13]. Liner corrosion represents a primary form of aging-related degradation in the NCS, and the degradation of the material properties of corroded liners can threaten the leak-tight function of the NCS under accident conditions. To examine the impact of liner corrosion on the NCS, the Nuclear Regulatory Commission (NRC) has carried out a systematic study [14]. Firstly, a criterion for predicting the tearing of corroded liners in finite element (FE) simulations was proposed. Subsequently, FE models for typical NCSs were developed. Finally, the effect of liner corrosion on the pressure capacity of these NCSs was evaluated through nonlinear numerical simulations. Utilizing the simulation method provided by the NRC, [PERSON] et al. [15] investigated the effect of different corrosion degrees and corrosion regions on the pressure capacity of a reinforced concrete containment structure. [PERSON] et al. [5] explored the structural behavior of a prestressed concrete containment structure under liner corrosion conditions and evaluated the corrosion impact on its ultimate bearing capacity. Additionally, [PERSON] et al. [16] assessed the fragility of the NCS with different degrees of liner corrosion in conjunction with the probabilistic method. To guarantee the safe operation of nuclear power plants, it is important to identify the impact of various forms of aging on the NCS as well as to evaluate the corresponding leakage risks. Since the liner plays a key role in preventing the release of radioactive material, it is necessary to clarify the impact of liner corrosion on the leak-tightness of the NCS in the aging assessment. However, investigations into the NCS under liner corrosion conditions are very limited, with some studies conducted many years ago. Considering the significance of the liner in preventing the release of radioactive material, it is necessary to further investigate the influence of liner corrosion on the leak-tight function of the NCS by using current analytical technology. In addition, the loss-of-coolant accident (LOCA) condition is a critical concern in nuclear engineering.