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Taking into account the aforementioned background related to helium impurities, graphite components, and metal parts in high-temperature gas-cooled reactors, the common types of corrosion can be classified as follows: 1. High-temperature corrosion induced by gaseous media. High-temperature oxidation corrosion: Water vapor in helium, air impurities, and oxygen introduced due to intake system failures can cause oxidation of stainless steel and nickel-based alloys at temperatures above 600°C. The oxidation rate increases significantly at 800–900°C, and the resulting loose oxide layer tends to flake off, providing very poor protection. Carburization/decarburization corrosion: Impurities such as CO and CH4 in the coolant can cause carburization of stainless steel at temperatures above 650°C, altering the material’s composition and reducing its mechanical properties ； Under certain operating conditions, decarburization may also occur, reducing the fatigue strength of the steel. Graphite high-temperature reaction corrosion: Above 650°C, the graphite components within the reactor undergo a reaction with CO₂ to produce CO. In the event of an air intrusion accident, when large amounts of air enter the reactor core, the graphite suffers from oxidative corrosion, which undermines the structural strength of the reactor. II. Other typical types of high-temperature corrosion: Thermal corrosion: If trace amounts of sedimentary salts such as sulfates are present in the coolant, within the temperature range of 650–980°C, these salt films can destroy the protective oxide layer on the metal surface, leading to accelerated corrosion. This type of corrosion is divided into two categories: high-temperature uniform corrosion and low-temperature pitting corrosion. Internal oxidation corrosion: Elements in the alloy such as aluminum, titanium, and silicon, which have a greater affinity for oxygen, form stable oxides within the metal, creating defective structures that significantly reduce the contact fatigue and bending fatigue strength of the components, as well as their service life.