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Considering the background related to intergranular corrosion of stainless steel in nuclear industry production reactors, the detection of intergranular corrosion in nuclear-grade stainless steel must meet the stringent safety requirements of nuclear power. The common methods are as follows: 1. Oxalic acid electrolytic etching method (rapid preliminary screening). In accordance with GB/T 4334 standards, the sample is subjected to anodic electrolytic etching using a 10% oxalic acid solution; bulk preliminary testing can be completed within 2 hours. This method is only used for rapid screening and cannot serve as a basis for final acceptance. 2. Sulfuric acid-copper sulfate-copper shavings method (universal arbitration method for nuclear power): This is the most commonly used arbitration testing method in the nuclear power industry. The sample is immersed in a boiling solution of sulfuric acid and copper sulfate for 24 hours, after which an 180° bending test is conducted to check for the appearance of intergranular cracks. Nuclear power-specific standards such as RCC-M and NB/T 20004-2014 specify clear requirements regarding sensitization treatment for this method. 3. 65% nitric acid corrosion test method: For stainless steel components exposed to severe corrosion conditions in nuclear power applications, the specimens are placed in 65% boiling nitric acid for 5 cycles of corrosion testing, and the average corrosion rate is calculated to accurately assess the sensitivity of the material to intergranular corrosion in highly oxidizing media. 4. The electrochemical potential reactivation method (EPR) is a non-destructive/minimum-destructive testing technique; it calculates the reactivation rate through electrochemical polarization tests, allowing for a rapid assessment of the degree of intergranular corrosion sensitivity in operational nuclear components without damaging them. It is suitable for regular random inspections of operational equipment. 5. Metallographic microscopy: The cross-section of the corroded specimen is mounted and polished, and under a high-power microscope, it is possible to directly observe whether there are continuous corrosion grooves at the grain boundaries; this method serves as the final means of resolving doubts regarding the results of bending tests.