Radioactive waste treatment or management remains a challenge topic to all countries discovering nuclear energy. To deal with those radioactive wastes, metal materials using for equipments which could directly or indirectly contact to radioactive wastes require high-level of safety performance. Anti-corrosion is one of the critical safety requirement for those metal materials, and above all types of corrosions might happen to metal materials, intercrystalline corrosion is one of the most challenge corrosion type due to its extremely fast corrosion speed and horrible corrosion consequences. In order to avoid intercrystalline corrosion, nickel alloy are considered to be one of the solutions with good anti-corrosion performance and economical consideration. In this article, a brief discussion of the intercrystalline corrosion and its influence factors on nickel alloy Incoloy-825 material were studied based on the first China-made nickel-based pressure vessel evaporator which designed for middle-level radioactive liquid waste treatment purposes. Intercrystalline corrosion testing method of 65% nitric acid method (method D in GB/T4334-2020, Corrosion of metals and alloys—Test methods for intergranular corrosion of stainless steels) was employed in the testing of both raw material and welded joint during manufacture of the evaporator, influence factor of proportion of elementary composition are discussed in this article; the influence factors of 65% nitric acid test method like sample treatment options, nitric acid concentration and data acceptable judgment methods were discussed in this article too.