Duke Electric's Catawba nuclear plant in South Carolina was the first to use 2205 (UNS S32205) dual-phase stainless steel in its system. This brand contains about 3.2% molybdenum, which improves corrosion resistance and is significantly better than 304L and 316L stainless steels in microbial corrosion resistance. The carbon steel lining of the above-ground portion of the piping system for delivering the replenishment water to the cooling tower of the main condenser was replaced with 2205 duplex stainless steel piping.
Newly replaced 2205 duplex stainless steel piping was installed in 2002. The length of the pipe is 60 meters, the diameter is 76.2 cm and 91.4 cm, and the wall thickness of the pipe is 0.95 cm. The system was built in accordance with ASME B31.1 Power Piping Code Case 153. This code is one of the management codes for the safe use of piping system in power plants and is widely used in the world.
Large diameter 2205 duplex stainless steel piping installed at the Catawba Nuclear Power Plant
After 500 days of pipe use, the system was thoroughly overhauled. No evidence of scaling or corrosion was found during the inspection, and the performance of 2205 duplex stainless steel was very good. 2205 stainless steel pipes have been performing well for more than a decade since their installation. Based on this experience, Duke Electric has used 2205 duplex stainless steel piping in other parts of its system.
After 500 days of use, the inside of 2205 pipe. After removing the surface stain, no corrosion of the weld was found
Now, designers of nuclear power plants' water systems have another option when choosing piping materials that resist corrosion cooling water. The successful application of 2205 duplex stainless steel reduces maintenance costs, reduces downtime and ensures safe operation of nuclear power plants.