Surface Coating Technology on the Zirconium Base Alloy for High Temperature Application

The Fukushima Nuclear Power Plants were struck by the Pacific Ocean Earthquake and the ensuring tsunami on March 11, 2011. It was a very serious nuclear accident in the most recent. In this accident, the hydrogen related explosion was one of the major concerns of the reactor safety after the Earthquake attack. It was known that the hydrogen was generated by the corrosion reaction of the zirconium base alloys such as fuel cladding, spacer grid, and channel box at a high temperature steam environment. Thus, the high temperature corrosion of zirconium base alloy was attracted to the NPPs accident. Recently, the concept of zirconium alloy development was focused on the decrease of corrosion rate at a normal operation condition of NPPs to increase the operation economy. However, it is unclear that the normal operation corrosion resistance of zirconium alloy can be maintained up to high temperature steam condition. Since it was known that the decrease of high temperature corrosion rate of zirconium base alloy was caused for a lot of hydrogen generation, it is necessary to reduce the hydrogen generation up to high temperature steam condition. So, this work is studied on the coating techniques to reduce the corrosion rate of zirconium base alloy at a high temperature steam environment