Company News
TISCO’s SS Clad Plate Applied to China’s Third-generation Nuclear Power Unit

By Shi Ying & Wang Yongze UpDate 2017-06-14

The water pressure test for the safety injection tank of No.1 generator unit of China’s first CAP1400 PWR nuclear power plant demonstration project achieved one-time success recently. All the stainless steel (SS) clad plate for safety injection tank was supplied by TISCO, and replaced the imports, which marks that TISCO is the first to grasp key technology to produce SS clad plate dedicated for nuclear power by explosive process, and has realized mass production.  
 
CAP1400 PWR nuclear power unit,with domestic independent intellectual property, is an advanced and large-scale passive PWR nuclear power unit, embodying independent innovations in China’s third generation nuclear power technology. The demonstration power plant that is under construction has two units and 60 years life expectancy. The safety injection tank is full of boron water, pressurized by nitrogen under low temperature. And it is connected to pressure vessel of reactors. In normal operation, the valve between the tank and reactor is closed; in the event of emergency, the safety injection tank can inject high flow boron water into reactor’s pressure vessel in short time to cool down the reactor core quickly.   
 
Boron water is corrosive, so the safety injection tank was made of common SS before. The advance in equipment and technology of nuclear power has placed higher requirements on material of safety injection tank in term of strength and service life. Therefore, the SS clad plate with high strength, strong corrosion resistance and low cost became the preferred material. For a long period in the past, this kind of technology was monopolized by other countries.       
  
TISCO is an important clad plate producer in China. For many years, it has had production processes and technologies in entire procedures, from producing high strength base plate, SS cladding plate to following explosion bonding technology. With Long-term technology accumulation, following stringent requirements of China’s new generation nuclear power unit on material, the S&T personnel worked hard and solved technological challenges such as plate profile, intercrystalline corrosion resistance, shear property of bonding layer and etc., to develop successfully new SS clad plate for safety injection tank for CAP1400. It was known that, contrasting with normally-rolled SS clad plate, the SS clad plate produced by explosion process has stronger bonding strength and longer service life, and it is safer. The new SS clad plate provided strong support for fully independence of third-generation nuclear power technology in China.