Study Of Iodine Induced Stress Corrosion Of New Zirconium Alloys Cladding

The people have taken into account how to enhance the security of nuclear power more and more along with the application of nuclear powerincreasingly in the world. At the same time high powered fuel is being investigated in order to bring down the cost of nuclear power. This expounded the high require for the ability of fuel cladding to prevent cracking in high burn-up.To the iodine induced stress corrosion of zirconium alloys cladding , a lot of imitative tests of in-pile and out-of-pile had been done. The result showed out-of-pile imitative tests is a safe, economy and effect study method.In order to systematically study the dependency of stress corrosion crack growth on stress intensity factor , iodine concentration , temperature and materials condition , this paper had established the methodology of direct current potential drop (DCPD) measuring crack length in the high temperature and serious corrosion environment and did quantitative calibration to the relation between voltage transformation and crack length. It has been confirmed that creep of samples to an effect manner and degree on DCPD measurement methodology. This paper carried out control tests of stress corrosion crack growth at a different iodine concentration (40C,65C and 110C) and temperature (300C,350C and 400C) according with zirconium alloys of different composition (N36,N18)and heat-treatments (RXA, SRA).The results showed that temperature , iodine concentration and materials condition have obviously of affected on stress corrosion crack growth of zirconium alloys. According to the observed morphology on the fracture surface , the fracture surface had pseudo-cleavage feature and plastic tearing feature in the last stage of crack growth in high magnification.