EFFECT OF CORROSION ON TEARING PERFORMANCE OF STEEL LINER OF NUCLEAR CONTAINMENT STRUCTURES

To study the effect of corrosion on the tearing performance of the steel liner of nuclear containment structures, 36 steel liner plates with different corrosion rates are tested under uniaxial tension. The degradation mechanism and the law of mechanical properties of corroded steel liners are analyzed. The constitutive model of corroded steel liners is established. Based on the test results, a tearing criterion and a numerical simulation method for corroded steel liner are proposed. The effect of corrosion on the tearing of the steel liner of containment is analyzed by numerical simulation. Finally, the difference between the simulation method and the Nuclear Regulatory Commission (NRC) method is compared, and a suggestion on the value of the corrosion influence coefficient in the NRC method is developed. The results show that: the elastic modulus of the steel liner is not affected by corrosion, but with the increase of corrosion rate, the yield strength, peak strength, peak strain and, fracture strain show linear degradation. The constitutive model of the corroded steel liner established agrees well with the experimental results; with the increase in corrosion rate, the internal pressure at the time of steel liner tearing gradually decreases, and when the corrosion rate is 50%, the internal pressure decreases by 29.06%. Compared with the NRC simulation method, the method proposed can directly reflect the influence of corrosion on the steel liner and is closer to the actual corrosion situation. For the corrosion influence coefficient recommended by NRC, the upper bound can be selected when the corrosion rate is less than 20%. The best estimation is recommended when the corrosion rate is 20% ~ 40%, and the lower bound should be selected when the corrosion rate exceeds 40%. The research work can provide a reference for the performance evaluation of containment with a corroded steel liner.