蒸汽中的溶解氧对锆合金腐蚀行为的影响

EFFECT OF DISSOLVED OXYGEN IN STEAM ON THE CORROSION BEHAVIORS OF ZIRCONIUM ALLOYS

研究了400℃,10.3 MPa蒸汽中,溶解氧(DO)的存在对Zr-4,N18(Zr-1.0Sn-0.3Nb-0.3Fe-0.1Cr)以及N36(Zr-1.0Sn-1.0Nb-0.3Fe)合金腐蚀行为的影响,采用微循环动水回路将溶解氧含量分别控制在0.1×10^(-6)和1.0×10^(-6).结果表明,2种溶解氧浓度条件下,腐蚀90 d后,N18合金的腐蚀增重与Zr-4合金的腐蚀增重接近,而N36合金的腐蚀增重最高.腐蚀初期,DO含量更高的条件下3种合金的腐蚀增重反而更低;随着腐蚀时间的延长,1.0×10^(-6)DO条件下合金的腐蚀增重逐渐超过0.1×10^(-6)DO条件下的腐蚀增重,Nb含量越高的合金,所需的时间越短.

Advanced boiling water reactors （ABWRS） show optimistic application prospect in the future. However, in these reactors, influence of dissolved oxygen （DO） on the corrosion rate of zirconium fuel claddings should be seriously considered. In this work, the effect of the dissolved oxygen （DO） on the corrosion behaviors of Zr-4, N18 （Zr-1.0Sn-0.3Nb -0.3Fe-0.1Cr） and N36 （Zr-1.0Sn-1.0Nb-0.3Fe） alloys in 400 ℃ and 10.3 MPa steam was investigated. A recirculation loop was used to control the DO level at about 0.1 × 10^-6 and 1.0 × 10^-6, respectively. The results showed that, under the two DO level conditions, N18 had almost the same weight gain as Zr-4 after ex- posure for 90 d, and N36 had the highest weight gain. In the initial period of the corrosion test, the three alloys had lower weight gain under higher DO level condition. With the increase of exposure time, the weight gain under 1.0×10^-6 DO level exceeded gradually the weight gain under 0.1 × 10^-6 level for each alloy, and the time needed for exceeding was significantly shorter for the alloy with higher Nb content.