Corrosion, Stress-Corrosion Cracking and Corrosion-product Deposition in Supercritical Water-Cooled Reactors (SCWRs)

超临界水冷堆（SCWR）的成功设计和运行最终取决于芯内和芯外组件材料的选择，以及为减少腐蚀和降解所采用的水化学策略。与关键部件腐蚀相关的还有腐蚀产物进入冷却剂，导致腐蚀产物在反应堆堆芯和下游部件中运输和沉积。这是非常不可取的，因为它们在反应堆堆芯的中子场中可能被激活，并随后向下游传输，导致堆芯外组件上的辐射场。利用UNB SCW测试回路，该项目将在SCWR的模拟操作条件下研究选定材料的腐蚀和降解机制（一般腐蚀和应力腐蚀开裂- SCC）；也就是说，在温度高达625摄氏度，压力约25兆帕的名义纯水中，水中溶解氧和氢的浓度各不相同。另外的实验将在UNB SCW测试回路中进行，以评估将发生在SCWR堆芯的腐蚀产物沉积的程度和动力学，以及可能存在于运行反应堆中的氯化物、硫酸盐和铅等少量杂质的影响。

The successful design and operation of a supercritical water-cooled reactor (SCWR) will ultimately be determined by the choice of materials for in-core and out-of-core components and the water chemistry strategies employed to minimize corrosion and degradation. Also related to corrosion of key components is the input of corrosion-products to the coolant that will lead to their transport and deposition in the reactor core and downstream components. This is highly undesirable due to their potential activation in the neutron field of the reactor core and subsequent transport downstream leading to radiation fields on out-of-core components. Using the UNB SCW test loop, this program will investigate the corrosion and degradation mechanisms (general corrosion and stress-corrosion cracking - SCC) on selected materials under simulated operating conditions expected in a SCWR; namely, temperatures up to 625 degC and pressures of ~ 25 MPa in nominally pure water with various concentrations of dissolved oxygen and hydrogen in the water. Additional experiments will be run in the UNB SCW test loop to evaluate the extent and kinetics of corrosion-product deposition that will occur in the SCWR core and the effects of minor impurities such as chloride, sulfate and lead that may be present in an operating reactor.