Post-irradiation examination (PIE) in the form of transmission electron microscopy (TEM) was used to characterize the microstructure of several specimens of Zircaloy-2 and Zircaloy-2 plus 1% Nb that had previously underwent in-pile creep testing in the HALDEN reactor. The purpose of the examination was to explore a microstructural basis for an apparent substantially increased rate of hardening over that observed with similar materials in the higher fast-flux environments of the ATR or HFIR, and to investigate the increased creep strength exhibited by the Nb-containing alloy relative to pure Zircaloy-2. The analysis of irradiation-induced defects indicated a higher than expected density, which was consistent with the observed high hardening rate. Modeling based on mean field rate theory suggests the lower neutron flux in the HALDEN reactor results in a higher fraction of irradiation-induced defects being available for sink (loop) nucleation and growth.

使用透射电子显微镜（TEM）形式的辐照后检查（PIE）来表征Zalcaloy-2和Zircaloy-2加1％Nb的几个标本的显微结构，这些标本此前曾在HALDEN中进行过堆蠕变测试反应堆。该检查的目的是探索显微结构基础，以使硬化速率明显高于在ATR或HFIR的较高快速通量环境中用类似材料观察到的硬化速率，并研究Nb-所表现出的蠕变强度提高。含有相对于纯Zircaloy-2的合金。辐照引起的缺陷分析表明密度高于预期，这与观察到的高硬化率相符。