Evaluation of reactor process tubes 2255KE and 3056KE

The process for removing hydride case layers from Zircaloy-2 by anodic treatment in 3% HNO3 was tested on several KE reactor process tubes during February 1970. This process can be supplemented by continued anodic treatment in 3% HNO3--1.2% NH4F . HF to remove the residual anodic oxide layer left from the 3% HNO3 processing and to dissolve a uniform layer of underlying metal and dispersed hydride platelets. Together, these processes are capable of removing non-uniform surface hydrogen concentrations so that they cannot be redistributed and thus embrittle the underlying metal. A test of both of these treatments on several KE-reactor process tubes was conducted by DUN. The results were evaluated by discharging Tubes 2255 and 3056 and subjecting the downstream five foot section of the tubes to hydrogen analyses and metallography at BNW. This report covers the examination of the downstream five foot sections of Tubes 2255 and 3056