Analysis of a Radioactive Corrosion Material Collected from Control Rod Drive Mechanism Housing of a PWR Using an EPMA

Radioactive corrosion product materials collected from the control rod drive mechanism (CRDM) housing in a pressurized water reactor (PWR, HANBIT-1 KNPP) were analyzed using an electron probe micro analyzer (EPMA). It is challenging to analyze the composition of radioactive corrosion products using an EPMA due to the rough surface shape and size, and even more so when the products are stacked in the form of small grains.

The purpose of this study is to determine whether the corrosive products found inside the CRDM housing are stuck in contact with primary coolant or just oxide. In this study, not only was the surface condition of the samples very rough, but the samples that were quantitatively analyzed using a normal method had extremely low electrical conductivity using a normal method. We therefore tested a new semiquantitative analysis method using X-ray image mapping. In this technical note, we propose a method for collecting and analyzing corrosion products adsorbed in the CRDM. Reference papers on radioactive corrosion products collected from the CRDM could not be found.

It is consequently difficult to argue that the method of collecting samples and performing the quantitative analysis suggested in this study is the best, but it can be said that it is an appropriate analysis method. Finally, the usefulness of the semiquantitative analysis is reviewed by verifying the analysis results of radioactive corrosion products collected from the CRDM housing in a PWR.