Why carry out corrosion tests?
We must recognize that there are very few laboratories in the world that use highly concentrated radioactive water. It is not a question of radioactive water traces present in light water, but the reverse. By its nature, this medium is very reactive and its properties are completely different that in light water. Corrosion of stainless steels or super alloys are thus completely different and no comparison is possible.

Tritium corrosion
Corrosion tests must make it possible:

• to study the initiation and evolution of corrosion phenomena in the presence of concentrated radioactive water and radiolytic species,
• to know and understand the behavior of materials in the concentrated radioactive media,
• to monitor the corrosion resistance in this radioactive medium.

To reach the overall goal, the operator of nuclear processing installation, must, to ensure its correct operation and safety, apply a material and equipment maintenance and monitoring policy as well as an on-going survey in replacing corroded components. If he does not apply this policy and is satisfied with a simple monitored storage system, his installation will soon become obsolete. To avoid this, he must implement resources for monitoring and follow-up of the most highly stressed and defective components as well as for specialized examinations that can be directly applied to his installations.

Various inspection methods have been extensively used to meet these requirements.

These make possible:

• analysis of radioactive water for its radioactive and radiolytic species and impurities. This knowledge makes it possible to determine their involvement in corrosion,
• identification of defects on the passivating oxide layers and metals after aging,
• observation by televisual examination from the interior of the component located in situ in the nuclear installation.