Decommissioning study for some radioactive parts of the ET-RR-1 reactor

The first Egyptian research reactor ET-RR-1 is a 2MW tank type, with light water as moderator, coolant and reflector. It went critical for the first time in the fall of 1961. As the lifetime of this reactor is approaching 40 years, a plan for decommissioning is essential to be ready in case it is decided to decommission the reactor. The paper presents an illustrative calculation of the activity of some radioactive parts, i.e. core tank, core grid, cast iron, graphite in the thermal column and concrete biological shield. The operation time and shutdown of the reactor through its lifetime are taken into consideration in activity calculations of the above radioactive components. An extended cooling time of 50 years is made for the main radioactive inventories existing in the radioactive components under study. This study showed that the important radioactive radionuclides are expected to be 60Co and 55Fe which are present in the core tank as a trace elements and in large quantities in other construction materials. The main sources of activity from the radioactive inventory are discussed and presented in some figures. (author)