Host: The Japan Society of Mechanical Engineers
Name : Proceedings of FDR2024 International Topical Workshop on Fukushima Decommissioning Research
Date : October 10, 2024 - October 13, 2024
Decommissioning of a nuclear installation generates radioactive liquid wastes that are more complex compared to the liquid wastes being handled in the operational phase. Different types of wastewater involved in the dismantling processes and decontamination processes challenge the capability and performance of the existing liquid waste treatment facilities. The ultimate goal of any radioactive liquid waste management is to immobilize the radionuclides contained in the liquid and ensure a safe and stable final state of the radioactive waste matrix. Processes such as evaporation, drying, precipitation and ion exchange are typically used and combined depending on the waste composition. The case-by- case approach is considered the best strategy where the process is optimized for the specific waste matrix. Volume reduction, i.e. to minimize the amount of wastes that ends up in a final repository is prioritized in the design and planning of the treatment system. A significant volume reduction helps mitigate the risks involved in the unknown final disposal costs in many countries.
In this work, we share Fortum’s experiences in managing radioactive liquid wastes in recent nuclear decommissioning projects. Mobile treatment systems incorporating an ultra- selective ion-exchange process is the most suitable candidate for purifying a diversely-sourced liquid waste. The maximum volume reduction originates from the fact that the radionuclides are selectively captured and subsequently conditioned for disposal. Here, we present a recent liquid waste treatment system delivered to a central Germany nuclear power plant with the aim of purifying 1300 m3 of high salt evaporator concentrate containing mostly Co-60, Cs-137, Cs-134 and Sb-124 radionuclides. Through a straightforward step- wise filtration process the radionuclides are intercepted by the selective ion-exchange columns, enabling a free-releasable output liquid after the treatment. In addition, we present recent developments in further treatment of decontaminated waste liquids to minimize e.g. boron releases. NURES® technology considers the entire radioactive waste treatment from liquid generation to final disposal, and by knowledge and experiences as an operator, ensures the safe waste treatment throughout the process.
