NEW SYSTEM INSTALLED FOR NUCLIDE REMOVAL AND BORON RECOVERY AT THE PAKS NPP IN HUNGARY

A new radioactive liquid waste treatment system is in commissioning phase at the Paks Nuclear Power Plant in Hungary. Fortum Nuclear Services Ltd from Finland has designed and supplied a NUclide REmoval System (NURES) and a boron recovery system. Other parts of the system were supplied by the Paks NPP, and the whole system is implemented in cooperation between the parties. The system is going to treat evaporator concentrates and other radioactive liquids. The purpose of the system is to recover boron for reuse and to separate target radionuclides (Cs and corrosion products) allowing release of the purified liquid. The NURES system was originally developed to remove cesium from evaporator concentrates at the Loviisa Nuclear Power Plant in Finland, where it has been successfully operated since 1991. For the application of Paks NPP, the original NURES-technology has for the first time been complemented with boron recovery system. The boron that is dissolved into liquid waste will be re-used in primary coolant. The new radioactive liquid waste treatment system consists of separate subsystems: the Boron Recovery System, the NUclide REmoval System (NURES), a system to destroy organic complexes, the Ultrafiltration System and a transport system for liquids. Compared to conventional treatment methods, such as direct solidification with cement or bitumen, the new system minimises the volume of interim storage and the amount of waste to be disposed of and allows considerable savings in waste management costs. The system reduces the volume of the existing and future liquid wastes effectively. Depending on the quality of original waste the overall volume reduction factor for evaporator concentrates is expected to vary in the range of 40 to 90. The amount of secondary waste is dominated by the waste outcoming from the Ultrafiltration System. The commissioning of the new system is scheduled to take place in the shift of 2003/2004. Today, industrial applications of the same technology in other countries cover also treatment of spent fuel reprocessing liquids, reactor coolant liquids, spent fuel pool waters, floor drains, groundwater and laboratory wastes and a wide range of target nuclides.