A study on a magnetic separation of radioactive corrosion products from NPP using permanent magnets

Abstract

It is important to emphasize that the current trend to longer fuel cycles (18-24 months) has complicated the dilemma of finding optimum chemical condition for the primary coolant because of some problems such as increase of radioactive corrosion products, possibility of axial offset anomaly and so on. Radioactive corrosion products which are generated by the neutron activation of general corrosion products at a nuclear power plant are the major source of occupational radiation exposure. Generally, radioactive corrosion products exit in soluble and insoluble forms, and are removed by ion exchangers and purification filters. Most of the insoluble radioactive corrosion products have the characteristic of showing strong ferrimagnetism. Along with the new development and production of permanent magnets (rare earth magnets) which generate much stronger magnetic fields than conventional permanent magnets, a new type of magnetic filter is suggested that can efficiently separate corrosion products using rotation of permanent magnets. This new magnetic filter reveals good performance results in filtering magnetite, cobalt ferrite and nickel ferrite from aqueous coolant simulation. (C) 2004 Elsevier B.V. All rights reserved.