DETERMINATION OF ~(93)Zr IN MEDIUM AND LOW LEVEL RADIOACTIVE WASTES FROM BRAZILIAN NUCLEAR POWER PLANTS

摘要

The majority of long-lived radionuclides produced in the nuclear power plants can be regarded as difficult-to-measure radionuclides (RDM), hence chemical separation is necessary before the nuclear measurement of them. The zirconium isotope ~(93)Zr is a long-lived pure β-particle-emitting radionuclide produced from ~(235)U fission and from neutron activation of the stable isotope ~(92)Zr and thus occurring as one of the radionuclides found in nuclear reactors. Due to its long half-life, ~(93)Zr is one of the radionuclides of interest for the performance of assessment studies of waste storage or disposal. Two different methodologies based on extractive resins and LSC and ICP-MS techniques that enables the ~(93)Zr determination in medium (ILW) and low level (LLW) radioactive wastes samples from Brazilian nuclear power plants has been developed in our laboratory. Analyzing real samples 65% and 75% chemical yields for ~(93)Zr recovery were achieved for ICP-MS and LSC techniques, respectively. The detection limits were 0.045 μg.L~(-1) for ICP-MS and 0.05 Bq.L~(-1) for LSC techniques.