Hot Cell Dissolution Protocol and Apparatus for High Precision Characterization of Spent Nuclear Fuels

摘要

This year, the detailed characterizations of Three Mile Island (TMI) fuel rod segments are being completed at the Oak Ridge National Laboratory (ORNL) to determine the post-irradiation chemical distribution. Gamma spectra were taken at several locations along TMI fuel pin axial profile length to compare fission product gamma peak ratios to burnup in the fuel. Also, 3D core depletion models were completed to determine the expected isotopics in the fuel. Both the gamma measurements and the 3D core models will be validated against the destructive analyses. This work will be used to improve NDA measurements of spent fuel for safeguards purposes. The Nuclear Analytical Chemistry and Isotopics Laboratories (NACIL) at Oak Ridge National Laboratory is performing the detailed destructive post-irradiation examinations (PIE) on selected segments from the TMI fuel rods. The analytical process involves high precision quantitative dissolution of designated fuel segments in a shielded hot cell for measurements of select fission products and actinide isotopes employing isotope dilution mass spectrometry (IDMS) among other analyses. The hot cell dissolution protocol which includes the collection of the fuel’s acid resistant metallic particulates will be presented. The development of the robust dissolution apparatus capable of withstanding the high radiation generated by spent nuclear fuels coupled with the desire to minimize cross contamination in a hot cell or glovebox environment will be its focus.