UNIQUE RADIOANALYTICAL PROTOCOLS FOR CHARACTERIZATION AND VERIFICATION DURING DECONTAMINATION AND DECOMMISSIONING

In order to successfully decontaminate, deactivate and decommission surplus Department of Energy (DOE) facilities throughout the Savannah River Site (SRS), a variety of characterizations must be completed to sufficiently identify and quantify potential contaminants of concern. The ultimate goal is to rapidly and efficiently characterize, decontaminate (if necessary), and verify that the remnants meet specified limits established by either an industrial worker model or a groundwater model. To meet this end, the Savannah River National Laboratory (SRNL) developed a series of radioanalytical strategies and methodologies which can be used to characterize targeted facilities and prove that decontamination has been sufficient. To our knowledge, this is the first application of this novel methodology within the DOE complex. This methodology has been successfully utilized with nearly 1000 samples from over a dozen facilities. The application of this approach to just a single facility shortened the schedule by 30 days and resulted in non-labor dollar savings of over $60K. Cost savings for a second facility was determined to be$375K. Based on the success of this methodology at SRS, this approach will be valuable to other nuclear facilities in the USA and abroad involved with the decontamination and decommissioning process

Optical Conductivity of Manganites: Crossover from Jahn-Teller Small Polaron to Coherent Transport in the Ferromagnetic State

We report on the optical properties of the hole-doped manganites Nd_{0.7}Sr _{0.3}MnO_{3}, La_{0.7}Ca_{0.3}MnO_{3}, and La_{0.7}Sr_{0.3}MnO_{3}. The low-energy optical conductivity in the paramagnetic-insulating state of these materials is characterized by a broad maximum near 1 eV. This feature shifts to lower energy and grows in optical oscillator strength as the temperature is lowered into the ferromagnetic state. It remains identifiable well below Tc and transforms eventually into a Drude-like response. This optical behavior and the activated transport in the paramagnetic state of these materials are consistent with a Jahn-Teller small polaron. The optical spectra and oscillator strength changes compare well with models that include both double exchange and the dynamic Jahn-Teller effect in the description of the electronic structure.Comment: 27 pages (Latex), 6 figures (PostScript