Site characterization of ORNL D&D facilities: Fid-Bau Portal

Site characterization of ORNL D&D facilities

A. P. Kelsey / G. J. Mandry / M. H. Haghighi

Site characterization for decontamination and decommissioning (D&D) planning purposes was done for two surplus facilities at Oak Ridge National Laboratory (ORNL) in late 1993 and early 1994. This site characterization includes measurements of radiological and chemical contaminants, assessment of general structural conditions, and investigation of unknown conditions within the buildings. It will serve as input to decisions on D&D engineering, D&D task sequences, radiological and contamination control, and waste management. This paper presents the methods used to investigate these facilities and discusses the preliminary results as they apply to D&D planning. Investigation methods include gross alpha, beta, and gamma surveys; directional gamma surveys; gamma spectroscopy; concrete coring; photography; and collection of soil and miscellaneous samples that are analyzed for radiological and chemical contaminants. Data will be analyzed using radiological models to sort sources and estimate exposure rates and waste volumes due to D&D. The former Waste Evaporator Facility (WEF), consisting of two concrete cells and an operating gallery, once contained a liquid radwaste evaporator. Subsequently it was used for an incinerator experiment and as a dressing area for remediation work on an adjacent tank farm. The building has been partially decontaminated. Figure 1 is a photograph of the WEF. The Fission Product Pilot Plant (FPPP) is a small concrete building containing two cells. It was used to extract isotopes of ruthenium, strontium, cesium, cerium, and other elements from liquid waste. This facility is highly contaminated. In 1960 all doors into FPPP were sealed with concrete block and mortar, and concrete block shielding was added to the external walls making them up to five feet thick. Prior to this study, almost nothing was known about the interior of this building.