Results of the Independent Radiological Verification Survey of Remediation at Building 31, Former Linde Uranium Refinery, Tonawanda, New York (LI001V)

Abstract

As part of the Formerly Utilized Sites Remedial Action Progmq a team from Oak Ridge National Laboratory (ORNL) conducted a radiological veriihtion survey of Building 31 at the former Linde Uranium Refinery, Tonawau& New York. The purpose of the survey was to ver@ that remedial action completed by the project management contractor had reduced contamination levels to within authorized limits. Prior to remediatioq tied radioactive material was prevalent throughout the building and in some of the ductwork Decontaminadon consisted of removing surfhce contamination from floors, baseboards, and overhead areas; removing some air ducts; and vacuuming dust. Building 31 at the former Linde site in TonawandA New Yorlq was thoroughly investigated inside and outside for radionuclide residues. The verification team discovered previously undetected contaminadon beneath the concrete pad on the first floor and underneath floor tiles on the second floor. All suspect floor tiles were removed and any contamination beneath them cleaned to below guideline levels. The verification team also discovered elevated radiation levels associated with overhead air lines that led to the eventual removal of the entire air lige and a complete investigation of the history of all process piping in the building. Final verification surveys showed that residual surface beta-gamma activity levels were slightly elevated in some places but below U.S. Department of Energy applicable guidelines for protection against radiation (Table 1). Similarly, removable radioactive contamination was also below applicable guidelines. Exposure rates within the building were at typical background levels, and no consistently elevated indoor radon concentrations were measured. However, radionuclide analysis of subsurface soil from beneath the concrete floor on the ground level showed concentrations of `*U and'% that exceeded applicable guidelines. At the time of this survey, there was no measured exposure pathway for this subslab contamination under current use scenarios, and there was low risk associated with this contaminadon if the conaete slab is not cracked or penetrated. However, any penetration of the concrete slab caused by renovations, repairs, demolitio% or a naturally-occurring craclq would require further investigation and evaluation. Analysis of the project management contractor's post-remedial action data and results of this independent radiological vaification survey by ORNL confirm that all radiological measurements inside the building, on the exterior walls, and on the roof are below the limits prescribed by applicable guidelines for protection against radiation.