Authorized limits for disposal of PCB capacitors from Buildings 361 and 391 at Argonne National Laboratory, Argonne, Illinois.

Cheng, J.-J. ; Chen, S.-Y. ; Environmental Science Division

关键词: AR FACILITIES;    BUILDUP;    CAPACITORS;    COMBUSTION;    CONTAMINATION;    COST BENEFIT ANALYSIS;    DOSE LIMITS;    GAMMA SPECTROSCOPY;    HAZARDOUS MATERIALS;    LOW-LEVEL RADIOACTIVE WASTES;    NEUTRONS;    POLYCHLORINATED BIPHENYLS;    RADIATION DOSES;    RADIATIONS;    RADIOACTIVITY;    RADIOISOTOPES;    RELEASE LIMITS;    RESIDUES;    SANITARY LANDFILLS;    TOXIC SUBSTANCES CONTROL ACTS;    WASTES;   

DOI  :  10.2172/972628
RP-ID  :  ANL/EVS/RP-65867
PID  :  OSTI ID: 972628
Others  :  TRN: US1001511

美国|英语

来源: SciTech Connect

【 摘 要 】

This report contains data and analyses to support the approval of authorized release limits for the clearance from radiological control of polychlorinated biphenyl (PCB) capacitors in Buildings 361 and 391 at Argonne National Laboratory, Argonne, Illinois. These capacitors contain PCB oil that must be treated and disposed of as hazardous waste under the Toxic Substances Control Act (TSCA). However, they had been located in radiological control areas where the potential for neutron activation existed; therefore, direct release of these capacitors to a commercial facility for PCB treatment and landfill disposal is not allowable unless authorized release has been approved. Radiological characterization found no loose contamination on the exterior surface of the PCB capacitors; gamma spectroscopy analysis also showed the radioactivity levels of the capacitors were either at or slightly above ambient background levels. As such, conservative assumptions were used to expedite the analyses conducted to evaluate the potential radiation exposures of workers and the general public resulting from authorized release of the capacitors; for example, the maximum averaged radioactivity levels measured for capacitors nearest to the beam lines were assumed for the entire batch of capacitors. This approach overestimated the total activity of individual radionuclide identified in radiological characterization by a factor ranging from 1.4 to 640. On the basis of this conservative assumption, the capacitors were assumed to be shipped from Argonne to the Clean Harbors facility, located in Deer Park, Texas, for incineration and disposal. The Clean Harbors facility is a state-permitted TSCA facility for treatment and disposal of hazardous materials. At this facility, the capacitors are to be shredded and incinerated with the resulting incineration residue buried in a nearby landfill owned by the company. A variety of receptors that have the potential of receiving radiation exposures were analyzed. Based on the dose assessment results, it is indicated that, if the disposition activities are completed within a year, the maximum individual dose would be about 0.021 mrem/yr, which is about 0.02% of the primary dose limit of 100 mrem/yr set by U.S. Department of Energy (DOE) for members of the public. The maximum individual dose was associated with a conservative and unlikely scenario involving a hypothetical farmer who intruded the landfill area to set up a subsistence living above the disposal area 30 years after burial of the incineration residue. Potential collective dose for worker and the general public combined was estimated to be less than 4 x 10{sup -4} person-rem/yr, about 0.004% of the DOE authorized release objective of 10 person-rem/yr for collective exposure. In reality, the actual radiation doses incurred by workers and the general public are expected to be at least two orders of magnitude lower than the estimated values. To follow the ALARA (as low as reasonably achievable) principle of reducing potential radiation exposures associated with authorized release of the PCB capacitors, a dose constraint of 1 mrem/yr, corresponding to a small fraction of the 25 mrem/yr limit set by DOE, was initially used as a reference to derive the authorized release limits. On the basis of the dose assessment results, the following authorized release limits are proposed - 0.6 pCi/g for Mn-54, 0.6 pCi/g for Na-22, 0.1 pCi/g for Co-57, and 2.3 pCi/g for Co-60, with a corresponding maximum individual dose of 0.21 mrem/yr. This maximum dose, about 0.2% of the DOE primary dose limit of 100 mrem/yr for members of the public from all sources and exposure pathways, was then selected as the final dose constraint for releasing the PCB capacitors through the authorized process. The proposed authorized release limits would satisfy the DOE requirements for the release of non-real properties to a commercial treatment and disposal facility. In addition, due to the relatively short half-lives (< 5.27 years) of radionuclides of concern, there will be no long-term buildup of doses either in groundwater or through other exposure pathways associated with this particular release action. Contact with Clean Harbors and the State of Texas has been initiated. The radioactivity levels in the PCB capacitors meet the State of Texas radiological exemption limits and would be accepted by Clean Harbors, subject to the approval by DOE for the authorized release process. Cost benefit analysis shows that authorized release of the PCB capacitors would provide significant cost saving over the low-level radioactive waste (LLRW) disposition alternative, i.e. sending the PCB capacitors to a certified LLRW facility for treatment and disposal, and would not cause a significantly different impact in terms of human health protection. Therefore, authorized release is determined to be the preferred alternative for the disposition of Argonne PCB capacitors.