Screening assessment of dose rates to wildlife related to the nuclear medicine Mo99 facility
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Date
2017-04-27
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Australian Nuclear Science and Technology Organisation
Abstract
ANSTO has performed a screening assessment on potential dose rates to environmental receptors (wildlife) associated with the planned ANSTO Nuclear Medicine (ANM) Mo99 Facility. The ANM facility will be located on the 50 hectare ANSTO Lucas Heights site, which is surrounded by a 1.6 km radius buffer zone owned by the Commonwealth or its Agencies. The buffer zone is used by humans for recreational purposes and is home to a range of plant and animal wildlife. During its routine operations in producing medical isotopes and performing research, ANSTO releases small amounts of radionuclides through stack emissions and, after testing, through liquid discharges to the public sewer system. The purpose of this assessment is to use a standard screening approach to determine if potential dose rates to local wildlife from future releases, including the ANM Mo99 Facility, are below international benchmarks.
The assessment used methods from international best practice as laid out by the ARPANSA Guide: Radiation Protection of the Environment, which is consistent with current approaches set forth by the International Commission on Radiological Protection (ICRP) and the International Atomic Energy Agency (IAEA). The screening evaluations considered exposure to a range of terrestrial organisms in the buffer zone from stack emissions via the air pathway, and, to a range of marine organisms near the ocean outlet at Potter Point, New South Wales via the liquid effluent pathway. Dose assessments were performed using the ERICA tool with radioactivity concentrations for air and water determined from data collected during routine monitoring of stack emissions and effluent releases at ANSTO. Concentration values along air and water pathways were overestimated, consistent with an approach of using conservative assumptions in this screening assessment.
In summary, despite using overestimates for radioactivity concentrations associated with ANSTO’s emissions, results indicate potential risk quotients that are below standard benchmarks for all organisms and all pathways considered. Dose rates to organisms were determined to be below the lowest benchmark for potential harmful effects (10 μGy hr-1). These results are consistent with previous studies in determining no significant impacts from ANSTO effluents. Therefore, potential radioactivity releases from the ANM Facility are unlikely to impact local wildlife. Although projected dose rates are low, the release of low levels of radionuclides in air and water discharges indicates the need for ongoing monitoring and periodic re-evaluation.
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Keywords
Radiation protection, Particulates, Dose rates, Molybdenum 99, ANSTO, Radioactivity, Radiation monitoring
Citation
Johansen, M. & Corry, M. (2017). Screening assessment of dose rates to wildlife related to the nuclear medicine Mo99 facility (ANSTO-E-785). Lucas Heights, NSW: Australian Nuclear Science and Technology Organisation.