Little Forest legacy site - technical report : dose rate estimates to humans and wildlife for a range of potential future scenarios

Purpose The objective of this report is to describe the human and wildlife dose-modelling used to compare various potential management options for the Little Forest Legacy Site (LFLS). Scope This work aligns with international standards and guidance which are primarily set forth in a series of documents published by the International Atomic Energy Agency (IAEA), Vienna (IAEA, 2011, 2012, 2014). The process envisioned by the IAEA was developed primarily for planned disposal facilities, but is also applicable to existing sites such as the LFLS: • SSG-23 (P.90, 6.86) “The approach to support the decision-making process . . . is also directly applicable to existing facilities (IAEA, 2011, 2012, 2014).” The IAEA documents address a scope that includes the Safety Case and Safety Assessment. This report focuses specifically on a human dose assessment for the post-closure period (assumed 100-year Institutional Control Period and through to 1000 years into the future). The dose work compares modelled radiological dose rates to hypothetical human receptors under a range of future management options and conditions at the LFLS. Five types of management options and multiple receptor types were evaluated. The approach used here is site-specific as it uses measurements of site samples, data from site documents, local meteorological and hydrological data as well as local site configuration and layout. The document also includes a wildlife dose assessment consistent with international best practice and, for Australia, the Radiation Protection of the Environment Guide (ARPANSA, 2015). The model results reported here address many different scenarios which, while not covering every possibility, are intended to provide a sufficient range of useful input data into selection of a sound management plan for the future of the LFLS. Following selection of an option a more detailed dose assessment should be performed to optimise the design. This dose assessment was conducted within, and relies on data from, a multi-year project that assessed the waste characteristics and environmental setting of the LFLS as described in a series of reports and papers (Johansen et. al., 2020).
Radioactive waste disposal, ANSTO, Australia, Underground disposal, Radioactive waste management, Underground disposal, Waste disposal, Radioactive materials, Dispersions, Wastes
Johansen, M. P., Payne, T. E., Comarmond, M. J., Harrison, J. J., Blackley, R., & Kabir, A. (2020). Little Forest legacy site - technical report : dose rate estimates to humans and wildlife for a range of potential future scenarios (ANSTO-E-787). Lucas Heights, NSW: Australian Nuclear Science and Technology Organisation.