Background report on the Little Forest Burial Ground legacy waste site
Australian Nuclear Science and Technology Organisation
The Australian Atomic Energy Commission (AAEC) buried low-level radioactive waste at the Little Forest Burial Ground (LFBG) near Lucas Heights between 1960 and 1968. The disposal site has since been under a constant care, maintenance and routine monitoring regime by the AAEC and its successor, the Australian Nuclear Science and Technology Organisation (ANSTO). The routine environmental measurements at the site have been reported in ANSTO’s series of monitoring reports. ANSTO has commenced a detailed scientific study of the status of the site, including sampling of vegetation, groundwater and soils. The project has undertaken soil coring, geophysical surveys and installation of groundwater sampling bores. The research applies advanced analytical techniques, such as accelerator mass spectrometry, which have not been employed in the analysis of environmental samples from the LFBG in the past. Project personnel are reviewing documents related to the disposal operations, as well as information and data from over 40 years of monitoring and investigation of the LFBG. In addition to relatively shortlived radionuclides, such as 60Co, 137Cs and 90Sr, the site contains both nonradioactive toxic contaminants (including more than 1000 kg of beryllium) and longlived alpha-emitting radionuclides including plutonium, uranium and thorium. Over the period since operations ceased, a plume of tritium in groundwater has developed and there has been intermittent subsidence of the soil covering the trenches. This subsidence is attributed to voids developing in the buried wastes, due to deterioration of containers and disposed objects. Contamination of the ground surface with radionuclides has been documented in some AAEC reports. The data obtained by the research project at LFBG will enable the assessment of possible management options including continuing the current regime of maintenance and monitoring, in-situ remediation, or exhumation. Unless the site is remediated, it will require some form of institutional control in perpetuity, due to the presence of beryllium and long-lived actinides. The present report provides an overview of the disposal operations at LFBG, briefly reviews previous reports and describes current ANSTO research activities at the site.
Radioactive wastes, Sampling, Ground water, Mass spectrometers, Radioisotopes, Toxoids
Payne, T. E. (2012). Background report on the Little Forest Burial Ground legacy waste site (ANSTO/E-780). Lucas Heights, NSW: Australian Nuclear Science and Technology Organisation.