Australian Eggs

CHERPAC is a code developed by AECL to predict the time-dependent concentrations of 25 radionuclides in environmental compartments and the resulting radiation dose (ingestion, inhalation, immersion and groundshine) to humans, following an accidental release to the atmosphere from a nuclear facility. CHERPAC was used to investigate environmental sensitivities in agricultural and forest ecosystems. Given the assumptions in the CHERPAC code, it was concluded that doses to humans from agricultural food products are higher than those from groundshine and forest food products. Doses from agricultural products are highest from radionuclide deposition in summer because all plants are at their peak growth and are ingested fresh after the deposition event. The dose is higher if the deposition occurs in dry conditions rather than during heavy rain, because radionclides adhere better to dry plant leaves. For Cs-137, ingestion dose is higher for adults than other age groups, but for Sr-90 and I-131, ingestion dose is highest for infants. This is due to relative food product concentrations, intake rates and DCFs (dose conversion factors). In the forest ecosystem, adult doses are higher than those for children and infants because of the higher rates of intake by adults of forest food products.

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No abstract available.

In the fall of 2008, a low-altitude airborne geophysical survey was carried out at a military installation in Australia, the primary goal of which was detection and mapping of infrastructure, buried wastes, and other buried and surface metallic objects within a 1738 hectare area. The primary survey system was the Battelle VG-16 vertical magnetic gradient system. Because the base is active, the time frame for conducting the survey was limited to a few weeks. The short time frame and the added expense of an additional system were factors against adding on an electromagnetic survey. However, the Australian Department of Defence suggested that there might be non-ferrous targets of significance that the magnetic system would not detect. Moreover, the base was located some tens of kilometers from a field of extinct volcanoes, presenting the possibility of magnetic geology in the form of mafic igneous units. Therefore, it was determined that an airborne transient electromagnetic system should be included in the project. The added electromagnetic system proved valuable, but not in the way that was expected. Concentrations of strong anomalies appeared in the magnetic data, the sources of which could be either buried debris or geological. The TEM-8 system was flown over some of the more dense concentrations of magnetic anomalies. In some of these areas the TEM data showed very few anomalies, indicating that either the VG-16 anomalies are associated with magnetic rock types, or that the metallic sources detected by the VG-16 system are too deeply buried to be detected with the TEM-8 system. A few carefully located excavations indicated that the sources of the magnetic anomaly concentrations without associated electromagnetic anomalies were localized concentrations of very magnetic iron-bearing rock.