RESUMO
To date, impacts of ionising radiations have been largely disregarded in Life Cycle Assessment (LCA). This omission can be linked to the lack of a standard and comprehensive framework for including the effects of radionuclides alongside other emissions from industrial processes. Drawing on a recent review of Radiological Impact Assessment methodologies for LCA studies, this article proposes an overarching framework for integrating impacts of radionuclides in the Impact Assessment phase of LCA. From this framework, two alternative methodologies have been derived. They differ mainly in the way transport and dispersion of radionuclides in the environment are modelled: UCrad represents the first-of-its-kind compartment-type methodology for radionuclides, whereas the alternative Critical Group Methodology (CGM) has been adapted from standard Risk Assessment practices. Characterisation factors for a range of emitted species have been calculated using both methodologies and compared with those obtained from the Human Health Damages methodology, which is the only approach to radiological impacts yet implemented in LCA. For both UCrad and CGM the results are in general agreement with the Human Health Damages methodology, but UCrad gives factors closer to those obtained by the CGM approach. UCrad represents a major step towards incorporating ionising radiation impacts in LCIA. A subsequent paper will explore quantitatively the main differences between the UCrad and CGM methodologies.
RESUMO
On the Sellafield site there are several legacy storage tanks and silos containing sludge of uncertain properties. While there are efforts to determine the chemical and radiological properties of the sludge, to clean out and decommission these vessels, the physical properties need to be ascertained as well. Shear behaviour, density and temperature are the key parameters to be understood before decommissioning activities commence. However, limited access, the congested nature of the tanks and presence of radioactive, hazardous substances severely limit sampling and usage of sophisticated characterisation devices within these tanks and therefore, these properties remain uncertain. This paper describes the development of a cheap, compact, and robust device to analyse the rheological properties of sludge, without the need to extract materials from the site in order to be analysed. Analysis of a sludge test material has been performed to create a suitable benchmark material for the rheological measurements with the prototype. Development of the device is being undertaken with commercial off the shelf (COTS) components and modern rapid prototyping techniques. Using these techniques, an initial prototype for measuring shear parameters of sludge has been developed, using a micro-controller for remote control and data gathering. The device is also compact enough to fit through a 75 mm opening, maximising deployment capabilities.
