The corrosion of depleted uranium in terrestrial and marine environments.

Depleted Uranium alloyed with titanium is used in armour penetrating munitions that have been fired in a number of conflict zones and testing ranges including the UK ranges at Kirkcudbright and Eskmeals. The study presented here evaluates the corrosion of DU alloy cylinders in soil on these two UK ranges and in the adjacent marine environment of the Solway Firth. The estimated mean initial corrosion rates and times for complete corrosion range from 0.13 to 1.9 g cm(-2) y(-1) and 2.5-48 years respectively depending on the particular physical and geochemical environment. The marine environment at the experimental site was very turbulent. This may have caused the scouring of corrosion products and given rise to a different geochemical environment from that which could be easily duplicated in laboratory experiments. The rate of mass loss was found to vary through time in one soil environment and this is hypothesised to be due to pitting increasing the surface area, followed by a build up of corrosion products inhibiting further corrosion. This indicates that early time measurements of mass loss or corrosion rate may be poor indicators of late time corrosion behaviour, potentially giving rise to incorrect estimates of time to complete corrosion. The DU alloy placed in apparently the same geochemical environment, for the same period of time, can experience very different amounts of corrosion and mass loss, indicating that even small variations in the corrosion environment can have a significant effect. These effects are more significant than other experimental errors and variations in initial surface area.

A review of the potential for radium from luminising activities to migrate in the environment.

During the first half of the twentieth century, radium, mixed with other components, was used to luminise many items, including watches, clocks, dials and meters. On many sites, and in particular MoD sites, luminised instruments and paint were disposed of by burning and burial. This paper presents a review of the potential for radium from such sites to migrate in the environment. The most likely mechanisms of migration of radium from former luminising sites in the UK are surface-water erosion and transport, and the action of animals and people. Plant uptake or rainsplash followed by cropping of the plants is another possible mechanism, but the extent of impact is uncertain. The migration of significant quantities of radium through soils or rocks, or due to landsliding or wind transport, is considered to be of minimal importance to most UK sites. A low pH, high salinity (in particular of group II metals) or reducing groundwater would need to be present for migration through soils/rocks to occur and such conditions are unlikely to be present in most shallow aquifer systems in the UK. To reduce the potential for migration to occur it is recommended that luminising wastes at ground surface are removed or covered, that controls are put in place to limit animal activity and that human entry to former luminising sites is restricted.