Chemistry & Metallurgy
Actinide Chemistry
The Actinide Chemistry Research is responsible for expanding AWE's understanding of the chemistry of the actinides relevant to weapon functionality, with particular emphasis on the corrosion behaviour of actinide weapon components when exposed to atmospheres containing hydrogen, oxygen and water. The team undertakes fundamental studies designed to elucidate the kinetics, thermodynamics and mechanism of these corrosion processes.
The team uses custom-built gas handling lines to study these reactions as a function of temperature, pressure and gas composition and have the ability to monitor the real-time growth of corrosion sites using and optical reaction cell and dedicated image capture system. The team's technical output feeds directly into the modelling group's efforts to develop quantitative models of the corrosion behaviour of weapon components.
Actinide Surface Science
The surface science discipline sits on the boundary between solid state chemistry and condensed matter physics. In the former it can be used to investigate the chemical mechanism of corrosion, whereas in the latter the electronic density of states can measured. The AWE surface science facility is specially designed for working with plutonium materials and is predominantly used to investigate corrosion mechanisms of this unusual element.
It consists of non-monochromatic X-ray, monochromatic ultraviolet photoelectron spectroscopy, inverse photoelectron spectroscopy and dynamic secondary ion mass spectrometry. All the techniques typically have an analysis area of 1 mm2. The equipment can be used for gas dosing from Langmuir (10-6 mbar) to 10 bar in pressure, atomic hydrogen and oxygen dosing and sample heating and cooling. Sample cleaning is achieved using one of three ion mills.
Plutonium Metallurgy
Plutonium is a highly radioactive metal that suffers the ingrowth of radiogenic impurities from the moment it is formed into a solid. The plutonium metallurgy research team is responsible for developing our understanding of the metallurgical properties of plutonium alloys and how these properties change with age.
The team also supports certification of the plutonium used in production, makes and fabricates plutonium alloys in support of numerous trials and research programmes, and supplies expert advice on how changes in the production route may impact on the metallurgy of the finished component.
The team utilises a wide range of experimental techniques in support of its programme including differential scanning calorimetry, thermo-mechanical analysis, resistively measurement, metallography and mechanical testing.
Organic Materials
The organic materials team undertakes ageing and lifetime prediction studies on a number of polymer materials. They also perform programmes to develop new materials based upon nano and molecularly filled systems as well as alternative foam structures.
A selection of characterisation techniques are utilised to understand materials. These range from chemical characterisation methods such as UV/Vis, IR and NMR spectroscopy, through thermal and physical methods like DSC, TMA and DMTA to structure visualisation techniques based upon NMR imaging and X-ray microtomography.
Inorganic Materials
Recently the glass section has been focused on the immobilization of halide-containing radioactive wastes in glass and ceramic hosts. A method of immobilizing several chloride and fluoride containing wastes in a number of calcium phosphate minerals (apatite, spodiosite and whitlockite) is being developed. These mineral phases are then encapsulated within a glass matrix to yield a solid monolithic and durable wasteform.
The group supports the Immobilisation Science Laboratory (ISL) at Sheffield University, but has also worked on a number of other projects including: glass-ceramic composites, chemically-strengthened frangible glass (command break), glass-ceramic-to-metal seals and coatings, crystallization kinetics of glasses; additionally, the section offers a problem solving service for glass related queries.