Sim-Fuel and Alpha-Active Material Manufacturing and Characterisation Capability

Lead Research Organisation: University of Manchester
Department Name: Mechanical Aerospace and Civil Eng

Abstract

The aim of this proposal is to provide key equipment that will deliver an internationally-unique open-access academic capability to manufacture, irradiate, and examine the pre- and post-irradiation characteristics of a range of alpha-active radioactive materials containing uranium, thorium, and plutonium and other trans-uranic elements. This equipment will be pivotal in linking together around £35M of existing nuclear research infrastructure at the University of Manchester in order to fully realise their capabilities to explore a wide range of materials that are of critical importance to the nuclear sector.

The specific equipment requested is:
1. a Focussed Ion Beam Scanning Electron Microscope;
2. a Scanning/Transmission Electron Microscope; and
3. a plutonium-active inert-atmosphere glove-box for sample preparation.

Hitherto, the capability to manufacture, irradiate, and characterise uranium and plutonium containing materials has only been available within large government-owned national laboratory facilities. Whilst such facilities remain vital for research into very highly active samples and materials containing large quantities of trans-uranic elements, the availability of an academic capability that is able to work with kg-quantities of uranium and gram-quantities of plutonium will provide an opportunity for a far wider range of access, and the means to undertake highly detailed and insightful studies at costs and time-scales that are simply not possible within larger nuclear-licensed facilities.

The range of science and technology impacts enabled by the new equipment cover the full spectrum of the nuclear fuel cycle, and include: improved understanding of the performance of existing nuclear fuels to improve safety; the development of new fuel materials for existing and next-generation reactors; the production of representative surrogate irradiated fuels (i.e. SimFuels) to assist in the development of new recycle technologies for spent fuel; improved understanding of the behaviour of U and TRU-bearing materials within environmental samples; and improved understanding and development of materials to facilitate the disposal of radioactive wastes (e.g. immobilisation matrix materials). Researchers from all of these communities will be encouraged to access the internationally-leading capability that the new equipment provides.

In addition to creating a major body of knowledge on the performance of alpha-emitting radioactive materials for the variety of different applications mentioned above, the facilities will play a major role in providing training and education in the safe handling of alpha-active materials. This will provide a new generation of post-doctoral researchers with a range of skills that will be vital in ensuring the successful implementation of the Government's nuclear strategy in the coming decades.

Planned Impact

The proposed new capability to manufacture, characterise, irradiate (with protons and heavy-ions) materials containing U/Th and Pu, and to subject the pre- and post-irradiated material to detailed microstructural and chemical analysis at atomic length scales, is a capability thought to be unique within international academic organisations. It will enable research that delivers impacts across the nuclear fuel cycle, as well as providing an important source of training in the safe handling of alpha-active materials. Potential areas of impact are as follows.

1. Improving the Safety of Nuclear Fuels for Existing, New Build, and Advanced Gen-IV Reactors.
There is strong international interest in the development of Accident Tolerant Fuels that can be used in currently operating and new build reactors (mainly LWRs). There is also strong interest in developing advanced fuel materials for next-generation reactors (e.g. fast reactors and HTGRs). The proposed facility is capable of producing the full range of fuel materials that are currently of interest for ATF and Gen-IV fuel studies (uranium oxides, nitrides, carbides, silicides, and borides; a full range of cer-cer and cer-met composites; and metallic alloys). These materials can be characterised to determine composition, microstructure, and thermos-physical properties, and subject to ion-beam irradiation. The proposed new equipment will enable very detailed comparisons between pre- and post-irradiated materials in order to fully understand the effects of both processing conditions and irradiation, which will be critical in developing improved materials with improved performance.

2. Development of Improved Recycle Processes for Current and Advanced Nuclear Fuels
Advanced recycle technologies, including highly selective ligands, efficient flowsheets, and novel techniques such as pyrochemical processing, require validation: ultimately necessitating the use of spent nuclear fuel. However, such research requires highly specialised facilities, and is both expensive and time-consuming. Significant progress can be made at much lower cost by developing recycle technologies using simulated spent fuel (or SimFuel). The proposed facility will provide the means of manufacturing SimFuel containing a representative mix of uranium and fission products and, if required, plutonium (and potentially other transuranic elements). In addition to current oxide-based fuels, SimFuel representing advanced fuels (such as those mentioned above) can also be produced.

3. Development of Materials for the Immobilisation and Disposal of Radioactive Wastes
The identification and validation of materials suitable for the immobilisation and long-term disposal of radioactive wastes are critical to the delivery of the UK's nuclear waste disposal strategy. The proposed facility will be able to manufacture, test (including irradiation), and characterise the performance of a range of candidate materials, including simulated wastes that contain uranium, thorium, and plutonium. A wide range of ceramic and metallic materials will be able to be produced using a range of techniques, including: conventional sintering, spark plasma sintering, hot isostatic pressing, and arc and induction melting and casting.

4. Understanding the Behaviour of Radioactive Isotopes within Environmental Materials
The facility will be able to produce U/Th/Pu-bearing analogues for environmental materials using techniques similar to those for immobilisation materials described above, as well as introducing alpha-active materials into existing environmental samples. The same wide range of testing and characterisation capabilities will be available.

In addition to creating a major body of knowledge on the performance of alpha-emitting radioactive materials, the facility will play a major role in providing training and education in the safe handling of alpha-active materials for a new generation of nuclear researchers.

Publications

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