Treatment of Legacy waste

Lead Research Organisation: Lancaster University
Department Name: Engineering

Abstract

The treatment of legacy waste is an issue facing the nuclear industry. Current methods of disposal and decontamination are both costly and inefficient. The use of incineration, compaction and cementation all hold relative merits and drawbacks. Whilst incineration is useful in reducing the volume of low-level nuclear waste it does release gases that require further treatment before they can be released into the atmosphere. The ash produced from incineration is likely to contain a significant amount of nucleoids and thus will be required to be treated before containment. Compaction is an important technique to reduce the overall volume of waste before immobilisation. Despite the ability to reduce the volume of waste by a factor of 3 to 10, the quantity of energy needed to compact the waste is a factor that should be considered. By forming a sludge or a precipitate from nuclear waste allows for the immobilisation of the waste. After selecting a suitable matrix material that allows for safe storage over period of time, by placing the container in a monolithic concrete block the waste is ready for storage.
Whilst allowing for the safe storage of legacy waste, this is only a temporary solution as this process will need to be repeated once the decay of the storage block has occurred. This leads to the necessity to find a process that allows for further reduction of the volume of nuclear waste produced.
Electrochemical methods to reduce nuclear waste vary in approach. There has been research into the viability of processing spent oxide fuels by "pyroprocessing" (Choi and Jeong, 2015). This involves the reduction of the fuel to metallic form using a closed fuel cycle in conjunction with a metal fuel fast reactor. Results gained from this were positive and allowed for future development to an industrial scale.
The Electrochemical treatment of low-level nuclear waste (Bockris and Kim, 1996) is a useful paper when analysing the level of research conducted in the area of interest. The paper focuses on the reduction of waste which led to the removal of ruthenium, a precious metal that helps with the economic viability of the project, as well as removing mercury and chromate, both that have adverse effects on the environment. This was achieved through the use of multiple packed bed electrodes as well as a plate electrode. The arrangement of these plates and beds allows for separation of the previously mentioned metals as well as the transformation of nitrates and nitrites into gaseous nitrogen and ammonia - preventing damage to the surrounding environment.
The literature indicates that there is a good grounding of results and techniques already in place that would help the initial stages of my research and allow for development ideas in the future.
I have preciously undertaken research in the recovery of precious metals from end of life fuel cell membranes. Whilst not directly related to this project I feel the necessary skills I have gained from the project will give me a good grounding. The knowledge of electrochemical techniques that can be used to separate metals could prove useful when dealing with heterogeneous mixtures of nuclear waste. The process of leaching and recovery is one that I have a good base of knowledge and feel that it could be successfully applied to this project. The ability to effectively research papers and translate the necessary techniques from paper to the lab is a skill that I have effectively developed. This could be essential given the specific nature of the project.
I believe having previous research experience would prove to be an asset given the length and nature of the project. The planning and necessary foresight needed to effectively complete tasks within a project are skills that I have developed by undertaking a Masters by Research. By meeting self-set deadlines, I have been able to keep track of the overall progress made over the course of my master's research project. I feel that by applying

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/R511997/1 01/10/2017 30/09/2022
2342444 Studentship EP/R511997/1 30/09/2019 30/09/2022 Dylan Jordan
EP/S022295/1 01/04/2019 30/09/2027
2342444 Studentship EP/S022295/1 30/09/2019 30/09/2022 Dylan Jordan