Overview
Within this project, you will advance operational effectiveness and enhance sustainability of decommissioning operations of the UK legacy nuclear sites. You will achieve so by using state-of-the-art laboratory facilities and cutting-edge, high-performance software for Computational Fluid Dynamics (CFD). Your activities as a Postgraduate student will include: working in contact with the Nuclear Decommissioning authority (NDA), a placement at the SLC or the supply chain (e.g.: Sellafield ltd), and participating to SATURN CDT’s activities.
About this opportunity
Nuclear sludge is a radioactive product of corrosion/degradation of spent nuclear fuel and associated materials in aqueous environments (for instance, spent fuel ponds), along with chemical precipitates, fission products and organic contaminants. Safe decommissioning demands the removal of nuclear sludge residues and consolidated heels from complex pipeworks. However, removal operations are complicated by the complexity of the pipeworks, the difficulty of inspecting them, and nuclear sludge’s complex flow characteristic like adhesiveness and non-Newtonian rheology, which are poorly understood because nuclear sludge’s radioactivity prevents from performing effective characterization.
Your aim will be to produce effective nuclear sludge removal protocols based on flushing pipeworks with ad-hoc flushing solutions, at controlled flow rates. You will achieve this aim through a series of activities involving labwork, numerical modelling and designing of flushing protocols:
Labwork:
- Develop harmless test solutions to replicate the rheological behavior of radioactive sludge
- Develop high-viscosity flushing solutions for improved removal of consolidated heels
- Characterize scourability of settled material from the test solutions, in reduced-complexity lab tests (straight pipe flow, with a flushable solution)
- Test high-viscosity flushing solutions to evaluate their effectiveness in mobilizing consolidated sludge.
Numerical modelling:
- Use advanced CFD techniques (the Lattice-Boltzmann method and, specifically, OpenLB) to model flow patterns in complex pipework
- Perform Lattice-Boltzmann simulations on GPUs of a pipe network for nuclear purposes
- Validate models against experimental data to ensure accuracy and reliability.
Design of flushing protocols:
- Develop and validate flow protocols for pipework with varying levels of complexity, aiming to minimize residual deposits
- Provide design recommendations that will inform the Best Available Techniques (BAT) for the nuclear industry.