Tag Archives: fission energy

Predicting release rates of hydrogen from stainless steel

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Decorative photograph showing electrolysis cellThe influence of hydrogen on the structural integrity of nuclear power plant, where water molecules in the coolant circuit can be split by electrolysis or radiolysis to produce hydrogen, has been a concern to engineers for decades.  However, plans for a hydrogen economy and commercial fusion reactors, in which plasma-facing structural components will likely be exposed to hydrogen, has accelerated interest in understanding the complex interactions of hydrogen with metals, especially in the presence of irradiation.  A key step in advancing our understanding of these interactions is the measurement and prediction of the uptake and release of hydrogen by key structural materials.  We have recently published a study in Scientific Reports in which we developed a method for predicting the amount hydrogen in a steel under test conditions.  We used a sample of stainless steel as an electrode (cathode) in an electrolysis cell that split water molecules producing hydrogen atoms that were attracted to the steel. After loading the steel with hydrogen in the cell, we measured the rate of release of the hydrogen from the steel over two minutes by monitoring the drop in current in the cell, using a technique called potentiostatic discharge.  We used our measurements to calibrate a model of hydrogen release rate, based on Fick’s second law of diffusion, which relates the rate of hydrogen motion (diffusion) to the surface area perpendicular to the motion and the concentration gradient in the direction of motion.  Finally, we used our calibrated model to predict the release rate of hydrogen over 24 hours and checked our predictions using a second measurement based on the hydrogen released when the steel was melted.  So, now we have a method of predicting the amount of hydrogen in a steel remaining in a sample many hours after exposure during electrolysis without destroying the test sample.  This will allow us to perform better defined tests on the influence of hydrogen on the performance of stainless steel in the extreme environments of fission and fusion reactors.

Source:

Weihrauch M, Patel M, Patterson EA. Measurements and predictions of diffusible hydrogen escape and absorption in cathodically charged 316LN austenitic stainless steel. Scientific Reports. 13(1):10545, 2023.

Image:

Figure 2a from Weihrauch et al , 2023 showing electrolysis cell setup for potentiostatic discharge experiments.

Reasons I became an engineer: #4

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Images from the optical microscope showing the tracks of bacteria interacting with a surfaceThis is the last in a series of posts reflecting on my steps towards becoming an engineer.  At the end of the previous post, I described how I moved to Canada becoming a biomedical engineer in the Medical School at the University of Calgary.  It was a brief period of my career, because shortly after I started, I was encouraged to apply for a lectureship in mechanical engineering at my alma mater which I did successfully.  So, I returned to the University of Sheffield and started my career as an academic engineer.  I continued to work in biomedical engineering, focussing initially on cardiac mechanics [see ‘Tears in the heart’ on July 20th, 2022], then on osseointegrated prostheses [see ‘Turning the screw in dentistry’ on September 9th, 2020] and, more recently, on computational biology [see ‘Hierarchical modelling in engineering and biology’ on March 14th, 2018] and cellular dynamics [see ‘Label-free real-time tracking of individual bacterium’ on January 25th, 2023].  However, the dominant application area of my research has been aerospace engineering informed by, if not also influenced by, my experiences in the Royal Navy, including flying a jet trainer aircraft shortly before leaving.  In the last decade, I have been introduced to nuclear reactor engineering, both fission and fusion, and have used them as vehicles for developing research in digital engineering [see ‘Thought leadership in fusion engineering’ on October 9th, 2019].  This biographical series of posts has described my evolution as an engineer – it was not an ambition I ever had nor did anyone push me towards engineering but I have found that my way of thinking about problems is well-suited to engineering, or perhaps engineering has taught me a way of thinking.

Image: Figure 4 – Tracks (yellow lines) of the sections (purple circles) of four E. coli bacteria experiencing: (a) random diffusion above the surface; (b) rotary attachment; (c) lateral attachment; (d) static attachment. The dynamics of the four bacteria was monitored for approximately 20 s. The length of the scale bars is 5 μm. From Scientific Reports, 12:18146, 2022.

Digitally-enabled regulatory environment for fusion powerplants

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Digital twins are a combination of computational models and real-world data describing the form, function and condition of a system [see ‘Can you trust your digital twin?‘ on November 23rd 2016]. They are beginning to transform design processes for complex systems in a number of industries.  We have been working on a proof-of-concept study for a digital reactor in fission energy based on the Integrated Nuclear Digital Environment (INDE) [1].  The research has been conducted by the Virtual Engineering Centre (VEC) at the University of Liverpool together with partners from industry and national laboratories with funding from the UK Government for nuclear innovation.  In parallel, I having been working with a colleague at the University of Manchester and partners at the Culham Centre for Fusion Energy on the form of a digital environment for fusion energy taking account of the higher order of complexity, the scale of resources, the integration of novel technologies, and the likely diversity and distribution of organisations involved in designing, building and operating a fusion powerplant.  We have had positive interactions with the regulatory authorities during the digital fission reactor project and the culture of enabling-regulation [2] offers an opportunity for a new paradigm in the regulation of fusion powerplants.  Hence, we propose in a new PhD project to investigate the potential provided by the integration of digital twins with the regulatory environment to enable innovation in the design of fusion powerplants.

The PhD project is fully-funded for UK and EU citizens as part of a Centre for Doctoral Training and will involve a year of specialist training followed by three years of research.  For more information following this link.

References:

[1] Patterson EA, Taylor RJ & Bankhead M, A framework for an integrated nuclear digital environment, Progress in Nuclear Energy, 87:97-103, 2016.

[2] http://www.onr.org.uk/documents/2018/guide-to-enabling-regulation-in-practice.pdf

Image: https://www.pexels.com/photo/diagram-drawing-electromagnetic-energy-326394/