Q&A - Professor Bernard Kelly

Materials World magazine
,
4 Sep 2014

Professor Bernard Kelly FREng, Technical Director at DBD Ltd, speaks to Rhiannon Garth Jones about the future of nuclear decomissioning and UK policy. 

Can you tell me a bit about how you got into the nuclear industry?
After graduating from the University of Manchester Institute of Science and Technology with a degree in Chemical Engineering, I joined Laporte, working in plant support initially and then as a plant manager. I moved to Unilever Research Laboratories Bedford, where I undertook a wide range of food technology projects. Next I joined ICI Organics Division at several sites in northern England and Scotland, and it was there that I first worked on large engineering projects that involved many design and engineering contractors. At that time, ICI Organics Division concentrated on producing dyestuffs, and competing with lower cost companies in the emerging world became particularly difficult. Our markets began to shrink quite rapidly.

In 1980, British Nuclear Fuels Ltd (BNFL) was recruiting at an unprecedented rate to cope with a massive capital expenditure profile at its Sellafield site in Cumbria. In 1981, I joined the Thermal Oxide Reprocessing Plant (aka Thorp) design team at BNFL and later became Chief Process Engineer and then Managing Director of BNFL Instruments Ltd, based at Sellafield.

What has been your most exciting experience working within the nuclear sector?
I was also CEO of BNFL Instruments Inc in Los Alamos, USA, so I spent a lot of time commuting to and fro across the Atlantic. I have worked on nuclear projects in Europe, North America and Japan, but a short visit to China some years ago opened my eyes to the scale of investment in nuclear power out there. In the later stages of my BNFL career, I was fortunate to work within a strategy team setting out the strategic decommissioning and clean-up options for the entire Sellafield site over the short and long term. This was a fascinating experience and a career highlight.

What are you working on now?
In 2007, I was appointed to the post of Professor of Nuclear Decommissioning at the University of Manchester, where I still teach on an occasional basis. In 2010, I joined DBD, a UK-based independent enterprise, which provides services in North America, Europe, the Middle East, Japan and South Africa as well as to key nuclear sites in the UK.

My current main task as Technical Director at DBD is designing and delivering a series of nine lectures aimed at transferring the hard-won experience of our older experts to our younger engineers within DBD. This type of knowledge is highly valuable and yet so many of my generation of nuclear engineers do not even realise they possess it – it has become second nature, and so it is notoriously difficult to extract and teach. Unless we intervene now, when the older experts retire they will take all this knowledge out of the industry with them.  

What do you think are the main materials challenges in nuclear decommissioning?
I can see the attraction of working on building new nuclear stations, but to my mind, the absorbing challenges centre on knocking them down in a sustainable and safe manner.
Materials lie at the heart of decommissioning and nuclear waste management. Government policy is to dispose of all nuclear wastes in an underground deep geological disposal facility (GDF) at a future date. The intermediate and higher level nuclear wastes arising from decommissioning will finish up inside this GDF. On current predictions of radioactivity, the GDF is expected to feature a design life running into centuries. But it is exciting to realise that there is an interplay here between the design life of the GDF and the decommissioning methods adopted. By careful partitioning of the various waste streams, we may be able to significantly reduce the design life of the GDF, and materials science will be so important if this interplay is addressed.

A knowledge of history will be needed if we are to progress successfully. We know a lot about the materials used in the time of the Egyptians, for example, and we will need to tap into this history to help predict future behaviour of conditioned wastes in concrete and so on.

What technology is needed to address these challenges?
The technology behind decommissioning has, until recently, been very basic, and innovation is sorely needed if we are to deliver decommissioning to an acceptable end-state and at a cost and schedule significantly below current estimates, which are, frankly, unaffordable. In my experience the key aim in decommissioning is speed. If you can decommission quickly, you will also achieve lower costs, less exposure to operators, reduced surveillance of the site and a faster reduction in the hazards associated with decommissioning the older facilities.

We are fortunate in the UK to have a regulatory regime flexible enough to allow faster decommissioning. Provided downstream waste treatment plants can be provided safely and sustainably, there is no need to build them to the same standards as the original nuclear facilities.

What do you think is the future of nuclear in the UK?
Regarding the future of nuclear power in the UK, I am persuaded by the scenario predicting a heavier reliance on nuclear power, particularly for baseload demand – say, up to 75GW(e) of nuclear power in total by 2050. Light water reactors (LWRs) would be the initial choice, with probably a later reliance on mixed-oxide and fast reactors. Unlike gas, coal and oil, uranium has few other uses aside from nuclear power.

What is your biggest concern about the current nuclear industry?
Past Government policy has led to a demographic time bomb today. Between about 1988–2003, the successive UK Governments’ lack of support for nuclear power has closed down University courses, wound down R&D and ensured that not enough bright and motivated graduates have entered the industry. During the same time period, the generation of nuclear engineers and scientists who built Windscale in the 1950s and their successors who built Thorp in the 1980s have reached retirement age or have left the industry altogether. Their tricks of the trade and institutional memory have been lost to the upcoming generation, and all this is occurring while the previous anti-nuclear-new-build policy is being reversed.

Overall, I am very pleased that all three political parties in the UK currently support an expansion in nuclear power, but I am unconvinced that the importance of this institutional memory has been fully recognised. Passing on the tricks of the trade does not lend itself to taught courses.  

Three DBD Ltd employees give an overview of recent work they have done to solve management, technical and engineering issues in the nuclear sector.  

Resilience architecture methodology
We designed and implemented a process that assesses the response capability of facilities in the nuclear industry to a severe accident scenario, such as a prolonged loss of grid power to a nuclear site or a beyond-design-basis seismic or flood event. These scenarios are of high consequence and low probability. The process is in-line with the European Nuclear Sites Regulator’s stress tests, as part of the UK regulatory response to the accident at the Fukushima power plant. We believed that a Probabilistic Risk Assessment alone would not provide the range of data required for a thorough examination of the facility’s resilience and the adequacy of the emergency response, so a deterministic approach was developed to fully understand the realistic responses to such an event. High-hazard facility fault sequences and potential consequences were identified, and the adequacy and availability of the mitigating response were assessed. For each response, a timeline to implement, maintain and fail was developed in order to identify a ‘cliff edge’ time for realising consequences.  

Evaporator D
The Evaporator D project is based on the Sellafield Site in Cumbria, and will provide a new evaporator capable of concentrating highly radioactive fission products dissolved in nitric acid. The resultant fission product concentrate is then converted into a glass matrix within the waste vitrification plant, which manufactures a product suitable for disposal in a future underground waste repository.

Our scope of work includes the commissioning, planning, delivery and safety case management. We have provided the management team, lead commissioning engineers and supporting roles to inactively commission the evaporator and hand over the plant to the site licence-holder, Sellafield Ltd, who will introduce the radioactive materials. The plant’s robust design offers assurance of long life and meets strict safety case requirements, such as resistance to seismic events. Required to support the remaining years of the Magnox and Thorp reprocessing operations, Evaporator D will operate under reduced pressure to lower the liquid boiling point and control the corrosion of the plant items that are subject to elevated temperatures. Temperature is also controlled for safety reasons. Liquid movements are created using equipment that requires no moving parts or maintenance within the shielded cells that contain the evaporator, such as ejectors and reverse flow diverters.  

International liquid effluent treatment process
We analysed the current technology and design of a UK facility, and adapted it to the requirements of an international client for their facility. The technology was then taken overseas and integrated to meet the local requirements. The proposed design involved innovative solutions and included:

• specification checking and development of the client’s requirements

• feasibility design study of a new radioactive effluent treatment facility

• hazards identification, assessment, management and control through design, design reviews and design assessments

Additional work is being undertaken to develop the design study further with a view to the construction of this new facility.