Nuclear: the future is here

Materials World magazine
,
4 Sep 2014

EDF Energy is planning the construction of four new nuclear reactors in the UK, including Hinkley Point C. Rhiannon Garth Jones talks to three of the company’s employees about their different roles on the project, the materials challenges and the future of nuclear.  

 

 

 

 

 

Nigel Knee Head of External Affairs, Nuclear New Build
Nigel Knee is responsible for nuclear policy and external affairs within EDF Energy’s nuclear new build team. He was part of the team that prepared the planning application for Hinkley Point C, a major new nuclear power station proposed on the Somerset coast.

Nigel trained as a metallurgist at Cambridge University, has a doctorate for mechanical engineering research from the University of Bristol, and is a chartered engineer. He has over 30 years’ experience in the power industry, starting out in engineering and research for the Central Electricity Generating Board.  

How have you seen the nuclear sector change during your time in the industry?
I joined the Electricity Supply Industry in 1978 as a metallurgist, when the UK nuclear industry was going through a period of rapid development, as the first advanced gas-cooled reactors (AGR) were commissioned. I have seen massive change over the years, with privatisation, the break-up of the Central Electricity Generating Board and the introduction of a competitive market. More recently, China has emerged as the leading nuclear nation, with around 30 plants under construction and more planned.

The nuclear sector has been in and out of favour over that time, and events such as Fukushima in 2011 have caused some to question whether nuclear power should have a role in the energy mix. However, I believe that throughout these ups and downs, nuclear power has provided safe, secure baseload power for the UK. We are now once again looking at a resurgence in nuclear power, and an opportunity for the UK to take the lead in building the next generation of nuclear power stations.

What do you think are the biggest materials challenges the industry faces?
The latest generation of nuclear reactors relies on the highest standards in terms of materials quality and conformance to specification throughout the plant. The reactor pressure vessels weigh around 500 tonnes and are made from some of the largest forgings in the world – there is only one steelworks in the world that has the proven capability to make these components. The forged components need to be welded, then rigorously inspected and tested to ensure they will endure for a service life of at least 60 years.
We also have to make sure that the existing fleet is safe to keep running. The materials challenges are diverse – from the integrity of welds in hard-to-inspect areas of the boilers, to the physical properties of graphite that needs to withstand high levels of neutron exposure at high temperatures.

Lastly, we have to look forward to the next generation of reactors, which may involve liquid metal coolants and even higher temperatures. These will create new and interesting challenges for materials performance and in-service inspection.

How does your specific role address these challenges?
My job is to make sure that those in Government have confidence that we understand all the risks as we embark on projects such as Hinkley Point C, and that we don’t overlook the importance of the existing fleet as we move forward with new builds.

Tell me a bit more about the project you are currently working on.
I am working on EDF Energy’s nuclear new build project, which aims to build two new nuclear stations – at Hinkley Point in Somerset and Sizewell in Suffolk. We now have the reactor design approved in principle by the Office for Nuclear Regulation (ONR) and the Environment Agency, and have development consent from the Department of Energy and Climate Change. Construction will start in earnest once we have reached agreements with the Government and with potential investors in the project, and had the key contracts cleared by the European Commission.

What impact will this have?
Hinkley Point C will be the first new nuclear power station in the UK for more than 20 years. It will comprise two pressurised water reactors (PWRs) that together will be able to generate enough power for more than five million homes – that’s about 7% of the UK’s needs. A successful first new-build project will provide the foundation for follow-on projects in the UK and a platform for export opportunities. It will require investment in engineering skills and should reinvigorate the whole sector.

Where do you see nuclear power sitt ing within the wider UK energy mix over the next five years?
Nuclear power will continue to play a key role in our energy mix, providing roundthe- clock electricity. We aim to keep the existing nuclear fleet – which produces almost 20% of our electricity today – running until well into the 2020s, but at some point it will need to be replaced, so it’s important we make decisions now to start the long-term programme of replacing them, and perhaps even increase the contribution of nuclear.
The challenge we face in terms of reducing CO2 emissions means that we need serious investment in both renewable energy and nuclear power if we are to meet our targets and avoid the worst effects of climate change.   

Andy Wilby Metallurgy and Welding Engineer, Design Authority

Andy started his metallurgical career with an HNC in Metallurgy from Bradford and Ilkley College, and after eight years in the manufacturing and fabrication industry joined the Central Electricity Generating Board (CEGB). He has since accumulated 28 years’ experience in the power generation industry. Andy is also an International Welding Engineer and a registered Chartered Engineer.

His role in the Design Authority is to ensure that engineering aspects of materials and welding are adequately presented and supported in the safety case for the UK EPR. His role involves identifying materials testing programmes, particularly in the area of fracture toughness. He also contributes to expert panels, where, for the high-integrity welded joints, the likelihood and characteristics of defects that may arise due to welding process parameter failure are defined.  

How have you seen the nuclear sector change during your time in the industry?
Since I joined the Electricity Supply Industry (ESI) in 1986, the single biggest change has been its privatisation. This resulted in the loss of world-leading R&D facilities as well as the major administrative and organisational effort to merge several regions into one coherent entity that could support a nationwide fleet of nuclear power stations.

What do you think are the biggest materials challenges the industry faces?

For the existing fleet, there are many challenges to ensure they remain operational while the new build is being prepared. The AGRs operate at high temperature and the steam pipework is exposed to creep, and some regions, particularly within the concrete pressure vessel, are very difficult to inspect. The graphite moderator is also an area that cannot be replaced and is subject to in-service degradation.

For the proposed UK EPR, the materials are very similar to previous generation PWRs, so there is plenty of relevant operating experience to draw on and the materials are well understood. The UK EPR has a design life that is longer than previous PWRs, so ensuring that material properties remain valid for a longer period than have been deployed in service is key. Building such a plant with the required quality is another key area. It has been some time since the UK has been involved in such a project, and it will be important to ensure that the required skills are available and developed.

Future generation plants will provide even bigger materials challenges, particularly if alternative reactor designs are contemplated. The materials will be more difficult to fabricate and inspect, and there is also the issue of ensuring that the right level of knowledge is available in the UK.

How does your specific role address these challenges?
I work in the Structural Integrity team of Design Authority, where I am involved in developing fracture toughness testing programmes for the components and materials that need to have the highest integrity. This means identifying which materials are available to support the programmes, what tests can be conducted and what those tests need to demonstrate. Many of these considerations are specific to the UK and the requirements of the regulator. Considerable time has been spent with the designers and our parent organisation, EDF SA, to ensure the supporting information that has previously been used in France is properly adapted for the UK. Where do you see nuclear power sitt ing within the wider

UK energy mix over the next five years?
We’re looking further ahead than the next five years. To ensure the UK meets its carbon reduction targets, we need a balanced mix of generation, including nuclear. EDF Energy’s nuclear stations already generate around a sixth of the UK’s electricity and avoids more than 30 million tonnes of CO2 every year. Extending the lives of the nuclear power stations makes absolute sense in terms of bridging the energy gap.

Based on the expected life extensions, all seven of the EDF Energy’s existing AGR stations will be operating in 2023 when the new nuclear power station at Hinkley Point C is due to be commissioned if a final investment decision is taken in 2014.

Life extension helps with the short-term risk but doesn’t change the need or urgency of the new nuclear programme in the longer term. The fundamental need for new capacity remains – the inability of old coal to meet tighter emissions limits being the foremost factor.  

Ajit Ghosh Programme Manager, Nuclear Steam Supply System
Ajit trained as an Engineer at Cambridge University, graduating with a BA. He has more than 30 years of experience in the power industry, starting with the Central Electricity Generating Board and subsequently with its successor companies, Nuclear Electric and British Energy.
Ajit has extensive project and programme management experience, for in-house and external projects. He worked on the project to build the first pressurised water reactor power station in the UK, Sizewell B, from its Public Inquiry through to commissioning. He has also worked on an international bid for the Nuclear Island, for a new nuclear power station in Taiwan.  

How have you seen the nuclear sector change during your time in the industry?
I joined the industry as a graduate engineer in 1975 when it was nationalised (the CEGB). Those were exciting times – a lot was going on in almost all facets of electricity production and there were endless opportunities for a young engineer. Privatisation of the industry caused inevitable contraction of that scope of activities, and in British Energy, where I ended up, the focus moved to nuclear operations and its support, along with completion of one major project – Sizewell B. The completion of Sizewell caused us to focus even more on operations, and there were certainly a lot of interesting challenges in improving safety and reliability, though there were no major national infrastructure projects. With the EDF Energy acquisition of British Energy, and its determination to build Hinkley Point C, opportunities are once again available for engineers to be part of a venture to design and build safe, reliable electricity power plants that will supply our country with affordable electricity for the next 60 plus years.

What do you think are the biggest materials challenges the industry faces?
I think our operating fleet faces the expected challenges of corrosion, fatigue and embrittlement, although we do have comprehensive plans to ensure we continue operating safely. In addition, rising standards in safety are moving us towards using cleaner steels that are more readily inspected in-service, and are – to all intents and purposes – free from defects and inclusions.

Can you tell me a bit more about the project you are currently working on?
I am currently working on the Hinkley Point C Nuclear New Build project, which is still in its early phases. In my role as Project Manager for the nuclear steam supply system, I plan and co-ordinate the many technical, licensing, procurement and construction activities, and work to build relationships between customer and supplier. All this has to be undertaken within acceptable cost, schedule and risk constraints, without compromising safety or quality, so there are many interesting challenges and opportunities to deal with.

What impact will this have?
If everyone involved understands the specification and what is expected of them, we can have much greater confidence that the nuclear steam supply system will be delivered on time, within budget and, crucially, to the required quality. This will not only continue to provide UK citizens and industry with safe, reliable electricity, but give us more control over our energy, and provide high-quality jobs within the industry and supply chain over this period.

Where do you see nuclear power sitt ing within the wider UK energy mix over the next five years?
My personal belief is that the future holds many unknowns, and to be robust as a nation to the many challenges that will undoubtedly arise, we need an energy mix. Some of the primary fuels we use today were laid down by processes that occurred over millions of years, and it would be sad if, within a few generations, we exhausted these and denied future generations other possible uses.

I believe nuclear power will continue to have an important role for this country. The challenge to the industry is to have safe, reliable and economic designs, operated to the highest standards, and to earn public confidence on the right level of nuclear power that satisfies other high-level objectives related to the energy mix.