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EDF Energy Nuclear Generation: a decade of transformation

15 June 2018

Over the last decade, the safety and operational performance of EDF Energy's UK nuclear plants has been transformed. After years of sustained improvement, combined safety and operational results now represent the best overall performance in the past 40 years and are, in many instances, world leading. 

Dungeness B, Kent - Image: EDF
Dungeness B, Kent - Image: EDF

EDF Energy owns and operates the United Kingdom’s eight operational nuclear power stations, providing 9GW of capacity, around 20% of the UK’s electricity, from 14 advanced gas cooled reactors (AGR) and one pressurised water reactor (PWR).

These reactors are now demonstrably, the safe, reliable ‘workhorses’ of the UK’s low carbon electricity sector, playing a key role in supporting the UK electricity system. 

Brian Cowell, Managing Director of EDF Energy’s Generation Business describes how this transformation has been achieved and the lessons that could help support the UK’s Nuclear Industrial Strategy in the decades to come. 


Returning to work in January 2018, the staff and the leadership cadre of EDF Energy Generation were able to reflect on a hugely successful year. The Tier 1 safety performance metrics were all tracking at lowest-ever levels. Lifetime extensions had been delivered for Hartlepool, Heysham 1, Torness and Heysham 2, bringing the average plant life extension to 8.3 years since EDF acquired the UK’s nuclear generation assets in 2009. In addition, in 2016, the Nuclear Generation (NG) team had delivered its aspirational target of generating an annual output of 65TWh, the highest since 2003, two years ahead of plan.

The reliability of the nuclear fleet, measured by Unit Capability Factor (UCF) and Unplanned Capability Loss Factor (UCLF) were both trending at 'best ever' outcomes by some margin. In 2016 Heysham 2, near Lancaster, set a new world record of 940 days for the longest continuous period of operation for any commercial nuclear reactor, recording a three year average UCF of 90%. Sizewell B, the company’s 1200MWe PWR in Suffolk, completed its third breaker to breaker (continuous production run) with 100% UCF.

This level of excellence is now accepted as the new normal for the UK fleet, but this has not always been the case. These nuclear plants have had a mixed record since the first AGRs were commissioned in 1976, occasionally registering good individual station performance but never consistently delivering the desired safety and operational outcomes as a combined nuclear fleet.

In achieving this improved performance, the leadership team have communicated a clear, consistent vision that has aligned the entire organisation. They’ve worked hard to dismantle organisational silos, drive collaboration and create a 'one team' environment, engaging both staff and contract partners. They’ve encouraged the identification and deployment of international best practice, welcomed external advice and constructive criticism. They’ve set prudent business plan targets whilst agreeing more stretching aspirational goals, reviewing progress and making course corrections where needed. Most importantly, the team has ensured a ‘consistency of approach’ over many years by deploying a globally recognised nuclear governance system.

To understand the scale of the transformation it’s useful to look back at the history of the UK’s civil nuclear programmes. Following the success of the first programme, the construction of the Magnox fleet, the Labour Government’s October 1965 white paper on fuel policy set the target for a second nuclear programme, delivering 8,000MW of new nuclear capacity[1]. After consideration of other designs, the Advanced Gas Cooled Reactor, a development from the UKAEA designed Magnox reactor, was chosen as the vehicle to deliver the government’s nuclear target.

The AGR is designed to operate with a reactor gas outlet temperature of around 650oC, exposing the irreplaceable in-vessel components to high temperatures and consequently their behaviour must be modelled and assessed throughout the reactor life. They were intended to be refuelled ‘on-load’, significantly improving the economics of the design, but also introducing operational complexity which, on the earlier reactor designs (Dungeness, Hartlepool, Heysham 1), proved too challenging and led to the abandonment of on-load refuelling on these reactors.

Construction of the first of seven commercial AGR power stations began at Dungeness in Kent in January 1966. The Central Electricity Generating Board had responsibility for the development, construction and operation of the stations in England whilst the South of Scotland Electricity Board had that responsibility for the two AGR stations in Scotland. The AGR design was reviewed and refined during the early years of the programme and different consortia were engaged in programme delivery, this led to there being significant technical differences between the earlier and later designs[2], impacting, to this day, the ability to derive technical synergies across the fleet.

The first AGRs entered commercial operation in 1976 at Hinkley Point B and Hunterston B, and the final AGR stations were commissioned in 1988 at Torness and Heysham 2. Benefitting from the lessons emerging from the earlier designs, these stations retained the ability to carry out on-load refuelling, albeit at reduced load. In 1995, just prior to the privatisation of the nuclear business, the company’s PWR at Sizewell, a four-loop Westinghouse design modified for UK licensing and intended to be the first of four identical plants, entered commercial operation.

The AGR stations and Sizewell B were privatised as British Energy in 1996. The story of the six years following privatisation, the change in UK market environment, consequential financial difficulties leading to failure in December 2002, government rescue and restructuring, is well known and well documented[3].

Creating the future

EDF Energy nuclear generation safety output
EDF Energy nuclear generation safety output

The difficulties experienced during 2002 and 2003 provided the catalyst for the creation of a new organisational culture and enabled significant changes in the way the nuclear operational business was run. During this period, the foundations were formed upon which the successful turnaround was built.

In 2003, British Energy completed an intense, intrusive and rigorous assessment of its potential for operational improvement. The work was carried out by staff from within the organisation in collaboration with a consortium of independent consultants with a range of experiences of operational turnaround in both nuclear and other sectors. The report produced from this assessment comprised three detailed volumes and provided a recipe for performance improvement from which was developed a detailed programme that the senior team resolved to deliver. 

A large proportion of the individuals holding executive leadership positions in EDF Energy’s Generation business today were heavily involved in developing and delivering this programme, which described what the future operational business would become, what it would feel like, the results that would be achieved and how the organisation would get there. That description has evolved to become the vision for operational excellence that NG has targeted ever since.

With nuclear safety firmly positioned as the overriding priority, the key foundation blocks on which operational excellence would be built were:

*  Equipment Reliability

*  Operational Focus

*  Management of Work

*  Human Performance

*  Training

By deploying recognised world best practice in these areas, the organisation was able to address its declining operational performance, giving sufficient confidence to French state-owned electricity group EDF to acquire British Energy in 2009.

Delivering eight years of operational improvement and commercial success

After acquisition, the UK nuclear business was now integrated with a global nuclear company running 58 reactors in France with executives who fully understood the business, the nuclear safety imperative and the need for investment in plant and people. All agreed that there was enormous potential for further improvement in the UK fleet which in 2009 produced only 40.2TWh.

The ongoing improvements needed to be injected with a sense of urgency and the legacy capital investment deficit addressed to correct the years of underinvestment. Since 2009 EDF Energy has invested £4 billion in the UK nuclear fleet, including the programme of life extensions, driving improved plant reliability and profitability.

Of course it’s not all about money, since acquisition the nuclear business has become the highly connected, efficient, well-oiled machine that was envisioned post restructuring. We’ve seen collaborative approaches being developed between stations, central functions and key suppliers that have allowed the business to deliver significant improvement whilst dealing with some very difficult technical issues. It’s been a relentless but very positive journey, gradually identifying and breaking down any barriers to success and facilitating very effective relationships between people at all levels.

In 2011, a new means of describing the vision was created. The Safe Reliable Generation over Extended Life vision was encapsulated in three golden numbers that became a beacon for the organisation: 0/65/9, representing zero harm to people and the environment, 65TWh of output annually by 2018 and 9 years average life extension for the AGRs. These numbers became an incredibly effective alignment tool, if you were doing something that didn’t support the achievement of one of these numbers, then you were probably doing the wrong thing.

The nuclear plants are not price setters in the UK. Output is sold ahead and hedged therefore commercial success for the nuclear generation business is driven predominantly by how much electricity the stations can produce. In almost all business case scenarios, goal number one is to safely produce more output and goal number two is to drive down controllable costs, without impacting negatively on output.

As part of this 0/65/9 mantra, people at all levels were empowered to find ways to align the parts of the business they controlled with the overarching goals. A genuine collective sense of purpose became more and more visible and a common language was created that connected different parts of the business.

In common with other nuclear turnarounds, the management model and the supporting suite of process documents were refreshed and populated with detailed descriptions of the methodologies, processes and guides that were deemed global best practice. The majority of these were drawn from the US Institute of Nuclear Power Operations (INPO) approved process document ‘suite’[4] that had worked so well in North America. The organisation also drew on strengths identified in World Association of Nuclear Operators (WANO) corporate peer reviews and, in 2012, had the opportunity to test the improvement trajectory during NG’s own WANO Corporate Peer Review, a very positive interaction that resulted in some subtle adjustments to the improvement programme and reassurance that the programme was working. 

In 2012, it became clear that some plants were making significantly more progress than others in producing improved results. The best plants felt different, exuding control and confidence, and seemed to have embraced the changes and were making them work well. Some work was undertaken to expose the behavioural characteristics prevalent in these more successful plants. This work exposed four overarching organisational behaviours which were described as:

*  a bias for action

*  open and collaborative relationships

*  personal and collective responsibility

*  engaged thinking/openness to ideas

The findings were widely publicised and branded as Nuclear Generation’s ‘Behaviours for Success’.

To avoid disempowering any part of the business, people were given the trust and autonomy to embed these desired behaviours and to make the processes work in whichever way they considered best in their particular business environment.

This worked extremely well and as results improved, the organisation used various communication tools to engender a collective sense of achievement, promoting successes and creating joint ownership of that success. Teams were encouraged to produce and distribute stories that helped others understand more fully what they were doing to support key business objectives. This led to improved ownership, created trust and improved empathy between different parts of the organisation and thereby reduced the tendency for senior executives to ‘micro-manage’.

The fleet approach

Of course unfettered autonomy will bring only limited success - it is equally important to have structured, rigorous governance from the line organisation and independent oversight and assessment.

Fleet managers and process owners were appointed as process experts in the functional areas that are fundamental to running a successful nuclear business: nuclear, industrial, environmental, radiological and fire safety, operations, maintenance, engineering, outage, human performance, work management, training, organisational learning etc. These experienced and respected individuals work with plant personnel to achieve top industry performance in their functional area, interacting via Peer Groups to identify and apply industry best practices and escalate issues causing performance gaps.

The fleet approach has transformed the business in these key areas, for example the application of Engineering best practice through the Equipment Reliability programme which included: identifying critical components and ensuring they would not fail in service, addressing single point vulnerabilities, conducting structured fleet wide loss analysis and addressing root causes.

This has seen quarterly unplanned output losses drop by 85%, and a 60% reduction in unplanned outages from 2010 to 2017.

Torness, Scotland - Image: EDF
Torness, Scotland - Image: EDF

Nuclear safety and nuclear safety culture have continually improved. EDF Energy has conducted a detailed Nuclear Safety Culture Survey of all staff and contractors every two years, which uses as its foundation WANO’s ‘Traits of a healthy nuclear safety culture’ [5]. The survey has helped leaders to measure and benchmark internationally the cultural trends in their teams and in the wider business. It helps identify early any areas of concern, allowing prompt intervention.

NG’s technical training programmes are independently accredited by a Training Standards and Accreditation Board comprising independent experts from across Europe and North America, and standards have improved immeasurably using this approach. Since 2010, 1,500 leaders have been through at least one of the comprehensive Nuclear Leadership Programmes. These teach leadership skills from First Line Leader all the way to Station Director/Senior Executive. 

The company’s approach to Asset and Risk Management was changed to align with international standard ISO 55001, building a comprehensive risk management capability allowing investment plans to be properly risk-informed. This enabled a significant reduction in capital spend, without impacting plant reliability.

Through the years the AGRs have thrown up some significant technical challenges. At the point of acquisition, all four reactors at Hartlepool and Heysham 1 were off-line to address issues affecting boiler closure structures. NG has a very effective team specifically to deal with these types of (initially) unbounded technical issues. This small team uses architect engineering processes and programme management skills to consider and present options, address the technical problem and enact solutions. Working collaboratively with engineering, design authority, projects and contract partners, they have been instrumental in allowing NG to manage some unique technical problems and avoid large output loss.

Finally, as part of the programme of plant life extensions completed in 2016, NG has built long term contractual relationships with key strategic partners, enabling joint planning and problem solving, supplier engagement at the earliest possible stage and professional partnerships leading to win-win outcomes.

Whilst it’s true that nuclear power plant operations require a unique approach, these plants are essentially production facilities that must function with exceptional safety performance and high reliability. The same safety performance, coupled with the reliable delivery of agreed outcomes, will be required as the AGRs approach their end of life and move through a sequence of defueling (with one reactor on-line and the other in defueling operations), decommissioning and eventual dismantling.  The lessons learned and capability created over the past decade is directly applicable in this last phase of the AGR programme and indeed will support the success of the UK’s new nuclear build programme.

The experiences that have shaped EDF Energy’s Nuclear Generation business have left a valuable nuclear legacy. A successful, highly skilled and professional nuclear workforce with the commitment and ‘know-how’ to help drive forward the UK’s Nuclear Industrial Strategy.


[1] Simon Taylor, The fall and rise of Nuclear Power in Britain, (2016)

[2] Leslie Hannah, Engineers, Managers and Politicians, The first fifteen years of nationalised electricity supply in Britain, (1982)

[3] Simon Taylor, Privatisation and Financial Collapse in the Nuclear Industry, (2007)

[4] INPO 14-004, Conduct of Performance Improvement (2014)

[5] WANO PL 2013-1, Traits of a healthy nuclear safety culture (2013)

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About the author

Brian Cowell, Managing Director, EDF Energy Generation, has executive responsibility for EDF Energy’s nuclear, coal, gas and renewables operations. Brian has spent most of his 40 year career in the UK nuclear industry, moving from coal operations to Torness in 1985 as a C&I commissioning engineer. Previously Station Director of Hunterston and Torness Power Stations, Brian joined the Nuclear Generation executive team in 2009 as one of three Chief Nuclear Officers, taking up the role of Director of Nuclear Operations in 2014 before appointment to his current role in 2017.


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