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Nuclear's half-time report: How are the six sites progressing?

The UK is now midway between the government’s announcement of new nuclear sites in 2011 and the 2025 tipping point when swathes of existing supply will be shut down. CN takes the opportunity to analyse how each of the six nuclear new-builds is getting on.

Seven years ago this month, the then-coalition government published a list of eight sites suitable for new nuclear plants.

Fast-forward to 2018, and the only sites on that list without any development plans in the pipeline are Sellafield and Hartlepool.

However, the intervening years have seen nuclear power face growing competition from renewable sources. Solar and wind power construction costs have fallen and no longer require as much government subsidisation as before.

Developments in technology meant that in 2017 the government was able to agree a guaranteed electricity price of £57.50 per MWh for two new offshore wind developments – significantly lower than the £92.50 EDF is guaranteed for Hinkley Point C.

In the UK, nuclear accounted for 21 per cent of the energy mix in 2017.

However, of the UK’s 15 reactors currently in operation, 14 are scheduled to be shut down by 2025 (barring any expensive lifetime extension work), with EDF Energy’s Sizewell B plant – built in 1995 – the only exception. What’s more, coal contributed 9 per cent to the energy mix in 2017, yet the last of Britain’s coal plants are also scheduled to be closed down in 2025. m

Combined, this means the source of more than 25 per cent of the country’s energy will be gone in seven years’ time.

The government has previously said it expects wind and nuclear to fill a large part of this gap, with nuclear expected to account for 35 per cent of the energy mix by 2030. For this to happen, Britain needs new nuclear plants to start generating power in or around 2025.

In 2006 the government introduced the Office for Nuclear Regulation’s Generic Design Assessment: the approval processes every new nuclear reactor must go through before it can be used in the UK. To date, only three types of reactor have passed the GDA, one of which – the AP1000 – belongs to Westinghouse Electric, which filed for bankruptcy in March 2017.

Seven years on from the coalition’s announcement and seven years out from the 2025 tipping point, Construction News assesses the progress of the UK’s nuclear build programme across the six sites which have seen any new build development activity.

Hinkley Point C

  • Developer: EDF Energy

    Hinkley Point C_Oct 2017_Aerial view of concrete batching plant and temporary jetty

    Hinkley Point C – concrete batching plant and temporary jetty

  • Cost: £20.3bn
  • Start of GDA process: April 2007
  • Statement of Community Consultation: 2009
  • Reactor technology: UK EPR (approved)
  • Generation date: 2025
  • Generation capacity: 3.2 GW
  • Nuclear licence and consent order status: Approved

The first nuclear power plant to be built in the UK since Sizewell B in 1995, the delivery of EDF’s Hinkley Point C plant will have massive repercussions far beyond Somerset.

For a start, the £18bn cost of the project has recently risen to £20.3bn, making it the most expensive power plant in the world, while EDF has also been forced to reject claims it will miss its delivery date of 2025.

Construction started in the second half of 2016 and more than 4 m cu m of earth has since been removed.

Concrete was poured for the first permanent structures on site in early 2017 for the 8km network of tunnels, which will carry cables and pipes under the plant.

The first in a line of six new nuclear plants planned in the UK over the next 15 years, Hinkley Point C will act as a litmus test for the government’s programme as well for the future of UK nuclear energy.

In September 2017, a government auction awarded 11 Contracts for Difference (which fix the price energy firms receive for electricity generated) to low‑carbon electricity generation projects. This saw the electricity price guaranteed to offshore wind developers fall to as low as £57.50 per MWh.

Five years earlier, EDF managed to secure a guaranteed price of £92.50 per MWh for Hinkley Point C; inflation-adjusted, this is now closer to £100.

By the time Hinkley is operational in 2025, wind and solar technologies are expected to have made further advances, potentially translating to lower strike prices in future – and making nuclear costlier still in comparison.

Construction of the Hinkley plant has not been without troubles either, with Costain pulling out if its £350m marine and tunnelling contract at the site due to a delayed start, with Balfour Beatty replacing the contractor. 

And after concrete was poured for the 8km tunnels under the site, 150 cu m had to be dismantled and laid again as parts of the geology were unsuitable for the concrete used.

Despite this, the UK is second only to China in the scale of its nuclear ambitions.

Its pipeline has encouraged France’s EDF to target the construction of two more plants, while developers backed by Chinese, Korean and Japanese companies are also eyeing their own projects.

EDF meanwhile has run into trouble away from Hinkley, announcing in October 2017 that it was repairing pumping station pipes across 20 reactors.

In February 2018, the company said sterling’s slide against the euro following the Brexit vote cost it €608m. And in its domestic market, EDF announced in April that its under-construction Flamanville plant could face further delays and budget overruns, after welding faults were found in some pipes (the same design is being used at Hinkley).

With an output of 3.2 GW from its two UK EPR reactors, Hinkley is expected to generate 7 per cent of the UK’s energy needs while avoiding the emission of nine million tonnes of carbon dioxide. 

Wylfa Newydd

  • Developer: Horizon Nuclear Power

    Wylfa Aerial CGI View CREDIT Horizon Nuclear Power

    Credit: Horizon Nuclear Power

  • Cost: £15bn
  • Start of GDA: January 2013
  • Statement of Community Consultation: 2014
  • Reactor technology: UK ABWR (approved)
  • Generation date: 2026-27
  • Generation capacity: 2.7 GW
  • Nuclear licence and consent order status: Expected late 2018

Wylfa is on course to be the UK’s second new nuclear power plant after Hinkley Point C.

It is being developed by Horizon Nuclear Power, a wholly owned subsidiary of Japanese technology giant Hitachi.

Unlike Hinkley, which received no public money to fund its construction, energy secretary Greg Clark has said the government could part-fund the Wylfa power plant. Hitachi began negotiating with the government in June 2018 on the £15bn project. 

A three-way funding model is on the table, in which Hitachi, the UK government and the Japanese state (potentially through its export credit agency) would all take equal shares. This would leave the British taxpayer with a £5bn bill, and mark a policy reversal after the government previously ruled out taking a stake in new nuclear builds.

A potential strike price of £77.50 per MWh has been mooted, with an announcement on a potential funding model from government expected this summer.

The Wylfa site is located beside the former Magnox Wylfa Power Station in Anglesey, Wales, which was shut down in 2015.

Horizon will use Hitachi’s UK Advanced Boiling Water Reactor (UK ABWR) at Wylfa, which received design acceptance confirmation from the Office for Nuclear Regulation (ONR) in December 2017. The company applied for a nuclear site licence in spring 2017, which it hopes to receive towards the end of this year.

Horizon also submitted its application for a development consent order with the Planning Inspectorate on 1 June; the PI has until the end of this month to either reject or accept the application.

If the consent order is accepted, stakeholders and members of the public will have the opportunity to comment on and challenge the plans, a process that could take up to 18 months. Wylfa also received environmental approval from the EU this month, and now needs the equivalent sign-off from Natural Resources Wales.

Following the successful navigation of these final checks, the biggest issues left to sort out before construction can begin will be the funding model and strike price. This element of the project could take another 24 months to finalise.

Sizewell C

  • Developer: EDF Energy

    sizewell b credit dave croker geograph

    Credit: Geograph – Dave Croker

  • Cost: £16bn
  • Statement of Community Consultation: 2012
  • Reactor technology: UK EPR (approved)
  • Generation date: Late 2020s
  • Generation capacity: 3.2 GW
  • Nuclear licence and consent order status: Not yet applied for

EDF’s second project in the UK’s new nuclear pipeline, construction of Sizewell C could start in the early 2020s.

Sizewell is already home to two plants: Sizewell A, which is currently being decommissioned, and Sizewell B, the UK’s most modern plant built in 1995 (also operated by EDF).

Unlike at Hinkley Point C, to which EDF committed £12bn and China’s CGN Power the remaining £6bn, EDF is exploring a funding model which incorporates a wider pool of backers, such as pension funds and other institutional investors.

And with the government signalling its willingness to part-fund Horizon’s Wylfa project, EDF is also exploring the possibility of government backing for Sizewell C. EDF has suggested its plans at Sizewell could cost as much as £4bn less than Hinkley by replicating the Somerset project’s design and utilising a more mature UK supply chain.

The company plans to use the same UK EPR reactors already approved by the ONR, producing the same output as Hinkley Point C at 3.2 GW.

Until last year, Sizewell C was expected to be the fourth new power plant after Hinkley, Wylfa and Moorside. However, following the financial difficulties that have dogged Moorside’s developers, Sizewell C is now third in line.

Sizewell C is almost two-thirds of the way through its consultation process and could be granted a nuclear site licence and development consent order in the next three to four years.


  • Developer: TBC (previously NuGeneration)

    NuGen Moorside power plant Cumbria CGI

    NuGen – Moorside power plant in Cumbria CGI

  • Cost: £10bn
  • Start of GDA: Not yet started
  • Statement of Community Consultation: 2015 (issued under Toshiba-Engie JV) 
  • Reactor technology: UK AP1400 (not approved)
  • Generation date: Late-2020s
  • Generation capacity: 2.8 GW
  • Nuclear licence and consent order status: Not yet applied for

Plans for a new plant at Moorside are now in doubt after the exit of Toshiba from the project.

The Japanese group’s subsidiairy NuGen had been seeking a new owner for 18 months, but is now set to be wound up after failing to find a buyer.

Moorside’s site will be handed over to the Nuclear Decommissioning Authority. While the government moved to reaffirm its commitment to new nuclear following Toshiba’s announcement, it now faces the challenging task of securing a replacement developer for the Cumbrian site.

Toshiba described its withdrawal as the “economically rational decision” after it factored in the “additional costs entailed in continuing to operate NuGen”.

The gradual demise of its involvement can be traced back to early 2017. 

Toshiba’s US subsidiary Westinghouse Electric was set to use its AP1000 reactor at Moorside, receiving design acceptance confirmation from the ONR in March 2017 following a 10-year approval process.

Following writedowns in its CB&I Stone & Webster business, however, Westinghouse filed for bankruptcy in March 2017. These developments prompted Moorside co-developer Engie to trigger a contract clause to sell its 40 per cent stake to Toshiba in April last year – Toshiba was forced to pay $138.5m for the shares.

In May 2017 Toshiba posted an $8.4bn loss in its full-year accounts and launched a review of the Moorside project. In December that year the scheme appeared to have been saved, after the Japanese firm confirmed that South Korean nuclear giant Kepco as preferred bidder to take over.

However, in August it was announced that Toshiba had begun looking at alternative options after negotiations with Kepco failed to reach a conclusion.

The protracted talks also forced NuGen to restructure its business. In September it was revealed that the developer had halved its headcount from 100 to fewer than 40 due to the delays in finding a new owner.

Toshiba’s withdrawal two months later will see NuGen wound up by the end of March 2019, with a phased reduction in its staff from the 32 remaining at the time of the announcement.


  • Developer: Horizon Nuclear Power

    oldbury nuclear credit david exworth geograph

    Credit: Geograph – David Exworth

  • Cost: £15bn-£20bn
  • Statement of Community Consultation: Not yet issued
  • Reactor technology: UK ABWR (approved)
  • Generation date: Early 2030s
  • Generation capacity: 2.7 GW
  • Nuclear licence and consent order status: Not yet applied for

Oldbury is still in the early stages of its development.

Horizon is proposing to build a new plant on a site adjacent to the Oldbury Magnox plant, which is based on the banks of the River Severn, north of Bristol. The Magnox plant was shut down in 2012 after 44 years of service.

A subsidiary of Hitachi, Horizon is expected to use the Japanese giant’s UK ABWR reactors at Oldbury, which were approved for UK use by the (ONR) in December 2017. Horizon first started consulting with the local community about construction of the nuclear plant in 2010.

The company expects this project to be cheaper than its Wylfa venture, as it plans to replicate the majority of the design and construction work carried out at the Cumbria plant.

The developer is yet to give any indication as to the funding model it will pursue for the project, but Horizon has succeeded in convincing the UK government to consider taking a one-third stake in its Wylfa project.

Further details on Oldbury are likely to emerge as negotiations on Wylfa progress.

Bradwell B

  • Developer: General Nuclear System

    bradwell nuclear credit wikimedia commons rwendland

    Credit: Wikimedia Commons – Rwendland

  • Cost: TBC
  • Start of GDA: January 2017
  • Statement of Community Consultation: Not yet issued 
  • Reactor technology: UK HPR1000 (not approved)
  • Generation date: Early 2030s
  • Generation capacity: 2.3 GW
  • Nuclear licence and consent order status: Not yet applied for

China’s CGN has been looking for a way to enter the UK’s new nuclear programme in its own right for several years.

The company contributed a third of the cost towards EDF’s privately funded Hinkley Point C plant, on the understanding that it would take the lead on the Bradwell B project in return.

General Nuclear System is a JV between CGN and EDF established in 2015 for this purpose – the pair have worked together for more than 30 years. CGN has a 66.5 per cent stake in the company, with EDF holding the remaining 33.5 per cent.

General Nuclear System started the GDA process with the ONR for CGN’s HPR1000 reactor in January 2017. The reactor has since cleared the initial preparatory step and started the second stage in November 2017.

Only three types of reactor have been approved since the GDA process was introduced in 2006, with an average of six years taken to complete the process.

Like Oldbury, the Bradwell B project is still in its initial stages. As a result, projections around cost and the funding model that could be used are yet to materialise.  

This article was updated in November 2018 to reflect the news that Toshiba had withdrawn from Moorside

This article was amended in July 2018 to specify when Statements of Community Consultation were issued

Readers' comments (2)

  • A couple of pretty glaring errors in there.

    First, on the sites that haven't yet got development plans.

    Moorside IS Sellafield (the sites adjoin). The second site after Hartlepool that hasn't got a planned development is Heysham, and that's mainly because its the most space restricted of the sites. It'd be hard to fit a modern twin unit LWR station until one of the existing stations is at least part cleared.

    Second on Oldbury. It has GDA clearance already, as its to use the same design as Wylfa (GDA stands for GENERIC DESIGN Approval)

    There's another point, too. I think you're being rather pessimistic on GDA timescales - that average is rather inflated by the fact that the process on AP1000 was put on hold for three years when there appeared to be no likely builder. ABWR too about 54 months from end to end, and HPR1000 is scheduled for about the same.

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  • Thanks for your comment, Andy.

    Moorside has not been referred to as Sellafield for the sake of drawing a clear line between the historic site and the new development. The new development is referred to as Moorside by government and NuGeneration.

    As you note and as the article states, the reactor to be used at Oldbury has received GDA clearance.

    What has not been issued is the Statement of Community Consultation. The article has been updated to reflect this.

    With regards to GDA timescales, the average time taken is 5.8 years.

    The timescales below have been taken from the Office for Nuclear Regulation:

    UK EPR – 69 months
    AP1000 – 87 months (excluding 26-month gap)
    UK ABWR – 54 months

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