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Nuclear deal paves way for 11km of subsea tunnels 22 Oct 2015
TunnelTalk reporting
After more than five years in the planning and negotiation stage French energy supplier EDF says it is ready to announce its final investment decision on the £18 billion nuclear power station at Hinkley Point on the west coast of England “within weeks.”
Hinkley Point C “weeks away” from final go-ahead

Hinkley Point C “weeks away” from final go-ahead

The news comes as EDF finally signed a future pricing agreement with the UK Government yesterday (21 October), as well as a deal with its long-term Chinese nuclear partner CGN over funding. The announcements were made during this week’s high-level China state visit to London, with the relevant signatures witnessed by UK Prime Minister David Cameron and Chinese President Xi Jinping
The series of deals that have been struck also include the £2 billion contract with Buoygues/Laing O’Rourke for the civils, originally awarded in 2012 but which is now in “final agreed form.” Its Tier 1 contractor for the underground works – the scope of which includes two cool water intake tunnels plus a shared outfall tunnel – is Costain.
All the tunnels are designed to be excavated by TBM. An underground water-cooling pumping station will also be constructed.
Costain Chief Executive Andrew Wylie said yesterday: “Costain will design and construct three marine tunnels, around 11km in total length and each one approximately 7m in diameter, to take in cooling water from the Severn Estuary for the nuclear reactor before it is cleansed, recycled and returned.”
EDF said in a statement: “Conditions to allow the Hinkley Point C project to go ahead are in place. These are the signing of the Strategic Investment Agreement, all the agreements between EDF and the UK Government being in a final agreed form, as are the contracts with the key suppliers. Under the Strategic Investment Agreement, EDF’s share in Hinkley Point C will be 66.5% and CGN’s will be 33.5%. Without reducing this initial stake below 50%, EDF intends in due course to bring other investors into the project.”
Deal witnessed by UK Premier Cameron and Chinese President Jinping

Deal witnessed by UK Premier Cameron and Chinese President Jinping

The announcement also puts the underground construction industry on alert for future major contracts, because it includes agreement for a wider partnership for the joint development of more new nuclear power stations at Sizewell and Bradwell on the east coast.
EDF Chairman Jean-Bernard Lévy said: “Our ambitious nuclear projects are strongly supported by the governments of the UK, China and France and they will bring benefits to all three countries. I am confident that our experience and ability mean we will successfully deliver Hinkley Point C and subsequent projects. We are planning for a final investment decision within weeks so that we can move forward with construction.”
First operation of Hinkley Point C is expected in 2025, when it will meet approximately 7% of the country’s electricity needs. The investment in nuclear energy by the UK comes at a time when much of Europe is moving away from this form of energy production. However, the UK’s reliance on Russia for its power needs has prompted a complete revision of its energy security policy.
UK advances underground nuclear facilities 23 Oct 2013
Peter Kenyon, TunnelTalk
Agreement on key investment terms between the UK Government and French electricity company EDF paves the way for construction of the UK's first nuclear power reactors in nearly two decades.
New nuclear plant will have two pressurised water reactors

New nuclear plant will have two pressurised water reactors

An announcement earlier this week reconfirms the Bouygues/Laing O'Rourke JV as preferred bidder for a £2 billion civil works package and Costain as the delivery and design partner for marine work that includes construction of extensive underground water intake and outfall infrastructure.
The marine package will include two cool water intake tunnels, one for each of the two pressurised water reactors (PWRs) that are planned for construction. These will extend 3.3km into the Bristol Channel and will be 6m in diameter. A shared 7m diameter outfall tunnel will extend 2km from the shoreline. All three tunnels will be excavated by TBM. Construction also comprises a forebay, an underground cooling water pumping station plus two concrete outfall ponds that will link with the shared outfall tunnel.
Hinkley Point C primary structures and tunnels

Hinkley Point C primary structures and tunnels

Planning permission for the £14 billion project is already in place, and this week's agreement between the UK Government and EDF over a wholesale "strike price" ceiling for electricity that will be generated when the reactors come online in 10 years time means that one of the final hurdles for the huge development has been overcome. Agreement is also reached over future decommissioning, and confirmation is made that the project will benefit from the government's Infrastructure Guarantee, under which up to 65% of project costs prior to operations starting will be underwritten by public debt. A final investment decision will be made by EDF in July next year (2014), but the latest agreements and confirmation that a significant Chinese investment of up to 40% of total project cost will be acceptable, paves the way for a final financing deal to be reached.
Hinkley Point C design plans and intake/outfall structures

Hinkley Point C design plans and intake/outfall structures

The strike price agreed is £89.50/MWh to rise in line with the Consumer Price Index, or £93.50 if EDF's plans to construct two new Sizewell C reactors do not go ahead. The current wholesale price is £45/MWh.
Under the current financing structure, spread over 35 years, EDF will be the majority equity partner with a 45-50% stake, AREVA (an international nuclear supply industry company) 10%, and the China General Nuclear Corporation (CGN) and China National Nuclear Corporation (CNNC) 30-40% between them. Discussions are also taking place with a shortlist of other investors who could take an investment stake of up to 15%. EDF has been in an industrial partnership with CNNC and CGN for the last 30 years, including involvement in a joint venture with CGN to build two EPR reactors at Taishan, China.
Current and future nuclear reactor facilities in the UK

Current and future nuclear reactor facilities in the UK

The two EPR type reactors planned for the UK, design for which is already approved by regulators, will be built at Hinkley Point in Somerset. Project scope also includes construction of temporary spent fuel storage facilities. There are also plans that are less well advanced for two identical reactors to be built at the existing nuclear facility at Sizewell (Sizewell C), as well as proposals for similar constructions in the future that would have a "series benefit" from shared design, supply chain and engineering work.
"We are delighted that Costain will play a key role in delivering the secure, low carbon energy the UK needs for the future through our role as a Tier One contractor in the Hinkley Point C project", said Andrew Wyllie, Chief Executive of Costain. "The project will also help ensure Costain can play its part in building the skills of the UK and showcasing them to the world in a way which will help us to compete for other such contracts. We estimate that this contract will lead to the creation of hundreds of new jobs at Costain alone, including apprentices, specialist technical and engineering roles and programme management. We are very much looking forward to working with all our partners in this project to design and deliver a world class power station at Hinkley Point."
Construction of Hinkley Point C will create up to 25,000 jobs, including 400 apprentices, as well as a further 900 jobs once fully operational. Hinkley Point B, which comprises two gas-cooled type reactors, took eight years to build and began its operational life in 1976. It is scheduled for decommissioning in 2023, and since 2006, owing to its age, has been operating at only 70% capacity.
Pressurised water reactor design
In a Pressurised Water Reactor (PWR) like the EPR (European Pressurised Reactor) to be constructed at Hinkley Point, ordinary (light) water is utilised to remove the heat produced inside the reactor core by nuclear fission.
Water pressurised reactor schematic

Water pressurised reactor schematic

This water also slows down (or moderates) neutrons (constituents of atomic nuclei that are released in the nuclear fission process). Slowing down neutrons is necessary to sustain the nuclear chain reaction (neutrons have to be moderated to be able to break down the fissile atom nuclei).
The heat produced inside the reactor core is transferred to the turbine through the steam generators. Only heat is exchanged between the reactor cooling circuit (primary circuit) and the steam circuit used to feed the turbine (secondary circuit).
No exchange of cooling water takes place. The primary water is pumped through the reactor core and the primary side of the steam generators, in four parallel closed loops, by coolant pumps powered by electric motors. Each loop is equipped with a steam generator and a coolant pump. The reactor operating pressure and temperature are such that the cooling water does not evaporate and remains in the liquid state, which increases its cooling effectiveness. A pressuriser connected to one of the coolant loops is used to control the pressure in the primary circuit. Feedwater entering the secondary side of the steam generators absorbs the heat transferred from the primary side and evaporates to produce saturated steam. The steam is dried in the steam generators then delivered to the turbine. After exiting the turbine, the steam is condensed and returns as feedwater to the steam generators. The generator, driven by the turbine, generates electricity.
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