IT Enters Reality

18 March 2013 Caroline Peachey



With over 80% of the procurement agreements signed, a nuclear licence granted, and construction set to start on the ITER tokamak complex this year, the international fusion research project is truly underway. By Caroline Peachey


In 2014, the first overweight and over-size components are expected to begin arriving at the ITER site in Cadarache, France, where one of the largest, most complex scientific projects ever conceived is underway. And almost six years on from its launch, significant progress has been achieved in licensing, construction and procurement for the biggest-ever experiment to design and build an experimental fusion reactor, which is costing the seven parties involved (Europe, China, Japan, Korea, Russia and the USA) around EUR15 billion to build. The aim of the project is to demonstrate the technical feasibility of generating 500MW of fusion energy (deuterium+tritium) from 50MW of input power.

In November 2012, the 30-month-long licensing process came to an end when Jean-Marc Ayrault, prime minister of host country France, signed a decree authorizing the creation of a basic nuclear installation, and clearing the way for ITER construction. This was the first time in worldwide history that a nuclear fusion device has undergone scrutiny by a nuclear regulator to obtain licensing.

The past year has also seen major contract awards for the fusion project, including the contract for the principal civil engineering works, the cryostat (which will be the largest in history), an award for the welding the vacuum vessel, an award for the liquid helium plant, and the selection of a logistics service provider to coordinate transport of the components ITER site. On the other hand, in July 2012, a major tender for the ITER poloidal field coils was cancelled by the European domestic agency, Fusion for Energy (F4E), after it only received one bid for the contract (a joint bid from the French firm Alstom and the German company Babcock Noell). F4E has now opted to break down the delivery of the components into smaller contracts to "foster greater involvement and competition." Tendering is already underway, and the first contracts are due to be awarded in March 2013.

Over the last year there has also been major progress in the research and development programme in Japan for the ITER tungsten target divertor. In Korea welding is underway on segments of the vacuum vessel.

In southern France the Cadarache site has been transformed from tree-covered terrain since preliminary work started in early 2007. The headquarters building was finished in 2012, and is now home to 450 or so staff. The massive poloidal field coils winding facility is also complete and ready for commissioning later this year. The foundations of the tokamak complex have been poured, the seismic isolation system completed, and construction should begin on the building after the design is finalized around March 2013. In December 2012, a EUR230 million contract for principal civil engineering work, including the tokamak complex and assembly building, was signed by a French consortium.

So, despite the one-year delay caused by the March 2011 earthquake and tsunami in Japan, which severely damaged many ITER fabrication and testing facilities, the ITER project remains on track for first plasma in November 2020, and operation seven years later. Costs also remain under control despite the 'stress tests' or comprehensive safety assessments carried out by ITER as a EU requirement. On its website the ITER Organization said that "given the robustness of the ITER safety design, the stress test report should not lead to additional cost."

Components

ITER hardware procurements are being shared between the seven ITER members. Around 90% of the items will be provided as 'in kind' contributions, in which no money changes hands, with the remainder being purchased through a joint fund under the control of the ITER Organization.

The system is made up of the main fusion machine (the tokamak) and several external systems including vacuum systems, cryogenics, remote handling facilities, power supplies, fuel cycle facilities, hot cells, tritium plants and cooling facilities.
The main components of the tokamak are the magnets, the 5000 ton vacuum vessel, the blanket wall, the plasma-facing divertor (which acts like a giant exhaust), a complex diagnostic system that comprises about 50 individual measuring systems, external heating systems, and a huge cryostat.

Magnets
There are 18 superconducting toroidal field and 6 poloidal field coils, a central solenoid, and a set of correction coils that magnetically confine, shape and control the plasma.

During is most recent council meeting in November ITER said that 'significant progress' has been achieved in the manufacturing of the ITER magnets. More than 350 tons of toroidal field conductor Nb3Sn strand (~75% of total amount needed) has been produced by the six members involved (all except India).

Japan has also completed one-third scale toroidal field double pancake winding, as well as a set of full-size prototype sections for the toroidal field coil cases. Companies in Europe and Japan have also successfully manufactured full-size radial plate prototypes for the toroidal field magnets.

F4E announced on 5 December that a EUR160 million ($212 million) contract for the supply of 70 radial plates had been awarded to a consortium of Simic and Constructions Industrielles de la Mediterranee (CNIM).

Some 65 tons (or around 25%) of the niobium-titanium (NbTi) poloidal field conductor has also been produced by China, Europe and Russia. However, in November the ITER Council urged the European and Russian domestic agencies to "work together to develop synergies in order to prevent schedule slippage for the manufacturing of the poloidal field magnets," suggesting that work may not be progressing as well as it could.

Russia is responsible for procurement of one of the six poloidal field coils: the smallest eight-metre PF1 coil, which will be delivered to the ITER site. Europe is responsible for procuring the remaining five coils. However, as noted above, this process has experienced some delays. The European domestic agency cancelled its original tender last summer and unveiled a new procurement strategy. In an effort to attract more bidders, it has now broken the original contract down into seven smaller ones: i) PF coils engineering, ii) manufacturing, iii) cold test facility, iv) winding, tooling and equipment, v) impregnation tooling and equipment, vi) additional tooling and equipment, vii) infrastructure and building operations.

Tenders for two of the seven contracts are already underway, however it is key that the new procurement strategy remains on track. Two of the five poloidal field coils that Europe is supplying (PF6 & PF5) will be the first to be installed in the tokamak. They must be manufactured by March 2016 in order to prevent delays to first plasma beyond November 2020, according to a schedule released by F4E in October. According to ITER the fabrication of each poloidal field coil will require at least 24 months.

The US Domestic Agency is responsible for the construction of the six central solenoid modules plus one spare, and for the associated pre-compression structure. Due to its large size, the central solenoid needs to be assembled on the ITER site, and the US partner is also responsible for the design, procurement and delivery of the special tools needed to do that job.

Delivery of these tools is planned to start in June 2016 and thus manufacturing of the early delivery items, the assembly platform, and the lifting tool is expected to start at the beginning of 2015.

Finally, the last magnetic components, the correction coils, are being manufactured by China. In April 2012, it inaugurated the manufacturing line for the ITER correction coils, marking the official launch of construction. Commissioning was carried out over the summer.

The vacuum vessel
The supply of the 5000t donut-shaped sealed steel vacuum vessel that contains the fusion reaction is being shared between Europe and Korea. In-wall shielding to be bolted inside the vessel's walls will be delivered by India, and the 44 ports to be welded on to the D-shaped sectors will be manufactured by Russia and Korea.

An Italian consortium of Ansaldo Nucleare, Mangiarotti and Walter Tosto will deliver the seven European sectors of the vacuum vessel under a EUR300 million contract awarded in 2010. Hyundai Heavy Industries (HHI) is responsible for manufacturing the remaining two sections of the ITER vacuum vessel and ports. Cutting work began on one of these Korean sectors (number 6) in February 2012, and welding is now in full swing.

The nine sectors of the vacuum vessel, each 13 meters high, 6.5 metres wide and 6.3 metres deep, and made from thick special grade stainless steel [F316L(N) IG] will, like many other components, be welded together on site. In November 2012, Spanish company Equipos Nucleares signed a EUR74.5 million contract with the ITER Organization for that work, which also includes the development of specialized welding and tools. The project is expected to last four years in total. ITER director-general Osamu Motojima has described the signing of the welding contract as a 'landmark,' as it represents the first contract signed for the assembly of the ITER tokamak.

Cryostat
The ITER cryostat is a complex stainless-steel vessel that houses the vacuum vessel. Indian company Larsen & Toubro (L&T) is responsible for its supply under a contract awarded in August 2012. The 3800-ton steel-structure, 29.3m tall by 28.6m wide, will be the world's largest high-vacuum pressure chamber ever built out of stainless steel. It will be manufactured at L&T's Hazira plant, near Surat, in the Western state of Gujarat, and dispatched in 54 modules to the ITER site. There, it will be pre-assembled in a temporary workshop, before being transported to the tokamak pit for welding using the advanced narrow-groove all-position gas tungsten arc welding technique.

The cryostat will have 23 penetrations to allow internal access for maintenance as well as over 200 penetrations -- some as large as four metres in size -- providing access to the vacuum vessel for cooling systems, magnet feeders, auxiliary heating, diagnostics, and the removal of blanket sections and parts of the divertor.

The wall and divertor
The ITER blanket, which covers the internal surfaces of the vacuum vessel, is one of the most critical and technically challenging components in ITER: together with the divertor it directly faces the hot plasma.

Beryllium has been chosen as the element to cover the first wall, with the rest of the blanket shield to be made of high-strength copper and stainless steel. The task of manufacturing prototype semi-scale first wall panels has recently been awarded to a consortium consisting of Iberdrola Ingeniería y Construcción, AMEC Nuclear UK and Mecánica Industrial Buelna (also of Spain). This is the first cautious step in a process that will eventually lead to ITER's first wall, which must serve to protect the reactor's vulnerable components from high-energy neutrons and any escaping plasma. A contract for the manufacture of full-scale prototype panels should be launched in 2013.

Meanwhile, work is also progressing on the divertor, whose purpose will be to extract heat, helium-ash -- the products of the fusion reaction -- and other impurities from the plasma, in effect acting like a giant exhaust pipe. It will comprise two main parts: a supporting structure made primarily from stainless steel, and the plasma-facing component, weighing about 700t in total. For maintenance purposes, the divertor will be made up of 54 sections or cassettes.

Initially the plan was to employ a carbon-based divertor for the first phase of operation. However, driven by the urgent need to bring the project costs down, ITER management in the summer of 2011 began investigating the feasibility of using tungsten right from the beginning of operations. Cost savings would be around EUR400 million by going down that route, according to estimates by the procuring party, Europe.

ITER therefore decided to delay the final decision on the choice of divertor targets for 'up to two years,' focussing on research and design activities for the tungsten option.

In October 2012 a milestone was achieved when first testing of plasma-facing components for ITER's outer divertor began on a full-scale Japanese-made prototype at the Efremov Institute in St Petersburg, Russia. Within that facility, an 800 kW electron injector exposes the components to the same heat loads they will face inside the ITER vacuum vessel in the standard operational mode, allowing their reliability to be tested. The results from the tests will allow adjustments to be made to the manufacturing technology before series production begins in 2015. The divertor will only be needed once hydrogen-helium operation begins in 2022.

The Joint European Torus (JET) tokamak has recently completed 14 months of operation with a beryllium tungsten lining, after a wall upgrade transformed it into a mini-ITER (see NEI February 2012 p44-47). From the first test in August 2011, the beryllium and tungsten lining enabled more reliable plasmas to be produced. Crucially, researchers from the 27 European fusion laboratories that participate in JET also found that the amount of fuel being retained in the wall is at least ten times less than in the previous carbon-based configuration. The results achieved may lead ITER to drop plans for an initial phase of operation with carbon and adopt a beryllium-tungsten wall from the outset, bringing a significant saving in time and cost for the project, although further research is still needed.

Diagnostics
ITER's diagnostics system will comprise some 50 individual measuring systems drawn from the full range of modern plasma diagnostic techniques, including lasers, X-rays, neutron cameras, impurity monitors, particle spectrometres, radiation bolometers, pressure and gas analysers, and optical fibres.

The progress in diagnostics took a big step forward during the 11th ITER Council meeting (November 2012). Contracts for six systems that will monitor, amongst other things, the plasma electron density, electron temperature and divertor surface temperature, were signed between the US Domestic Agency and the ITER Organization. In addition, a memorandum of understanding was signed with the European Domestic Agency relating to the manufacture of port plugs.

Earlier, in March 2012, F4E awarded its first Framework Partnership Agreement (FPA) for the design of diagnostics components to a consortium consisting of three laboratories from the Hungarian fusion association: Wigner RCP, MTA EK, and the Budapest University of Technology and Economics. The deal is valued at EUR3.7 million, and covers a period of up to four years.

Also, in 2011 China was tasked with procuring the first of four neutron flux monitors (for equatorial port 07). It will be used during the early deuterium phase of operation and for initial tritium operation to measure low/medium fusion power levels.

External heating
The ITER Tokamak will rely on three sources of external heating that work together to provide the 50 MW input heating power of required to bring the plasma to the temperature necessary for fusion (150 million °C). These are neutral beam injection, which smashes uncharged particles into the plasma, and two sources of high-frequency electromagnetic waves: Ion Cyclotron Resonance Heating (ICRH) and Electron Cyclotron Resonance Heating (ECRH).

The Neutral Beam Test Facility, PRIMA, is currently under construction in Padua, Italy, hosted by Consorzio-RFX (and funded by Italy). The facility will host the prototypes of the ITER neutral beam injector.

The NBTF will include two independent test beds: SPIDER (Source for Production of Ion of Deuterium Extracted from Radio Frequency plasma), where the first full-scale ITER ion source will be tested and developed with an acceleration voltage up to 100 kV; and MITICA (Megavolt ITER Injector & Concept Advancement), which will be the first 1:1 full ITER injector aiming at operating up to the full acceleration voltage of 1 MV and at full power (16.5 MW).

In November 2012, three important procurement contracts were awarded for NBTF components by F4E. These were: the contract for the SPIDER beam source and vacuum vessel, worth approximately EUR7.5 million, which was awarded to a European consortium of Thales (France), Galvano-T (Germany) and CECOM and Zanon (Italy). A EUR8 million contract for the NBTF cooling plant system, which will evacuate 70 MW of heat from the SPIDER and MITICA test beds, was awarded to Italian company Delta-ti Impianti. And finally, a EUR2.5 million contract for design and construction of the vacuum and gas injection plant awarded to Angelantoni Test Technologies (Italy). The remaining procurement for the NBTF should be concluded during 2013.

The second system, the cyclotron resonance heating (ICRH) system will deliver 20 MW of radio frequency power to the plasma for up to one hour. The power will be injected through two huge antennas, measuring 1.8 x 3.5 x 2.5m, which will be contributed by Europe. In 2010, F4E signed a contract for the "build-to-print" design of these antennas with the CYCLE consortium, made up of several European fusion associations with ICRH expertise: CCFE, UK; CEA, France; ERM, Belgium; IPP, Germany; and ENEA-Torino, Italy.
The design will be based on technologies developed for other fusion machines such as Alcator C-mod, JET, Asdex-Upgrade, TEXTOR and Tore Supra. In May 2012, a 50-strong team met to review the preliminary design of the ICRH system, and concluded that it was "on the right track," according to technical officer Dharmendra Rathi. With no showstoppers identified, the ICRH team will now prepare for the final design review scheduled for 2015.

The final system, electron cyclotron resonance heating (ECRH), will heat the electrons in the plasma with a high-intensity beam of electromagnetic radiation at a frequency of 170 GHz, the resonant frequency of electrons. The electrons in turn transfer the absorbed energy to the ions by collision.

In mid-2012 the procurement arrangement for eight of the 13 electron cyclotron high-voltage power supplies, which form the backbone of the plant, was signed with the European domestic agency. The remaining five power supplies will be procured by the Indian domestic agency. The first high voltage power supply is scheduled to arrive at the ITER site in late 2015.

Cryogenic plant
The ITER tokamak will rely on the largest cryogenic plant infrastructure ever built, comprising three liquid helium plants, working in parallel, to cool the ITER superconducting magnets to -269°C (4K). Together the three plants will provide a total average cooling capacity of 75 kW at 4.5 K and a maximum cumulated liquefaction rate of 12,300 litres/hour.

On 11 December, ITER director-general Osamu Motojima and the managing director of Air Liquide Advanced Technologies, Xavier Vigor, signed the contract for the design, manufacturing, installation and commissioning of the three LHe plants. The contract is worth EUR83 million.

Manufacturing of the main plant components will start after design finalization in 2014. The first compressor station will be delivered at the end of 2015 and the LHe plants will be ready for the cool-down of sub-systems in 2018.

Eyes on site

In total, 39 buildings and technical areas will be needed to house the plant systems necessary for the operation of the ITER tokamak. The infrastructure is all being built on an artificial level platform, 1 kilometre long by 400 metres wide, which was completed in 2009.

The European consortium Engage (Assystem, France; Atkins, UK; Empresados Agrupados, Spain; and Iosis, France) has been chosen as architect/engineer. Under a EUR150 million contract, signed in 2010, Engage is responsible for construction design for all buildings, site infrastructure and power supplies, and the monitoring of construction activity. To date two buildings have been completed, construction is underway on two more, and there have been numerous other contracts agreed.

In 2013, construction is set to begin on the 360,000 ton tokamak complex, the heart of the ITER structure, where experiments are set to begin in November 2020.

The tokamak complex will be a seven-story facility, measuring 118 x 180 metres, and towering 57 metres above the platform. A building integration task force was created to go through the building floor-by-floor in order to ensure that all the necessary pipes, ducts, structures, cable trays and penetrations were correctly defined before the pouring of the concrete. The detailed design of the rebar arrangement has been completed, and a review of where the 55,000 steel plates to be cast into the concrete to support heavy loads is under way. The design is due to be finalized around March 2013, after which pouring will begin on the basement (B2) level slab.

In December 2012, a consortium of Vinci, Razel Bec and Ferrovial Agroman was awarded a major ITER civil engineering contract for this work. The EUR230 million ($305 million) contract covers the design and construction of 11 buildings and storage areas on the ITER site, including the tokamak building and the assembly hall, a 60-metre high workshop that will host custom-made tools as well as two cranes to pre-assemble components for the tokamak.

Meanwhile, another approx. EUR35 million deal has been signed with COMSA EMTE for civil engineering works. This will see the site undergo further transformation with construction of lighting, a drainage system, roads and car parks over the next five years.

Getting parts there

Between 2008 and 2011, large-scale public works were carried out along the 104 kilometres of roads between the site and Fos-sur-Mer, the so called ITER Itinerary. Workers widened, reinforced bridges and modified intersections in preparation for the transport of exceptional size (up to 9 meters wide) and weight (up to 900 tons) ITER components. The works cost some EUR110 million, and was shared by the Bouches-du-Rhône department Council (66%) and the French State (34%).

After arriving at the Fos-sur-Mer harbour, south of Cadarache, the components will be loaded onto special flatbed transporters, and will travel slowly, at night, in convoys to the ITER site. Around 300 convoys are expected to travel along the route over the first five years of construction, one every 8 to 10 nights. Two test convoys will be organized in 2013 before the arrival of the first loads in 2014.
DAHER was selected in 2012 as the logistics service provider, and will be responsible for the transport, logistics and insurance of ITER components. By mid-2013 DAHER should have provided the ITER Organization with a comprehensive transport and logistics plan containing all the organizational and scheduling details for bringing the ITER components to Cadarache.

Tokamak complex Tokamak complex
Tokamak pit excavations Tokamak pit excavations
Concrete foundations for Tokamak Concrete foundations for Tokamak
Seismic basemat completed Seismic basemat completed
Tokamak foundations Tokamak foundations
ITER headquarters ITER headquarters
ITER vacuum vessel forging ITER vacuum vessel forging
Coil winding facility Coil winding facility


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