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Simulation of tritium transport for the European Test Blanket System

F4E News - vr, 27/04/2018 - 02:00
F4E develops computer code to predict the transport of tritium through the different components and materials of the European TBS.

Success for Europe’s ITER Toroidal Field coil cold tests

F4E News - di, 24/04/2018 - 02:00
F4E and SIMIC join forces to finalise the production of the first magnet.

The crown | Unique but inspired by history

ITER - ma, 23/04/2018 - 17:32


On the floor of the vast amphitheatre that will accommodate the ITER machine, one of the most complex and most strategic structures of the Tokamak Building is taking shape.
Reminiscent of a spiked crown—not unlike the one atop the Statue of Liberty—the structure is designed to support the combined mass of the cryostat and Tokamak (25,000 tonnes) while transferring the forces and stresses generated during plasma operations to the ground.
Aptly enough, the structure sitting at the bottom of the Tokamak Pit is called ... a "crown."
Its principle is inspired by the "flying buttress"—an architectural solution that was implemented eight centuries ago to prevent a cathedral's walls from collapsing outward under the weight of its stone ceiling and slate roof.
In the long story of the design of the ITER buildings, the crown is a relative newcomer: up until 2012, the baseline solution to support the machine consisted of a circular arrangement of 18 sturdy steel columns.
However as models and simulations were refined, it became clear that the load transfer from the Tokamak's mass and movements to the floor of the Tokamak Complex (the B2 slab) was not totally satisfying.
Machine "up lift" from a potential vertical displacement event,  cryostat "shrinkage" from a possible ingress 1 cooling event  ... these potential events were of particular concern to safety experts.
Developing an alternate option to the columns led to a one-year collaborative effort involving several ITER departments, the European Domestic Agency responsible for building construction, and their architect engineer Engage.

Engage eventually suggested mobilizing the resistance capacity of the bioshield wall (3.2 metres thick at its base) and using it as an abutment for a set of 18 deeply imbedded radial walls—the "flying buttress" solution.
The full constructability of this innovative structure, both inspired by history and unique to ITER, needed to be demonstrated however. In October 2017, a full-scale mockup, three metres high, was erected on the ITER platform to answer the questions that even the most detailed 3D models couldn't.
Six months have passed. Down on the floor of the Tokamak Pit the steel reinforcement for about one-fourth of the crown has been set into place and—thanks partly to a recently-implemented night shift—work is progressing quickly on the remaining three-fourths.
Massive steel transition pieces, 3.5 tonnes each, have been placed atop every radial wall to optimize the transfer of loads to the ground. Lengths of thin red plastic piping are being inserted into the steel rebar to circulate cooling water during the concrete pouring phase; two kilometres of this piping will be required in all for the crown. Finally, workers are busy welding a thin "fire mesh" to the outer face of the walls to within millimetric tolerances. (See gallery below for details.)
"Everything we are implementing now has been tested and validated on the mockup: the rebar installation sequence, the concrete formulation and pouring procedures, the temperature monitoring, the cooling system arrangement and sequences ..." explains Armand Gjoklaj of the ITER Building & Civil Works Section.
And the mockup's mission is not over yet—the installation procedure for high-strength "top plates" still needs to be tested and validated. These 3.5-tonne elements will sit on top of the steel transition pieces to receive 18 semi-spherical "bearings."
The first concrete pour for the crown is scheduled in mid-May and the entire structure should be finalized by September. And as all surfaces of the nuclear buildings need to be clean and decontaminable, a huge paint job will follow on the bioshield inner walls, on the crown's radial walls and on the floor.
The concrete amphitheatre of today will turn into a polished jewel box, ready to accommodate one of the most extraordinary creations of the human mind: the ITER Tokamak. 
¹The liquid helium cooling circuits for the superconducting magnets pass through the cryostat. In case of a breach, the sudden drop in temperature would cause a "shrinking" of the cryostat.

All forgings and plates for European vacuum vessel sectors have been delivered

F4E News - ma, 23/04/2018 - 02:00
All the remaining forgings and plates which will be used on the vacuum vessel sectors that Europe is contributing to the ITER project have been produced and delivered.

Spanish companies reaffirm benefits from their participation in ITER

F4E Events - vr, 20/04/2018 - 02:00
Catalan Association of Industrial Engineers holds an ITER day

Closing the circle: Final JT-60SA Toroidal Field coil is installed

F4E News - vr, 20/04/2018 - 02:00
The eighteenth and final Toroidal Field coil has been installed in JT-60SA.

Out now: flying JT-60SA Toroidal Field coils on film

F4E News - wo, 18/04/2018 - 02:00
Our latest clip shows one of the most challenging transports ever contracted by F4E: the air freight of the last two TF coils for JT-60SA.

Plasma physics | Be clean, be strong

ITER - ma, 16/04/2018 - 17:33

To achieve maximum fusion efficiency in a tokamak device it is essential to limit the impurities in the plasma. But this can be a challenge, as interaction between the hot plasma and the material surfaces of the vacuum vessel causes material particles to detach and enter the swirling cloud of gas.
The laws of physics dictate the maximum plasma density that can be achieved for a given current in a tokamak, which means that in ITER—as in other tokamak devices—there will be an upper limit to the number of atoms that can be confined.
Within this limit, it is important that the plasma contain as many atoms as possible that are capable of reacting to produce fusion—in ITER's case, atoms of deuterium and tritium.
Even in trace amounts, other atoms ("impurities") dilute the core of the plasma by taking the space that could be occupied by the fusion fuels, resulting in fewer reactions and a reduction in energy production. And because fusion reactions occur in a roughly proportional manner to the square of fuel density, the "multiplier" effect sets in quickly—fewer fuel atoms result in a dramatic drop-off in fusion reactions, while more fuel results in a rapid increase.
Impurities originate from vacuum vessel and the in-vessel component materials ... iron from the steel components, beryllium from the top layers of the first-wall panels protecting the vacuum vessel, and tungsten from the divertor targets. 
Impurities not only dilute the plasma but—depending on the physical properties of the atoms involved (the number of electrons)—they can also cool it to differing degrees. "The process is similar to that in a fluorescent lamp," explains Alberto Loarte, who leads the Confinement & Modelling Section at ITER. "The electrons of the impurity atoms run into the electrons in the plasma and drain their energy, re-emitting it as electromagnetic radiation—including visible light."
The heavier elements, in particular, drain a lot of energy from the plasma through radiation because of a high number of electrons (tungsten has 74). The energy lost through impurity radiation cools the plasma down and the fusion reactions stop.
In ITER, to keep these radiative losses to a minimum, the divertor will be working from its position at the bottom of the machine to continually exhaust impurities from the plasma and limit contamination.
The very properties that make impurities unwelcome in the core of the plasma, however, can be applied to beneficial effect in the plasma edge region.
Because the energy confinement provided by the machine's magnetic fields is not perfect, large power fluxes can find their way to the edge of the plasma and onto the divertor targets. To avoid localized depositions that would be too high for the material components to withstand, scientists will inject impurity gases at the plasma edge. The radiative properties of the impurities will act to reduce the power fluxes to the material elements by dissipating their energy over a larger zone.
As the plasma in this edge/divertor region is already at temperatures much lower than those required to produce fusion power, this plasma cooling will not affect fusion power production in ITER.

Europe is ready to switch on SPIDER - the most powerful negative ion source experiment to date

F4E News - ma, 16/04/2018 - 02:00
The test bed of the ITER Neutral Beam Test Facility is ready!

The EU Council mandates the Commission to formally approve the new ITER baseline at the next ITER Council

F4E News - ma, 16/04/2018 - 02:00
Europe reaffirms its commitment to the ITER project and to the 2025 target date

Ring coils | Hot resin before the deep cold

ITER - ma, 09/04/2018 - 16:23



It has been almost one year since the fabrication of the first ring coil was launched in the on-site Poloidal Field Coil Winding Facility by European Domestic Agency contractors. Out of the eight "double pancake" conductor windings needed to finalize the 350-tonne magnet, three have been wound and are ready to pass through the resin-impregnation phase—an operation that contributes to both electrical insulation and structural strength.
On one of the circular platforms on the southern end of the silent, clean and temperature-controlled facility, a double pancake sits, still attached by 24 lifting points to the circular spreader beam that has just moved it from the stacking station.
A few metres away, technicians are busy assembling the vacuum containment vessel—the "mould"—that will enclose the double pancakes throughout the lengthy and delicate resin impregnation process.
"During impregnation, we inject some 600 litres of epoxy resin at a temperature of 55-60 °C through entry ports in the mould," explains Gian Battista Fachin of the European Domestic Agency, who works in the facility where Europe is fabricating the four largest ITER poloidal field coils. "At that temperature the resin is as liquid as water and easily penetrates through the fiberglass wrapping of the double pancake."
Once extra pressure has been applied inside the leak-tight mould to insure that all micro spaces are properly filled, the resin's temperature is ramped up first to 100 °C for a few hours of "gelling," then to 140 °C for a full day and a half of "curing." By then, the resin has become rock solid and the shining white double pancake has turned into a massive block the colour of caramel.
The resin impregnation process was tested and validated on a "dummy" conductor winding that is presently stored at the far end of the building.
"We learned a lot from the dummy, right from the beginning operations that began in November 2015," confirms Gian. "We established metrics and procedures, refined bending parameters, impregnation and injection durations ... everything a dummy is for."
The dummy is a perfect replica of an actual double pancake for the 17-metre-in-diameter poloidal field coil #5 (PF5). For reasons of cost however, it is wound from copper conductor rather than from superconducting niobium-titanium alloy.
When all eight double pancakes for PF5 are finalized (winding is underway on the fourth in the series now) they will be stacked to form a winding pack—the coil's very core—which will be wrapped with insulating fiberglass tape and impregnated with resin as one single component.
The winding pack will then receive additional equipment such as clamps, protection covers and pipes. At that point, one last crucial operation remains to be performed before the component can be considered fit for duty.
When ITER enters operation, liquid helium circulating inside the conductor will bring the coil temperature down to 4 K (minus 269 °C) to create the physical conditions for superconductivity in the niobium-titanium conductor.
Throughout the manufacturing process, sample tests and quality control have insured that the conductor's performance in such extreme conditions is in line with the magnet system's requirements.
What remains to be tested however, is the coil's behaviour as a whole. How is it affected by the thermal contractions generated by the ultra-cold temperature? Does the liquid helium circuit within the cable-in-conduit conductor remain leak-tight? Can cracks develop in the resin and hinder electrical insulation?
These questions can be answered without having to cool the coil all the way down to 4 K. At the temperature of liquid nitrogen (80 K or minus 193 °C) thermal contractions have already reached their maximum and all the potential issues can be identified. Also, cooling with liquid nitrogen is much cheaper and easier to implement than cooling with liquid helium.
In May, the cold testing equipment will arrive from Italy for installation in the northern end of the workshop. The four coils manufactured on site (ranging from 17 to 24 metres in diameter) will be tested one after the other in the cold testing vacuum vessel, as will a smaller coil (10 metres in diameter) that is being manufactured in China under an agreement with Europe.
Cold-testing operations are scheduled to begin in the summer of 2019 and last for more than one year.

Object Kinetic Monte Carlo and Finite Element developments for the creation of a Macroscopic Rate Equation model of fusion reactor walls

EFDA - di, 03/04/2018 - 09:14

This 2 years post-doctoral position is offered in the framework of the collaborative project WHeSCI (piim.univ-amu.fr/amidex/whesci), financed by the A*MIDEX foundation (amidex.univ-amu.fr) and proposed in the context of the International Thermonuclear Experimental Reactor (ITER), the international project that aims to demonstrate the technological and scientific feasibility of fusion energy with the Tokamak design (www.iter.org). The WHeSCI project seeks to describe the interactions of the fusion fuel (deuterium (D) and tritium (T)) and ashes (helium (He) and neutron) with the walls of the exhaust of the reactor (the divertor made of Tungsten, W). The induced material properties modifications are indeed critical for the reactor operation and safety and the successful operation of ITER requires a detailed understanding of the plasma-wall interactions.

In this context, the post-doctoral fellow will be involved in the further development of the MHIMS and HIIPC Macroscopic Rate Equation (MRE) models [1-4], which are describing so far the D/T fuel trapping in bulk metals, in absence or in presence of bubbles in the micrometre range. In particular, he/she will study and implement synergistic effects between D/T/He implantations and neutron-induced defects in tungsten materials. Object Kinetic Monte Carlo (OKMC) simulations will be used to obtain a dynamical insight onto temporal and thermal evolution of D/T/He and defects in W. Ultimately, OKMC simulations will provide information on bubble nucleation. The input parameters for the OKMC code LAKIMOCA [5] will come from the literature but also from several WHeSCI project partners: atomic-scale events energies and attempt frequencies will come from DFT calculations, spatial distribution of defects and D/T/He species will come from experiments. Once bubble nucleation is understood, its growth will be investigated with Finite Element Methods (FEM) [6]. Based on this numerical approach, D/T/He trapping and bubble growth will be included in the MRE simulations. This work will be done in close collaboration with a PhD student at CNRS/LSPM who is currently developing the Abaqus Finite Element Method (FEM) code as well as a staff of the CEA group working on the MHIMS program.

The candidate should have a PhD in computational physics, a solid background in solid state physics and show skills in the field of metallic materials. At least one experience of OKMC or FEM simulations is required. As the candidate will have to interact with the various actors in the project, good oral and written communication skills are necessary and the ability to work in a collaborative research environment is essential. Knowledge of French would be appreciated but is not mandatory.

The 1st year of the contract will be located in Lille (France) and will focus on OKMC simulations with Charlotte Becquart (CNRS/UMET – University Lille). The 2nd year will be located in Paris and will focus on FEM and MRE implementations with Yann Charles and Jonathan Mougenot (CNRS/LSPM – University Paris 13). Christian Grisolia (CEA/IRFM) will coordinate the simulation work. The postdoctoral contract is financed by the WHeSCI project (coordinated by Régis Bisson, Aix-Marseille University/PIIM).

Application is open until May 31 and the earliest starting date is July 1 2018. Questions should be sent directly to the following contact persons:

Christian Grisolia christian.grisolia AT cea DOT fr
Laboratoire IRFM – CEA Cadarache – 13115 Saint-Paul-lez-Durance

Charlotte Becquart charlotte.becquart AT univ-lille1 DOT fr
Laboratoire UMET- Université Lille 1 – 59655 Villeneuve d’Ascq

Yann Charles yann.charles AT univ-paris13 DOT fr

Jonathan Mougenot jonathan.mougenot AT univ-paris13 DOT fr
Laboratoire LSPM – Université Paris 13 – 93430 Villetaneuse

Régis Bisson regis.bisson AT univ-amu DOT fr
Laboratoire PIIM – Aix-Marseille University – 13013 Marseille

 

[1] E.A. Hodille et al Nucl. Fusion 57 076019 (2017)

[2] E.A. Hodille et al Phys. Scr. T167 014011 (2016)

[3] C. Sang et al Nucl. Fusion 52 043003 (2012)

[4] C. Quiros et al Nucl. Mat. Ener. 12 1178-1183 (2017)

[5] C.S. Becquart et al. J. Nucl. Mater. 403 75-88 (2010)

[6] Y. Charles et al IJHE 42 20336-350 (2017)

The post Object Kinetic Monte Carlo and Finite Element developments for the creation of a Macroscopic Rate Equation model of fusion reactor walls appeared first on EUROfusion.

The easy JET – European device will move to Berlin

EFDA - zo, 01/04/2018 - 10:36

(The construction site of the BER International airport in Germany from above. It offers not only a lot of space but also state-of-the-art hotels and restaurants as well as a direct fly-in for JET’s scientists. Picture: Creative Commons)

Sources close to the European Commission Directorate Research, Science and Innovation have finally confirmed what used to be only talk behind closed doors. The Joint European Torus (JET), EUROfusion’s flagship and a pioneer experiment of the European Union, will be transferred to the European mainland.
Representatives of the European Commission, the United Kingdom and the German government agreed in Brussels to move the fusion experiment over to Berlin, right into the heart of Europe.

“JET is the most developed fusion experiment in the world. We saw an urgent need to keep the machine, the knowledge and, above all, our 300 international scientists safe”, says a relieved Lorne Horton, JET’s exploitation manager, shortly after the two hours of intense talks.

JET’s Torus Hall Picture: © Copyright protected by United Kingdom Atomic Energy Authority

Before Queen Elizabeth II and François Mitterrand inaugurated The Joint European Torus as a frontier European experiment in 1984, Germany and the United Kingdom fought fiercely to become the host. But in 1977, to Germany’s disappointment, Culham was chosen.

JET is the only machine in the world able to operate the ‘real’ fusion fuel: a mixture of deuterium and tritium. JET has proven this capability in 1997 when its first Deuterium-Tritium (DT) campaign broke the record for the highest amount of fusion power ever produced.

EUROfusion, the European consortium for fusion research, together with the Culham Center for Fusion Energy (CCFE) had originally planned for a second DT campaign in Culham. The preparations and the installation of new diagnostics had been going for years. Since the new set of DT experiments was scheduled for 2019/2020, representatives of EUROfusion lobbied for a new JET site as Britain is supposed to formally break away from continental Europe in 2019.

The German government which did not succeed to host JET in the first run offered now a suitable area. According to our information, the long-delayed Brandenburg airport will definitely not be finalised. Colleagues close to Engelbert Lütke Daldrup, the Head of the BER airport, heard him saying: “Before we tear the whole compound down, we rather make use of it in order to show our support for the European Union.”

Just like the former Culham airfield, JET will get a large base including brand new runways, hotels and restaurants. In fact, EUROfusion’s scientists, who come from 30 different countries in order to carry out experiments at the European tokamak, will undeniably benefit from the well-developed and, above all, modern infrastructure around its new facilities.

Also, the travel expenses could decrease if EUROfusion decides to collaborate with a new industrial partner. The flight company EasyJET had recently announced to expand in Berlin. It is said that EUROfusion’s Programme Manager Tony Donné is currently discussing an irresistible deal with EasyJET’s Chief executive Johan Lundgren about extra low fares for European fusion scientists with destination Berlin: “The name says it all and we should make use of it”, he adds smilingly.

The post The easy JET – European device will move to Berlin appeared first on EUROfusion.

Plant systems | Entering the stage, one by one

ITER - ma, 26/03/2018 - 17:19

As buildings rise out of the earth and equipment is progressively installed, ITER's Science & Operations Department is busy making plans to commission the first plant systems.
Commissioning is the final check that each of the components and plant systems have been designed, manufactured and installed correctly. It is an opportunity to transfer knowledge to the operations team, test all the procedures, and get ready to start the first experiments.
To commission a facility as complicated as ITER it is necessary to proceed in small and gradual steps—checking each part before moving onto the next, and bringing together more and more pieces of the puzzle until the whole facility is working as one. At that point we will be ready to turn on the Tokamak and make plasma.
We will start this year by energizing the electrical distribution systems, since without electricity nothing can work. ITER is directly connected to France's 400 kV public transmission network. Transformers and switchgears located on the ITER platform will "propagate" this power all over the site to provide the correct voltage for each of the clients.
Last year, a test was performed with the first energization of a 400 kV bay, in order to validate all procedures and contractual requirements with French transmission system operator.
Once power is available, the central control system will be turned on and made ready to control, monitor and record data from each of the systems to come. The first task for the control system will then be to start up the cooling water systems and the cooling towers, testing each pump and valve before starting the circulation and flow tests.
_To_134_Tx_With power, control and cooling in place we will begin commissioning the production and distribution networks for various gases and liquids, as well as the air conditioning to remove heat generated by the plant in each building. We then start up the nitrogen and helium production facilities in the cryogenic plant and the various auxiliary vacuum pumping systems.
The specialized Tokamak systems come next—the electron cyclotron system that generates megawatts of microwave energy to heat the plasma, cryogenic pumping systems able to produce ultra-high vacuum, and the power supplies needed to energize the superconducting magnets.
When all of these systems have passed their tests we are ready: the construction phase of ITER is complete and we can start the operations phase with integrated commissioning of all systems working together. All air will be evacuated out of the vacuum vessel and cryostat to bring the pressure inside to one millionth of normal atmospheric pressure; the magnets will be cooled down to -269 °C and energized to create the magnetic confinement field; and a tiny amount of hydrogen gas will be injected and heated up to produce a critical milestone for ITER—First Plasma.
Once this has been achieved we will press on—turning up the current on the magnets to full power and completing their stress testing under all the various field combinations.
At that point we will have shown that the ITER machine is ready for the researchers.

Success for Europe’s equipment that will be used to heat up ITER plasma

F4E News - ma, 26/03/2018 - 02:00
F4E, Ampegon and ITER IO test the first of the Electron Cyclotron power supply units.

Blanket shield blocks | Full-scale prototype passes key test in China

ITER - ma, 19/03/2018 - 16:22


A full-scale prototype of a blanket shield block manufactured in China successfully passed acceptance tests, including the challenging hot helium leak testing in February. An important qualification milestone has been achieved in the ITER blanket program ...

On 14 February, two days before the start of the Chinese New Year, the Chinese Domestic Agency successfully accomplished the last in a series of back-to-back qualification milestones in its program to procure 50 percent of the blanket shield blocks required by ITER.
The ITER blanket consists of 440 individual modules covering a surface of 600 m² inside of the vacuum vessel. The plasma-facing surface of the blanket—the first wall—is attached to massive components called shield blocks that provide neutron shielding for the vessel and magnet coil systems. These thick steel blocks, weighing up to four tonnes apiece, interface with many other systems, in particular a large number of diagnostics. For this reason there are a total of 28 major design variants and 150 or more minor design variants. The Chinese and Korean Domestic Agencies are each providing 220 shield blocks.
In December 2017, Chinese suppliers in Guangzhou completed an 18-month program to manufacture a full-scale prototype of shield block SB09A. The next month, a dedicated facility for hot helium leak testing was commissioned in Chengdu—just in time to begin test activities on the SB09A prototype. From 6 to 14 February, hot helium leak tests were carried out according to ITER Organization accepted procedures, and witnessed by ITER Organization representatives. The results met all relevant ITER requirements.
The shield block module SB09A, located in the upper region inside the vacuum vessel, represents probably the most complex type of shield block structure—making it the most challenging to manufacture of all shield blocks to be procured by China. It has the most complex geometry, with several cut-outs to accommodate interfacing systems and diagnostics, and is largely tapered. For this reason it was selected as a full-scale prototype to qualify the manufacturing technologies that will be used in series production.
Chinese manufacturers started on the full-scale prototype in July 2016, progressively accomplishing all of the fabrication steps including machining datum, drilling the deep holes of the cooling channel, side machining, welding of cover plates, and final machining. From nine tonnes of original stainless steel forgings, the final full-scale prototype after machining was 2.8 tonnes. Many tests were performed throughout the fabrication process to verify quality—such as preliminary dimensional examination, non-destructive examination, and hydraulic pressure tests, which all showed acceptable manufacturing results.
The shield blocks, like all the in-vessel components, have to operate under ultra-high vacuum conditions (ten billion times lower than atmospheric pressure). Therefore stringent design, manufacturing and testing provisions have to be planned in order to ensure that the demanding vacuum requirements are met. In this regard, the so-called hot helium leak test represents the definitive demonstration of the fitness for purpose of the component to operate in an ultra-high vacuum environment. This test foresees the cycling of the components up to the operational temperature and pressure in order to be able to detect the tiniest microleaks, which would not be detectable by other means.
During commissioning tests at the dedicated hot helium leak test facility in Chengdu, operators verified that the sensitivity of the helium detector and the background helium leak rate could reach ITER requirements; in both cases the facility performed well.
During two full cycles of testing on the full-scale prototype, results showed that the maximum helium leakage rate was well within ITER requirements. As the first hot helium leak test on a large ITER blanket component, the results provide valuable reference data for the further investigation of the acceptance criteria of ITER blanket components. They also provide an important benchmark for developing hot helium leak test standards for the large vacuum components of future tokamaks.
See the gallery of photos below.

Important manufacturing milestone for ITER’s sixth Poloidal Field coil

F4E News - ma, 19/03/2018 - 01:00
F4E and ASIPP half way to completing the winding and impregnation of the superconductors.

Optical properties of tungsten surfaces submitted to fusion reactor conditions

EFDA - wo, 14/03/2018 - 12:00

PhD description:

Thesis advisor:
Laurent Gallais
laurent.gallais AT fresnel DOT fr
+33 (0)6 20 98 69 46
Thesis co-advisor:
Regis Bisson
regis.bisson AT univ-amu DOT fr
+33 (0)4 91 28 83 55

download pdf

This 3 years PhD thesis is offered in the framework of the collaborative project WHeSCI (piim.univ-amu.fr/amidex/whesci), financed by the A*MIDEX foundation (amidex.univ-amu.fr) and proposed in the context of the International Thermonuclear Experimental Reactor (ITER), the international project that aims to demonstrate the technological and scientific feasibility of fusion energy with the Tokamak design (www.iter.org). The WHeSCI project seeks to describe the interactions of the fusion fuel (deuterium and tritium ions) and ashes (helium ions and neutron) with the walls of the exhaust of the reactor (the divertor made of Tungsten, W). The induced material properties modifications are indeed critical for the reactor operation and safety and the successful operation of ITER requires a detailed understanding of the plasma-wall interactions.

In this context, the PhD candidate will be particularly involved in the study of the optical properties of W samples and their evolution with the (near-) surface properties (implanted ions, oxidation, microstructure, roughness…) and applied heat loads (temperature gradients). This work will involve experimental development allowing performing ellipsometric measurement on laser-heated samples from 120 K to > 2000 K in well-controlled conditions (Ultra High Vacuum) and on a variety of W samples, from model (single crystal) to realistic tokamak materials. The experiments analysis will be associated with modelling for the description of ion interactions with W and for the description of the optical properties dependencies with intrinsic material properties and surface state.

The position is based at both the PIIM laboratory and the Institut Fresnel (same campus in Marseille, Provence, France). A highly motivated and experimentally skilled individual is sought, with strong background in physics or chemical physics, knowledge in high vacuum and optics being a plus.

References:
- Minissale M, Pardanaud C, Bisson R and Gallais L, “The temperature dependence of optical properties of tungsten in the visible and near-infrared domains: an experimental and theoretical study” Journal of Physics D: Applied Physics 50, 455601 (2017)
- Hodille EA, Ghiorghiu F, Addab Y, Založnik A, Minissale M, Piazza Z, Martin C, Angot T, Gallais L, Barthe M-F, Becquart CS, Markelj S, Mougenot J, Grisolia C and Bisson R, “Retention and release of hydrogen isotopes in tungsten plasma-facing components: the role of grain boundaries and the native oxide layer from a joint experiment-simulation integrated approach”, Nuclear Fusion 57, 076019 (2017)

The post Optical properties of tungsten surfaces submitted to fusion reactor conditions appeared first on EUROfusion.

The lid of the ITER Bioshield is on!

F4E News - wo, 14/03/2018 - 01:00
A spectacular lifting operation delivered by F4E, its contractors, and ITER International Organization.

F4E participates in the first Big Science Business Forum (BSBF2018) alongside Europe’s largest Big Science organisations

F4E Events - di, 06/03/2018 - 01:00
1000 participants from 30 countries gather in Copenhagen from 26-28 February 2018

Pagina's