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ITER NEWSLINE 232
In the pre-2001 design, when ITER was to be nearly the size of Saint-Peter's Basilica in Rome, 16 cryopumps were to be accommodated at the divertor level of the vacuum vessel.
Cryopumps have the essential function of removing impurities and helium ash from the plasma, enabling the plasma to continue to burn and produce fusion power.
The requirements for vacuum pumping are linked to the plasma fuelling rates—even in the "smaller" ITER these had to be maintained. Design developments in cryo-pumping allowed the machine to be optimized with ten cryopumps in 2001 and eight in 2003.
Eight cryopumps has been the Baseline design figure until recently, when the ITER Director-General proposed to simplify the divertor ports of the machine and remove all "T-shaped" branch ducts. This left only five or six positions where cryopumps could be placed.
This bold proposal was quite a challenge for the ITER vacuum team. "Let's say our creativity was strongly stimulated..." recounts ITER Vacuum Section Head, Robert Pearce. "A five-pump solution was proposed, but this was considered rather risky for the goal of achieving ITER's fusion power mission."
Following discussions at the Science and Technology Advisory Committee (STAC) in November 2011 and at the Ninth ITER Council later that month, a much improved solution was found: there would be six divertor cryopumps in ITER doing the job that was originally assigned to sixteen.
"Basically, improvements in the cryopumping system design over many years have allowed the cryopumps to sit in bigger housings, enabling them to pump longer and store more gas and impurities," says Robert. The new housings are "simpler" and have a volume of greater than 14 m³, as compared to 8 m³ in 2003. As the pumping configuration at the bottom of the machine (divertor level) was changed, it became possible to make improvements that resulted in the easier integration of other systems.
"We think that the overall six-pump solution is better in the end: we now have six identical systems. Operations are made simpler and the performance of the system is not affected," conclude Robert and his vacuum team.
Considering that each branch duct and cryopump is a multimillion-euro component, the savings for the ITER Project are considerable.
The ITER toroidal field conductor is a cable-in-conduit conductor (CICC); in this type of conductor a cable is contained inside a metal conduit that is assembled through the "butt welding" of individual jacket sections.
ITER Korea, which is responsible for 20.18 percent of ITER toroidal field conductor, has completed the procurement of the necessary quantity (approximately 20 km) of jacket sections from POSCO Specialty Steel company. The production was completed officially on 14 July 2012 with the approval from the ITER Organization of the authorization to proceed point (ATPP) for the last batch of jacket sections.
A jacket section is a seamless stainless steel tube with special characteristics. For higher strength, the material is very low in cobalt and carbon for lower neutron activation, and relatively high in nitrogen content compared to standard 316LN-grade stainless steel. The jacket sections produced by POSCO Specialty Steel have an outer diameter of 48 mm, a thickness of 1.9±0.1 mm, and a unit length of 13 m.
The thickness/tolerance is only a half of that of conventional seamless tubes, so a series of high-precision drawing processes are required. The most important and toughest requirement is the low temperature (< 7 K) mechanical property for which the elongation at break must exceed 20 percent. Among the six Domestic Agencies procuring ITER toroidal field conductor, only three companies have been qualified to supply the jacket sections.
POSCO Specialty Steel, the largest seamless tube supplier in Korea, was awarded the contract from ITER Korea in August 2009. The Italian Consortium for Applied Superconductivity (ICAS), conductor supplier for the European and Korean Domestic Agencies, also awarded POSCO Specialty Steel a contract for the same item. To date, POSCO Specialty Steel has completed production for ITER Korea; the production for F4E/ICAS is ongoing.
Within the framework of the Site Support Agreement, CEA-Cadarache as "Host Organization" has provided office space to ITER staff and contractors on its side of the fence; bus transportation and medical services; access to the cafeteria; and such basic amenities as water and electricity.
But as the Headquarters will be handed over to the ITER Organization in late August—and as all staff and contractors will be removed from the CEA site by the end of this year—the modalities of the CEA Site Support Agreement are being adapted to this new context.
The provision of some services, such as bus transportation or the cafeteria, will be taken over by the ITER Organization. Some services will continue to be requested; for others, the terms will be revisited within the context of a five-year forecast that ITER has established.
Exchanging information on the new modalities and all practical and legal consequences formed the core of the fifth meeting of the Site Support Agreement Liaison Committee that was held on Tuesday 17 July at ITER in the presence of CEA Administrator-General Bernard Bigot and under the chairmanship of ITER Director-General Osamu Motojima.
While the dismantlement of the ITER installation will only begin some thirty years from now at the earliest, the two parties have decided to set up a Decommissioning Advisory Committee that will meet under the chairmanship of the ITER Organization Director-General. The Committee will be established in conformity to Article 6.5 of the Annex to the Headquarters Agreement in order to ensure proper management of the Decommissioning Fund.
In his capacity as High Representative for the Realization of ITER in France, Mr Bigot opened the last debate of the afternoon: the review by participants of the present state of discussions between France and the ITER Organization on issues pertaining to licensing, customs, and CE marking, a mandatory conformity mark for goods (i.e. the ITER components) imported into Europe.
French Academician Guy Laval coined the expression in his 2007 book "Blue Energy: a history of nuclear fusion."
Laval's book opened with a scene from a not-too-distant future. In an unnamed "northern European country," the president is about to inaugurate the world's first commercial fusion reactor. "By connecting this reactor to the grid," he says to the audience, "mankind is entering a new era. This moment marks the end of a time of restrictions and the dawn of new industrial developments, freed from the constraints and anxieties of the past."
The day and month of the ceremony has been chosen to coincide with the anniversary of the JET's inauguration, in 1984. Laval, however, does not tell us the year—it could be 30 years from now, it could be further away in the future.
As the president pushes the button that connects the reactor to the grid, words flash in every European language on a giant screen: "Blue energy will save the Blue Planet."
Jaye Louis Douce, a 28 year-old graphic design student at University College, Falmouth (UK) never read Guy Laval's book, but he too was inspired by the promises of what he calls "atomic fusion." He chose "Blue Energy" as the subject of his third-year final project and accordingly produced design, catchphrases and posters that would befit an advertising blitz for fusion energy.
What Jaye's campaign aims to achieve is to "eradicate the stigma that surrounds all forms of nuclear energy and make nuclear energy a movement that will inspire and encourage people to enrol in an energy efficient revolution."
Since "the process that is to give us limitless amounts of clean energy has been right above our heads the whole time," Jaye has chosen to create "a widely understood image of our solar system" with the sun like the core of an apple (or like the vacuum vessel of a tokamak "sliced in half") sitting at the centre and the planets, each carrying a symbol of everyday technology, orbiting around it.
The poster's colour scheme is of course blue, with a slogan saying: "There was a time when energy was a dirty word ..."
Fusion has not reached the stage, yet, when a massive advertising campaign is necessary to promote what Jaye calls "its amazing benefits." But it will someday, in the not-so-distant future that Academician Laval described in the opening of his 2007 book.
The European winding line for toroidal field coils in La Spezia, Italy is now ready. This impressive line—40 metres long, 20 metres wide, 5 metres high—has made it possible to carry out winding trials that have never been done before on a line of this scale and with such precision: recently, the first full-size double pancake turn was successfully completed with the large dummy conductor that had been delivered in May.
The toroidal field winding facility is located on the premises of ASG, supplier to the European Domestic Agency and part of a European consortium that includes Iberdrola and Elytt.
"The winding line in La Spezia will have the task of winding niobium-tin superconducting cables into the characteristic shape of ITER's toroidal field coils—a D-shaped double spiral called a double pancake. The spooled cable will be delivered in a single 760-metre length weighing seven tons", explains Alessandro Bonito-Oliva, who together with Jordi Cornella Medrano and Robert Harrison, part of the Fusion for Energy's technical toroidal field coil team, have been following closely these activities in La Spezia.
The first task of the winding line will be to unspool and straighten the cable, after which the cable will be cleaned and sandblasted. The continuous, 760-metre length will then shaped into the 12 m x 9 m double pancake and heat treated at over 650 °C in a specially constructed inert atmosphere oven. Finally, following electrical insulation, the double pancake will be transferred into the grooves of the stainless steel radial plates to form a double pancake module.
So that the double pancake fits precisely into the radial plate grooves, it is vital to control the accuracy of the conductor's trajectory in the double pancakes. The winding line is thus required to achieve precision in bending the conductor on the order of a few tens of parts per million—a very demanding target considering its large dimensions. Successful results of the first trial winding of a full-size turn demonstrated that the winding line is, indeed, capable of achieving the required precisions.
After insertion into the radial plates, each double pancake module will be impregnated with epoxy resin, stacked in groups of seven, and jointed electrically to form "winding packs." These winding packs will be inserted into stainless steel cases that, in turn, are welded together to form the completed toroidal field coil.
For the moment, the winding line will continue to undergo testing. In total, 70 superconductor lengths are needed to produce the European contribution to ITER's toroidal field magnet system (ten toroidal field coils); Japan will contribute the other nine toroidal field coils.
Europe's superconductor lengths will be produced by five different suppliers. Each specific supplier's conductor will have slightly different mechanical behaviour; therefore, testing will be carried out in the winding line during the next few months on prototypes from each supplier before the start of real production. Final qualification, to take place in the autumn, will consist of winding a real (not a dummy) superconducting cable into a full-size double pancake prototype.
Another large technical area is also in its final installation phase in the ASG premises: a large inert atmosphere oven measuring 48 x 20 x 5 metres that will be used to carry out the heat treatment of the double pancakes. The oven has been dimensioned to heat treat up to three double pancakes at a time. After the successful completion of leak testing—carried out to verify the capability of the furnace to keep the concentration of impurities during the heat treatment below the required threshold of tens of parts per million—the oven is now in the final installation phase. Workers are completing the assembly of external components (electrical connections, sensors, piping, fans and vacuum pumps) and the final testing should start at the end of July.
With the completion of the winding line and the oven, Europe can report that the principal and most complex elements for the production of the toroidal field coils are now in place.
Some eighty members of the ITER Organization gathered on Thursday 12 July to share the traditional monthly Intercultural Breakfast, an opportunity for everyone employed at ITER to experience each other's cooking and eating habits. Thanks to the American community (brilliantly organized by Ed Daly) we were able to feast on pancakes straight off the griddle, omelettes, grits, muffins, bagels and cream cheese, banana bread, peanut butter and jelly sandwiches, French toast, cereal, and more in a very friendly and relaxed atmosphere. Colourful tablecloths, flags, big band music and one-hundred-dollar-bill napkins added the perfect touch.
For those of you wondering how someone could have invented the (in)famous peanut butter and jelly sandwich, an American staple, please read on:
1880 - A St. Louis physician, Dr Ambrose W. Straub, crushed peanuts into a paste for his geriatric patients with bad teeth. At the 1893 Chicago World's Fair, also known as the World's Columbian Exposition, his invention gained exposure and popularity.
1903 - On February 14, 1903, Straub received Patent No. 721,651 for "a mill for grinding peanuts for butter." Dr Straub encouraged the owner of a food products company, George A. Bayle Jr., to process and package ground peanut paste as a nutritious protein substitute for people with poor teeth who couldn't chew meat. Bayle Food Products of St. Louis purchased all commercial rights to the physician's peanut spread and went on to become peanut butter's first American vendor.
1904 - Bayle Food Products took its new peanut butter to the 1904 St. Louis World Fair. It was a big success, selling out in three days at a penny-a-sample, earning a profit of USD 705.11. Soon grocers across America were selling bulk peanut butter in large wooden tubs to satisfy their customers' demand.
1920s-1930s - Commercial brands of peanut butter such as Peter Pan and Skippy were introduced.
1941-1945 - Both peanut butter and jelly were on the US Military ration menus in World War II. It is said that the American soldiers added jelly to their peanut butter to make it more palatable. Peanut butter provided an inexpensive and high protein alternative to meat for soldiers. It was an instant hit and returning servicemen made peanut butter and jelly sales soar in the United States. Food historians haven't found any ads or other mentions of peanut butter and jelly sandwiches before the 1940s.
1943 - Nationwide food rationing was instituted in the United States during World War II. Each member of the family was issued ration books, and it was the homemaker's challenge to pool the stamps and plan the family's meals within the set limits. Margarine, butter, sugar, lard, shortening, oils and assorted fresh meats were rationed and expensive. Peanut butter was a good and cheap alternative (peanut butter sold for 24 cents a jar) and a readily available source of protein. Peanut butter was not rationed.
And peanut butter was launched. Today, this quintessential American item can be found in three-quarters of US pantries. More than 50 percent of the annual US peanut crop goes into the production of peanut butter.
The Czech book Řízená termojaderná fúze pro každého (Controlled thermonuclear fusion for everyone) introduces the idea of fusion energy to the generally interested reader. In 17 chapters, the authors cover historical milestones, introduce the principles of fusion, describe the significant fusion facilities in the world, and conclude with the international ITER collaboration and an outlook on the future of fusion.
The book contains a useful glossary of fusion terms and 110 photos, charts and drawings to render the subject accessible to non-experts. The authors Milan Řípa, Jan Mlynář, František Žáček and Vladimír Weinzettl are scientists at the Institute of Plasma Physics Academy of Sciences of the Czech Republic, v.v.i..
The book, one of two general books about fusion energy available in the Czech language, has now been published in its third edition. It was published in 2011 by the Institute of Plasma Physics Academy of Sciences of the Czech Republic as part of the series The Energy World which aims at popularizing different energy sources. The Czech electricity company CEZ Group supported the publication.
Publication title: Řízená termojaderná fúze pro každého
Author: Milan Řípa, Jan Mlynář, František Žáček, Vladimír Weinzettl
Publication type: Book (Paperback)
Publication date: 01 December 2011
Number of pages: 151
ISBN number: 80-902724-7-9