Because of their large magnetized volume, tokamaks could be used to detect the elusive particles that are postulated to constitute dark matter/dark energy.
A huge chunk of mass appears to be missing from the Universe. The billions and billions of galaxies that telescopes observe, the giant gas and dust clouds that float in the immensity of intergalactic space account for only a fraction of what is really there. The rest is invisible and remains undetectable.
The existence of a "dark matter" permeating the Universe and accounting for such gravitational phenomena as the rotational speed of galaxies or the "bending" of light around massive astronomical objects was inferred by cosmologists as early as the 1930s. Theories were established that remain unconfirmed to this day.
Decades later, observations of the accelerating expansion of the Universe led cosmologists to postulate the existence of another mysterious entity, a force whose nature can only be surmised— the so-called "dark energy".
It is generally estimated that the mass-energy content of the Universe is made up of approximately 74 percent dark energy, 22 percent dark matter and only 4 percent ordinary matter such as stars, planets, dust and intergalactic gas.
Dark matter and dark energy
hold the answers to our ultimate destiny. Will the Universe expand forever in all directions or will it eventually retract and end in a Big Crunch? The question is definitely worth pondering ...
There is a consensus among cosmologists and particle physicists that "exotic" particles are key to understanding dark energy and dark matter. Dubbed "chameleons" (they are able to change their own mass) and "axions" (in reference to the US detergent Axion because their existence may help to clean up some theory problems) these hypothetical particles have been assigned a set of properties that would explain the behaviour of the Universe. As of today, however, both chameleons and axions have escaped detection.
Now, there's big news on the cosmic front. Tokamaks—and specifically the CEA-Euratom machine Tore Supra
in Cadarache, France—could play a decisive role in the detection of some of these elusive particles: the "solar chameleons" that may originate in the Sun, and the "relic axions" that were produced right after the Big Bang ...
Axions and chameleons are postulated to interact weakly with matter (they traverse it as if it didn't exist) and to change into photons via the "Primakoff effect
" in the presence of an intense magnetic field. However, experiments aimed at confirming their existence, like the CERN Axion Solar Telescope
(CAST) in Geneva, have failed, to this day, to detect either axions or chameleons.
CAST, which is basically a 9.2-metre-long dipole magnet
aiming at the Sun, has a strong magnetic field (~9 T) but a rather small magnetized volume (~ 0.06 m3). "Since the probability of producing a photon by the Primakoff conversion of an axion is proportional to the magnetized volume multiplied by the magnetic field squared," says Dr Jean-Claude Vallet, of CEA's Institut de Recherche sur la Fusion Magnétique
(IRFM) "with Tore Supra (31 m3), we have a device which, equipped with the proper detectors, should be at least 150 times more efficient than the CAST experiment."
Tore Supra would also be considerably more powerful than the Axion Dark Matter eXperiment
at the University of Washington, USA, which stands as the reference in axion detection today.
And there's more. "Tore Supra would also make a very decent detector for solar chameleons. To further improve its intrinsic quality, our colleagues at CERN suggest that we couple one or more X-ray telescopes of the XMM
type to our tokamak and aim them at the Sun, where solar chameleons are postulated to originate ..."
In this configuration, the X-ray telescope, positioned just outside the tokamak, would be aligned with both the Sun and the detectors inside the vacuum vessel.
Reactions to the proposal of using Tore Supra as an exotic particle detector have been very enthusiastic here in Cadarache and at CEA headquarters in Paris. "The way we operate, doing 'plasma campaigns' interspersed with periods of pause and maintenance, leaves room for hosting these new and unexpected experiments," says Vallet. "We believe that we could provide up to 12 weeks of observation in the coming two years."
Preliminary discussions are ongoing between CERN, IRFM and the European Space Agency (ESA) that owns the XMM X-ray telescopes. A "strategic plan" should soon be finalized and submitted to the CERN Council in July.
Tore Supra's potential, assures Vallet, is recognized by the international community of cosmologists and particle physicists. By entering a part-time quest for axions and chameleons, the CEA-Euratom machine could contribute to unveiling one of nature's most nagging mysteries.
Following the nuclear accident at the Fukushima Daiichi Power Plant in Japan in March 2011, the European Union declared "that the safety of all 143 nuclear power plants [in Europe] should be reviewed on the basis of a comprehensive and transparent risk assessment." These assessments are known as stress tests.
As the first fusion reactor to undergo full nuclear licensing, ITER will also have to pass this complementary safety assessment, In the words of Licensing Officer Joëlle Elbez-Uzan, the stress tests are "a targeted reassessment of ITER's safety margins in the light of the events that occurred at Fukushima."
"What this means, is that we will look into the resistance of the facility in the face of a set of extreme situations leading to the sequential loss of the ITER lines of defence—irrespective of the probability of this loss. In other words, we are imagining the unimaginable."
The type of extreme situation under examination: very severe flooding, a severe earthquake beyond that postulated in the ITER safety case, or a combination of both. "Special focus will be given to our crisis management plan describing how to react in such an extreme situation," explains Joëlle.
As a first step, the French regulator (Autorité de Sûreté Nucléaire, ASN) asked the ITER Organization to draft a report describing the methodology by which the stress tests will be performed. This report was sent to Paris on 15 January and the methodology has been approved.
Currently the Safety, Quality & Security Department is carrying out its stress test evaluation and the outcome will be submitted to the authorities mid-September.
From May 21-25, a very successful Plasma-Surface Interactions (PSI) conference was held in the historic city of Aachen, Germany, which houses Roman baths and is known as "The Emperor's City" due to its status as Charlemagne's favourite place of residence.
The conference, which is held every two years, focuses on the region of the fusion plasma that is closest to the inner wall of the containment vessel, exploring both how the wall is affected and how the plasma responds to the release of wall material. Approximately 400 people came from all of the ITER Member countries, with the number of participants quadrupling since 1980, reflecting the importance of plasma-surface effects in high-performance devices like ITER and fusion power stations.
ITER is considering changing the wall material from carbon to tungsten for the areas that receive the highest heat loads. The conference was very timely in that many of the presentations discussed the properties of tungsten, from melting and gas trapping to less familiar effects caused by plasma exposure such as the formation of bubbles and nanostructures on the surface.
Of particular note was the presentation of initial experimental results from the ITER-like wall that was recently installed in the JET
Tokamak. The wall tiles are made from tungsten and beryllium, and are arranged in a way that is similar to the ITER design. There was quite a bit of good news, including fuel retention levels consistent with the ITER requirements and the production of clean, high performance plasmas.
Other topics covered included heat load control, plasma transport, and computer simulations, as well as a look to the future with respect to advanced wall materials, novel magnetic field designs, and reactor requirements.
The final presentation was a lively retrospective by Volker Philipps from Forschungszentrum Jülich that celebrated the 40-year history of the conference and highlighted progress that has been made in the field. The conference location moves between North America, Europe, and Asia; Kanazawa, Japan was announced as the next host city.
Read the conference's official press release here
Nearly all of the heat generated during ITER operation, whether it be from the fusion reaction, auxiliary systems, electrical cabinets, (or even warm bodies!) will be collected by the Component Cooling Water System (CCWS) or the Chilled Water System (CHWS). These systems subsequently reject the heat to the atmosphere, either directly or via ITER's Heat Rejection System (HRS).
Although the CCWS and CHWS systems use standard, proven technology, the design of the systems is highly complex. The systems will serve a wide variety of clients, all with different requirements and with designs at different levels of maturity. Approximately 200 unique interface documents are required to define the CCWS and CHWS interfaces with clients, buildings, and services.
The design and procurement
of these systems is under the responsibility of the Indian Domestic Agency. On 11-14 June, the preliminary design review for the CCWS and CHWS cooling water systems was held in Cadarache, gathering representatives from the ITER Organization, the Indian Domestic Agency, and experts in the field. One of the experts was Warren Curd, former ITER Cooling Water Section leader, who travelled from China where he is currently a construction coordinator for two of the first Westinghouse AP1000 reactors to be built.
Sekhar Basu, chief executive at the Department of Atomic Energy in India, was chairman of the Design Review. During a meeting of the review panel on the final day, he received a phone call informing him that he had just been appointed Director of the Bhabha Atomic Research Centre (BARC), India's premier nuclear research facility based in Mumbai. This announcement was greeted with a spontaneous round of applause and congratulations from the panel members.
One of the important topics discussed during the review was the approach taken to seismic design of the system piping that will crisscross the site and be installed in nearly every building. "While the analytical approach we took was satisfactory, this meeting gave participants the opportunity to ensure agreement on assumptions and inputs so that safety, regulatory, and investment protection goals are met," says Prashant Wani, project engineer for Tata Consulting Engineers, who performed preliminary design on behalf of the Indian Domestic Agency.
A few other key issues, inherent to this stage of design, were identified during the review. Following the resolution of these issues and one last review of interfaces, the next step will be for ITER-India to launch a call for tender to select an engineering and procurement contractor to perform final design and procurement of piping and equipment.
The first shipment of piping is due on site in the summer of 2014.
The preliminary design review of the Tokamak Cooling Water System (TCWS) and the Heat Rejection System (HRS) took place in March 2012. |
And the winner is ... François Sagot! By uploading the "RAMI Summary Report for the ITER Cryoplant" into the ITER Collaborative Platform (ICP), the ITER technical officer officially became the platform's ten-millionth customer.
"Ten million objects is a really impressive number," says web application officer Carlo Capuano. "An aircraft carrier is made up of about ten million parts ... and ten million is not the end of the ITER story!"
Less than three years ago, we reported on the one-millionth ICP object.
ICP is a one-stop shop for all data related to ITER, from Word documents stored on ITER's document management system IDM, to Catia data files used by the designers. Today, the biggest portion of stored data is associated with the Engineering Database which was launched in February. However with 100,000 accesses per day, IDM accounts for the largest traffic within ICP.
The platform developed for ITER is now a precedent for other projects. ICP is currently installed at the European Domestic Agency in Barcelona, Spain; at the JT-60SA worksite in Garching, Germany; and at the Chinese Domestic Agency in Bejing.
A certain number of well-established commercial tools provide strong support for the most important activities inside the ITER Organization. Whenever those tools do not provide needed functionality, however, the ICP platform can provide solutions quickly to manage any kind of data and workflow.
In the past five years more than 50 applications have been developed and are in use with the same user interface—available at any location in the world—thanks to the strict adherence to web interfaces. Applications cover engineering problems like magnet conductor production, for example, or action tracking.
Before long, ITER will have its own facility in which to organize its all-staff meetings—a 500-seat amphitheatre in the new Headquarters Building. For now though, the hospitality of the CEA meeting room René Gravier is essential: on Tuesday 12 June, close to 400 ITER employees gathered in two consecutive sessions in the Salle Gravier for a meeting with senior management.
Director-General Osamu Motojima updated the staff on the recommendations of the recent Management Advisory Council in preparation for the upcoming ITER Council meeting (20-21 June in Washington DC). He also spoke of the status of the ITER project schedule and the near-term challenges the project is facing. His talk was followed by presentations from senior management members Sachiko Ishizaka, ITER Council secretary; Rem Haange, director of the Department for ITER Project; Joo-Shik Bak, chief engineer; and Rich Hawryluk, director of the Department of Administration, each highlighting some of the specific challenges within their respective areas of responsibility.
The all-staff meetings were followed by animated question-and-answer sessions during which management and staff exchanged views and opinions.
Can solar energy provide the entire world's electricity? Should we abandon nuclear power after Fukushima? How much energy do we save by installing windows with double glazing? The Energy Survical Guide is a reliable source for all those who want to know the facts.
The author is Jo Hermans, professor emeritus of physics at the University of Leiden in the Netherlands, who has lectured on energy and environment topics for decades. Jo has dedicated this book to his grandsons David and Thomas and those of their age around the globe "who are the heirs to our successes and failures in making this world sustainable."
A book about energy would not be complete without mentioning nuclear fusion and by looking both at its advantages and its disadvantages. His conclusion: "The enormous potential of nuclear fusion means that it is worth pursuing research and development by all means."
The "Energy Survival Guide" is published by Beta-Text in cooperation with Leiden University Press, ISBN 978 90 8728 123 6. The hardcover is €24.95 - 184 pages. For discount on larger orders please contact BetaText