Recently the standard ITER CODAC (Control, Data Access and Communication) technologies successfully demonstrated their adaptability and operability for tokamak control at the Korea Superconducting Tokamak Advanced Research (KSTAR), in operation since 2008.
Like ITER CODAC, the KSTAR control system is using EPICS as middleware for tokamak control and operation. Therefore, KSTAR is a natural target for evaluating and validating CODAC technologies as has been identified in the Memorandum of Understanding between ITER Organization and National Fusion Research Institute (NFRI).
During the last 15 months, the KSTAR control team has implemented a duplication of the fuel control system and a part of the plasma control system using CODAC technologies (standardized hardware and CODAC Core System). On July 26th, 2012, a first test was successfully executed by injecting deuterium gas into the vacuum vessel based on pre-configured waveforms from the plasma control system.
The project will be completed in November by using real density signals from a millimetre-wave interferometer and closing the density feedback control loop during the KSTAR plasma operation.
The KSTAR fuelling system operates with four different gases for plasma creation, wall cleaning and diagnostics. For the experiment, one piezo-electric valve (for deuterium gas) was selected as an actuator. Various pre-configured patterns were used as reference inputs to the plasma control system (PCS) for controlling the fuel injection. The PCS was implemented on a high performance computer using ATCA form factor, CODAC standard real-time operating system (MRG-R) and MARTe real-time framework originally developed at JET.
The density signal was simulated by programmable waveforms. A CODAC standard fast controller (fuel controller) was also implemented to control the embedded piezo-valve controller and to acquire diagnostics signals such as vacuum vessel pressure, gas flow, valve drive voltage, etc. at 10 kHz. The plasma control system communicated with the fuel controller over the standard CODAC real time network at 1 kHz.
As the measurements from the first test showed identical results as the KSTAR fuelling system, it was confirmed that the technologies adopted or being considered for ITER CODAC were applicable for the plant control at tokamak, that is, CODAC is heading in the right direction.
|As an international organization—and one applying for nuclear licensing in France—ITER is required to have a well-documented management system, with approved procedures describing the process flow for every area of the project.
Since 2008, the Quality Assurance Division has been developing the Management and Quality Program (MQP), a process-based system that organizes ITER’s management documents into a structure governing relations, procedures, and working instructions.
„The written procedures contained in the MQP program basically instruct end users how to do their work,” says Florence Tadjer, who joined the Division in April. „But of course it is not enough that these documents exist: they must also be well understood and applied throughout the project.”
As MQP Liaison Officer for the Administration and Plasma Operation Directorates, Florence will work in an advisory role with process „owners” on management documents, ensuring that the proper rules are followed to write documents, and deciding whether the document contains the type of guidelines that should be incorporated into the MQP framework or not. „In fact, not every departmental document needs to be part of the MQP,” says Florence. „On the other hand, it is also my role to identify those documents that should be incorporated.”
Florence comes to ITER from the International Atomic Energy Agency (IAEA), where she was a quality manager in the laboratory responsible for analyzing safeguard samples from nuclear facilities. It was her responsibility to maintain the laboratory’s quality certification by updating the quality management system and conducting regular audits in order to make sure that the quality system was well implemented in all areas of the laboratory.
„Training and auditing are part of the quality manager’s job,” insists Florence. At ITER, the team of Liaison Officers will work to improve the MQP documentation, and expend a lot of effort to communicate about the program and make sure that training is offered on the implementation of the system.
„ITER is a young organization and things are still evolving. A lot remains to be done and I know I’ll enjoy the lack of routine!"
|The Indian Domestic Agency has signed two contracts for the development of the Radio Frequency (RF) sources forming part of ITER’s Ion Cyclotron Heating and Current Drive (IC H&CD) system. The contracts were signed with the American company Continental Electronics Corporation and with Thales Electron Devices, France.
The IC H&CD system is one of the major tools for achieving the plasma performances foreseen in ITER’s operation scenarios. This system is designed to provide 20 MW into the plasma, at frequencies included in the band 40 MHz to 55 MHz. ITER India is in charge of the procurement of the RF sources subsystem and the corresponding Procurement Arrangement was signed in February 2010. A total of nine RF sources will be provided: eight sources used for plasma operation, plus one spare.
For ensuring 20 MW power availability for plasma operation, 24 MW is required at the output of the transmitter at frequencies up to 65 MHz. As there is no unique amplifier chain able to meet the output power specifications, the layout consists of two parallel four-stage amplifier chains, with a combiner circuit on the output side. This configuration is used in ASDEX upgrade ICRF facilities since 1998.
Each amplifier chain is made of a wide band solid state amplifier cascaded to a three tube based tuned amplifier: a pre-driver, followed by a driver stage and a final stage. But, even in this configuration, the final stage tubes have to achieve challenging power levels.
Only two suppliers worldwide are able to reach the target. In order to identify the best and most reliable technology for building this amplifier chain, R&D contracts were signed with both companies. Results are expected by the end of next year followed by the Preliminary Design Review.