S. Simrock

Advanced Data Acquisition system implementation for the ITER neutron diagnostic use case using EPICS and FlexRIO technology on a PXIe platform

To aid in assessing the functional performance of ITER, Fission Chambers (FC) based on the neutron diagnostic use case deliver timestamped measurements of neutron source strength and fusion power. To demonstrate the Plant System Instrumentation & Control (I&C) required for such a system, ITER Organization (IO) has developed a neutron diagnostics use case that fully complies with guidelines presented in the Plant Control Design Handbook (PCDH). The implementation presented in this paper has been developed on the PXI Express (PXIe) platform using products from the ITER catalog of standard I&C hardware for fast controllers. Using FlexRIO technology, detector signals are acquired at 125 MS/s, while filtering, decimation, and three methods of neutron counting are performed in real-time via the onboard Field Programmable Gate Array (FPGA). Measurement results are reported every 1 ms through Experimental Physics and Industrial Control System (EPICS) Channel Access (CA), with real-time timestamps derived from the ITER Timing Communication Network (TCN) based on IEEE 1588-2008. Furthermore, in accordance with ITER specifications for CODAC Core System (CCS) application development, the software responsible for the management, configuration, and monitoring of system devices has been developed in compliance with a new EPICS module called Nominal Device Support (NDS) and RIO/FlexRIO design methodology.

Present status of the ITER real-time Plasma Control System development

ITER will be the worlds largest magnetic confinement tokamak fusion device and is currently under construction in southern France. The ITER Plasma Control System (PCS) is a fundamental component of the ITER Control, Data Access and Communication system (CODAC). It will control the evolution of all plasma parameters that are necessary to operate ITER throughout all phases of the discharge. The design and implementation of the PCS poses a number of unique challenges. The timescales of phenomena to be controlled spans three orders of magnitude, ranging from a few milliseconds to seconds. Novel control schemes, which have not been implemented at present-day machines need to be developed, and control schemes that are only done as demonstration experiments today will have to become routine. In addition, advances in computing technology and available physics models make the implementation of real-time or faster-than-real-time calculations to forecast and subsequently to avoid disruptions or undesired plasma regimes feasible. A further novel feature is a sophisticated event handling system, which provides a means to deal with plasma related events (such as MIlD instabilities or LH transitions) or component failure. Finally, the schedule for design and implementation poses another unique challenge. The beginning of ITER operation will be in late 2020, but the conceptual design activity has already commenced as required by the on-going development of diagnostics and actuators in the domestic agencies and the need for integration and testing. In this paper, an overview about the functional requirements for the plasma control system will be given. The main focus will be on the requirements and possible options for a real-time framework for ITER and its interfaces to other ITER CODAC systems (networks, other applications, etc.). The limited amount of commissioning time foreseen for plasma control will make extensive testing and validation necessary. This should be done in an environment that is as close to the PCS version running the machine as possible. Furthermore, the integration with an Integrated Modeling Framework will lead to a versatile tool that can also be employed for pulse validation, control system development and testing as well as the development and validation of physics models. An overview of the requirements and possible structure of such an environment will also be presented.

High-performance image acquisition and processing system with MTCA.4

Fast evolution of high-performance cameras in recent years has made them promising tools for observing transient and fast events in large-scale scientific experiments. Complex experiments, such as ITER, take advantage of high-performance imaging system consisting of several fast cameras working in the range of visible and infrared light. The paper presents a first implementation of complete image acquisition system built on the basis of MTCA.4 architecture, which is dedicated for operation with high-resolution fast cameras equipped with Camera Link interface. Image data from the camera are received by the frame grabber card and transmitted to the host via PCIe interface. The modular structure of MTCA.4 architecture allows connecting several cameras to a single MTCA chassis. The system supports precise synchronization with the time reference using Precision Time Protocol (IEEE 1588). The software support for the system includes low-level drivers and API libraries for all components and high-level EPICS-based environment for system control and monitoring.

IEEE 1588 Time Synchronization Board in MTCA.4 Form Factor

Distributed data acquisition and control systems in large-scale scientific experiments, like e.g. ITER, require time synchronization with nanosecond precision. A protocol commonly used for that purpose is the Precise Timing Protocol (PTP), also known as IEEE 1588 standard. It uses the standard Ethernet signalling and protocols and allows obtaining timing accuracy of the order of tens of nanoseconds. The MTCA.4 is gradually becoming the platform of choice for building such systems. Currently there is no commercially available implementation of the PTP receiver on that platform. In this paper, we present a module in the MTCA.4 form factor supporting this standard. The module may be used as a timing receiver providing reference clocks in an MTCA.4 chassis, generating a Pulse Per Second (PPS) signal and allowing generation of triggers and timestamping of events on 8 configurable backplane lines and two front panel connectors. The module is based on the Xilinx Spartan 6 FPGA and thermally stabilized Voltage Controlled Oscillator controlled by the digital-to-analog converter. The board supports standalone operation, without the support from the host operating system, as the entire control algorithm is run on a Microblaze CPU implemented in the FPGA. The software support for the card includes the low-level API in the form of Linux driver, user-mode library, high-level API: ITER Nominal Device Support and EPICS IOC. The device has been tested in the ITER timing distribution network (TCN) with three cascaded PTP-enabled Hirschmann switches and a GPS reference clock source. An RMS synchronization accuracy, measured by direct comparison of the PPS signals, better than 20 ns has been obtained.

Electronic Components Exposed To Nuclear Radiations In Iter Diagnostic Systems: Current Investigations And Perspectives

The ITER diagnostics systems will have sensors (e.g. cameras, detectors) and signal conditioning electronic components (e.g. preamplifiers) located in the Tokamak building and in particular in the port-cell area. These components will be exposed to gamma and neutron fluxes from the plasma, from the activated water circulating in the pipes of the water cooling system and from the cask transporting activated components during maintenance operation. Potential damage caused by the nuclear radiation range from function degradation (e.g. signal corruption) to component destruction. Neutronic calculations show that the total ionizing dose and neutron fluence are higher than what commercial components can withstand. In this context, an expert study for the selection of tolerant electronic components for the ITER diagnostic systems has been recently carried out. This paper is based on the outcome of this report. First the different options to mitigate radiation effects are reviewed and assessed according to the draft ITER policy presently under discussion on electronic exposed to nuclear radiation. Next, several options are elaborated based on the requirements for individual diagnostic systems (e.g. magnetics, neutronics, bolometers) with main focus on preamplifiers, ADCs and optical converters. The options include proposal of available commercial off-the-shelf components with shielding, or components already qualified for radiation hard environment (e.g. for space applications), or development of custom components. Evaluation criteria include availability, integration issues, cost, as well as development effort in case of a special development option is taken.

Integration of diagnostics on ITER

Diagnostics play a very important role in the modern Tokamak where optimum performance is essential. To achieve this, the device must be equipped with reliable and robust sensors and instrumentation that allow the operation envelope to be fully explored. Development of these diagnostics to maintain this reliability is necessary. Further to the development, the systems must be integrated in a way that maintains their performance while simultaneously satisfying the key requirements needed for safety and tokamak operation. ITER will have 50 diagnostics; almost all of which are utilized primarily for the real-time operation of the tokamak. While there is still much work to do, to date, significant progress has been made in the development of these systems. The work load for the developments is shared across all the ITER partners. This paper focuses on the challenges for the integration of the systems.

Data archiving system implementation in ITER's CODAC CORE SYSTEM

A new data archiving implementation developed by the CIEMAT-INDRA-SGENIA-UPM Consortium (in alphabetical order) has been fully integrated into ITERs CODAC CORE SYSTEM at the beginning of year 2015. This software includes components on the client and server sides that are responsible for the distribution and archiving of acquired or process-generated data, with important restrictions. On the one side, ITERs high pulse length requires that any data archiving implementation include a steady state archiving mechanism with continuous storage of the data acquired and processed throughout the experiment. On the other side, all these data must be safely archived and continuously available for read systems on the client side in a short time from their acquisition. On the side of client systems, a new software library has been developed with two main goals. The first one is to provide simple and complete data archiving functionality, while the second pursues to implement a continuous and efficient data distribution engine including different data sources as well as a diversity of potential consumer systems. From the server-based perspective, a complete solution has been implemented using the HDF5 files as the underlying data storage technology, while adapting the metadata structures and data access protocols to meet ITERs CODAC requirements.