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The Tore Supra Cryoplant control system upgrade
Fusion Engineering and Design 58 – 59 (2001) 217– 223 www.elsevier.com/locate/fusengdes
The Tore Supra Cryoplant control system upgrade R. Garbil *, J.L. Mare´chal, B. Gravil, D. Henry, J.Y. Journeaux, D. Balaguer, J. Baudet, A. Bocquillon, P. Fejoz, P. Prochet, C. Roux, J.P. Serries De´partement de Recherche sur la Fusion Controle´e, Association Euratom/CEA, CEA/CADARACHE, 13 108 Saint-Paul lez Durance Cedex, France
Abstract The Tore Supra Cryoplant is a vital and integral part of the experiment. It operates fully automatically and has been built for maximum specific operation for a tokamak. It includes over ten operating modes in order to save energy outside of plasmas operations. The present control system ‘Architecture 7’ is based on distributed Intel 8086 microprocessors. It includes over 1300 digital and 950 analogue input/output (I/O) cards. It has given excellent service for 10 years but difficulties of faultfinding, replacement of components and ageing circuit boards have degraded now the reliability of the cryosystem. Consequences of failures, faults and malfunctions might vary between some experimental hours lost to damage of some plant components. Cost maintenance and growing difficulties dictated an upgrade. © 2001 Elsevier Science B.V. All rights reserved. Keywords: Tore Supra Cryoplant; Architecture 7; Intel 8086 microprocessors
1. Introduction Tore Supra was built by the Euratom-CEA association and established at the Cadarache Nuclear Research Centre in Provence, southeastern region of France. It is a medium-size tokamak (major radius of 2.250 m, plasma radius of 0.800 m) designed to study long-duration pulses (a 1000 s is our next goal). Its constant toroidal magnetic field operation of 4.5 T at the plasma axis (9 T peak field on the
conductor) required the use of 18 high field NbTi alloy superconducting toroidal magnets. Twelve years of operation have shown the CEA took the bold and successful decision to operate with large quantities of pressurised superfluid helium (over 4000 l of HeII at 1.8 K and 1.25 bar). A proven success throughout the world showing that the technology can be used on an industrial scale. [1] The CERN LHC and ITER projects followed our recommendations and are deeply based on our technology. 2. The cryogenic system
* Corresponding author. Tel: +33-4-42-257680; fax: + 334-42-252661. E-mail address: [email protected] (R. Garbil).
The compressors and warm pumps are located at 70 m from the cold box and connected by underground pipe runs. The refrigerator was built
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in close collaboration with Air Liquide. Its cold power is distributed to three cryostats, so-called ‘cryogenic satellites’ located in the torus hall 7– 10 m to the coils. Each of these feeds six coils and is connected to the refrigerator by a horizontal cryogenic line. The cold box includes an 80 K helium stage (10– 30 kW) to cool the 20 tons coil shields (7) using turbine T1, a liquid nitrogen bath or both. Three further levels of expansion are obtained with turbines T2, T3 and a reciprocating machine T4 (1 kW at 4.5 K) which produces liquid helium (LHe) then stored in a 20 000 l storage tank. Before the final expansion, supercritical gas cooled in the thermal ballast (6) by the 4K cold sources (4) is used to cool the 120 tons 18 thick casings (5) Fig. 1. The HeII refrigerating power (300 W at 1.8 K) for the 45 tons NbTi alloy conductor is obtained
Fig. 2. The Tore Supra Toroidal Magnet. A detailed overview of the superconducting magnet coil, NbTi conductor, glass epoxy spacers, 1.8 K/1.25 bar thin casing, polyimide alumina chocks and 4.5 K/18 bar stainless steel thick casing.
by a pumping system comprising in series two cold compressors, suction at 13 mbar, 4.4 K, discharge at 80 mbar, 15 K and two oil ring pumps, discharging at atmospheric pressure. The total amount in normal operation is of 15 000– 20 000 l of LHe at 4.4 K and 5000 l of HeII with 4000 l (at T= 1.8 K and 1.25 bar) in the winding.
3. The toroidal magnet 18 coils, each of them consists of an assembly of a double pancake separated by insulating studs [2].A thin walled enclosure is filled with HeII for the NbTi conductor and the stainless steel thick casing giving the assembly its mechanical rigidity is cooled by supercritical He at 4 K. It also shields the superconductor against induced eddy currents Fig. 2.
4. Operating schedule Fig. 1. The Tore Supra Cryogenic System. A helium flow diagram overview of the cryogenic system, its compressor and pumps, the refrigerator coldbox, the cryogenic lines, the cryogenic satellites and the toroidal superconducting magnets.
For energy saving purpose, the Tore Supra operating schedule has led us to create over 10 automatic operating modes depending on plasma
R. Garbil et al. / Fusion Engineering and Design 58–59 (2001) 217–223
operations. They correspond to the stoppage of part of the refrigerating units. The nominal operating schedule at 1.8 using 1.1 MW is only maintained when the magnet is in use [3]. A typical week of operation is from Tuesday to Friday: 1.8 K operating mode from 08:00 to 21:00 h for plasma experiments, 2.1 K idle mode every week night. Part of the pumping system is stopped. The winding temperature is maintained at 2.1 K. Return to nominal conditions is reached within 1 h, 4.5 or 4.5 K LHe idle mode other the weekend. The all pumping system is stopped. The winding temperature goes up to 4.5 K. Nominal conditions are reached within 8 h. Monday is maintenance day. Normal operation is reached within 6 h, 80 K idle or 80 K LHe idle mode are used for stoppage periods of more than a week without the toroidal magnet. Only the 80 K shield refrigeration is maintained. Nominal conditions are reached within 2–7 days depending on the duration of these modes. The cooldown from warm takes: 7 days to bring the 20 tons thermal shields and the 165 tons of the magnet at 80 K, 7 days to bring the coils temperature from 80 to 4.5 K, one day to bring the superconducting winding at 1.8 K. The warm-up takes one day to bring the magnet to 80 K and 8 days to bring the assembly up to 300 K.
5. Control system topology Central elements are Programmable Logical Controllers (PLC) from Schneider Te´ le´ me´ canique (TPMX 87455 with a 386 CPU, 220 KB of RAM) including PID processing and over 100 function blocs (OFB): arithmetic, data transform, bit operations and diagnostic tools. All the plant’s instrumentation control devices (1300 digital, 950 analogue I/O including 300 control and on/off valves, 300 transmitters for pressures, temperatures, flows and levels) are now driven by the PLCs.
219
All previous operating schedule and backup systems have been integrated in the new control system. A distributed PLC topology is a key element for a reliable system. One PLC in the compressor house, three in the cryogenic hall (coldbox, LHeLN2 and 80K backup systems) and three in the Torus Hall (one for each cryogenic satellite) have been implemented Fig. 3. Standard ICEC1131 programming language (sequential function chart (SFC), ladder diagram (LD) and structured text (ST)) is generated from a dedicated PC workstation connected to the PLC via an Ethernet TCP-IP network protocol (10 Mbit/s). The latest OS2 operating system and X-TEL/PL7-3 programming software package have been installed on this workstation. [4] FIPIO is a high-speed serial link protocol implementing the WorldFIP network protocol with X-TEL field communication system. Data rates of 2.5 Mbit/s via twisted shielded pair copper cable and 5 Mbit/s via optical fibres are achieved. The cable system consists of a trunk cable with drop cables connected by tap boxes and connecting each node. Deterministic operation is provided at all times, even in abnormal conditions, managing cyclic input and output data exchanges, I/O base parameter assignment (at start-up and in operation) and processing diagnostic information. The layout of the programme is dictated by the operation of the plant, during transients (cooldown, warm-up, between two operating modes) or in a stable state (80, 4, 2 K idle modes). Nine stable and 27 transient states have been defined. Our general operation sequential functional chart (SFC) states and controls these operating modes. It also shows the only logical path that can be followed during operations Fig. 4. In each mode, a set of systems (80 K shields, turbines, cold compressors etc…) is enabled or disabled. A total of 37 have been defined, six in the compressor house (first compressor stage, second compressor stage, high pressure compressors, oil ring pumps 1 and 2 and oil removal systems), 19 for the coldbox, four for each satellite. Each system is made of several functions. For instance, four have been defined for the 80 K shields: pressurisation, cooldown from 300 to
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R. Garbil et al. / Fusion Engineering and Design 58–59 (2001) 217–223
80 K, normal operation and operation when the Torus is baked. The general operation chart requests the 80 K shields and enables the associated macro step. Depending on the plant status, we will start the cooldown of the shields with Turbine 1, LN2 Bath or both. When the sequence is completed, we will go in 80 K operation Fig. 5. Transitions are always written in Ladder logic. Programming of interlocks, alarms, processing of the I/O and OFBs (PIDs, temperature fitting curves) are written in subroutines. A cryoplant failure chart has been defined. The predefined MSIT function block is always monitoring the operation of the plant and executes a controlled sequential shutdown if a power supplies, compressed air, water systems outage or any sub-system on the plant would occur. The execution of macros is stopped, a reset and re-initialisa-
tion of the sub-systems is carried out where necessary. This analysis from the top of a multitask environment (compressors, turbines, cold compressors, expansion engines etc…) using macros allows a logical overview of the programme. Subsystems’ operation can be displayed on a limited number of pages and even on a single one. A macro step is most of the time associated with three lower levels in order to describe elementary operations (up to 64 were allowed). The macro activated is executed following the SFC rules. A macro step can call other macro steps. The PLC multitask environment gives a general method in writing the programme. Additional rules have been implemented for any software implementation on the Tore Supra control system (LHCD, water cooling systems etc…). Each func-
Fig. 3. The Tore Supra Cryoplant Control System Upgrade. Network layout of the distributed PLC control system (compressor house, cryogenic hall and torus hall) and its Panorama supervisory system.
R. Garbil et al. / Fusion Engineering and Design 58–59 (2001) 217–223
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Fig. 4. The Tore Supra General Operation Sequential Functional Chart. The general operation sequential functional chart with nine stable and 27 transient modes.
tion (dialogue, communication, control etc…) is implemented using three tasks (MAST, AUX0 and AUX1) comprising sub-routines and executed at different pre-defined scan times. MAST is the core task of the application allowing the activation or not of the other tasks or subroutines. It is executed in less than 100 ms, reading of the inputs, presets, subroutines, interlocks, execution of the programme and writing of the outputs are performed. AUX0 is mainly used for processing, execution of comparison function blocs, PID control, and simulation of the programme before online commissioning. AUX1 is the communication task between PLCs but also dialog with the cryoplant Panorama supervisory system.
The latest industrial standard 32 Bit software PANORAMA plant supervisory system (comprising four PCs running Windows NT4 workstation operating system) is used [5]. The system provides real-time and history data to the plant operators presented in the form of mimics, actual and historical trends and alarms. An advanced user-friendly operator interface is also developed to integrate our 10 years of experience. Online help is being implemented to improve diagnosis of any potential problem on the plant. Procedures, an everyday logbook and checklist will be computerised to facilitate operators diagnostics and to keep an electronic trace of the plant events. The cryoplant network is separated from the main Tore Supra office network for security rea-
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R. Garbil et al. / Fusion Engineering and Design 58–59 (2001) 217–223
sons, creating its own domain. [6] The server is used for files sharing, backups and replication on local PC’s of configuration files and storage of shared software. The server is also the only machine, which can be accessed from outside the main control room by special users to use shared files and programmes.
6. Backup systems Mechanical stress has to be limited during transients or after a plant stoppage. Therefore, the DeltaTmax between any two location of the magnet and the shields should be lower than 40 K. The low thermal conductivity of the insulating blocks also requires a cooling and warming up speed lower than 2 K an hour. In the event of a supply failure (water, compressed air, power supplies), all the necessary 80 K backup systems have to keep the plant running or be powered in less than 2 h. [7] If the refrigerator cold box would fail (blockage due to impurities after long operating periods, vacuum system failure), an auxiliary 80 K cold box can be started
in less than an hour to take other. Additional Kabelmetal cryogenic lines were installed. De-carbonated water system can be swapped to the mains. A standby compressed air compressor will run. A third mobile compressor can be connected. The 15 kV backup supply and another 380 V/1600 kVA transformer can be used as backup. The controlled circuits (relays, instrumentation and valves) and the contro1 system have a 1 h battery backup supply. An auxiliary PLC (80 K backup PLC) has been set up with its own redundant power supply.
7. Conclusion The Tore Supra cryoplant control system will be operated 24 h per day and 7 days a week. Its control system allows a maximum operational flexibility and will show its complete reliability during the next operations. This upgrade is a heavy task but the full benefit of our operating experience, the integration of standard and industrial solutions, will make it a great success.
Fig. 5. The Tore Supra 80 K shields Macro Step. Our programming method explained (sequential functional chart, ladder diagram) using the example of the 80 K shields system.
R. Garbil et al. / Fusion Engineering and Design 58–59 (2001) 217–223
References [1] B. Gravil, R. Garbil, D. Henry and the Tore Supra cryogenic team, Operating Experience of the Tore Supra Cryogenic System, ICEC18, Gandhinagar, Gujarat, India, 28 –29 February 2000. [2] B. Gravil, D. Henry, F. Minot, Operation with the 1.8 K Tore Supra cryogenic system, 13th Topical Meeting on the Technology of Fusion Energy, Nashville, Tennessee, USA, 7 –11 June 1998. [3] B. Gravil, Operational experience with a large cryogenic system, I.A.E.A. Workshop on Technological Aspects of
[4] [5] [6]
[7]
223
Steady State Devices, Garching, Germany, 20 – 23 February 1995. Schneider Te´ le´ mecanique X-TEL/PL7-3 Reference guide, 1997. Panorama Concept and Planning User manuals, 1998. Microsoft Windows NT4 Server and Workstation, Concept and Planning, Networking Supplement, 1997. B. Gravil, B. Jager, G. Bon mardion, F. Minot, Back-up Systems of the Tore Supra Superconducting Toroidal Magnet Refrigeration, ICEC 15 Proceedings, Cryogenics, vol. 34, 1994.
The Tore Supra Cryoplant control system upgrade R. Garbil *, J.L. Mare´chal, B. Gravil, D. Henry, J.Y. Journeaux, D. Balaguer, J. Baudet, A. Bocquillon, P. Fejoz, P. Prochet, C. Roux, J.P. Serries De´partement de Recherche sur la Fusion Controle´e, Association Euratom/CEA, CEA/CADARACHE, 13 108 Saint-Paul lez Durance Cedex, France
Abstract The Tore Supra Cryoplant is a vital and integral part of the experiment. It operates fully automatically and has been built for maximum specific operation for a tokamak. It includes over ten operating modes in order to save energy outside of plasmas operations. The present control system ‘Architecture 7’ is based on distributed Intel 8086 microprocessors. It includes over 1300 digital and 950 analogue input/output (I/O) cards. It has given excellent service for 10 years but difficulties of faultfinding, replacement of components and ageing circuit boards have degraded now the reliability of the cryosystem. Consequences of failures, faults and malfunctions might vary between some experimental hours lost to damage of some plant components. Cost maintenance and growing difficulties dictated an upgrade. © 2001 Elsevier Science B.V. All rights reserved. Keywords: Tore Supra Cryoplant; Architecture 7; Intel 8086 microprocessors
1. Introduction Tore Supra was built by the Euratom-CEA association and established at the Cadarache Nuclear Research Centre in Provence, southeastern region of France. It is a medium-size tokamak (major radius of 2.250 m, plasma radius of 0.800 m) designed to study long-duration pulses (a 1000 s is our next goal). Its constant toroidal magnetic field operation of 4.5 T at the plasma axis (9 T peak field on the
conductor) required the use of 18 high field NbTi alloy superconducting toroidal magnets. Twelve years of operation have shown the CEA took the bold and successful decision to operate with large quantities of pressurised superfluid helium (over 4000 l of HeII at 1.8 K and 1.25 bar). A proven success throughout the world showing that the technology can be used on an industrial scale. [1] The CERN LHC and ITER projects followed our recommendations and are deeply based on our technology. 2. The cryogenic system
* Corresponding author. Tel: +33-4-42-257680; fax: + 334-42-252661. E-mail address: [email protected] (R. Garbil).
The compressors and warm pumps are located at 70 m from the cold box and connected by underground pipe runs. The refrigerator was built
0920-3796/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 0 - 3 7 9 6 ( 0 1 ) 0 0 4 3 7 - 9
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R. Garbil et al. / Fusion Engineering and Design 58–59 (2001) 217–223
in close collaboration with Air Liquide. Its cold power is distributed to three cryostats, so-called ‘cryogenic satellites’ located in the torus hall 7– 10 m to the coils. Each of these feeds six coils and is connected to the refrigerator by a horizontal cryogenic line. The cold box includes an 80 K helium stage (10– 30 kW) to cool the 20 tons coil shields (7) using turbine T1, a liquid nitrogen bath or both. Three further levels of expansion are obtained with turbines T2, T3 and a reciprocating machine T4 (1 kW at 4.5 K) which produces liquid helium (LHe) then stored in a 20 000 l storage tank. Before the final expansion, supercritical gas cooled in the thermal ballast (6) by the 4K cold sources (4) is used to cool the 120 tons 18 thick casings (5) Fig. 1. The HeII refrigerating power (300 W at 1.8 K) for the 45 tons NbTi alloy conductor is obtained
Fig. 2. The Tore Supra Toroidal Magnet. A detailed overview of the superconducting magnet coil, NbTi conductor, glass epoxy spacers, 1.8 K/1.25 bar thin casing, polyimide alumina chocks and 4.5 K/18 bar stainless steel thick casing.
by a pumping system comprising in series two cold compressors, suction at 13 mbar, 4.4 K, discharge at 80 mbar, 15 K and two oil ring pumps, discharging at atmospheric pressure. The total amount in normal operation is of 15 000– 20 000 l of LHe at 4.4 K and 5000 l of HeII with 4000 l (at T= 1.8 K and 1.25 bar) in the winding.
3. The toroidal magnet 18 coils, each of them consists of an assembly of a double pancake separated by insulating studs [2].A thin walled enclosure is filled with HeII for the NbTi conductor and the stainless steel thick casing giving the assembly its mechanical rigidity is cooled by supercritical He at 4 K. It also shields the superconductor against induced eddy currents Fig. 2.
4. Operating schedule Fig. 1. The Tore Supra Cryogenic System. A helium flow diagram overview of the cryogenic system, its compressor and pumps, the refrigerator coldbox, the cryogenic lines, the cryogenic satellites and the toroidal superconducting magnets.
For energy saving purpose, the Tore Supra operating schedule has led us to create over 10 automatic operating modes depending on plasma
R. Garbil et al. / Fusion Engineering and Design 58–59 (2001) 217–223
operations. They correspond to the stoppage of part of the refrigerating units. The nominal operating schedule at 1.8 using 1.1 MW is only maintained when the magnet is in use [3]. A typical week of operation is from Tuesday to Friday: 1.8 K operating mode from 08:00 to 21:00 h for plasma experiments, 2.1 K idle mode every week night. Part of the pumping system is stopped. The winding temperature is maintained at 2.1 K. Return to nominal conditions is reached within 1 h, 4.5 or 4.5 K LHe idle mode other the weekend. The all pumping system is stopped. The winding temperature goes up to 4.5 K. Nominal conditions are reached within 8 h. Monday is maintenance day. Normal operation is reached within 6 h, 80 K idle or 80 K LHe idle mode are used for stoppage periods of more than a week without the toroidal magnet. Only the 80 K shield refrigeration is maintained. Nominal conditions are reached within 2–7 days depending on the duration of these modes. The cooldown from warm takes: 7 days to bring the 20 tons thermal shields and the 165 tons of the magnet at 80 K, 7 days to bring the coils temperature from 80 to 4.5 K, one day to bring the superconducting winding at 1.8 K. The warm-up takes one day to bring the magnet to 80 K and 8 days to bring the assembly up to 300 K.
5. Control system topology Central elements are Programmable Logical Controllers (PLC) from Schneider Te´ le´ me´ canique (TPMX 87455 with a 386 CPU, 220 KB of RAM) including PID processing and over 100 function blocs (OFB): arithmetic, data transform, bit operations and diagnostic tools. All the plant’s instrumentation control devices (1300 digital, 950 analogue I/O including 300 control and on/off valves, 300 transmitters for pressures, temperatures, flows and levels) are now driven by the PLCs.
219
All previous operating schedule and backup systems have been integrated in the new control system. A distributed PLC topology is a key element for a reliable system. One PLC in the compressor house, three in the cryogenic hall (coldbox, LHeLN2 and 80K backup systems) and three in the Torus Hall (one for each cryogenic satellite) have been implemented Fig. 3. Standard ICEC1131 programming language (sequential function chart (SFC), ladder diagram (LD) and structured text (ST)) is generated from a dedicated PC workstation connected to the PLC via an Ethernet TCP-IP network protocol (10 Mbit/s). The latest OS2 operating system and X-TEL/PL7-3 programming software package have been installed on this workstation. [4] FIPIO is a high-speed serial link protocol implementing the WorldFIP network protocol with X-TEL field communication system. Data rates of 2.5 Mbit/s via twisted shielded pair copper cable and 5 Mbit/s via optical fibres are achieved. The cable system consists of a trunk cable with drop cables connected by tap boxes and connecting each node. Deterministic operation is provided at all times, even in abnormal conditions, managing cyclic input and output data exchanges, I/O base parameter assignment (at start-up and in operation) and processing diagnostic information. The layout of the programme is dictated by the operation of the plant, during transients (cooldown, warm-up, between two operating modes) or in a stable state (80, 4, 2 K idle modes). Nine stable and 27 transient states have been defined. Our general operation sequential functional chart (SFC) states and controls these operating modes. It also shows the only logical path that can be followed during operations Fig. 4. In each mode, a set of systems (80 K shields, turbines, cold compressors etc…) is enabled or disabled. A total of 37 have been defined, six in the compressor house (first compressor stage, second compressor stage, high pressure compressors, oil ring pumps 1 and 2 and oil removal systems), 19 for the coldbox, four for each satellite. Each system is made of several functions. For instance, four have been defined for the 80 K shields: pressurisation, cooldown from 300 to
220
R. Garbil et al. / Fusion Engineering and Design 58–59 (2001) 217–223
80 K, normal operation and operation when the Torus is baked. The general operation chart requests the 80 K shields and enables the associated macro step. Depending on the plant status, we will start the cooldown of the shields with Turbine 1, LN2 Bath or both. When the sequence is completed, we will go in 80 K operation Fig. 5. Transitions are always written in Ladder logic. Programming of interlocks, alarms, processing of the I/O and OFBs (PIDs, temperature fitting curves) are written in subroutines. A cryoplant failure chart has been defined. The predefined MSIT function block is always monitoring the operation of the plant and executes a controlled sequential shutdown if a power supplies, compressed air, water systems outage or any sub-system on the plant would occur. The execution of macros is stopped, a reset and re-initialisa-
tion of the sub-systems is carried out where necessary. This analysis from the top of a multitask environment (compressors, turbines, cold compressors, expansion engines etc…) using macros allows a logical overview of the programme. Subsystems’ operation can be displayed on a limited number of pages and even on a single one. A macro step is most of the time associated with three lower levels in order to describe elementary operations (up to 64 were allowed). The macro activated is executed following the SFC rules. A macro step can call other macro steps. The PLC multitask environment gives a general method in writing the programme. Additional rules have been implemented for any software implementation on the Tore Supra control system (LHCD, water cooling systems etc…). Each func-
Fig. 3. The Tore Supra Cryoplant Control System Upgrade. Network layout of the distributed PLC control system (compressor house, cryogenic hall and torus hall) and its Panorama supervisory system.
R. Garbil et al. / Fusion Engineering and Design 58–59 (2001) 217–223
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Fig. 4. The Tore Supra General Operation Sequential Functional Chart. The general operation sequential functional chart with nine stable and 27 transient modes.
tion (dialogue, communication, control etc…) is implemented using three tasks (MAST, AUX0 and AUX1) comprising sub-routines and executed at different pre-defined scan times. MAST is the core task of the application allowing the activation or not of the other tasks or subroutines. It is executed in less than 100 ms, reading of the inputs, presets, subroutines, interlocks, execution of the programme and writing of the outputs are performed. AUX0 is mainly used for processing, execution of comparison function blocs, PID control, and simulation of the programme before online commissioning. AUX1 is the communication task between PLCs but also dialog with the cryoplant Panorama supervisory system.
The latest industrial standard 32 Bit software PANORAMA plant supervisory system (comprising four PCs running Windows NT4 workstation operating system) is used [5]. The system provides real-time and history data to the plant operators presented in the form of mimics, actual and historical trends and alarms. An advanced user-friendly operator interface is also developed to integrate our 10 years of experience. Online help is being implemented to improve diagnosis of any potential problem on the plant. Procedures, an everyday logbook and checklist will be computerised to facilitate operators diagnostics and to keep an electronic trace of the plant events. The cryoplant network is separated from the main Tore Supra office network for security rea-
222
R. Garbil et al. / Fusion Engineering and Design 58–59 (2001) 217–223
sons, creating its own domain. [6] The server is used for files sharing, backups and replication on local PC’s of configuration files and storage of shared software. The server is also the only machine, which can be accessed from outside the main control room by special users to use shared files and programmes.
6. Backup systems Mechanical stress has to be limited during transients or after a plant stoppage. Therefore, the DeltaTmax between any two location of the magnet and the shields should be lower than 40 K. The low thermal conductivity of the insulating blocks also requires a cooling and warming up speed lower than 2 K an hour. In the event of a supply failure (water, compressed air, power supplies), all the necessary 80 K backup systems have to keep the plant running or be powered in less than 2 h. [7] If the refrigerator cold box would fail (blockage due to impurities after long operating periods, vacuum system failure), an auxiliary 80 K cold box can be started
in less than an hour to take other. Additional Kabelmetal cryogenic lines were installed. De-carbonated water system can be swapped to the mains. A standby compressed air compressor will run. A third mobile compressor can be connected. The 15 kV backup supply and another 380 V/1600 kVA transformer can be used as backup. The controlled circuits (relays, instrumentation and valves) and the contro1 system have a 1 h battery backup supply. An auxiliary PLC (80 K backup PLC) has been set up with its own redundant power supply.
7. Conclusion The Tore Supra cryoplant control system will be operated 24 h per day and 7 days a week. Its control system allows a maximum operational flexibility and will show its complete reliability during the next operations. This upgrade is a heavy task but the full benefit of our operating experience, the integration of standard and industrial solutions, will make it a great success.
Fig. 5. The Tore Supra 80 K shields Macro Step. Our programming method explained (sequential functional chart, ladder diagram) using the example of the 80 K shields system.
R. Garbil et al. / Fusion Engineering and Design 58–59 (2001) 217–223
References [1] B. Gravil, R. Garbil, D. Henry and the Tore Supra cryogenic team, Operating Experience of the Tore Supra Cryogenic System, ICEC18, Gandhinagar, Gujarat, India, 28 –29 February 2000. [2] B. Gravil, D. Henry, F. Minot, Operation with the 1.8 K Tore Supra cryogenic system, 13th Topical Meeting on the Technology of Fusion Energy, Nashville, Tennessee, USA, 7 –11 June 1998. [3] B. Gravil, Operational experience with a large cryogenic system, I.A.E.A. Workshop on Technological Aspects of
[4] [5] [6]
[7]
223
Steady State Devices, Garching, Germany, 20 – 23 February 1995. Schneider Te´ le´ mecanique X-TEL/PL7-3 Reference guide, 1997. Panorama Concept and Planning User manuals, 1998. Microsoft Windows NT4 Server and Workstation, Concept and Planning, Networking Supplement, 1997. B. Gravil, B. Jager, G. Bon mardion, F. Minot, Back-up Systems of the Tore Supra Superconducting Toroidal Magnet Refrigeration, ICEC 15 Proceedings, Cryogenics, vol. 34, 1994.