Status of ITER collaboration for Machine Protection I. Romera On behalf of the colleagues who contribute to the project Thanks to: Sigrid, Markus, Rüdiger, Manuel, Jonathan et all…

Outline  Introduction  Magnet Powering Layout  Current activities ongoing  Next milestones

Facts Q ≥ 10 (500 MW) 840m 3 of plasma 150M °C Tons 12.8 Billion Euros 34 nations ITER Tokamak

CERN-ITER agreement  Agreement nº 7 of 2007 cooperation between ITER and CERN  4 tasks:  Consultancy for the set up of a MPWG  Definition of overall architecture of Machine Protection and Central Interlock System  Specifications for the fault scenario simulations  Definition of tools for diagnostics

Outline  Introduction  Magnet Powering Layout  Current activities ongoing  Next steps

Magnet Powering Layout Toroidal Field coils  Plasma confinement  18 coils / 1 circuit  Stored energy = 41 GJ  Nominal current = 68 kA

Magnet Powering Layout Poloidal Field coils  Keep plasma away from walls  6 coils / 6 circuits  Stored energy = 4 GJ  Nominal current = 48 kA

Magnet Powering Layout Central Solenoid coils  Induce plasma current by changing current in the CS  6 coils / 5 circuits  Stored energy = 6 GJ  Nominal current = 45 kA

Magnet Powering Layout Corrector coils  Compensation of errors in confining magnetic field  18 coils / 9 circuits  Stored energy = 2 GJ  Nominal current = 10 kA

Magnet powering layout

Outline  Introduction  Magnet Powering Layout  Current activities ongoing  Next steps

 Functional specification of necessary logic in CIS for magnet powering protection  3 levels of protection:  Circuit level  Family level  Global level  Defining dependability level for each IPF  Includes fault tree representations of IPF Activities ongoing – IPF

 Circuit level IPF CF-QFCPA Quench in any circuit has to result in: Opening of all FDUs: o Case of the Toroidal Field Circuit at least 7oo9 o No action (no FDUs) in the case of Corrector Coils Fast Power Abort of the corresponding Power Converter Fast Discharge Request detected by PC, CIS and FDUs Inhibit Start of Powering/next plasma discharge Inform PCS to start Plasma ramp down/disruption mitigation A FDU spurious opening in any circuit (no action in case of Corrector Coil circuits) result in the same procedure as above. A CIS Fast Discharge Request has to result in the same actions as in the case of Quench. A Power Converter Fast Discharge Request has to result in the same actions as in the case of Quench Required SIL level SIL 3 equivalent. Direct hardwired loop, daisy chaining all involved user systems (quench loop)

Activities ongoing – IPF  Family level IPF CF-QFCPA Quench in any circuit of a family has to result in: Opening of all FDUs for the family of circuits considering: o No action (no FDUs) in the case of Corrector Coils Fast Power Abort of the Power Converters for all circuits of the corresponding family Fast Discharge Request detected by PC, CIS and FDUs Inhibit Start of Powering/next plasma discharge Inform PCS to start Plasma ramp down/disruption mitigation A FDU spurious opening in any family of circuits (no action in case of Corrector Coil circuits) result in the same procedure as above. A CIS Fast Discharge Request has to result in the same actions as in the case of Quench. A Power Converter Fast Discharge Request has to result in the same actions as in the case of Quench Required SIL level SIL 2 equivalent. ‘Configurable’ function implemented in Safety PLC and probably additional redundant HW module.

Activities ongoing – IPF  Global level IPF GF-CR2A less critical failure in the Cryogenics system due to a for instance an unbalanced coil cool down distribution implies: Inhibit Start for all the circuits of all families Slow Abort of the Power Converters for all circuits of all families Inform PCS to start Plasma ramp down/disruption mitigation Required SIL level SIL 2 equivalent. Hardware signal exchange with safety PLC I/O

 Functional specification of signal exchange between clients  Dependability requirements for different signals types  Transmission type and architecture  Electrical properties of interfaces and connections (interface box, safety PLC I/O) Activities ongoing – Hardware interfaces

 Fast discharges in magnet coils limited to ~50 during ITER life (real+false)  To ensure investment protection, CIS design must not only account for high level of safety, but also for high availability (to limit mechanical stress)  Studies confirmed 2oo3 architecture as the best candidate to meet dependability requirements Activities ongoing – Dependability studies Courtesy of S.Wagner Quench Loop Interface (voting fault-free) Interface with loop components (voting fault-free)

Activities ongoing – Dependability studies Interface with voting component Courtesy of S.Wagner Interface with redundant voting component  Series of quantitative studies performed on architecture of  Quench Loop  Interface with fault-free voting  Interface with voting component prone to failures (with and without redundancy)  Interface with voting logic

Activities ongoing – Dependability studies Courtesy of S.Wagner Interface with voting logic A. Apollonio  Series of quantitative studies performed on architecture of  Quench Loop  Interface with fault-free voting  Interface with voting component prone to failures (with and without redundancy)  Interface with voting logic

Activities ongoing – Dependability studies Courtesy of S.Wagner Availability Safety  2oo3 is the best compromise for availability and safety, but… it is only efficient if does not stop at the level of the CIS, but … Quench Loop

Activities ongoing – Dependability studies Courtesy of S.Wagner Interface A_B1_B2_C1_C2_C3_B0CO_ Mission completed B7 7.95E E E E E E E E-01 Emergency success B5A 1.28E E E E E E E E-01 False successB5B 7.62E E E E E E E E-02 Emergency missed B6A 4.62E E E E E E E E-05 False missedB6B 5.87E-02 Availability Safety … continued to the client system.

 Several proposals based on PLC S series:  Redundant configuration: S7-400H + 2oo3  Redundant + Safety configuration: S7-400FH + 2oo3  Performance analysis on periphery based on:  Response times  MTBF figures from SIEMENS catalogue  Results shown:  F modules ~3 times slower than standard  F modules ~3 to 5 times more likely to fail than standard Activities ongoing – Interlock prototype Courtesy of M. Zaera-Sanz

 Provides unique interface to the Quench Loop with required dependability  Remote test facility  Simplified test and commissioning  Unique version common to all clients  Based on CIBU design Activities ongoing – Interface box Courtesy of J. Burdalo-Gil

Next milestones  First version of PLC program, implementing local and global IPFs  Performance measurements for realistic configuration  Functional verification of prototype  Remote diagnostics for user interfaces  Experimental setup being built in China with current leads QD

Next milestones

Thanks for your attention

Parameters of electrical circuits

Fault tree representations