Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – Current Plans for ITER Hydrogen Phase Presented by A. Loarte with input from P. J. Lomas, M. Bell, D. Campbell, R. Sartori, I. Nunes, M. Shimada, E. Synakowski, Y. Kamada, L. Horton, M. Wade, G. Sips, A. Costley, et al.,

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – ITER Research and Exploitation Plans  ITER Research Plan being prepared with the following aims Definition of research & exploitation plan to meet ITER mission goals Analysis of ITER facility’s capacity to meet mission Highlighting of R&D required to prepare efficient ITER operation Identification main thematic research areas to be integrated in the exploitation plan  ITER Exploitation Plan (~ 20 years) Hydrogen Phase (~ 2.5 years) Deuterium Phase DT1 Operational Phase (inductive/non-inductive) DT2 Operational Phase (towards power plant physics & technology) Foreseen operation (2 operational shifts/day for 2 weeks + 1 week maintenance & a few months shutdown per 1-2 year)

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – Assumptions for start of H Phase  Installation is essentially complete and ready for hydrogen phase (Magnets, Vacuum systems, Be-wall, CFC divertor)  Torus conditioning (without plasma) is complete  Individual subsystem commissioning is either complete or can be phased with plasma operation (T plant commissioned in parallel)  Operation days ~ 150 per year with 50% availability  Available H&CD systems NBI : 8 MW at 0.5 MeV (possibilty of higher power being explored) ICRH : 20 MW (40-55 MHz) ECRH : 20 MW (170 GHz) + 3 MW (127.5 GHz for 10s BD) Error field correction coils Minimum set of diagnostics (first plasma or ready for commissioning with plasma) : Magnetics, n e (r)-T e (r)-T i (r), Runaway diagnostics, visible-near UV & VUV spectroscopy, neutral pressure and gas composition, Halo current monitors, Bolometry and gas balance measurements

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – Objectives of H Phase  Demonstrate facility operation sufficient for commissioning with plasma  Commissioning of H&CD systems and diagnostics with plasma  Validation and consistency of measurements  Commissioning and integration of all installed control systems  Commissioning and integration of all safety related systems  Demonstration of plasma operation to full technical performance (15 MA, 5.3 T)  Demonstrate critical systems performance (i.e. divertor power loads)  Validation of licensing assumptions concerning loads (disruptions)  Characterise operational boundaries and off-normal events  Demonstrate (to possible extent) plasma performance and scenarios envisaged for DD and DT operation (ramp-up/down & flat top)  Characterise hydrogenic retention and demonstrate techniques to be used later for control of T inventory

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – Operation for commissioning with plasma Objective : Develop plasma operation/scenarios that allow commissioning of H&CD and diagnostic systems with plasmas  Breakdown : Null formation, Inductive breakdown and ECRH assisted breakdown  Initial plasma current rise  Controlled current rise in limiter configuration  Density control by gas fuelling  Demonstration of X-point operation  Demonstration of diverted phase with plasma current flat top  Controlled ramp-down and discharge termination (incl. emergency plasma shutdown) Proposed target plasmas : 3-7 MA, T with q 95 = 4-5 with 10 s flat top (50-100s with PFC protection & emergency shutdown) Exploration of divertor plasmas DL (operation at 80% n GW ) (If Breakdown at low field problematic  Full field option considered)

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – Commissioning of Installed systems with Plasma (I) Objective : Commissioning of heating systems and dedicated diagnostic commissioning  Possible reduced field operation for H&CD commissioning (2 nd  ) ECRH: MA(mp)/4-8MA(ul) & T(mp)/ T(ul) q 95 =3-5 ICRH : 3-8MA T q 95 =3-5 NBI : 5.5 MA T q 95 = ICRH ECRH ICRH ECRH

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – Commissioning of Installed systems with Plasma (II)  Proposed plan Common plasma for all systems (5-6 MA T with q 95 = 4) (if L-mode density limit higher than 0.8 n GW ) Commission in parallel of H&CD systems to 20 s (100 s flat top assumed)  IR systems (WAV + DIV) + Impurity monitors fully functional Dedicated time for CXRS, MSE calibration (if possible) and other diagnostics cross calibration + absolute calibration foreseen

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 –  Major topic of H campaign to proceed in parallel with system commissioning & expansion of plasma operation  Some dedicated time to specific to solve problems and discrepancies foreseen  Key measurements to be considered depend on achievable plasma regime : L-mode, poor quality H-mode (maybe possible), high quality Type I H-mode (unlikely)  Measurement validation programme to be linked to scientific objective of R&D programme : fast particle studies (incl. ripple), CD efficiency measurements, L-mode studies, NTM threshold determination in L-mode, fuelling studies (incl. pellets, etc.) Validation of diagnostic data & measurement consistency (I)

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – Validation of diagnostic data & measurement consistency (II)

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – Validation of diagnostic data & measurement consistency (III)

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 –  SICs protect plant against failure and some of their actions need to be commissioned with plasma Plasma termination (active protection) Fusion Power Shutdown (failure of tokamak cooling water system) Faults in coils and PF system switch-off Radiological and fire interfaces, etc.  Dedicated time to commissioning of non SIC machine protection systems/diagnostics (e.g. divertor thermography for over-heating avoidance, etc.) Commissioning/Integration of all Safety related systems

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 –  Push plasma parameters from commissioning level to 15 MA/5.3T and full heating power (~ 48 MW)  Proposed development routes : Constant q 95 ~ 3 : 7 MA  9.6 MA  11.3 MA  12.7 MA  15 MA ~ Constant B  = 5.3 T : 5-6 MA to 7 MA from 2.5 T  5.3T + 9 MA  MA  15 MA at 5.3 T (q 95 = 5  4  3) Initial pulse length secs (> 10  E ) to be extended together with divertor performance assessment Plasma Operation to full technical performance (I) 1.0 ICRH ECRH ICRH ECRH

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – R&D topics (with PWI emphasis) that must/could be addressed in this phase in addition to those in main objectives of H campaign  Development of ramp-up scenarios ( l i control) for VS and flux consumption assessment (aiming at l i ~ 0.85 – 1.0) by H&CD application in ramp-up (+ dI p /dt tuning) Plasma Operation to full technical performance (II)

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 –  SOL transport and divertor power scaling in L-mode (IR + edge plasma measurements) P input, n e, I p, q 95 scans ideal for transport analysis Investigation of divertor asymmetries and plasma flows Initial assessment of SOL effects by plasmas dominated by e- heating + equipartition in reactor scale plasmas Initial assessment of impurity generation and plasma contamination in large range of conditions in ITER (ICRH + W, fast particle effects, etc.)  Density limit characterisation (linked to disruption studies) First assessment of ITER “specific” divertor physics (Ly  re- absroption, n-n collisions, detachment physics, etc.) if high /n GW accessible in L-mode and medium/high currents L-mode : 15 MA, 48 MW, /n GW ~ 0.6  n sep ~ m -3, T sep ~ eV (P sep ~ 30 MW)  n div ~ m -3 for T div = 3 eV Plasma Operation to full technical performance (III)

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 –  Initial studies of plasma fuelling : fuelling efficiency for gas puffing (divertor & main chamber) and pellet injection for range of L- mode plasma conditions (if H pellets available)  First assessment of divertor erosion/ dust production and fuel retention (linked to retention and inventory control studies) and dependence on plasma characteristics  First assessment of divertor and first wall power and particle fluxes and dependence on plasma conditions Detailed R&D in support of these studies comparing L and H modes (in H & D) in existing devices would allow an initial guess to H-mode SOL plasma characteristics and power fluxes in ITER to be checked in H (if L-H threshold allows) Plasma Operation to full technical performance (IV)

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 –  Performance of critical systems need to be tested before DD and DT operations  steady-state power handling of divertor and first wall (limiters & upper X-point region) Plasmas to be employed for main wall PFC and divertor tests maybe different because p ~ 1/I p Expected maximum power flux at divertor in L-mode : I p = 15 MA, q 95 = 3, P input = 48 MW, n e /n GW ~ 0.3 and P rad /P input ~ 0.3 if p ~ 1 cm & P div out /P div in ~ 2  q div out ~ 6 MWm -2 (q mp out ~ 120 MWm -2 ) & q II (  R = 4 cm) ~ 2 MWm -2 + wall flux I p = 7.5 MA, q 95 = 3-6, P input = 48 MW, n e /n GW ~ 0.6 and P rad /P input ~ 0.6 if p ~ 2 cm & P div out /P div in ~ 2  q div out ~ 2 MWm -2 (q mp out ~ MWm -2 ) & q II (  R = 4 cm) ~ 5-10 MWm -2 + wall flux Length of P heat most likely set by flux consumption : Higher V loop in L-mode + higher l i  cause higher resistive and inductive flux than in reference H-mode Demonstration of critical system performance

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 –  Forces on Vacuum Vessel during disruptions and VDEs is a key parameter for licensing  Disruption forces on in-vessel components, disruption thermal loads on PFCs, runaway impact key issues for protection of the tokamak and development of operational strategies  Determination of operational boundaries required for minimisation of disruptive events (, q 95, P input ) during L-mode phases of ITER discharges  Issues to be studied : EM forces on vessel, Blanket modules, Divertor, TBMs, Port Plugs Halo current magnitude, poloidal and toroidal distribution Thermal loads on PFCs during thermal quench and current quench Validation of disruption models Validation of licensing assumptions (I) (disruptions and operational boundaries)

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – Runaway generation and suppression schemes/strategies Disruption/VDE mitigation by active methods (MGI)  Conditions to be explored : Upwards/downwards VDEs Density limit and radiative disruptions ideal MHD driven disruption (pressure peaking, low q 95, etc.) L-mode vs. H-mode target plasma before disruption/VDE  Total number of expected disruption several 100s including some at 15MA and highest W plasma achievable  possible in-vessel repairs needed (much easier in H than in DD or DT  Disruption programme to be interleaved with development of plasma performance to 15 MA to allow safe approach to full current plasma Validation of licensing assumptions (II) (disruptions and operational boundaries)

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – Plasma performance and scenarios suitable for DD and DT (I) Three areas of R&D during H phase could have major impact on subsequent DD and DT programme  Large hydrogenic retention  Poor H-mode confinement or marginal power for good H-mode  Large unacceptable ELMs for divertor/wall PFC lifetime Assessment of these issues may require additional experimental time and/or plasma conditions besides that already foreseen for the other topics

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – Plasma performance and scenarios suitable for DD and DT (II)  Determining as soon as possible hydrogenic retention and related issues in initial PFM choice (Be+W+CFC) important for PFC redesign and/or planning of PFC changes (CFC  W) Monitoring of gas balance in H  Dedicated system under consideration but problem of background H level in materials Analysis of long term or retrievable samples Collection and analysis of dust and flakes Test of techniques (night/weekend shifts) and strategies (operational sequence) to minimise in-vessel fuel inventory Dependence of fuel retention, dust production on plasma characteristics (P inp, I p, n e, L-mode vs. H-mode)

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – Plasma performance and scenarios suitable for DD and DT (III)  Understanding H-mode access and H-mode confinement in ITER plasmas as early as possible beneficial for further studies in H plasmas and R&D planning in DD and DT Determination of SOL power width in similar L-mode and H- mode conditions  need for high recycling/detached divertor operation at Q DT = 10 Influence of plasma regime on disruption and VDE dynamics and processes (thermal/mechanical loads, runaways) and mitigation systems Influence of H-mode operation and ELMs on fuel retention

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – Plasma performance and scenarios suitable for DD and DT (IV) Available power (48 MW) marginal for Type I H-mode operation  P LH = MW even at 7.5 MA/2.7T and /n GW ~ 0.6 Margin above threshold low ( depending on H-mode natural density) even for optimistic threshold scalings  H-mode studies in H will be very limited or impossible in ITER

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – Plasma performance and scenarios suitable for DD and DT (V) If H-mode access in ITER requires powers on the lower range of predictions  Type I ELM studies in H would be possible Determination of ELM size and power load characteristics at q 95 = 3 and 4 (~ 7.5 MA)  relevant ELMs for controlled ELM studies (material erosion) and marginally-uncontrolled ELM studies (material damage) and post-ELM plasma behaviour n ped = m -3 T ped = keV & W ped ~ 25 MJ (from 15MA no isotopic effect) * ped =   W ELM /W ped ~   W ELM < MJ & “natural” f ELM = 1(5MJ) – 4 (3.8MJ) Hz p,ELM ~ p,s.s. ~ 1 cm &  W ELM in /  W ELM out = 2  0.9 – 1.2 MJm -2 at inner divertor for uncontrolled ELMs Tolerable ELM of 0.5 MJm (  rise ~ 250  s)~0.7 MJm MA

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – Plasma performance and scenarios suitable for DD and DT (VI) If H-mode access in ITER requires powers on the lower range of predictions  Type I ELM studies in H would be possible Initial studies of ELM control by RMP (requires system to be able to operate in a range of q 95 if lowest field operation difficult) ELM control by pellet pacing (if H pellets available) possible with moderate frequency > 10Hz (i.e. 2 x largest “natural” largest f ELM ) Tests of other ELM control schemes developed in the future (e.g. second separatrix distance, etc.) If H-mode (ELM control) studies are considered essential before D operation and are impossible in H then He operation could be explored (lower P L-H but worse H-mode confinement and no retention studies)

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – Overall schedule for H-campaign 1 month  20 planned operational days 50% availability in H-phase  Multiplication by factor of 2 Real time for H-phase = 30.5 months  2.5 years duration for H- phase is not unreasonable

Alberto Loarte 10 th ITPA Divertor and SOL Physics Group Avila – Spain 7/10 – 1 – Conclusions  H phase in ITER key objectives concern system commissioning, critical system tests, acquisition of key measurements for licensing of DD and DT operations and pushing towards full current/field plasmas  Besides this “technical” objectives key Physics R&D will be addressed, such as SOL transport and power deposition in L-mode and, possibly, in a limited range for H-mode conditions Density limit and detachment physics in “typical” ITER conditions (optically thick and collisional neutrals) Runaway generation and suppression methods Disruption physics and mitigation schemes Evaluation of fuel retention and dust production in L-mode and, possibly, in a limited range for H-mode conditions Depending on H-mode access  ELM physics and control in “typical” ITER conditions (low * ped and high n ped /n GW ) Input from ITPA groups to refine further the foreseen R&D plan is very welcome