F P Orsitto ENEA1 Diagnostics for hybrid reactors Francesco Paolo Orsitto ENEA FUSION Technical Unit C R Frascati(Italy) FUNFI VARENNA 2011

Outline Hybrid reactor (HR) models considered and their characteristics: relation to ITER and relevance for DEMO HR : a small,low power DEMO with a (more) complex blanket( fusion + fission). Criteria determining the diagnostic systems needed for HR Classification of Diagnostic systems:i) machine protection;ii) basic plasma control (incl. DT reaction );iii)divertor control;iv) diagnostics for blanket (neutron source and transuranic burn) Requirement on measurements Technology / R&D needed Conclusion and further work F P Orsitto ENEA 2 FUNFI Varenna 2011

References and contribution W M Stacey Fus Sci & Tech 2007(SABR design) M Kotschenreuter Fus Eng Des 2009(ST design) M Wang Fus Eng Des 2010 ( Blanket FDS) Y Wu IAEA Conference Geneva 2008 (paper FT/P3-21) Contributions M Angelone, M Pillon for diamond detectors detectors M Ciotti,J Manzano, F Crisanti, A Botrugno for useful and lively discussions F P Orsitto ENEA 3 FUNFI Varenna 2011

Tokamak Hybrid reactor (HR) models F P Orsitto ENEA 4 FUNFI Varenna 2011

FDS-I China design F P Orsitto ENEA 5 FUNFI Varenna 2011 FDS-1 model

Georgia Model –SABR F P Orsitto ENEA 6 FUNFI Varenna 2011

Tokamak major radius R0= m Tokamak high aspect ratio A=3.4-4 ( higher than ITER A=3) Medium magnetic field B=5-6T (like ITER) Medium-High current IP=6-8MA( 0.5*IP ITER) Relatively low norm beta  N=2-2.8(like ITER) HIPB98 =1-1.1 Main scenario : H-mode Pulsed mode Q=Pfus/Pheating=3 ( Q ITER =5-10) Comparison between FEB/FDS-I (EM) and SABR F P Orsitto ENEA 7 FUNFI Varenna 2011

Comparison between Hybrid Reactor(HR) and ITER & relevance of HR to DEMO The Q_HR factor is of the order of 5-7 times that possible on JET at present And about ½- 1/3 of Q-ITER. Q_HR = 5-7 Q_JET Q_HR = ½-1/3 Q_ITER Q_HR is intermediate between JET and ITER Difference of HR with respect to ITER is the availability : 75% is supposed for HR While for ITER presently it’s 4%. The HR Tokamak can be considered a prototype at small scale of DEMO The HR availability is that hypotesized for a small ( R0=3m), LOW Q (low performance) DEMO With a complex blanket: FUSION + FISSION F P Orsitto ENEA 8 FUNFI Varenna 2011

Criteria determining the diagnostics needed for Hybrid F P Orsitto ENEAFUNFI VARENNA 2011 Tokamak as neutron source The plasma scenario is supposed assessed : no measurements dedicated to physics /scenario evaluation The engineering would permit the insertion of DIA for scenario ev. If needed. The measurements ARE NEEDED for 1. the CONTROL of the scenario ( including DT reactions and neutron production) 2. the safety of the device ( including the divertor and PWI) 3. Monitor the Blanket Modules dedicated to the tritium breeding

Criteria determining Diagnostics needed for Hybrid Reactor(HR) F P Orsitto ENEAFUNFI VARENNA 2011 HR as neutron source for fission The measurements ARE NEEDED to monitor 1. the fission of Main transuranic(TRU) elements 2. the secondary ( from fission) neutron production 3. energy production from fission

ITER assessed Diag Plan F P Orsitto ENEA 11 FUNFI Varenna 2011

An example of DIA set for tokamak : Diagnostics of JT-60SA F P Orsitto ENEA 12 FUNFI Varenna 2011

An example of control plan : Control plan JT-60SA F P Orsitto ENEA 13 FUNFI Varenna 2011

Tokamak/neutron source measurements and diagnostics Tab I Tokamak Diagnostics machine protection Basic-plasma measurements basic plasma diagnostics neutron monitors line average electron density Interferometer/polarime ter Neutron activation measurements fusion power neutron monitors D  emission monitors Zeff measurements brehmsstrahlung rad meas Divertor Langmuir probes impurity and D,T influx Infrared TV camera(divertor) resistive wall mode magnetic loops runawys electrons Halo current magnetic loops nT/nD in plasma core divertor erosion monitors QMB/Monitor Tiles Gas pressure (divertor and ducts) electron temperature ECE / Thomson scattering using Nd:YAG Dust plasma radiation bolometers surface temperature( divertor and first wall) plasma shape and position plasma current F P Orsitto ENEA 14 FUNFI Varenna 2011

Tokamak/neutron source Control Plan quantity to be controlledactuatorsSensors/diag systems plasma positionpoloidal field coilsmagnetic pick-up coils plasma shapein vessel coilsflux loops plasma currentpoloidal field coilsRogowsky coils electron density gas puff, pellet injector,divertor pumpingInterferometer Neutron emission rateP-NB (ECRH, LHCD)Neutron monitor Plasma stored energyP-NB (ECRH,LHCD)Diamagnetic loop Density profilePellet, gas puffInterferometer Current profileP-NB (ECRH,LHCD)Polarimeter Radiation powerImpurity gas puffBolometer Fusion powerP-NB, gas-puff,pellet (ECRH,LHCD)Neutron monitor TemperatureP-NB (ECRH,LHCD)ECE for Te F P Orsitto ENEA 15 FUNFI Varenna 2011

Blanket modules example from China FDS(*) Y Wu Fusion Engineering Design 2006 FDS I Hybrid Blanket design General scheme of a blanket for hybrid M Wang Fusion Engineering Design 2010 F P Orsitto ENEA 16 FUNFI Varenna 2011

Proposed scheme of blanket F P ORSITTO (ENEA) 17 FUNFI VARENNA 2011

Isotopes and decays elementMass Nr alpha decay(kev)gamma decay(keV)Half life Am y Pu e5y Pu y Np e6 y Pa y F P ORSITTO (ENEA) 18 FUNFI VARENNA 2011

Blanket diagnostics The blanket diagnostics need for measuring : i)The content of isotopes ( measurement alpha lines of various radionuclides) ii)The neutron multiplication ( neutron flux / neutron spectroscopy) iii)Tritium breeding ( monitors of tritium) Sensors can be inserted in the : i)FUEL zone ii)Tritium breeding zone iii)Outside the vessel F P ORSITTO (ENEA) 19 FUNFI VARENNA 2011

Meaurement of Isotopes The measurement of isotopes can be carried out both : i)Using alpha particle monitors inserted into the blanket very close to the containers of ling life isotopes to monitor on line the ‘transmutation’ of long lived isotopes ii) Using off-line alpha particle spectroscopy Sensors for alpha particle detection and spectroscopy in the range of 4-5MeV can be syntetic diamond diodes with technology and electronics Well known and tested These diodes have also a very good resistence to the high neutron flux F P ORSITTO (ENEA) 20 FUNFI VARENNA 2011

Neutron and gamma ray measurements Sensors for neutron can be inserted into the blanket in particular in the fuel zone As well as outside the vessel The technology for this detection is well known The gamma spectroscopy in particular made using high resolution Measurements by Ge detectors can be useful to characterize both Plasma and secondary gamma derived from decay of radionuclides. F P ORSITTO (ENEA) 21 FUNFI VARENNA 2011

Parameters important for determining the requirements on measurements Neutron flux Q=3, Pheating =50MW, A=4 and R0=3m F P ORSITTO (ENEA) 22 FUNFI VARENNA 2011

Requirements on measurements F P Orsitto ENEAFINFI VARENNA 2011 requirement on measurements for diagnostics of hybrid reactors Tokamak Neutron source measurementrange (keV) spatial resolution time resolut ion accura cysystem temperature a/101Hz 10-20% ECE & LIDAR Thomson scattering density E19 m-2line integral1Hz 10-20% CO2 interferometer neutron flux and emissivity 10 E14-10 E20 n/sintegral1Hz 10% diamond detectors neutron profile monitor 10 E14-10 E19 n/(m2 s)a/101Hz 10% diamond detectors or scintillators Zeff monitor line integral1Hz 10% vis bremmsthralu ng escaping alpha<2MW/m3 a/10 along poloidal direction100ms 10% scintillator probe

Requirements on measurements F P Orsitto ENEAFuNFI VARENNA 2011 divertor operational parameters divertor termography C 1Hz 10% erosion rate 1-10E-6 m/s10mm1s 30% Gas pressure 1E-4- 20Pa 50m s 20% blanket ( Fuel zone) alpha particle4-5MeVintegral1Hz 10% diamond detectors (off line and inside measurem ents) gamma ray keVintegral1Hz 10% Ge detectors (off line measurem ents)

DIA for Hybrids :R&D Needs Tokamak /neutron source : Erosion of divertor Lost alpha probe Blanket : Fuel Zone Test of Diamond detectors as Alpha particle diagnostic inside F P ORSITTO (ENEA) 25 FUNFI VARENNA 2011

conclusions F P Orsitto ENEA Tokamak for Hybrid concept is located between ITER and a low power proto-DEMO HR Tok :Q=3, availability 75%, long pulses (months?) ITER: Q=5-10, pulse duration 400s, availability 4% Diagnostics for hybrid share some characteristics with a low power proto-DEMO Diagnostic system: No scenario evaluation, monitor of main kinetic quantities, control of MHD Stability and current profile via Current Drive Diagnostics for the safety of the machine( Divertor erosion monitor) Diag systems can be used also to monitor the FUEL zone of the blanket Through the measurements of alpha decay of long term actinides