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12th ITPA TG Meeting on Diagnostics 26 - 30th March 07, Princeton Radiation Effects WG Benoit Brichar d for Eric Hodgson. Last meeting of Radiation Experts at 16th IEA Workshop held during SOFT-24 (13th Sept 06) in Warsaw. 21 people attended the 5 h meeting - (EU:15, JA:3, EFDA:2, ITER:1)
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12th ITPA TG Meeting on Diagnostics26 - 30th March 07, PrincetonRadiation Effects WGBenoit Brichard for Eric Hodgson • Last meeting of Radiation Experts at 16th IEA Workshop held during SOFT-24 (13th Sept 06) in Warsaw. • 21 people attended the 5 h meeting - (EU:15, JA:3, EFDA:2, ITER:1) unfortunately no RF or US colleagues. • Updates given on activities: JA (M. Yamauchi) EU / RF / US (E. Hodgson) Extended presentations on: TIEMF / RIEMF (R. Vila and L. Vermeeren) Optical fibres (B. Brichard) Common issues for Magnetic and Inertial Confinement (J.L. Bourgade, M. Decreton, E. Hodgson) Radiation R&D requirements for diagnostics - table update (G. Vayakis) • Following is a summary of the presentations + recent work/results ==>
EU Optical fibres (Belgium, France, Rumania): Benoit Brichard (separate presentation) Resistance type bolometers (Belgium, Germany, Spain): Pt on 3 different substrates: alumina, AlN, “SiN” to be irradiated in BR2, SCK/CEN General electrical contact problem* being addressed Ferroelectric type bolometers (Austria, Latvia, Spain): PbZrO3 with reliable electrical contacts* being prepared - but long delay Hall sensors (IPP:CR + Ukraine): New sensors based on solid solutions of InSb and InAs potential for > 200°C But problems with electrical connections*, solder joints, thin wire insulation Reactor irradiation later this year *Electrical contacts for small devices / components giving problems during irradiation
EU Plan to test various cable types for RIEMF/TIEMF effects with active heating, so a new rig design is necessary. Should give a clue on the performances of various types of MI cables (stainless steel vs. copper core; size effect; single-core vs. twin-core) and of ceramic coated wires and twisted-pair Sultzer cable (OFC). Awaiting cable delivery
EU RIEMF and TIEMF in MI cables and cables (Belgium, Spain): TIEMF (centre conductor) detailed study Examine EMF (V) vs T for Cu, Ni, and SS cored cables Will need some standard “QA” test (e.g. TIEMF for fixed temperature gradient over 1 m) Large EMFCu related to damage to soft Cu conductor during manufacture - probably no solution Probable cause of high EMF for Ni core also ==> use SS or twisted ceramic coated cables ? Severe damage in CuIncrusted silica
EU Alternative radiation resistant glasses (Belgium, Spain): Tests with Na2O-CaO-SiO2 (+ CeO2) glasses. Radiation induced absorption and RL ≥ 200 ºC shows much lower absorption: Na2O-CaO-SiO2 glass Absorption 0.5 MGy, 70ºCAbsorption 0.6 MGy, 200ºC
EU Alternative radiation resistant glasses (Belgium, Spain): Absorption recovers at RT following irradiation ==> unstable defects need in-situ measurements RL (and absorption) is intense in both glasses compared with KU1 and KS-4V: Now preparing RL measurements at high T (≤ 250 C) Absorption 0.2 MGy, 20ºCRadioluminescence, 20ºC
EU Windows, ceramics, mirrors (Spain): Enhanced surface degradation (optical and electrical) by low energy H and He bombardment. XPS analysis shows extreme O sputtering loss for silicas and aluminas Results => Si or Al rich surface zone Potential problem ? Ion conductivity at low residual gas (He, H) pressures (Spain): Necessary to determine potential currents - measure RIC at low pressure => pA/cc/Gy at 10-3mbar
EU Secondary overcoated mirrors (Spain): UV enhanced mirrors degrade - radiation modification of coating (thickness, refr. index) Manufacturers specifications not always reliable: HfO2 for MgF2 ==> activation ? SiO / SiO2 ratio ==> swelling cracking corrosion (LOCA)
JA(M. Yamauchi, T. Shikama, S. Nagata, K. Toh, B. Tsuchiya, A.Inouye) 1. RL (Radiation induced luminescence): Fused silica, Cr doped sapphire, and Eu and Dy doped strontium aluminates gamma-ray, ion, and 14 MeV neutron irradiation. Aim to separate ionization and displacement dose effects. RL as sensor for 14 MeV neutrons. Possibility of monitoring ion energy has been demonstrated (Cr in sapphire).
JA 2. Conversion of nuclear radiation energy directly into electricity: RIC is being studied in perovskite oxides with high proton conductivity. Neutron irradiation enhances proton conductivity even at low temperatures (20-200 C). Importance of hydrogen in radiation effects in oxide ceramics. May cause technological problems in nuclear fusion machines, so far not considered.
JA 3. Large EMF in proton conductors (CaZrInO) : Large EMFs observed in some proton conductors ionizing dose rate (monitor ?) Not the case in other similar materials (SrCeYbO)
RF(Ilya Orlovskiy and Konstantin Vukolov) Development of multilayer dielectric mirrors: heating and neutron irradiation Thermal loads play important role in damaging mirror coating. Sufficient adhesion of coating to substrate for large size mirrors. Sustain neutron fluences and temperatures expected in ITER (0.01 dpa little effect), shift to shorter Luch mirror ZrO2 / SiO2
RF Recent multilayer dielectric mirrors: heating and neutron irradiation TiO2/SiO2 23 layers KU1 and K8 substrates - stable under thermal loading
RF Multilayer dielectric mirrors: heating tests Stable under thermal loading repeated heating in vacuum to T ≤ 300 C for times up to 10 h Coatings undamaged, initially range shifts to longer , then stable
US(K. Leonard, R. Goulding, L. Snead and S. Zinkle) Post irradiation loss measurements at 100 MHz in ceramics for ICRH: Single crystal sapphire and spinel show lowest initial losses, but by 0.001 dpa all oxides similar (possible problem with Deranox sample). BeO almost insensitive. Nitrides worse.
US For oxides little change from 0.001 to 0.1 dpa - importance of ionization at onset Important to remember PIE, and low T (≈ 65C) irradiation in water - not vacuum or He
US Post irradiation thermal conductivity measurements in ceramics for ICRH: Relative insensitivity of loss to irradiation of BeO and high thermal conductivity make it an interesting potential candidate material (considered a candidate for many years for LH): Future work planned: Thermal conductivity for more ceramics Irradiation of multilayer mirrors
EU database work • TW6-IRRCER Database task now underway: UKAEA: Development of the implementation of the ceramic irradiation database, (M. Brooks and P. Karditsas + A. Gusarov and E. Hodgson) Provide reference to the results of the EFDA Ceramic Irradiation Programme by recording all relevant information Provide a searchable repository of documents Provide a searchable database suitable for designer of diagnostics and H&CD systems to find the available information and facilitate design choices. • Will use the current EU Fusion Materials Database as framework • To be extended for full ITER partner use at a later date • Now discussing how the data should be presented and what information it should contain ==>
George’s table - Irradiation tests: needs for ITER(Comments / input from RF and EU only)