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EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials1 Assessment of tritium retention and release from plasma facing materials under.

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Presentation on theme: "EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials1 Assessment of tritium retention and release from plasma facing materials under."— Presentation transcript:

1 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials1 Assessment of tritium retention and release from plasma facing materials under separate and simultaneous action of temperature, irradiation and magnetic field J. Tiliks, G. Kizane, A. Vitins, E. Kolodinska, G. Ivanov V. Tilika, J. Jansons, I. Reinholds Laboratory of Radiation Chemistry of Solids Institute of Chemical Physics University of Latvia

2 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials2 TW5-TTBB-006-D8. Assessment of the effects of magnetic field, radiation and temperature on the tritium release from beryllium pebbles Task JW6-FT-2.27 Investigation of the effect of magnetic field on detritiation of beryllium tiles from JET UT06-TTBBreeder. System for preparation of beryllium samples for tritium release

3 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials3 In the years 2004-2006 investigating tritium release from neutron irradiated pebbles and tiles a novel effect – increase in the tritium release at thermoannealing under simultaneous action of radition and magnetic field was observed.

4 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials4 Problem Samples Experimental Results – I Chemical forms of tritium II Sorption of tritium III Detritation of irradiated materials Conclusions Outlook

5 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials5 Problem Considerable amounts of T and He accumulate in Be materials of fusion device and may cause technical and environmental problems. Tritium release from materials (Be pebbles, tiles etc.) is impeded. Materials will be under the simultaneous action of temperature (700-1000 K), radiation (up to 10 18 neutrons·m -2 ·s -1 ), and magnetic field (MF, up to about 7-10 T).

6 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials6 The originality of the laboratory is a radiation thermomagnetic (RTM) rig developed on the basis of a linear electron accelerator ELU-4. The RTM rig enables investigations of both - separate simultaneous action of the 3 different factors – 1.Radiation 2.Temperature 3.Magnetic field on different processes, e.g., tritium release, corrosion, etc.

7 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials7 Be pebbles 1.0 non-irradiated - from FZK - 2006 0.5 g BERYLLIUM - from FZK - 2004 0.6 g EXOTIC-8-3/13 - from FZK - 2007 Be tiles 2 upper belt limiter tiles - irradiated JET - 2006 1 toroidal limiter tile - non-irradiated JET - 2006 Planned Be pebbles PBA (NRG) 2007 Be pebbles HIDOBE (FZK, NRG) 2008 Carbon tiles JET2008 other PFM2009 >> Organizational arrangements

8 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials8 Tiles JET (D+T) Pebbles BERYLLIUM Pebbles EXOTIC 8-3/13 Beryllium samples

9 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials9 No.Parameter/ The material investigated Be pebbles from experiment BERYLLIUM Be pebbles from experiment EXOTIC 8-3/13 Be tiles from JET 1.1.Material typeBrush Wellman FRP pebbles, 2 mm Brush Wellman, IGA pebbles, 0.1 to 0.2 mm Brush Wellman, Vacuum Hot Pressed, 250×80×40mm 2.2.Grain size40-200 μm 3.3.Main impurities3125 ppm BeO, 1200 ppm Mg 3400 ppm BeO, 100 ppm Mg 4.4.Irradiation97.4 days in 1994. HFR, Petten, fission spectra 449.8 days in 2000. HFR, Petten, fission spectra D+D, D+T, T (1989-1996) 5.5.Irradiation fluence1.24·10 25 m -2 (E>0.1 MeV) 2.70·10 25 m -2 (E>0.1 MeV) 6.6.Irradiation temperature 780 K800-900 K 7.7.Content of radiolytic gases: Helium Tritium 480 appm (1994) 12 appm (1994) 7 appm (2004) 285 appm (2000) 1,16 appm (2000) 8.8.Specific activity: tritium gamma-impurities - (Co-60, Zn-65, etc.) (1.2±0.4) GBq·g -1 (5±2) MBq·g -1 (0.034±0.004) GBq·g -1 (0.5±0.2) MBq·g -1 1.13 kBq/g

10 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials10 Experimental methods Lyomethod for analysis of tritium chemical forms and its distribution in Be samples - by measuring simultaneously the amount of H 2 evolved and the tritium activity during dissolution. Thermosorption of tritium in samples of unused Be tiles. Thermoannealing of irradiated or 3 H sorbed Be samples under action of Radiation and MF separately or simultaneously. Preparation of Be samples from irradiated and non-irradiated tiles.

11 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials11 Determination of chemical forms of T by lyomethod 1. Irradiated Be samples (T o, T 2,T + ) in 2 M H 2 SO 4 Be o + 2H + 2H o H o + H o H 2 (g. phase) =1.10 10 mol -1 s -1 H o + T o HT (g. phase) K~1.10 10 mol -1 s -1 T o + T o T 2 (doesnt go, because [T o ],< 10 -6 M) T 2 (solid) T 2 (g. phase) T + (solid) T + (solution) A =(A T2 +A To ) gas ph. + A T+ solut.

12 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials12 Be o + 2H + 2H o H o + H o H 2 K=1.10 10 mol -1 s -1 H o + Cr 2 O 7 -2 H + + 2Cr +3 K=2.6.10 10 mol -1 s -1 H o + T o HT K=1.10 10 mol -1 s -1 T o + Cr 2 O 7 -2 T + + 2Cr +3 K~1.10 10 mol -1 s -1 T 2 (solid) T 2 (gas ph.) T + (solid) T + (solut.) A sum =(A T2 +0,10 A To ) gas ph. + ( A T+ + 0,90 A To ) solut. Lyomethod with scavenger of T o 2. Irradiated Be samples (T o, T 2,T + ) in 2 M H 2 SO 4 and 0.5 M Na 2 Cr 2 O 7

13 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials13 Determination of chemical forms of tritium

14 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials14 A setup for dissolution experiments.

15 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials15 Beryllium dissolution system 1999.- 2002. 2002.- 2007.

16 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials16 Tritium monitor behind safety wall Thermomagnetic rig on the bases of electron accelerator LINAC-4 Possible planned experiments - 5.4 T mobile superconducting solenoid magnet (Institute of Physics of University of Latvia) Tritium release experiments

17 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials17 A scheme of radiation thermomagnetic rig 1 – P-10; 2 - He + 0.1% H2 3 – a needle valve and a rotameter; 4 – a quartz tube or ampoule + sample inside + thermocouple +heater; 5 –Zn+ thermocouple + heater; 6 –tritium monitor TEM 2100A + DDH 32 7 –tritium collecting; 8 – temperature control device; 9 – an analog-to-digital converter ADC-212/3 10 – poles of an electromagnet; 11 – a beam current detecting grid; 12 – a current-to-voltage transducer; 13 – a Hall-effect transducer; 14 – radiation shielding; LINAC – a linear electron accelerator ELU-4.

18 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials18 Parameters of the radiation thermomagnetic (RTM) rig Thermo-annealing of samples with and without radiation simultaneous action of magnetic field in the isothermal regime or with a constant rate of temperature increase in a continuous system of tritium measuring. Temperature range - up to 1123 K, rate 1-10 K/min. Duration of experiment - up to 10 hours. Ionizing radiation – fast electrons ( E = 5 MeV, max run in material up to 2.55 g/cm 2 ), the dose rate up to 14 MGy/h. The magnetic field where the sample is placed – up to 2 T. Sample volume 7 cm 3, size (with the oven) - thickness 20 mm, irradiated area – up to 30 mm 2 (diameter of the electron beam through the pole 20 mm). Interpolar distance – 15 mm. It is possible to register also the electrical and optical (radioluminescence) parameters during the experiment.

19 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials19 Thermal sorption of tritium. 5 5 5 mm cube-shaped Be samples from the non-irradiated limiter tile were used. A Be pebble irradiated in the BERYLLIUM experiment was used as a tritium source. Tritium sorption was performed at 773 K for 3 h under 5 MeV fast electron radiation of 14 MGy/h and/or magnetic field of 1.7 T. Setup for tritium sorption in the RTM rig

20 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials20 Preparation of samples from Be tiles

21 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials21 Cutting of samples from tooth17 of Be tile A

22 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials22 Results – I Chemical forms of tritium and distribution in Be materials

23 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials23 Chemical forms of localized tritium Pebbles BERYLLIUM (1994) 0.6 -1.6 GBq/g (2007) Pebbles EXOTIC – 8 -3/13 (2000) < flux 4 -18 MBq/g (2007 ) JET tile A (10-60 kBq/cm 2 ) B (2.4-4.8 kBq/cm 2 ) DT campaign

24 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials24 Distribution of the tritium (T 2 +T o ) localised in BERYLLIUM pebbles 1 - without treatment, 2 – 1123 K 2 h

25 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials25 Distribution of the tritium (T 2 +T o ) localised in BERYLLIUM pebbles after treatment: 1 – none, 2 –1123 K 2 h, F dif. =25%; 3 –1123 K 2 h,1.7 T P=14 MGy·h -1, F dif =52%; 4 – the same treatment as for the curve 3, F dif = 53.2%.

26 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials26 Inhomogeneous distribution of gaseous tritium in beryllium tile B annealed for 0.5 h under different conditions : T – temperature 773 K, R – radiation 14 MGy/h, M – magnetic field 1.7 T.

27 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials27 Results – II Sorption of tritium under action of 3 external factors

28 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials28 Thermosorption of tritium in non- irradiated beryllium tile (3h, 773 K) Chemical forms of the tritium sorbed in non- irradiated beryllium tile (3h, 773 K)

29 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials29

30 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials30 Results – III Degree of detritiation of Be materials

31 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials31 Tritium release from BERYLLIUM pebbles (2 mm)

32 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials32 Influence of MF on the tritium release from BERYLLIUM pebbles at thermo-annealing 2 h, 1123 K

33 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials33 Tritium fractional release at annealing of samples of Be tile A in a continuous flow of He + 0.1 % H 2. Curve labels denote: T – action of the given temperature; M – magnetic field of 1.7 T; R – 5 MeV fast- electron radiation of 14 MGy/h.

34 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials34 Facilitating influence of 3 factor action – T- temperature, R - radiation 14 MGy. h -1, MF magnetic field 1.7 T on tritium release from JET beryllium tile A 500 o C 0.5 h

35 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials35 Comparison of degrees of detritiation of JET Be tiles and BERYLLIUM pebbles

36 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials36 The main diffusing particle of tritium in Be is T o. T 2 is trapped in structural defects in a Be pebble (25 %)T ….. T (singlet) T 2 (recomb.) Diff. T o + T o T o.... T o Uncorrelatated (75 %)T ….. T (triplet) T o + T o (further diff.) The MF can affect singlet-triplet transformation and also change the ratio of T o / T 2 (decrease of the tritium release is observed experimentally ) The dissociation of the T 2 is going under irradiation T 2 (T 2 ) * T o …… T o (E dissoc.= 4.6 eV, G (T o ) = 17.6 at./100 eV) Correlated pair A pair T o …… T o is created in singlet state with life time >10 -9 s always, MF transforms it into triplet state and increases T o amount.

37 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials37 Conclusions 1.Simultaneous additional action of MF and radiation considerably increases tritium release from Be tiles and pebbles at annealing: by about a factor 2 for Be pebbles by about a factor 6 for beryllium tiles 2.The main form of tritium localized in the pebbles and tiles is T 2. The main diffusing form is T 0. Action of radiation and MF stimulate transformation of T 2 into T 0. 3.Irradiation and MF separately increases tritium thermo sorption in beryllium. Irradiation with fast electrons increased the sorption of tritium by about 80% at about 1 Pa of T2 at 773 K for 3 h in the unused beryllium, magnetic field increased the sorption of tritium by about 30%, but the simultaneous action of magnetic field and radiation did not change the amount of the tritium sorbed. 4. The most part of the tritium sorbed was localized in subsurface layers up to depth of 80 μm of the beryllium samples.

38 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials38 OUTLOOK 2008-2012 To implement project Determination of tritium and analysis of carbon-based plasma-facing components before and after their detritiation with different methods - EFDA JET TWP 2008 Detritiation of PBA and HIDOBE beryllium pebles, Be12Ti pebbles under separate and simultaneous action of temperature, radiation and magnetic field. Cooperation with HFR (Petten, the Netherlands) and FZK (Karlsruhe, Germany). To investigate magnetic field effects on detritiation of PFM using mobile superconducting solenoid of 5.4 T of the Institute of Physics of the University of Latvia on other irradiation devices in the EU. To determine tritium retention in metals using lyomethod for assessment of efficiency of developed tritium removal technologies. To begin exploration of new fuel removal technologies targeted at tritium retention in metals (for ITER with all metal divertor) To investigate possible effects of radiation and magnetic field on structure of very small lithium orthosilicate pebbles (FZK )

39 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials39 Liekie slaidi

40 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials40

41 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials41 To test and estimate 3H release Simulate disruption on neutron irradiated Be decrease Be radioactive waste up to Low Level Waste (Tritium 12 kBq/g ) from different materials in the RTM rig under action of temperature, radiation and MF separately and simultaneously Materials Continue to investigate : Be and BexTiy pebbles (HIDOBE, PBA) Be tiles (JET) Start to research: Carbon tiles (JET) Other plasma facing materials (Inconel, CFC, W,) Thermoannealing conditions: Temperature – a) up to 850 C with rate 5 – 10 C /min b) in isothermal regime 600, 700, 800, 850 C Magnetic field - step by step up to 2 T, Dose rate - step by step up to 14 MGy/h 3H release from materials at 5 T magnetic field ( at Insitute of Physics) Further - 3H release under action of neutrons, magnetic field - Salaspils – Cyclotrone Tritium sorption and desorption in different materials To obtain Li4SiO4 and Li2TiO3 pebbles with little grain size from their nanopowders by sol gel method `

42 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials42

43 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials43 Tritium release from Be tile B under different conditions of thermoannealing

44 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials44 No.SampleRatio of the tritium released with MF and/or R to the tritium released only with temperature T+MT+RT+M+R 1.Be pebbles BERYLLIUM 0.81.31.8 2.Be tiles JET A and B 1.35.07.0

45 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials45 Tritium release from Be tile B under different conditions of thermoannealing

46 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials46 Non irradiated sample Thermo sorption Ampoule (Temperature, radiation, magnetic field) Dissolution T 2, HT residual T 2, HT, H 2 distribution H 2 SO 4 Cr 2 O 7 2- LSM T+T+ T +, T o

47 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials47 Thermosorption of tritium in non-irradiated beryllium tile (3h, 773 K)

48 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials48

49 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials49 Thermosorption of tritium in Be tiles Ionizing radiation (fast electrons, P=14 MGy.h-1) considerably facilitates T 2 sorption, that may be connected with radiolysis of sorbed tritium molecules in a surface of Be and with increase a concentration of T o, which diffuses easily. MF (1.7 T) increase tritium sorbtion up to 40 %. Possible mechanism – formation of radical pair (T o... T o ) in singlet state from tritium sorbed on a surface of Be under thermodissociation. MF transforms radical pair in singlet state to triplet state and thus decreases recombination and increases T o concentration. At present, decrease of sorption under simultaneous action of temperature, MF and radiation is not understandable. Possible reason could be the life time of different T o radical pairs (thermodissociated and radiolysed) in comparison with the spin transformation time in the presence of MF.

50 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials50 Possible MF effect on the T release from a Be pebble T is localised in Be pebbles as atomic gas T o (gas dynamic solution), as T 2 (intergranular and intragranular bubbles), as chemically bound T + (example, OT - ). T diffusion in a Be pebble takes place by T o (faster) or T 2 (slower).

51 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials51 Tritium diffusion go in 2 kinds as T o (faster) and T 2 (slower) in the Be pebble (25 %)T ….. T (singlet) T 2 (recomb.) Diff. T o + T o T o.... T o Uncorelatated (75 %)T ….. T (triplet) T o + T o (further diff.) The MF can affect singlet-triplet transformation and also change the ratio of T o / T 2 (decrease of the tritium release is observed experimentally ) The dissociation of the T 2 is going under irradiation T 2 (T 2 ) * T o …… T o (E dissoc.= 4.6 eV, G (T o ) = 17.6 at./100 eV) Correlated pair A pair T o …… T o is created in singlet state with life time >10 -9 s always, MF transforms it into triplet state and increases T o amount.

52 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials52 Conclusions 1. Simultaneous action of temperature, MF and radiation sufficiently increases tritium release from Be tiles and pebbles. 2.The main form of tritium localized in the pebbles and tiles is T 2. The main difusing form is T 0. Action of radiation and MF stimulate transformation of T 2 into T 0. 3.Irradiation and MF separately increases tritium thermo sorption in beryllium. Increased sorption as the result of simultaneous action of those factors was not observed, must be tested in next experiments.

53 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials53 Experiments planned for the nearest next period to investigate the detritiation of real irradiated Be tiles and pebbles at kinetic thermo annealing process at different temperatures, radiation conditions and MF intensities to optimize working parameters for such detritiation technology and to obtain improved statistics to investigate the complex action of different factors on the T2 sorption in non-irradiated Be samples.

54 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials54 Outlook To determine distribution of tritium in CFC tiles To investigate properties of T To estimate T release and retentioin under action of T T+R T+R+M To develop detritiation method

55 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials55 OUTLOOK 2008-2012 To implement project Determination of tritium and analysis of carbon- based plasma-facing components before and after their detritiation with different methods - 2008 To investigate magnetic field effects on detritiation of PFM using mobile superconducting solenoid of 5.4 T of Institute of Physics of University of Latvia on other irradiation devices of EU. To determine tritium retention in metals using lyomethod for assessment of efficiency of developed tritium removal technologies To begin exploration of new fuel removal technologies targeted at tritium retention in metals (for ITER with all metall divertor) To investigate possible effects of radiation and magnetic field on structure of very small lithium orthosilicate pebbles (FZK ) To test and estimate 3 H release Simulate disruption on neutron irradiated Be decrease Be radioactive waste up to Low Level Waste (Tritium 12 kBq/g ) from different materials in the RTM rig under action of temperature, radiation and MF separately and simultaneously Materials Continue to investigate : Be and BexTiy pebbles (HIDOBE, PBA) Be tiles (JET) Start to research: Carbon tiles (JET) Other plasma facing materials (Inconel, CFC, W,) Thermoannealing conditions: Temperature – a) up to 850 C with rate 5 – 10 C /min b) in isothermal regime 600, 700, 800, 850 C Magnetic field - step by step up to 2 T, Dose rate - step by step up to 14 MGy/h 3 H release from materials at 5 T magnetic field ( at Insitute of Physics) Further - 3 H release under action of neutrons, magnetic field - Salaspils – Cyclotrone Tritium sorption and desorption in different materials To obtain Li 4 SiO 4 and Li 2 TiO 3 pebbles with little grain size from their nanopowders by sol gel method `

56 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials56 Lyomethod for determination chemical forms of tritium

57 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials57 Kinetics of the dissolution of a non-treated Be pebble in 2 M H 2 SO 4

58 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials58 Kinetics of T 2 and H 2 release at the dissolution of non treated Be pebbles 2 M H 2 SO 4 + 0.5M Na 2 Cr 2 O 7.

59 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials59 Possibilities of the RTM rig Continuous investigations of tritium release in different materials – Be, BeTi12, ceramics, Li17Pb83 etc. The RTM rig can be supplemented with a special additional system for investigations of corrosion of structural metal materials in liquid lithium. A special setup for investigations of mechanical strength of polymer composite materials. Investigations of formation of radiation-induced defects in solids by radioluminescence.

60 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials60 Kāda purge gas to liberate tritium labāka?/

61 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials61 Pebbles JET tiles Tritium is localized mostly in gas form ( T2 + To), amount of T+ form is insignificant. In the Be surface melted as the result of plasma exposure, tritium is found as small amounts of T+. In the side part of Be tile amount of tritium is insignificant, mostly in the form of T2. Simultaneous action of temperature, MF and radiation increase tritium release from Be tiles considerably. Irradiation and MF separately increases tritium thermo sorption in beryllium. Increased sorption as the result of simultaneous action of those factors was not observed, must be tested in next experiments.

62 EU-PWI Meeting Madrid 29 - 31 October 2007 Tritium_ release_ Be _materials62 T release from irradiated Be tiles in different thermoannealing proccesses By increasing temperature of thermoannealing up to 835 C, 34 % of tritium releases in 0.5 h (without MF and radiation). Thermoannealing 0.5 h at 835 C in the presence of MF (2.34 T), but without radiation increase tritium release by 6% (up to 40 %) Temperature is a main factor influencing tritium release rate, MF without radiation slightly increases it.


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