PIE program of STIP-V tungsten specimens for ESS target engineering Jemila Habainy, Yong Dai, Yongjoong Lee, Srinivasan Iyengar European Spallation Source, Paul Scherrer Institut, Lund University 6th High Power Targetry Workshop, 11-15th April 2016, Oxford

Outline ESS Tungsten target STIP-V project at PSI Scope of PIE program Preliminary results Summary HPTW-6, Oxford, April 2016 Jemila Habainy

ESS Tungsten Target Target will operate at max. 500°C Estimated lifetime of 5 years Accumulated damage max. 10 dpa dpa/year in Tungsten HPTW-6, Oxford, April 2016 Jemila Habainy

SINQ Target Irradiation Program - STIP 2 year irradiation program at PSI Spallation Neutron Source SINQ 560 MeV/ 1.3 mA Proton beam 360x Zircaloy-2 clad Pb rods, and 15-20 specimen rods HPTW-6, Oxford, April 2016 Jemila Habainy

STIP-V, Rods 3 and 5 STIP-V Irradiated between 2007-2008 Temperature and dose distribution profiles follow the 2-D Gaussian proton beam 2x hot-rolled tungsten bars, size: 60x8x1mm, at row 7; rods 3 and 5 5-28 dpa, 100°-800°C HPTW-6, Oxford, April 2016 Jemila Habainy Proton beam

2 pieces of Tungsten extracted from Rod 3 8 ~ 40 ~ 12 HPTW-6, Oxford, April 2016 Jemila Habainy

EDM cutting plan for Rod 3 6x small bend samples, 8x2x1 mm 4x tensile samples, 4x16 mm HPTW-6, Oxford, April 2016 Jemila Habainy

7 pieces of tungsten in Rod 5 20 mm The 5 larger pieces are about 15-20 mm long. HPTW-6, Oxford, April 2016 Jemila Habainy

EDM cutting plan for Rod 5 One 6 mm diameter disc and 4-6x bend samples of 8x2 mm were cut from each of the 5 larger pieces. HPTW-6, Oxford, April 2016 Jemila Habainy

Cold cutting with reference tungsten The entire cutting procedure was first performed on unirradiated reference tungsten HPTW-6, Oxford, April 2016 Jemila Habainy

Cutting of active samples in Hot cell R3 HPTW-6, Oxford, April 2016 Jemila Habainy

Results after EDM cutting (low dose) In total 31 samples successfully extracted: 4 Tensile 5 Discs 22 Small Bend Bars Sample extraction work:  800 hours manpower 10 days hot-cell Specimen type Size Dose rate Low dose specimen, handled manually HPTW-6, Oxford, April 2016 Jemila Habainy

High dose specimen Highly active samples: Dose rate up to 12 mSv/h at 10 cm (limit 20 mSv/person/year) Require special handling, currently waiting for licensing of semi-hot cell HPTW-6, Oxford, April 2016 Jemila Habainy

PIE plan for STIP-V tungsten specimen Bend tests 6 low dose , 16 high dose bars Ductility and flexural stress/strain Tensile tests 4 high dose specimen Yield and tensile strength Hardness tests Irradiation hardening as a function of dose Thermal diffusivity with Laser Flash Apparatus 2 low dose, 3 high dose discs Thermal conductivity and specific heat capacity SEM & TEM microscopy Fracture mode and microstructural changes at different doses and temperatures HPTW-6, Oxford, April 2016 Jemila Habainy

Bar sample preparation and PIE Starting with 6x low dose bars. Polishing Hardness measurements 3-point bend test Gamma spectrum analysis SEM fractography HPTW-6, Oxford, April 2016 Jemila Habainy

PIE: Gamma spectroscopy & Hardness measurements Nuclide/ Activity* [MBq] Hf-172 5.200 Ti-44 0.110 Lu-172 20.00 Co-57 0.081 Tm-172 0.890 Co-58 0.750 Lu-179 0.240 Co-60 0.096 Hf-182 0.450 Rh-102 0.082 Os-182 0.390 Ru-106 0.330 Re-188 Hardness increase from 400 to nearly 700 HV0.5 after 4.4 dpa Hf-172 (1.87y) and Lu-172 (6.70d) main nuclides (measured 7 years after irradiation) Radiation damage: 1.5-6.67 dpa *Results from SBB-5 specimen Specimen dpa Dose rate (mSv/h in 10 cm) Weight (g) Lu172 MBq/g SBB-1 1.64 0.82 0.27903 24.5 SBB-2 2.33 1.00 0.26940 28.7 SBB-3 3.3 1.30 0.27000 36.6 SBB-4 1.5 0.98 0.26547 29.5 SBB-5 4.4 1.40 0.27150 40.1 SBB-6 2.4 1.20 0.26935 33.6 Disc-1 6.67 2.90 0.50514 101.2 Disc-2 4.04 2.40 0.50977 83.8 HPTW-6, Oxford, April 2016 Jemila Habainy

PIE results: 3-point bending test SBB-6 SBB-2 SBB-1

PIE results: 3-point bending test HPTW-6, Oxford, April 2016 Jemila Habainy

Next step High dose specimen cannot be handled in glove box Currently waiting for licensing of new semi hot cell Low dose discs to be tested with LFA for thermal diffusivity data HPTW-6, Oxford, April 2016 Jemila Habainy

Summary Scope of PIE program Preliminary PIE results Tensile tests Thermal diffusivity measurements 3-point bending tests Hardness measurements TEM/SEM microscopy Preliminary PIE results Tungsten shows no ductility at 2.4 dpa and at target operating temperature. Hardness increased almost 40% after 4.4 dpa. Will provide crucial information about proton/neutron irradiation effects on tungsten HPTW-6, Oxford, April 2016 Jemila Habainy