Comparison of the mechanical properties of T91 steel from the MEGAPIE, LEXUR and TWIN-ASTIR irradiation programs M. J. Konstantinović, E. Stergar, M. Lambrecht and S. Gavrilov Belgian nuclear institute, SCK.CEN, Boeretang 200, 2400 Mol, Belgium
Outline Introduction - MYRRHA reactor MEGAPIE experiment LEXUR irradiation program TWIN-ASTIR irradiation program PIE Tensile tests Scanning electron microscopy
Role of material research for development of MYRRHA Design tools: Nuclear manufacturing codes: RCC-MRx, Fuel codes FE calculations Design Construction Data Required data for MYRRHA: Some basic characteristics of candidate materials (T91, SS 316L & 1.4970) Effects of LBE & irradiation on material properties Physical effects: Liquid metal embrittlement (LME), Liquid Metal Corrosion (LMC), SCC, etc.
MEGAPIE experiment Materials: T91, 316L Irradiation: High-E protons + spallation neutrons Dose: 0-7 dpa Environment: LBE Temperatures: 230-350 C Specimens extracted: Flat tensile, TEM discs, plates, bars Proton beam
MEGAPIE sample extraction H08 H07 H02 - The Beam Entrance Window (Calotte) H06 H05 H03 - lower liquid metal container (LLMC) H04 H03 H02 H04 - lower liquid metal container (LLMC)
LEXUR II irradiation program Irradiation experiment in BOR-60 reactor (RIAR, Russia) Materials: T91, 316L, 15-15Ti, ODS (Pb) Doses: 6 35 dpa Environment: LBE, Pb Temperatures: 350 C (LBE) & 550 C (Pb) Specimens: Round tensile, DCT, corrosion discs, pressurized tubes
TWIN-ASTIR irradiation conditions Irradiation experiment in BR2 reactor Materials: T91, 316L, High Silicon Steels, welds Dose: 0, 1.25 and 2.5 dpa Environment: LBE & PWR water Temperatures: 300-320 C & 350-370 C & 460-490 C Specimens: Round tensile, DCT, corrosion plates
MEGAPIE Temperatures: RT, 300 0 C Strain rate: 5 x10-5 1/s Environment: PbBi, ArH, Air Oxygen: ~10-6 wt% Tensile tests LEXUR Temperatures: RT, 350 0 C Strain rate: 5 x10-5 1/s Environment: PbBi, Air Oxygen: saturated TWIN-ASTIR Temperatures: RT, 300 0 C Strain rate: 5 x10-5 1/s Environment: PbBi, ArH, Air Oxygen: Oxygen: ~10-6 wt% Limets 2,
Tensile tests T91 A 2.8-3.9 dpa H03-1-13- Ac B 1.1-1.7dpa H03-1-13- Ba C 0.8-0.9dpa H03-1- 13-Cc
Comparison with literature data 1600 1400 Yield strength (MPa) 1200 1000 800 600 400 Literature data T test 300 0 C Literature data T test RT MEGAPIE T test 300 0 C MEGAPIE T test RT T irrad ~290-320 0 C 0 10 20 30 40 50 60 70 80 Dose (dpa)
LEXUR mechanical tests Liquid-metal embrittlement
LEXUR vs MEGAPIE Yield strength (MPa) 1600 1400 1200 1000 800 600 400 RT - test MEGAPIE PSI RT - test MEGAPIE SCK 300 0 C-test MEGAPIE PSI 300 0 C-test MEGAPIE SCK RT - test LEXUR 350 0 C-test LEXUR substantial defect annealing T MEGAPIE irrad ~230-350 0 C T LEXUR =330-370 0 C 0 2 4 6 8 10 Dose (dpa)
TWIN-ASTIR mechanical tests T91 TWIN-ASTIR Irr.: 2.5 dpa at 300 C Test: at 300 C at 5 10-5 /s
Twin-ASTIR vs MEGAPIE Yield strength (MPa) 1600 1400 1200 1000 800 600 RT - test MEGAPIE PSI RT - test MEGAPIE SCK RT - test ASTIR 300 0 C-test MEGAPIE PSI 300 0 C-test MEGAPIE SCK 300 0 C-test ASTIR T MEGAPIE irrad ~230-350 0 C T ASTIR =300 0 C 400 0 2 4 6 8 10 Dose (dpa)
Dose ~ 0.7 dpa No effect of EBW
SEM fractured surface MEGAPIE B 1.1-1.7dpa H03-1-13- Ba
SEM fractured surface MEGAPIE A 2.8-3.9 dpa H03-1-13- Ac
SEM fractured surface -LEXUR Liquid-metal embrittlement
TWIN-ASTIR mechanical tests TWIN-ASTIR Irr.: 2.5 dpa at 300 C Test: at 300 C at 5 10-5 /s
Step-like surface LEXUR Secondary surface cracks MEGAPIE
Conclusions Tensile properties consistently scale with respect of irradiation dose and test temperature. LM embrittlement is clearly observed. Yield strength values agree well with other measurements performed on the samples extracted from the target window, as well as to those obtained from LEXUR and TWIN ASTIR PIE. Consistent features associated with LM embrittlement are observed by SEM of the fractured surface. No particular effects are associated to spallation vs neutron irradiation conditions. No effects due to HAZ. TEM studies are under progress.
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